文件 AWS 開發套件範例 GitHub 儲存庫中有更多可用的 [AWS SDK 範例](https://github.com/awsdocs/aws-doc-sdk-examples)。

本文為英文版的機器翻譯版本，如內容有任何歧義或不一致之處，概以英文版為準。

# 使用適用於 Go V2 的 SDK 的 Amazon S3 範例
<a name="go_2_s3_code_examples"></a>

下列程式碼範例示範如何使用 適用於 Go 的 AWS SDK V2 搭配 Amazon S3 來執行動作和實作常見案例。

*基本概念*是程式碼範例，這些範例說明如何在服務內執行基本操作。

*Actions* 是大型程式的程式碼摘錄，必須在內容中執行。雖然動作會告訴您如何呼叫個別服務函數，但您可以在其相關情境中查看內容中的動作。

*案例*是向您展示如何呼叫服務中的多個函數或與其他 AWS 服務組合來完成特定任務的程式碼範例。

每個範例均包含完整原始碼的連結，您可在連結中找到如何設定和執行內容中程式碼的相關指示。

**Topics**
+ [開始使用](#get_started)
+ [基本概念](#basics)
+ [動作](#actions)
+ [案例](#scenarios)
+ [無伺服器範例](#serverless_examples)

## 開始使用
<a name="get_started"></a>

### 您好 Amazon S3
<a name="s3_Hello_go_2_topic"></a>

下列程式碼範例說明如何開始使用 Amazon S3。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/s3#code-examples)中設定和執行。

```
package main

import (
	"context"
	"errors"
	"fmt"

	"github.com/aws/aws-sdk-go-v2/config"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/smithy-go"
)

// main uses the AWS SDK for Go V2 to create an Amazon Simple Storage Service
// (Amazon S3) client and list up to 10 buckets in your account.
// This example uses the default settings specified in your shared credentials
// and config files.
func main() {
	ctx := context.Background()
	sdkConfig, err := config.LoadDefaultConfig(ctx)
	if err != nil {
		fmt.Println("Couldn't load default configuration. Have you set up your AWS account?")
		fmt.Println(err)
		return
	}
	s3Client := s3.NewFromConfig(sdkConfig)
	count := 10
	fmt.Printf("Let's list up to %v buckets for your account.\n", count)
	result, err := s3Client.ListBuckets(ctx, &s3.ListBucketsInput{})
	if err != nil {
		var ae smithy.APIError
		if errors.As(err, &ae) && ae.ErrorCode() == "AccessDenied" {
			fmt.Println("You don't have permission to list buckets for this account.")
		} else {
			fmt.Printf("Couldn't list buckets for your account. Here's why: %v\n", err)
		}
		return
	}
	if len(result.Buckets) == 0 {
		fmt.Println("You don't have any buckets!")
	} else {
		if count > len(result.Buckets) {
			count = len(result.Buckets)
		}
		for _, bucket := range result.Buckets[:count] {
			fmt.Printf("\t%v\n", *bucket.Name)
		}
	}
}
```
+  如需 API 詳細資訊，請參閱*《適用於 Go 的 AWS SDK API 參考》*中的 [ListBuckets](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.ListBuckets)。

## 基本概念
<a name="basics"></a>

### 了解基本概念
<a name="s3_Scenario_GettingStarted_go_2_topic"></a>

以下程式碼範例顯示做法：
+ 建立儲存貯體並上傳檔案到該儲存貯體。
+ 從儲存貯體下載物件。
+ 將物件複製至儲存貯體中的子文件夾。
+ 列出儲存貯體中的物件。
+ 刪除儲存貯體物件和該儲存貯體。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/s3#code-examples)中設定和執行。
定義包裝案例所使用之儲存貯體和物件動作的結構。  

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"io"
	"log"
	"os"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// BucketBasics encapsulates the Amazon Simple Storage Service (Amazon S3) actions
// used in the examples.
// It contains S3Client, an Amazon S3 service client that is used to perform bucket
// and object actions.
type BucketBasics struct {
	S3Client *s3.Client
}



// ListBuckets lists the buckets in the current account.
func (basics BucketBasics) ListBuckets(ctx context.Context) ([]types.Bucket, error) {
	var err error
	var output *s3.ListBucketsOutput
	var buckets []types.Bucket
	bucketPaginator := s3.NewListBucketsPaginator(basics.S3Client, &s3.ListBucketsInput{})
	for bucketPaginator.HasMorePages() {
		output, err = bucketPaginator.NextPage(ctx)
		if err != nil {
			var apiErr smithy.APIError
			if errors.As(err, &apiErr) && apiErr.ErrorCode() == "AccessDenied" {
				fmt.Println("You don't have permission to list buckets for this account.")
				err = apiErr
			} else {
				log.Printf("Couldn't list buckets for your account. Here's why: %v\n", err)
			}
			break
		} else {
			buckets = append(buckets, output.Buckets...)
		}
	}
	return buckets, err
}



// BucketExists checks whether a bucket exists in the current account.
func (basics BucketBasics) BucketExists(ctx context.Context, bucketName string) (bool, error) {
	_, err := basics.S3Client.HeadBucket(ctx, &s3.HeadBucketInput{
		Bucket: aws.String(bucketName),
	})
	exists := true
	if err != nil {
		var apiError smithy.APIError
		if errors.As(err, &apiError) {
			switch apiError.(type) {
			case *types.NotFound:
				log.Printf("Bucket %v is available.\n", bucketName)
				exists = false
				err = nil
			default:
				log.Printf("Either you don't have access to bucket %v or another error occurred. "+
					"Here's what happened: %v\n", bucketName, err)
			}
		}
	} else {
		log.Printf("Bucket %v exists and you already own it.", bucketName)
	}

	return exists, err
}



// CreateBucket creates a bucket with the specified name in the specified Region.
func (basics BucketBasics) CreateBucket(ctx context.Context, name string, region string) error {
	_, err := basics.S3Client.CreateBucket(ctx, &s3.CreateBucketInput{
		Bucket: aws.String(name),
		CreateBucketConfiguration: &types.CreateBucketConfiguration{
			LocationConstraint: types.BucketLocationConstraint(region),
		},
	})
	if err != nil {
		var owned *types.BucketAlreadyOwnedByYou
		var exists *types.BucketAlreadyExists
		if errors.As(err, &owned) {
			log.Printf("You already own bucket %s.\n", name)
			err = owned
		} else if errors.As(err, &exists) {
			log.Printf("Bucket %s already exists.\n", name)
			err = exists
		}
	} else {
		err = s3.NewBucketExistsWaiter(basics.S3Client).Wait(
			ctx, &s3.HeadBucketInput{Bucket: aws.String(name)}, time.Minute)
		if err != nil {
			log.Printf("Failed attempt to wait for bucket %s to exist.\n", name)
		}
	}
	return err
}



// UploadFile reads from a file and puts the data into an object in a bucket.
func (basics BucketBasics) UploadFile(ctx context.Context, bucketName string, objectKey string, fileName string) error {
	file, err := os.Open(fileName)
	if err != nil {
		log.Printf("Couldn't open file %v to upload. Here's why: %v\n", fileName, err)
	} else {
		defer file.Close()
		_, err = basics.S3Client.PutObject(ctx, &s3.PutObjectInput{
			Bucket: aws.String(bucketName),
			Key:    aws.String(objectKey),
			Body:   file,
		})
		if err != nil {
			var apiErr smithy.APIError
			if errors.As(err, &apiErr) && apiErr.ErrorCode() == "EntityTooLarge" {
				log.Printf("Error while uploading object to %s. The object is too large.\n"+
					"To upload objects larger than 5GB, use the S3 console (160GB max)\n"+
					"or the multipart upload API (5TB max).", bucketName)
			} else {
				log.Printf("Couldn't upload file %v to %v:%v. Here's why: %v\n",
					fileName, bucketName, objectKey, err)
			}
		} else {
			err = s3.NewObjectExistsWaiter(basics.S3Client).Wait(
				ctx, &s3.HeadObjectInput{Bucket: aws.String(bucketName), Key: aws.String(objectKey)}, time.Minute)
			if err != nil {
				log.Printf("Failed attempt to wait for object %s to exist.\n", objectKey)
			}
		}
	}
	return err
}



// UploadLargeObject uses an upload manager to upload data to an object in a bucket.
// The upload manager breaks large data into parts and uploads the parts concurrently.
func (basics BucketBasics) UploadLargeObject(ctx context.Context, bucketName string, objectKey string, largeObject []byte) error {
	largeBuffer := bytes.NewReader(largeObject)
	var partMiBs int64 = 10
	uploader := manager.NewUploader(basics.S3Client, func(u *manager.Uploader) {
		u.PartSize = partMiBs * 1024 * 1024
	})
	_, err := uploader.Upload(ctx, &s3.PutObjectInput{
		Bucket: aws.String(bucketName),
		Key:    aws.String(objectKey),
		Body:   largeBuffer,
	})
	if err != nil {
		var apiErr smithy.APIError
		if errors.As(err, &apiErr) && apiErr.ErrorCode() == "EntityTooLarge" {
			log.Printf("Error while uploading object to %s. The object is too large.\n"+
				"The maximum size for a multipart upload is 5TB.", bucketName)
		} else {
			log.Printf("Couldn't upload large object to %v:%v. Here's why: %v\n",
				bucketName, objectKey, err)
		}
	} else {
		err = s3.NewObjectExistsWaiter(basics.S3Client).Wait(
			ctx, &s3.HeadObjectInput{Bucket: aws.String(bucketName), Key: aws.String(objectKey)}, time.Minute)
		if err != nil {
			log.Printf("Failed attempt to wait for object %s to exist.\n", objectKey)
		}
	}

	return err
}



// DownloadFile gets an object from a bucket and stores it in a local file.
func (basics BucketBasics) DownloadFile(ctx context.Context, bucketName string, objectKey string, fileName string) error {
	result, err := basics.S3Client.GetObject(ctx, &s3.GetObjectInput{
		Bucket: aws.String(bucketName),
		Key:    aws.String(objectKey),
	})
	if err != nil {
		var noKey *types.NoSuchKey
		if errors.As(err, &noKey) {
			log.Printf("Can't get object %s from bucket %s. No such key exists.\n", objectKey, bucketName)
			err = noKey
		} else {
			log.Printf("Couldn't get object %v:%v. Here's why: %v\n", bucketName, objectKey, err)
		}
		return err
	}
	defer result.Body.Close()
	file, err := os.Create(fileName)
	if err != nil {
		log.Printf("Couldn't create file %v. Here's why: %v\n", fileName, err)
		return err
	}
	defer file.Close()
	body, err := io.ReadAll(result.Body)
	if err != nil {
		log.Printf("Couldn't read object body from %v. Here's why: %v\n", objectKey, err)
	}
	_, err = file.Write(body)
	return err
}



// DownloadLargeObject uses a download manager to download an object from a bucket.
// The download manager gets the data in parts and writes them to a buffer until all of
// the data has been downloaded.
func (basics BucketBasics) DownloadLargeObject(ctx context.Context, bucketName string, objectKey string) ([]byte, error) {
	var partMiBs int64 = 10
	downloader := manager.NewDownloader(basics.S3Client, func(d *manager.Downloader) {
		d.PartSize = partMiBs * 1024 * 1024
	})
	buffer := manager.NewWriteAtBuffer([]byte{})
	_, err := downloader.Download(ctx, buffer, &s3.GetObjectInput{
		Bucket: aws.String(bucketName),
		Key:    aws.String(objectKey),
	})
	if err != nil {
		log.Printf("Couldn't download large object from %v:%v. Here's why: %v\n",
			bucketName, objectKey, err)
	}
	return buffer.Bytes(), err
}



// CopyToFolder copies an object in a bucket to a subfolder in the same bucket.
func (basics BucketBasics) CopyToFolder(ctx context.Context, bucketName string, objectKey string, folderName string) error {
	objectDest := fmt.Sprintf("%v/%v", folderName, objectKey)
	_, err := basics.S3Client.CopyObject(ctx, &s3.CopyObjectInput{
		Bucket:     aws.String(bucketName),
		CopySource: aws.String(fmt.Sprintf("%v/%v", bucketName, objectKey)),
		Key:        aws.String(objectDest),
	})
	if err != nil {
		var notActive *types.ObjectNotInActiveTierError
		if errors.As(err, &notActive) {
			log.Printf("Couldn't copy object %s from %s because the object isn't in the active tier.\n",
				objectKey, bucketName)
			err = notActive
		}
	} else {
		err = s3.NewObjectExistsWaiter(basics.S3Client).Wait(
			ctx, &s3.HeadObjectInput{Bucket: aws.String(bucketName), Key: aws.String(objectDest)}, time.Minute)
		if err != nil {
			log.Printf("Failed attempt to wait for object %s to exist.\n", objectDest)
		}
	}
	return err
}



// CopyToBucket copies an object in a bucket to another bucket.
func (basics BucketBasics) CopyToBucket(ctx context.Context, sourceBucket string, destinationBucket string, objectKey string) error {
	_, err := basics.S3Client.CopyObject(ctx, &s3.CopyObjectInput{
		Bucket:     aws.String(destinationBucket),
		CopySource: aws.String(fmt.Sprintf("%v/%v", sourceBucket, objectKey)),
		Key:        aws.String(objectKey),
	})
	if err != nil {
		var notActive *types.ObjectNotInActiveTierError
		if errors.As(err, &notActive) {
			log.Printf("Couldn't copy object %s from %s because the object isn't in the active tier.\n",
				objectKey, sourceBucket)
			err = notActive
		}
	} else {
		err = s3.NewObjectExistsWaiter(basics.S3Client).Wait(
			ctx, &s3.HeadObjectInput{Bucket: aws.String(destinationBucket), Key: aws.String(objectKey)}, time.Minute)
		if err != nil {
			log.Printf("Failed attempt to wait for object %s to exist.\n", objectKey)
		}
	}
	return err
}



// ListObjects lists the objects in a bucket.
func (basics BucketBasics) ListObjects(ctx context.Context, bucketName string) ([]types.Object, error) {
	var err error
	var output *s3.ListObjectsV2Output
	input := &s3.ListObjectsV2Input{
		Bucket: aws.String(bucketName),
	}
	var objects []types.Object
	objectPaginator := s3.NewListObjectsV2Paginator(basics.S3Client, input)
	for objectPaginator.HasMorePages() {
		output, err = objectPaginator.NextPage(ctx)
		if err != nil {
			var noBucket *types.NoSuchBucket
			if errors.As(err, &noBucket) {
				log.Printf("Bucket %s does not exist.\n", bucketName)
				err = noBucket
			}
			break
		} else {
			objects = append(objects, output.Contents...)
		}
	}
	return objects, err
}



// DeleteObjects deletes a list of objects from a bucket.
func (basics BucketBasics) DeleteObjects(ctx context.Context, bucketName string, objectKeys []string) error {
	var objectIds []types.ObjectIdentifier
	for _, key := range objectKeys {
		objectIds = append(objectIds, types.ObjectIdentifier{Key: aws.String(key)})
	}
	output, err := basics.S3Client.DeleteObjects(ctx, &s3.DeleteObjectsInput{
		Bucket: aws.String(bucketName),
		Delete: &types.Delete{Objects: objectIds, Quiet: aws.Bool(true)},
	})
	if err != nil || len(output.Errors) > 0 {
		log.Printf("Error deleting objects from bucket %s.\n", bucketName)
		if err != nil {
			var noBucket *types.NoSuchBucket
			if errors.As(err, &noBucket) {
				log.Printf("Bucket %s does not exist.\n", bucketName)
				err = noBucket
			}
		} else if len(output.Errors) > 0 {
			for _, outErr := range output.Errors {
				log.Printf("%s: %s\n", *outErr.Key, *outErr.Message)
			}
			err = fmt.Errorf("%s", *output.Errors[0].Message)
		}
	} else {
		for _, delObjs := range output.Deleted {
			err = s3.NewObjectNotExistsWaiter(basics.S3Client).Wait(
				ctx, &s3.HeadObjectInput{Bucket: aws.String(bucketName), Key: delObjs.Key}, time.Minute)
			if err != nil {
				log.Printf("Failed attempt to wait for object %s to be deleted.\n", *delObjs.Key)
			} else {
				log.Printf("Deleted %s.\n", *delObjs.Key)
			}
		}
	}
	return err
}



// DeleteBucket deletes a bucket. The bucket must be empty or an error is returned.
func (basics BucketBasics) DeleteBucket(ctx context.Context, bucketName string) error {
	_, err := basics.S3Client.DeleteBucket(ctx, &s3.DeleteBucketInput{
		Bucket: aws.String(bucketName)})
	if err != nil {
		var noBucket *types.NoSuchBucket
		if errors.As(err, &noBucket) {
			log.Printf("Bucket %s does not exist.\n", bucketName)
			err = noBucket
		} else {
			log.Printf("Couldn't delete bucket %v. Here's why: %v\n", bucketName, err)
		}
	} else {
		err = s3.NewBucketNotExistsWaiter(basics.S3Client).Wait(
			ctx, &s3.HeadBucketInput{Bucket: aws.String(bucketName)}, time.Minute)
		if err != nil {
			log.Printf("Failed attempt to wait for bucket %s to be deleted.\n", bucketName)
		} else {
			log.Printf("Deleted %s.\n", bucketName)
		}
	}
	return err
}
```
執行互動式情境，示範如何使用 S3 儲存貯體和物件。  

```
import (
	"context"
	"fmt"
	"log"
	"os"
	"strings"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/awsdocs/aws-doc-sdk-examples/gov2/demotools"
	"github.com/awsdocs/aws-doc-sdk-examples/gov2/s3/actions"
)

// RunGetStartedScenario is an interactive example that shows you how to use Amazon
// Simple Storage Service (Amazon S3) to create an S3 bucket and use it to store objects.
//
// 1. Create a bucket.
// 2. Upload a local file to the bucket.
// 3. Download an object to a local file.
// 4. Copy an object to a different folder in the bucket.
// 5. List objects in the bucket.
// 6. Delete all objects in the bucket.
// 7. Delete the bucket.
//
// This example creates an Amazon S3 service client from the specified sdkConfig so that
// you can replace it with a mocked or stubbed config for unit testing.
//
// It uses a questioner from the `demotools` package to get input during the example.
// This package can be found in the ..\..\demotools folder of this repo.
func RunGetStartedScenario(ctx context.Context, sdkConfig aws.Config, questioner demotools.IQuestioner) {
	defer func() {
		if r := recover(); r != nil {
			log.Println("Something went wrong with the demo.")
			_, isMock := questioner.(*demotools.MockQuestioner)
			if isMock || questioner.AskBool("Do you want to see the full error message (y/n)?", "y") {
				log.Println(r)
			}
		}
	}()

	log.Println(strings.Repeat("-", 88))
	log.Println("Welcome to the Amazon S3 getting started demo.")
	log.Println(strings.Repeat("-", 88))

	s3Client := s3.NewFromConfig(sdkConfig)
	bucketBasics := actions.BucketBasics{S3Client: s3Client}

	count := 10
	log.Printf("Let's list up to %v buckets for your account:", count)
	buckets, err := bucketBasics.ListBuckets(ctx)
	if err != nil {
		panic(err)
	}
	if len(buckets) == 0 {
		log.Println("You don't have any buckets!")
	} else {
		if count > len(buckets) {
			count = len(buckets)
		}
		for _, bucket := range buckets[:count] {
			log.Printf("\t%v\n", *bucket.Name)
		}
	}

	bucketName := questioner.Ask("Let's create a bucket. Enter a name for your bucket:",
		demotools.NotEmpty{})
	bucketExists, err := bucketBasics.BucketExists(ctx, bucketName)
	if err != nil {
		panic(err)
	}
	if !bucketExists {
		err = bucketBasics.CreateBucket(ctx, bucketName, sdkConfig.Region)
		if err != nil {
			panic(err)
		} else {
			log.Println("Bucket created.")
		}
	}
	log.Println(strings.Repeat("-", 88))

	fmt.Println("Let's upload a file to your bucket.")
	smallFile := questioner.Ask("Enter the path to a file you want to upload:",
		demotools.NotEmpty{})
	const smallKey = "doc-example-key"
	err = bucketBasics.UploadFile(ctx, bucketName, smallKey, smallFile)
	if err != nil {
		panic(err)
	}
	log.Printf("Uploaded %v as %v.\n", smallFile, smallKey)
	log.Println(strings.Repeat("-", 88))

	log.Printf("Let's download %v to a file.", smallKey)
	downloadFileName := questioner.Ask("Enter a name for the downloaded file:", demotools.NotEmpty{})
	err = bucketBasics.DownloadFile(ctx, bucketName, smallKey, downloadFileName)
	if err != nil {
		panic(err)
	}
	log.Printf("File %v downloaded.", downloadFileName)
	log.Println(strings.Repeat("-", 88))

	log.Printf("Let's copy %v to a folder in the same bucket.", smallKey)
	folderName := questioner.Ask("Enter a folder name: ", demotools.NotEmpty{})
	err = bucketBasics.CopyToFolder(ctx, bucketName, smallKey, folderName)
	if err != nil {
		panic(err)
	}
	log.Printf("Copied %v to %v/%v.\n", smallKey, folderName, smallKey)
	log.Println(strings.Repeat("-", 88))

	log.Println("Let's list the objects in your bucket.")
	questioner.Ask("Press Enter when you're ready.")
	objects, err := bucketBasics.ListObjects(ctx, bucketName)
	if err != nil {
		panic(err)
	}
	log.Printf("Found %v objects.\n", len(objects))
	var objKeys []string
	for _, object := range objects {
		objKeys = append(objKeys, *object.Key)
		log.Printf("\t%v\n", *object.Key)
	}
	log.Println(strings.Repeat("-", 88))

	if questioner.AskBool("Do you want to delete your bucket and all of its "+
		"contents? (y/n)", "y") {
		log.Println("Deleting objects.")
		err = bucketBasics.DeleteObjects(ctx, bucketName, objKeys)
		if err != nil {
			panic(err)
		}
		log.Println("Deleting bucket.")
		err = bucketBasics.DeleteBucket(ctx, bucketName)
		if err != nil {
			panic(err)
		}
		log.Printf("Deleting downloaded file %v.\n", downloadFileName)
		err = os.Remove(downloadFileName)
		if err != nil {
			panic(err)
		}
	} else {
		log.Println("Okay. Don't forget to delete objects from your bucket to avoid charges.")
	}
	log.Println(strings.Repeat("-", 88))

	log.Println("Thanks for watching!")
	log.Println(strings.Repeat("-", 88))
}
```
+ 如需 API 詳細資訊，請參閱*《適用於 Go 的 AWS SDK API 參考》*中的下列主題。
  + [CopyObject](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.CopyObject)
  + [CreateBucket](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.CreateBucket)
  + [DeleteBucket](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.DeleteBucket)
  + [DeleteObjects](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.DeleteObjects)
  + [GetObject](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.GetObject)
  + [ListObjectsV2](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.ListObjectsV2)
  + [PutObject](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.PutObject)

## 動作
<a name="actions"></a>

### `CopyObject`
<a name="s3_CopyObject_go_2_topic"></a>

以下程式碼範例顯示如何使用 `CopyObject`。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/s3#code-examples)中設定和執行。

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"io"
	"log"
	"os"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// BucketBasics encapsulates the Amazon Simple Storage Service (Amazon S3) actions
// used in the examples.
// It contains S3Client, an Amazon S3 service client that is used to perform bucket
// and object actions.
type BucketBasics struct {
	S3Client *s3.Client
}



// CopyToBucket copies an object in a bucket to another bucket.
func (basics BucketBasics) CopyToBucket(ctx context.Context, sourceBucket string, destinationBucket string, objectKey string) error {
	_, err := basics.S3Client.CopyObject(ctx, &s3.CopyObjectInput{
		Bucket:     aws.String(destinationBucket),
		CopySource: aws.String(fmt.Sprintf("%v/%v", sourceBucket, objectKey)),
		Key:        aws.String(objectKey),
	})
	if err != nil {
		var notActive *types.ObjectNotInActiveTierError
		if errors.As(err, &notActive) {
			log.Printf("Couldn't copy object %s from %s because the object isn't in the active tier.\n",
				objectKey, sourceBucket)
			err = notActive
		}
	} else {
		err = s3.NewObjectExistsWaiter(basics.S3Client).Wait(
			ctx, &s3.HeadObjectInput{Bucket: aws.String(destinationBucket), Key: aws.String(objectKey)}, time.Minute)
		if err != nil {
			log.Printf("Failed attempt to wait for object %s to exist.\n", objectKey)
		}
	}
	return err
}
```
+  如需 API 詳細資訊，請參閱*《適用於 Go 的 AWS SDK API 參考》*中的 [CopyObject](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.CopyObject)。

### `CreateBucket`
<a name="s3_CreateBucket_go_2_topic"></a>

以下程式碼範例顯示如何使用 `CreateBucket`。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/s3#code-examples)中設定和執行。
使用預設組態建立儲存貯體。  

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"io"
	"log"
	"os"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// BucketBasics encapsulates the Amazon Simple Storage Service (Amazon S3) actions
// used in the examples.
// It contains S3Client, an Amazon S3 service client that is used to perform bucket
// and object actions.
type BucketBasics struct {
	S3Client *s3.Client
}



// CreateBucket creates a bucket with the specified name in the specified Region.
func (basics BucketBasics) CreateBucket(ctx context.Context, name string, region string) error {
	_, err := basics.S3Client.CreateBucket(ctx, &s3.CreateBucketInput{
		Bucket: aws.String(name),
		CreateBucketConfiguration: &types.CreateBucketConfiguration{
			LocationConstraint: types.BucketLocationConstraint(region),
		},
	})
	if err != nil {
		var owned *types.BucketAlreadyOwnedByYou
		var exists *types.BucketAlreadyExists
		if errors.As(err, &owned) {
			log.Printf("You already own bucket %s.\n", name)
			err = owned
		} else if errors.As(err, &exists) {
			log.Printf("Bucket %s already exists.\n", name)
			err = exists
		}
	} else {
		err = s3.NewBucketExistsWaiter(basics.S3Client).Wait(
			ctx, &s3.HeadBucketInput{Bucket: aws.String(name)}, time.Minute)
		if err != nil {
			log.Printf("Failed attempt to wait for bucket %s to exist.\n", name)
		}
	}
	return err
}
```
建立具有物件鎖定的儲存貯體，並等待其出現。  

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"log"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// S3Actions wraps S3 service actions.
type S3Actions struct {
	S3Client  *s3.Client
	S3Manager *manager.Uploader
}



// CreateBucketWithLock creates a new S3 bucket with optional object locking enabled
// and waits for the bucket to exist before returning.
func (actor S3Actions) CreateBucketWithLock(ctx context.Context, bucket string, region string, enableObjectLock bool) (string, error) {
	input := &s3.CreateBucketInput{
		Bucket: aws.String(bucket),
		CreateBucketConfiguration: &types.CreateBucketConfiguration{
			LocationConstraint: types.BucketLocationConstraint(region),
		},
	}

	if enableObjectLock {
		input.ObjectLockEnabledForBucket = aws.Bool(true)
	}

	_, err := actor.S3Client.CreateBucket(ctx, input)
	if err != nil {
		var owned *types.BucketAlreadyOwnedByYou
		var exists *types.BucketAlreadyExists
		if errors.As(err, &owned) {
			log.Printf("You already own bucket %s.\n", bucket)
			err = owned
		} else if errors.As(err, &exists) {
			log.Printf("Bucket %s already exists.\n", bucket)
			err = exists
		}
	} else {
		err = s3.NewBucketExistsWaiter(actor.S3Client).Wait(
			ctx, &s3.HeadBucketInput{Bucket: aws.String(bucket)}, time.Minute)
		if err != nil {
			log.Printf("Failed attempt to wait for bucket %s to exist.\n", bucket)
		}
	}

	return bucket, err
}
```
+  如需 API 詳細資訊，請參閱*《適用於 Go 的 AWS SDK API 參考》*中的 [CreateBucket](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.CreateBucket)。

### `DeleteBucket`
<a name="s3_DeleteBucket_go_2_topic"></a>

以下程式碼範例顯示如何使用 `DeleteBucket`。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/s3#code-examples)中設定和執行。

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"io"
	"log"
	"os"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// BucketBasics encapsulates the Amazon Simple Storage Service (Amazon S3) actions
// used in the examples.
// It contains S3Client, an Amazon S3 service client that is used to perform bucket
// and object actions.
type BucketBasics struct {
	S3Client *s3.Client
}



// DeleteBucket deletes a bucket. The bucket must be empty or an error is returned.
func (basics BucketBasics) DeleteBucket(ctx context.Context, bucketName string) error {
	_, err := basics.S3Client.DeleteBucket(ctx, &s3.DeleteBucketInput{
		Bucket: aws.String(bucketName)})
	if err != nil {
		var noBucket *types.NoSuchBucket
		if errors.As(err, &noBucket) {
			log.Printf("Bucket %s does not exist.\n", bucketName)
			err = noBucket
		} else {
			log.Printf("Couldn't delete bucket %v. Here's why: %v\n", bucketName, err)
		}
	} else {
		err = s3.NewBucketNotExistsWaiter(basics.S3Client).Wait(
			ctx, &s3.HeadBucketInput{Bucket: aws.String(bucketName)}, time.Minute)
		if err != nil {
			log.Printf("Failed attempt to wait for bucket %s to be deleted.\n", bucketName)
		} else {
			log.Printf("Deleted %s.\n", bucketName)
		}
	}
	return err
}
```
+  如需 API 詳細資訊，請參閱*《適用於 Go 的 AWS SDK API 參考》*中的 [DeleteBucket](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.DeleteBucket)。

### `DeleteObject`
<a name="s3_DeleteObject_go_2_topic"></a>

以下程式碼範例顯示如何使用 `DeleteObject`。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/workflows/s3_object_lock#code-examples)中設定和執行。

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"log"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// S3Actions wraps S3 service actions.
type S3Actions struct {
	S3Client  *s3.Client
	S3Manager *manager.Uploader
}



// DeleteObject deletes an object from a bucket.
func (actor S3Actions) DeleteObject(ctx context.Context, bucket string, key string, versionId string, bypassGovernance bool) (bool, error) {
	deleted := false
	input := &s3.DeleteObjectInput{
		Bucket: aws.String(bucket),
		Key:    aws.String(key),
	}
	if versionId != "" {
		input.VersionId = aws.String(versionId)
	}
	if bypassGovernance {
		input.BypassGovernanceRetention = aws.Bool(true)
	}
	_, err := actor.S3Client.DeleteObject(ctx, input)
	if err != nil {
		var noKey *types.NoSuchKey
		var apiErr *smithy.GenericAPIError
		if errors.As(err, &noKey) {
			log.Printf("Object %s does not exist in %s.\n", key, bucket)
			err = noKey
		} else if errors.As(err, &apiErr) {
			switch apiErr.ErrorCode() {
			case "AccessDenied":
				log.Printf("Access denied: cannot delete object %s from %s.\n", key, bucket)
				err = nil
			case "InvalidArgument":
				if bypassGovernance {
					log.Printf("You cannot specify bypass governance on a bucket without lock enabled.")
					err = nil
				}
			}
		}
	} else {
		err = s3.NewObjectNotExistsWaiter(actor.S3Client).Wait(
			ctx, &s3.HeadObjectInput{Bucket: aws.String(bucket), Key: aws.String(key)}, time.Minute)
		if err != nil {
			log.Printf("Failed attempt to wait for object %s in bucket %s to be deleted.\n", key, bucket)
		} else {
			deleted = true
		}
	}
	return deleted, err
}
```
+  如需 API 詳細資訊，請參閱*《適用於 Go 的 AWS SDK API 參考》*中的 [DeleteObject](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.DeleteObject)。

### `DeleteObjects`
<a name="s3_DeleteObjects_go_2_topic"></a>

以下程式碼範例顯示如何使用 `DeleteObjects`。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/workflows/s3_object_lock#code-examples)中設定和執行。

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"log"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// S3Actions wraps S3 service actions.
type S3Actions struct {
	S3Client  *s3.Client
	S3Manager *manager.Uploader
}



// DeleteObjects deletes a list of objects from a bucket.
func (actor S3Actions) DeleteObjects(ctx context.Context, bucket string, objects []types.ObjectIdentifier, bypassGovernance bool) error {
	if len(objects) == 0 {
		return nil
	}

	input := s3.DeleteObjectsInput{
		Bucket: aws.String(bucket),
		Delete: &types.Delete{
			Objects: objects,
			Quiet:   aws.Bool(true),
		},
	}
	if bypassGovernance {
		input.BypassGovernanceRetention = aws.Bool(true)
	}
	delOut, err := actor.S3Client.DeleteObjects(ctx, &input)
	if err != nil || len(delOut.Errors) > 0 {
		log.Printf("Error deleting objects from bucket %s.\n", bucket)
		if err != nil {
			var noBucket *types.NoSuchBucket
			if errors.As(err, &noBucket) {
				log.Printf("Bucket %s does not exist.\n", bucket)
				err = noBucket
			}
		} else if len(delOut.Errors) > 0 {
			for _, outErr := range delOut.Errors {
				log.Printf("%s: %s\n", *outErr.Key, *outErr.Message)
			}
			err = fmt.Errorf("%s", *delOut.Errors[0].Message)
		}
	} else {
		for _, delObjs := range delOut.Deleted {
			err = s3.NewObjectNotExistsWaiter(actor.S3Client).Wait(
				ctx, &s3.HeadObjectInput{Bucket: aws.String(bucket), Key: delObjs.Key}, time.Minute)
			if err != nil {
				log.Printf("Failed attempt to wait for object %s to be deleted.\n", *delObjs.Key)
			} else {
				log.Printf("Deleted %s.\n", *delObjs.Key)
			}
		}
	}
	return err
}
```
+  如需 API 詳細資訊，請參閱*《適用於 Go 的 AWS SDK API 參考》*中的 [DeleteObjects](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.DeleteObjects)。

### `GetObject`
<a name="s3_GetObject_go_2_topic"></a>

以下程式碼範例顯示如何使用 `GetObject`。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/s3#code-examples)中設定和執行。

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"io"
	"log"
	"os"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// BucketBasics encapsulates the Amazon Simple Storage Service (Amazon S3) actions
// used in the examples.
// It contains S3Client, an Amazon S3 service client that is used to perform bucket
// and object actions.
type BucketBasics struct {
	S3Client *s3.Client
}



// DownloadFile gets an object from a bucket and stores it in a local file.
func (basics BucketBasics) DownloadFile(ctx context.Context, bucketName string, objectKey string, fileName string) error {
	result, err := basics.S3Client.GetObject(ctx, &s3.GetObjectInput{
		Bucket: aws.String(bucketName),
		Key:    aws.String(objectKey),
	})
	if err != nil {
		var noKey *types.NoSuchKey
		if errors.As(err, &noKey) {
			log.Printf("Can't get object %s from bucket %s. No such key exists.\n", objectKey, bucketName)
			err = noKey
		} else {
			log.Printf("Couldn't get object %v:%v. Here's why: %v\n", bucketName, objectKey, err)
		}
		return err
	}
	defer result.Body.Close()
	file, err := os.Create(fileName)
	if err != nil {
		log.Printf("Couldn't create file %v. Here's why: %v\n", fileName, err)
		return err
	}
	defer file.Close()
	body, err := io.ReadAll(result.Body)
	if err != nil {
		log.Printf("Couldn't read object body from %v. Here's why: %v\n", objectKey, err)
	}
	_, err = file.Write(body)
	return err
}
```
+  如需 API 詳細資訊，請參閱*《適用於 Go 的 AWS SDK API 參考》*中的 [GetObject](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.GetObject)。

### `GetObjectLegalHold`
<a name="s3_GetObjectLegalHold_go_2_topic"></a>

以下程式碼範例顯示如何使用 `GetObjectLegalHold`。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/workflows/s3_object_lock#code-examples)中設定和執行。

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"log"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// S3Actions wraps S3 service actions.
type S3Actions struct {
	S3Client  *s3.Client
	S3Manager *manager.Uploader
}



// GetObjectLegalHold retrieves the legal hold status for an S3 object.
func (actor S3Actions) GetObjectLegalHold(ctx context.Context, bucket string, key string, versionId string) (*types.ObjectLockLegalHoldStatus, error) {
	var status *types.ObjectLockLegalHoldStatus
	input := &s3.GetObjectLegalHoldInput{
		Bucket:    aws.String(bucket),
		Key:       aws.String(key),
		VersionId: aws.String(versionId),
	}

	output, err := actor.S3Client.GetObjectLegalHold(ctx, input)
	if err != nil {
		var noSuchKeyErr *types.NoSuchKey
		var apiErr *smithy.GenericAPIError
		if errors.As(err, &noSuchKeyErr) {
			log.Printf("Object %s does not exist in bucket %s.\n", key, bucket)
			err = noSuchKeyErr
		} else if errors.As(err, &apiErr) {
			switch apiErr.ErrorCode() {
			case "NoSuchObjectLockConfiguration":
				log.Printf("Object %s does not have an object lock configuration.\n", key)
				err = nil
			case "InvalidRequest":
				log.Printf("Bucket %s does not have an object lock configuration.\n", bucket)
				err = nil
			}
		}
	} else {
		status = &output.LegalHold.Status
	}

	return status, err
}
```
+  如需 API 詳細資訊，請參閱《適用於 Go 的 AWS SDK API 參考》**中的 [GetObjectLegalHold](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.GetObjectLegalHold)。

### `GetObjectLockConfiguration`
<a name="s3_GetObjectLockConfiguration_go_2_topic"></a>

以下程式碼範例顯示如何使用 `GetObjectLockConfiguration`。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/workflows/s3_object_lock#code-examples)中設定和執行。

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"log"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// S3Actions wraps S3 service actions.
type S3Actions struct {
	S3Client  *s3.Client
	S3Manager *manager.Uploader
}



// GetObjectLockConfiguration retrieves the object lock configuration for an S3 bucket.
func (actor S3Actions) GetObjectLockConfiguration(ctx context.Context, bucket string) (*types.ObjectLockConfiguration, error) {
	var lockConfig *types.ObjectLockConfiguration
	input := &s3.GetObjectLockConfigurationInput{
		Bucket: aws.String(bucket),
	}

	output, err := actor.S3Client.GetObjectLockConfiguration(ctx, input)
	if err != nil {
		var noBucket *types.NoSuchBucket
		var apiErr *smithy.GenericAPIError
		if errors.As(err, &noBucket) {
			log.Printf("Bucket %s does not exist.\n", bucket)
			err = noBucket
		} else if errors.As(err, &apiErr) && apiErr.ErrorCode() == "ObjectLockConfigurationNotFoundError" {
			log.Printf("Bucket %s does not have an object lock configuration.\n", bucket)
			err = nil
		}
	} else {
		lockConfig = output.ObjectLockConfiguration
	}

	return lockConfig, err
}
```
+  如需 API 詳細資訊，請參閱《適用於 Go 的 AWS SDK API 參考》**中的 [GetObjectLockConfiguration](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.GetObjectLockConfiguration)。

### `GetObjectRetention`
<a name="s3_GetObjectRetention_go_2_topic"></a>

以下程式碼範例顯示如何使用 `GetObjectRetention`。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/workflows/s3_object_lock#code-examples)中設定和執行。

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"log"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// S3Actions wraps S3 service actions.
type S3Actions struct {
	S3Client  *s3.Client
	S3Manager *manager.Uploader
}



// GetObjectRetention retrieves the object retention configuration for an S3 object.
func (actor S3Actions) GetObjectRetention(ctx context.Context, bucket string, key string) (*types.ObjectLockRetention, error) {
	var retention *types.ObjectLockRetention
	input := &s3.GetObjectRetentionInput{
		Bucket: aws.String(bucket),
		Key:    aws.String(key),
	}

	output, err := actor.S3Client.GetObjectRetention(ctx, input)
	if err != nil {
		var noKey *types.NoSuchKey
		var apiErr *smithy.GenericAPIError
		if errors.As(err, &noKey) {
			log.Printf("Object %s does not exist in bucket %s.\n", key, bucket)
			err = noKey
		} else if errors.As(err, &apiErr) {
			switch apiErr.ErrorCode() {
			case "NoSuchObjectLockConfiguration":
				err = nil
			case "InvalidRequest":
				log.Printf("Bucket %s does not have locking enabled.", bucket)
				err = nil
			}
		}
	} else {
		retention = output.Retention
	}

	return retention, err
}
```
+  如需 API 詳細資訊，請參閱《適用於 Go 的 AWS SDK API 參考》**中的 [GetObjectRetention](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.GetObjectRetention)。

### `HeadBucket`
<a name="s3_HeadBucket_go_2_topic"></a>

以下程式碼範例顯示如何使用 `HeadBucket`。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/s3#code-examples)中設定和執行。

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"io"
	"log"
	"os"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// BucketBasics encapsulates the Amazon Simple Storage Service (Amazon S3) actions
// used in the examples.
// It contains S3Client, an Amazon S3 service client that is used to perform bucket
// and object actions.
type BucketBasics struct {
	S3Client *s3.Client
}



// BucketExists checks whether a bucket exists in the current account.
func (basics BucketBasics) BucketExists(ctx context.Context, bucketName string) (bool, error) {
	_, err := basics.S3Client.HeadBucket(ctx, &s3.HeadBucketInput{
		Bucket: aws.String(bucketName),
	})
	exists := true
	if err != nil {
		var apiError smithy.APIError
		if errors.As(err, &apiError) {
			switch apiError.(type) {
			case *types.NotFound:
				log.Printf("Bucket %v is available.\n", bucketName)
				exists = false
				err = nil
			default:
				log.Printf("Either you don't have access to bucket %v or another error occurred. "+
					"Here's what happened: %v\n", bucketName, err)
			}
		}
	} else {
		log.Printf("Bucket %v exists and you already own it.", bucketName)
	}

	return exists, err
}
```
+  如需 API 詳細資訊，請參閱《適用於 Go 的 AWS SDK API 參考》**中的 [HeadBucket](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.HeadBucket)。

### `ListBuckets`
<a name="s3_ListBuckets_go_2_topic"></a>

以下程式碼範例顯示如何使用 `ListBuckets`。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/s3#code-examples)中設定和執行。

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"io"
	"log"
	"os"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// BucketBasics encapsulates the Amazon Simple Storage Service (Amazon S3) actions
// used in the examples.
// It contains S3Client, an Amazon S3 service client that is used to perform bucket
// and object actions.
type BucketBasics struct {
	S3Client *s3.Client
}



// ListBuckets lists the buckets in the current account.
func (basics BucketBasics) ListBuckets(ctx context.Context) ([]types.Bucket, error) {
	var err error
	var output *s3.ListBucketsOutput
	var buckets []types.Bucket
	bucketPaginator := s3.NewListBucketsPaginator(basics.S3Client, &s3.ListBucketsInput{})
	for bucketPaginator.HasMorePages() {
		output, err = bucketPaginator.NextPage(ctx)
		if err != nil {
			var apiErr smithy.APIError
			if errors.As(err, &apiErr) && apiErr.ErrorCode() == "AccessDenied" {
				fmt.Println("You don't have permission to list buckets for this account.")
				err = apiErr
			} else {
				log.Printf("Couldn't list buckets for your account. Here's why: %v\n", err)
			}
			break
		} else {
			buckets = append(buckets, output.Buckets...)
		}
	}
	return buckets, err
}
```
+  如需 API 詳細資訊，請參閱*《適用於 Go 的 AWS SDK API 參考》*中的 [ListBuckets](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.ListBuckets)。

### `ListObjectVersions`
<a name="s3_ListObjectVersions_go_2_topic"></a>

以下程式碼範例顯示如何使用 `ListObjectVersions`。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/workflows/s3_object_lock#code-examples)中設定和執行。

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"log"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// S3Actions wraps S3 service actions.
type S3Actions struct {
	S3Client  *s3.Client
	S3Manager *manager.Uploader
}



// ListObjectVersions lists all versions of all objects in a bucket.
func (actor S3Actions) ListObjectVersions(ctx context.Context, bucket string) ([]types.ObjectVersion, error) {
	var err error
	var output *s3.ListObjectVersionsOutput
	var versions []types.ObjectVersion
	input := &s3.ListObjectVersionsInput{Bucket: aws.String(bucket)}
	versionPaginator := s3.NewListObjectVersionsPaginator(actor.S3Client, input)
	for versionPaginator.HasMorePages() {
		output, err = versionPaginator.NextPage(ctx)
		if err != nil {
			var noBucket *types.NoSuchBucket
			if errors.As(err, &noBucket) {
				log.Printf("Bucket %s does not exist.\n", bucket)
				err = noBucket
			}
			break
		} else {
			versions = append(versions, output.Versions...)
		}
	}
	return versions, err
}
```
+  如需 API 詳細資訊，請參閱《適用於 Go 的 AWS SDK API 參考》**中的 [ListObjectVersions](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.ListObjectVersions)。

### `ListObjectsV2`
<a name="s3_ListObjectsV2_go_2_topic"></a>

以下程式碼範例顯示如何使用 `ListObjectsV2`。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/s3#code-examples)中設定和執行。

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"io"
	"log"
	"os"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// BucketBasics encapsulates the Amazon Simple Storage Service (Amazon S3) actions
// used in the examples.
// It contains S3Client, an Amazon S3 service client that is used to perform bucket
// and object actions.
type BucketBasics struct {
	S3Client *s3.Client
}



// ListObjects lists the objects in a bucket.
func (basics BucketBasics) ListObjects(ctx context.Context, bucketName string) ([]types.Object, error) {
	var err error
	var output *s3.ListObjectsV2Output
	input := &s3.ListObjectsV2Input{
		Bucket: aws.String(bucketName),
	}
	var objects []types.Object
	objectPaginator := s3.NewListObjectsV2Paginator(basics.S3Client, input)
	for objectPaginator.HasMorePages() {
		output, err = objectPaginator.NextPage(ctx)
		if err != nil {
			var noBucket *types.NoSuchBucket
			if errors.As(err, &noBucket) {
				log.Printf("Bucket %s does not exist.\n", bucketName)
				err = noBucket
			}
			break
		} else {
			objects = append(objects, output.Contents...)
		}
	}
	return objects, err
}
```
+  如需 API 詳細資訊，請參閱《*適用於 Go 的 AWS SDK API 參考*》中的 [ListObjectsV2](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.ListObjectsV2)。

### `PutObject`
<a name="s3_PutObject_go_2_topic"></a>

以下程式碼範例顯示如何使用 `PutObject`。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/s3#code-examples)中設定和執行。
使用低階 API 將物件放入儲存貯體。  

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"io"
	"log"
	"os"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// BucketBasics encapsulates the Amazon Simple Storage Service (Amazon S3) actions
// used in the examples.
// It contains S3Client, an Amazon S3 service client that is used to perform bucket
// and object actions.
type BucketBasics struct {
	S3Client *s3.Client
}



// UploadFile reads from a file and puts the data into an object in a bucket.
func (basics BucketBasics) UploadFile(ctx context.Context, bucketName string, objectKey string, fileName string) error {
	file, err := os.Open(fileName)
	if err != nil {
		log.Printf("Couldn't open file %v to upload. Here's why: %v\n", fileName, err)
	} else {
		defer file.Close()
		_, err = basics.S3Client.PutObject(ctx, &s3.PutObjectInput{
			Bucket: aws.String(bucketName),
			Key:    aws.String(objectKey),
			Body:   file,
		})
		if err != nil {
			var apiErr smithy.APIError
			if errors.As(err, &apiErr) && apiErr.ErrorCode() == "EntityTooLarge" {
				log.Printf("Error while uploading object to %s. The object is too large.\n"+
					"To upload objects larger than 5GB, use the S3 console (160GB max)\n"+
					"or the multipart upload API (5TB max).", bucketName)
			} else {
				log.Printf("Couldn't upload file %v to %v:%v. Here's why: %v\n",
					fileName, bucketName, objectKey, err)
			}
		} else {
			err = s3.NewObjectExistsWaiter(basics.S3Client).Wait(
				ctx, &s3.HeadObjectInput{Bucket: aws.String(bucketName), Key: aws.String(objectKey)}, time.Minute)
			if err != nil {
				log.Printf("Failed attempt to wait for object %s to exist.\n", objectKey)
			}
		}
	}
	return err
}
```
使用傳輸管理員將物件上傳至儲存貯體。  

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"log"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// S3Actions wraps S3 service actions.
type S3Actions struct {
	S3Client  *s3.Client
	S3Manager *manager.Uploader
}



// UploadObject uses the S3 upload manager to upload an object to a bucket.
func (actor S3Actions) UploadObject(ctx context.Context, bucket string, key string, contents string) (string, error) {
	var outKey string
	input := &s3.PutObjectInput{
		Bucket:            aws.String(bucket),
		Key:               aws.String(key),
		Body:              bytes.NewReader([]byte(contents)),
		ChecksumAlgorithm: types.ChecksumAlgorithmSha256,
	}
	output, err := actor.S3Manager.Upload(ctx, input)
	if err != nil {
		var noBucket *types.NoSuchBucket
		if errors.As(err, &noBucket) {
			log.Printf("Bucket %s does not exist.\n", bucket)
			err = noBucket
		}
	} else {
		err := s3.NewObjectExistsWaiter(actor.S3Client).Wait(ctx, &s3.HeadObjectInput{
			Bucket: aws.String(bucket),
			Key:    aws.String(key),
		}, time.Minute)
		if err != nil {
			log.Printf("Failed attempt to wait for object %s to exist in %s.\n", key, bucket)
		} else {
			outKey = *output.Key
		}
	}
	return outKey, err
}
```
+  如需 API 詳細資訊，請參閱*《適用於 Go 的 AWS SDK API 參考》*中的 [PutObject](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.PutObject)。

### `PutObjectLegalHold`
<a name="s3_PutObjectLegalHold_go_2_topic"></a>

以下程式碼範例顯示如何使用 `PutObjectLegalHold`。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/workflows/s3_object_lock#code-examples)中設定和執行。

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"log"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// S3Actions wraps S3 service actions.
type S3Actions struct {
	S3Client  *s3.Client
	S3Manager *manager.Uploader
}



// PutObjectLegalHold sets the legal hold configuration for an S3 object.
func (actor S3Actions) PutObjectLegalHold(ctx context.Context, bucket string, key string, versionId string, legalHoldStatus types.ObjectLockLegalHoldStatus) error {
	input := &s3.PutObjectLegalHoldInput{
		Bucket: aws.String(bucket),
		Key:    aws.String(key),
		LegalHold: &types.ObjectLockLegalHold{
			Status: legalHoldStatus,
		},
	}
	if versionId != "" {
		input.VersionId = aws.String(versionId)
	}

	_, err := actor.S3Client.PutObjectLegalHold(ctx, input)
	if err != nil {
		var noKey *types.NoSuchKey
		if errors.As(err, &noKey) {
			log.Printf("Object %s does not exist in bucket %s.\n", key, bucket)
			err = noKey
		}
	}

	return err
}
```
+  如需 API 詳細資訊，請參閱《適用於 Go 的 AWS SDK API 參考》**中的 [PutObjectLegalHold](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.PutObjectLegalHold)。

### `PutObjectLockConfiguration`
<a name="s3_PutObjectLockConfiguration_go_2_topic"></a>

以下程式碼範例顯示如何使用 `PutObjectLockConfiguration`。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/workflows/s3_object_lock#code-examples)中設定和執行。
設定儲存貯體的物件鎖定組態。  

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"log"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// S3Actions wraps S3 service actions.
type S3Actions struct {
	S3Client  *s3.Client
	S3Manager *manager.Uploader
}



// EnableObjectLockOnBucket enables object locking on an existing bucket.
func (actor S3Actions) EnableObjectLockOnBucket(ctx context.Context, bucket string) error {
	// Versioning must be enabled on the bucket before object locking is enabled.
	verInput := &s3.PutBucketVersioningInput{
		Bucket: aws.String(bucket),
		VersioningConfiguration: &types.VersioningConfiguration{
			MFADelete: types.MFADeleteDisabled,
			Status:    types.BucketVersioningStatusEnabled,
		},
	}
	_, err := actor.S3Client.PutBucketVersioning(ctx, verInput)
	if err != nil {
		var noBucket *types.NoSuchBucket
		if errors.As(err, &noBucket) {
			log.Printf("Bucket %s does not exist.\n", bucket)
			err = noBucket
		}
		return err
	}

	input := &s3.PutObjectLockConfigurationInput{
		Bucket: aws.String(bucket),
		ObjectLockConfiguration: &types.ObjectLockConfiguration{
			ObjectLockEnabled: types.ObjectLockEnabledEnabled,
		},
	}
	_, err = actor.S3Client.PutObjectLockConfiguration(ctx, input)
	if err != nil {
		var noBucket *types.NoSuchBucket
		if errors.As(err, &noBucket) {
			log.Printf("Bucket %s does not exist.\n", bucket)
			err = noBucket
		}
	}

	return err
}
```
設定儲存貯體的預設保留期間。  

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"log"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// S3Actions wraps S3 service actions.
type S3Actions struct {
	S3Client  *s3.Client
	S3Manager *manager.Uploader
}



// ModifyDefaultBucketRetention modifies the default retention period of an existing bucket.
func (actor S3Actions) ModifyDefaultBucketRetention(
	ctx context.Context, bucket string, lockMode types.ObjectLockEnabled, retentionPeriod int32, retentionMode types.ObjectLockRetentionMode) error {

	input := &s3.PutObjectLockConfigurationInput{
		Bucket: aws.String(bucket),
		ObjectLockConfiguration: &types.ObjectLockConfiguration{
			ObjectLockEnabled: lockMode,
			Rule: &types.ObjectLockRule{
				DefaultRetention: &types.DefaultRetention{
					Days: aws.Int32(retentionPeriod),
					Mode: retentionMode,
				},
			},
		},
	}
	_, err := actor.S3Client.PutObjectLockConfiguration(ctx, input)
	if err != nil {
		var noBucket *types.NoSuchBucket
		if errors.As(err, &noBucket) {
			log.Printf("Bucket %s does not exist.\n", bucket)
			err = noBucket
		}
	}

	return err
}
```
+  如需 API 詳細資訊，請參閱《適用於 Go 的 AWS SDK API 參考》**中的 [PutObjectLockConfiguration](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.PutObjectLockConfiguration)。

### `PutObjectRetention`
<a name="s3_PutObjectRetention_go_2_topic"></a>

以下程式碼範例顯示如何使用 `PutObjectRetention`。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/workflows/s3_object_lock#code-examples)中設定和執行。

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"log"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// S3Actions wraps S3 service actions.
type S3Actions struct {
	S3Client  *s3.Client
	S3Manager *manager.Uploader
}



// PutObjectRetention sets the object retention configuration for an S3 object.
func (actor S3Actions) PutObjectRetention(ctx context.Context, bucket string, key string, retentionMode types.ObjectLockRetentionMode, retentionPeriodDays int32) error {
	input := &s3.PutObjectRetentionInput{
		Bucket: aws.String(bucket),
		Key:    aws.String(key),
		Retention: &types.ObjectLockRetention{
			Mode:            retentionMode,
			RetainUntilDate: aws.Time(time.Now().AddDate(0, 0, int(retentionPeriodDays))),
		},
		BypassGovernanceRetention: aws.Bool(true),
	}

	_, err := actor.S3Client.PutObjectRetention(ctx, input)
	if err != nil {
		var noKey *types.NoSuchKey
		if errors.As(err, &noKey) {
			log.Printf("Object %s does not exist in bucket %s.\n", key, bucket)
			err = noKey
		}
	}

	return err
}
```
+  如需 API 詳細資訊，請參閱《適用於 Go 的 AWS SDK API 參考》**中的 [PutObjectRetention](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.PutObjectRetention)。

## 案例
<a name="scenarios"></a>

### 建立預先簽章 URL
<a name="s3_Scenario_PresignedUrl_go_2_topic"></a>

下列程式碼範例示範如何建立適用於 Amazon S3 預先簽署的 URL，並上傳物件。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/s3#code-examples)中設定和執行。
建立可包裝 S3 預先簽章動作的函數。  

```
import (
	"context"
	"log"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	v4 "github.com/aws/aws-sdk-go-v2/aws/signer/v4"
	"github.com/aws/aws-sdk-go-v2/service/s3"
)

// Presigner encapsulates the Amazon Simple Storage Service (Amazon S3) presign actions
// used in the examples.
// It contains PresignClient, a client that is used to presign requests to Amazon S3.
// Presigned requests contain temporary credentials and can be made from any HTTP client.
type Presigner struct {
	PresignClient *s3.PresignClient
}



// GetObject makes a presigned request that can be used to get an object from a bucket.
// The presigned request is valid for the specified number of seconds.
func (presigner Presigner) GetObject(
	ctx context.Context, bucketName string, objectKey string, lifetimeSecs int64) (*v4.PresignedHTTPRequest, error) {
	request, err := presigner.PresignClient.PresignGetObject(ctx, &s3.GetObjectInput{
		Bucket: aws.String(bucketName),
		Key:    aws.String(objectKey),
	}, func(opts *s3.PresignOptions) {
		opts.Expires = time.Duration(lifetimeSecs * int64(time.Second))
	})
	if err != nil {
		log.Printf("Couldn't get a presigned request to get %v:%v. Here's why: %v\n",
			bucketName, objectKey, err)
	}
	return request, err
}



// PutObject makes a presigned request that can be used to put an object in a bucket.
// The presigned request is valid for the specified number of seconds.
func (presigner Presigner) PutObject(
	ctx context.Context, bucketName string, objectKey string, lifetimeSecs int64) (*v4.PresignedHTTPRequest, error) {
	request, err := presigner.PresignClient.PresignPutObject(ctx, &s3.PutObjectInput{
		Bucket: aws.String(bucketName),
		Key:    aws.String(objectKey),
	}, func(opts *s3.PresignOptions) {
		opts.Expires = time.Duration(lifetimeSecs * int64(time.Second))
	})
	if err != nil {
		log.Printf("Couldn't get a presigned request to put %v:%v. Here's why: %v\n",
			bucketName, objectKey, err)
	}
	return request, err
}



// DeleteObject makes a presigned request that can be used to delete an object from a bucket.
func (presigner Presigner) DeleteObject(ctx context.Context, bucketName string, objectKey string) (*v4.PresignedHTTPRequest, error) {
	request, err := presigner.PresignClient.PresignDeleteObject(ctx, &s3.DeleteObjectInput{
		Bucket: aws.String(bucketName),
		Key:    aws.String(objectKey),
	})
	if err != nil {
		log.Printf("Couldn't get a presigned request to delete object %v. Here's why: %v\n", objectKey, err)
	}
	return request, err
}



func (presigner Presigner) PresignPostObject(ctx context.Context, bucketName string, objectKey string, lifetimeSecs int64) (*s3.PresignedPostRequest, error) {
	request, err := presigner.PresignClient.PresignPostObject(ctx, &s3.PutObjectInput{
		Bucket: aws.String(bucketName),
		Key:    aws.String(objectKey),
	}, func(options *s3.PresignPostOptions) {
		options.Expires = time.Duration(lifetimeSecs) * time.Second
	})
	if err != nil {
		log.Printf("Couldn't get a presigned post request to put %v:%v. Here's why: %v\n", bucketName, objectKey, err)
	}
	return request, nil
}
```
執行互動式範例，產生並使用預先簽章的 URL 來上傳、下載和刪除 S3 物件。  

```
import (
	"bytes"
	"context"
	"io"
	"log"
	"mime/multipart"
	"net/http"
	"os"
	"strings"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/awsdocs/aws-doc-sdk-examples/gov2/demotools"
	"github.com/awsdocs/aws-doc-sdk-examples/gov2/s3/actions"
)



// RunPresigningScenario is an interactive example that shows you how to get presigned
// HTTP requests that you can use to move data into and out of Amazon Simple Storage
// Service (Amazon S3). The presigned requests contain temporary credentials and can
// be used by an HTTP client.
//
// 1. Get a presigned request to put an object in a bucket.
// 2. Use the net/http package to use the presigned request to upload a local file to the bucket.
// 3. Get a presigned request to get an object from a bucket.
// 4. Use the net/http package to use the presigned request to download the object to a local file.
// 5. Get a presigned request to delete an object from a bucket.
// 6. Use the net/http package to use the presigned request to delete the object.
//
// This example creates an Amazon S3 presign client from the specified sdkConfig so that
// you can replace it with a mocked or stubbed config for unit testing.
//
// It uses a questioner from the `demotools` package to get input during the example.
// This package can be found in the ..\..\demotools folder of this repo.
//
// It uses an IHttpRequester interface to abstract HTTP requests so they can be mocked
// during testing.
func RunPresigningScenario(ctx context.Context, sdkConfig aws.Config, questioner demotools.IQuestioner, httpRequester IHttpRequester) {
	defer func() {
		if r := recover(); r != nil {
			log.Println("Something went wrong with the demo.")
			_, isMock := questioner.(*demotools.MockQuestioner)
			if isMock || questioner.AskBool("Do you want to see the full error message (y/n)?", "y") {
				log.Println(r)
			}
		}
	}()

	log.Println(strings.Repeat("-", 88))
	log.Println("Welcome to the Amazon S3 presigning demo.")
	log.Println(strings.Repeat("-", 88))

	s3Client := s3.NewFromConfig(sdkConfig)
	bucketBasics := actions.BucketBasics{S3Client: s3Client}
	presignClient := s3.NewPresignClient(s3Client)
	presigner := actions.Presigner{PresignClient: presignClient}

	bucketName := questioner.Ask("We'll need a bucket. Enter a name for a bucket "+
		"you own or one you want to create:", demotools.NotEmpty{})
	bucketExists, err := bucketBasics.BucketExists(ctx, bucketName)
	if err != nil {
		panic(err)
	}
	if !bucketExists {
		err = bucketBasics.CreateBucket(ctx, bucketName, sdkConfig.Region)
		if err != nil {
			panic(err)
		} else {
			log.Println("Bucket created.")
		}
	}
	log.Println(strings.Repeat("-", 88))

	log.Printf("Let's presign a request to upload a file to your bucket.")
	uploadFilename := questioner.Ask("Enter the path to a file you want to upload:",
		demotools.NotEmpty{})
	uploadKey := questioner.Ask("What would you like to name the uploaded object?",
		demotools.NotEmpty{})
	uploadFile, err := os.Open(uploadFilename)
	if err != nil {
		panic(err)
	}
	defer uploadFile.Close()
	presignedPutRequest, err := presigner.PutObject(ctx, bucketName, uploadKey, 60)
	if err != nil {
		panic(err)
	}
	log.Printf("Got a presigned %v request to URL:\n\t%v\n", presignedPutRequest.Method,
		presignedPutRequest.URL)
	log.Println("Using net/http to send the request...")
	info, err := uploadFile.Stat()
	if err != nil {
		panic(err)
	}
	putResponse, err := httpRequester.Put(presignedPutRequest.URL, info.Size(), uploadFile)
	if err != nil {
		panic(err)
	}
	log.Printf("%v object %v with presigned URL returned %v.", presignedPutRequest.Method,
		uploadKey, putResponse.StatusCode)
	log.Println(strings.Repeat("-", 88))

	log.Printf("Let's presign a request to download the object.")
	questioner.Ask("Press Enter when you're ready.")
	presignedGetRequest, err := presigner.GetObject(ctx, bucketName, uploadKey, 60)
	if err != nil {
		panic(err)
	}
	log.Printf("Got a presigned %v request to URL:\n\t%v\n", presignedGetRequest.Method,
		presignedGetRequest.URL)
	log.Println("Using net/http to send the request...")
	getResponse, err := httpRequester.Get(presignedGetRequest.URL)
	if err != nil {
		panic(err)
	}
	log.Printf("%v object %v with presigned URL returned %v.", presignedGetRequest.Method,
		uploadKey, getResponse.StatusCode)
	defer getResponse.Body.Close()
	downloadBody, err := io.ReadAll(getResponse.Body)
	if err != nil {
		panic(err)
	}
	log.Printf("Downloaded %v bytes. Here are the first 100 of them:\n", len(downloadBody))
	log.Println(strings.Repeat("-", 88))
	log.Println(string(downloadBody[:100]))
	log.Println(strings.Repeat("-", 88))

	log.Println("Now we'll create a new request to put the same object using a presigned post request")
	questioner.Ask("Press Enter when you're ready.")
	presignPostRequest, err := presigner.PresignPostObject(ctx, bucketName, uploadKey, 60)
	if err != nil {
		panic(err)
	}
	log.Printf("Got a presigned post request to url %v with values %v\n", presignPostRequest.URL, presignPostRequest.Values)
	log.Println("Using net/http multipart to send the request...")
	uploadFile, err = os.Open(uploadFilename)
	if err != nil {
		panic(err)
	}
	defer uploadFile.Close()
	multiPartResponse, err := sendMultipartRequest(presignPostRequest.URL, presignPostRequest.Values, uploadFile, uploadKey, httpRequester)
	if err != nil {
		panic(err)
	}
	log.Printf("Presign post object %v with presigned URL returned %v.", uploadKey, multiPartResponse.StatusCode)

	log.Println("Let's presign a request to delete the object.")
	questioner.Ask("Press Enter when you're ready.")
	presignedDelRequest, err := presigner.DeleteObject(ctx, bucketName, uploadKey)
	if err != nil {
		panic(err)
	}
	log.Printf("Got a presigned %v request to URL:\n\t%v\n", presignedDelRequest.Method,
		presignedDelRequest.URL)
	log.Println("Using net/http to send the request...")
	delResponse, err := httpRequester.Delete(presignedDelRequest.URL)
	if err != nil {
		panic(err)
	}
	log.Printf("%v object %v with presigned URL returned %v.\n", presignedDelRequest.Method,
		uploadKey, delResponse.StatusCode)
	log.Println(strings.Repeat("-", 88))

	log.Println("Thanks for watching!")
	log.Println(strings.Repeat("-", 88))
}
```
定義範例用來提出 HTTP 請求的 HTTP 請求包裝函式。  

```
// IHttpRequester abstracts HTTP requests into an interface so it can be mocked during
// unit testing.
type IHttpRequester interface {
	Get(url string) (resp *http.Response, err error)
	Post(url, contentType string, body io.Reader) (resp *http.Response, err error)
	Put(url string, contentLength int64, body io.Reader) (resp *http.Response, err error)
	Delete(url string) (resp *http.Response, err error)
}

// HttpRequester uses the net/http package to make HTTP requests during the scenario.
type HttpRequester struct{}

func (httpReq HttpRequester) Get(url string) (resp *http.Response, err error) {
	return http.Get(url)
}
func (httpReq HttpRequester) Post(url, contentType string, body io.Reader) (resp *http.Response, err error) {
	postRequest, err := http.NewRequest("POST", url, body)
	if err != nil {
		return nil, err
	}
	postRequest.Header.Set("Content-Type", contentType)
	return http.DefaultClient.Do(postRequest)
}

func (httpReq HttpRequester) Put(url string, contentLength int64, body io.Reader) (resp *http.Response, err error) {
	putRequest, err := http.NewRequest("PUT", url, body)
	if err != nil {
		return nil, err
	}
	putRequest.ContentLength = contentLength
	return http.DefaultClient.Do(putRequest)
}
func (httpReq HttpRequester) Delete(url string) (resp *http.Response, err error) {
	delRequest, err := http.NewRequest("DELETE", url, nil)
	if err != nil {
		return nil, err
	}
	return http.DefaultClient.Do(delRequest)
}
```

### 鎖定 Amazon S3 物件
<a name="s3_Scenario_ObjectLock_go_2_topic"></a>

下列程式碼範例示範如何使用 S3 物件鎖定功能。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/workflows/s3_object_lock#code-examples)中設定和執行。
執行展示 Amazon S3 物件鎖定功能的互動式情境。  

```
import (
	"context"
	"fmt"
	"log"
	"strings"

	"s3_object_lock/actions"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/awsdocs/aws-doc-sdk-examples/gov2/demotools"
)

// ObjectLockScenario contains the steps to run the S3 Object Lock workflow.
type ObjectLockScenario struct {
	questioner demotools.IQuestioner
	resources  Resources
	s3Actions  *actions.S3Actions
	sdkConfig  aws.Config
}

// NewObjectLockScenario constructs a new ObjectLockScenario instance.
func NewObjectLockScenario(sdkConfig aws.Config, questioner demotools.IQuestioner) ObjectLockScenario {
	scenario := ObjectLockScenario{
		questioner: questioner,
		resources:  Resources{},
		s3Actions:  &actions.S3Actions{S3Client: s3.NewFromConfig(sdkConfig)},
		sdkConfig:  sdkConfig,
	}
	scenario.s3Actions.S3Manager = manager.NewUploader(scenario.s3Actions.S3Client)
	scenario.resources.init(scenario.s3Actions, questioner)
	return scenario
}

type nameLocked struct {
	name   string
	locked bool
}

var createInfo = []nameLocked{
	{"standard-bucket", false},
	{"lock-bucket", true},
	{"retention-bucket", false},
}

// CreateBuckets creates the S3 buckets required for the workflow.
func (scenario *ObjectLockScenario) CreateBuckets(ctx context.Context) {
	log.Println("Let's create some S3 buckets to use for this workflow.")
	success := false
	for !success {
		prefix := scenario.questioner.Ask(
			"This example creates three buckets. Enter a prefix to name your buckets (remember bucket names must be globally unique):")

		for _, info := range createInfo {
			log.Println(fmt.Sprintf("%s.%s", prefix, info.name))
			bucketName, err := scenario.s3Actions.CreateBucketWithLock(ctx, fmt.Sprintf("%s.%s", prefix, info.name), scenario.sdkConfig.Region, info.locked)
			if err != nil {
				switch err.(type) {
				case *types.BucketAlreadyExists, *types.BucketAlreadyOwnedByYou:
					log.Printf("Couldn't create bucket %s.\n", bucketName)
				default:
					panic(err)
				}
				break
			}
			scenario.resources.demoBuckets[info.name] = &DemoBucket{
				name:       bucketName,
				objectKeys: []string{},
			}
			log.Printf("Created bucket %s.\n", bucketName)
		}

		if len(scenario.resources.demoBuckets) < len(createInfo) {
			scenario.resources.deleteBuckets(ctx)
		} else {
			success = true
		}
	}

	log.Println("S3 buckets created.")
	log.Println(strings.Repeat("-", 88))
}

// EnableLockOnBucket enables object locking on an existing bucket.
func (scenario *ObjectLockScenario) EnableLockOnBucket(ctx context.Context) {
	log.Println("\nA bucket can be configured to use object locking.")
	scenario.questioner.Ask("Press Enter to continue.")

	var err error
	bucket := scenario.resources.demoBuckets["retention-bucket"]
	err = scenario.s3Actions.EnableObjectLockOnBucket(ctx, bucket.name)
	if err != nil {
		switch err.(type) {
		case *types.NoSuchBucket:
			log.Printf("Couldn't enable object locking on bucket %s.\n", bucket.name)
		default:
			panic(err)
		}
	} else {
		log.Printf("Object locking enabled on bucket %s.", bucket.name)
	}

	log.Println(strings.Repeat("-", 88))
}

// SetDefaultRetentionPolicy sets a default retention governance policy on a bucket.
func (scenario *ObjectLockScenario) SetDefaultRetentionPolicy(ctx context.Context) {
	log.Println("\nA bucket can be configured to use object locking with a default retention period.")

	bucket := scenario.resources.demoBuckets["retention-bucket"]
	retentionPeriod := scenario.questioner.AskInt("Enter the default retention period in days: ")
	err := scenario.s3Actions.ModifyDefaultBucketRetention(ctx, bucket.name, types.ObjectLockEnabledEnabled, int32(retentionPeriod), types.ObjectLockRetentionModeGovernance)
	if err != nil {
		switch err.(type) {
		case *types.NoSuchBucket:
			log.Printf("Couldn't configure a default retention period on bucket %s.\n", bucket.name)
		default:
			panic(err)
		}
	} else {
		log.Printf("Default retention policy set on bucket %s with %d day retention period.", bucket.name, retentionPeriod)
		bucket.retentionEnabled = true
	}

	log.Println(strings.Repeat("-", 88))
}

// UploadTestObjects uploads test objects to the S3 buckets.
func (scenario *ObjectLockScenario) UploadTestObjects(ctx context.Context) {
	log.Println("Uploading test objects to S3 buckets.")

	for _, info := range createInfo {
		bucket := scenario.resources.demoBuckets[info.name]
		for i := 0; i < 2; i++ {
			key, err := scenario.s3Actions.UploadObject(ctx, bucket.name, fmt.Sprintf("example-%d", i),
				fmt.Sprintf("Example object content #%d in bucket %s.", i, bucket.name))
			if err != nil {
				switch err.(type) {
				case *types.NoSuchBucket:
					log.Printf("Couldn't upload %s to bucket %s.\n", key, bucket.name)
				default:
					panic(err)
				}
			} else {
				log.Printf("Uploaded %s to bucket %s.\n", key, bucket.name)
				bucket.objectKeys = append(bucket.objectKeys, key)
			}
		}
	}

	scenario.questioner.Ask("Test objects uploaded. Press Enter to continue.")
	log.Println(strings.Repeat("-", 88))
}

// SetObjectLockConfigurations sets object lock configurations on the test objects.
func (scenario *ObjectLockScenario) SetObjectLockConfigurations(ctx context.Context) {
	log.Println("Now let's set object lock configurations on individual objects.")

	buckets := []*DemoBucket{scenario.resources.demoBuckets["lock-bucket"], scenario.resources.demoBuckets["retention-bucket"]}
	for _, bucket := range buckets {
		for index, objKey := range bucket.objectKeys {
			switch index {
			case 0:
				if scenario.questioner.AskBool(fmt.Sprintf("\nDo you want to add a legal hold to %s in %s (y/n)? ", objKey, bucket.name), "y") {
					err := scenario.s3Actions.PutObjectLegalHold(ctx, bucket.name, objKey, "", types.ObjectLockLegalHoldStatusOn)
					if err != nil {
						switch err.(type) {
						case *types.NoSuchKey:
							log.Printf("Couldn't set legal hold on %s.\n", objKey)
						default:
							panic(err)
						}
					} else {
						log.Printf("Legal hold set on %s.\n", objKey)
					}
				}
			case 1:
				q := fmt.Sprintf("\nDo you want to add a 1 day Governance retention period to %s in %s?\n"+
					"Reminder: Only a user with the s3:BypassGovernanceRetention permission is able to delete this object\n"+
					"or its bucket until the retention period has expired. (y/n) ", objKey, bucket.name)
				if scenario.questioner.AskBool(q, "y") {
					err := scenario.s3Actions.PutObjectRetention(ctx, bucket.name, objKey, types.ObjectLockRetentionModeGovernance, 1)
					if err != nil {
						switch err.(type) {
						case *types.NoSuchKey:
							log.Printf("Couldn't set retention period on %s in %s.\n", objKey, bucket.name)
						default:
							panic(err)
						}
					} else {
						log.Printf("Retention period set to 1 for %s.", objKey)
						bucket.retentionEnabled = true
					}
				}
			}
		}
	}
	log.Println(strings.Repeat("-", 88))
}

const (
	ListAll = iota
	DeleteObject
	DeleteRetentionObject
	OverwriteObject
	ViewRetention
	ViewLegalHold
	Finish
)

// InteractWithObjects allows the user to interact with the objects and test the object lock configurations.
func (scenario *ObjectLockScenario) InteractWithObjects(ctx context.Context) {
	log.Println("Now you can interact with the objects to explore the object lock configurations.")
	interactiveChoices := []string{
		"List all objects and buckets.",
		"Attempt to delete an object.",
		"Attempt to delete an object with retention period bypass.",
		"Attempt to overwrite a file.",
		"View the retention settings for an object.",
		"View the legal hold settings for an object.",
		"Finish the workflow."}

	choice := ListAll
	for choice != Finish {
		objList := scenario.GetAllObjects(ctx)
		objChoices := scenario.makeObjectChoiceList(objList)
		choice = scenario.questioner.AskChoice("Choose an action from the menu:\n", interactiveChoices)
		switch choice {
		case ListAll:
			log.Println("The current objects in the example buckets are:")
			for _, objChoice := range objChoices {
				log.Println("\t", objChoice)
			}
		case DeleteObject, DeleteRetentionObject:
			objChoice := scenario.questioner.AskChoice("Enter the number of the object to delete:\n", objChoices)
			obj := objList[objChoice]
			deleted, err := scenario.s3Actions.DeleteObject(ctx, obj.bucket, obj.key, obj.versionId, choice == DeleteRetentionObject)
			if err != nil {
				switch err.(type) {
				case *types.NoSuchKey:
					log.Println("Nothing to delete.")
				default:
					panic(err)
				}
			} else if deleted {
				log.Printf("Object %s deleted.\n", obj.key)
			}
		case OverwriteObject:
			objChoice := scenario.questioner.AskChoice("Enter the number of the object to overwrite:\n", objChoices)
			obj := objList[objChoice]
			_, err := scenario.s3Actions.UploadObject(ctx, obj.bucket, obj.key, fmt.Sprintf("New content in object %s.", obj.key))
			if err != nil {
				switch err.(type) {
				case *types.NoSuchBucket:
					log.Println("Couldn't upload to nonexistent bucket.")
				default:
					panic(err)
				}
			} else {
				log.Printf("Uploaded new content to object %s.\n", obj.key)
			}
		case ViewRetention:
			objChoice := scenario.questioner.AskChoice("Enter the number of the object to view:\n", objChoices)
			obj := objList[objChoice]
			retention, err := scenario.s3Actions.GetObjectRetention(ctx, obj.bucket, obj.key)
			if err != nil {
				switch err.(type) {
				case *types.NoSuchKey:
					log.Printf("Can't get retention configuration for %s.\n", obj.key)
				default:
					panic(err)
				}
			} else if retention != nil {
				log.Printf("Object %s has retention mode %s until %v.\n", obj.key, retention.Mode, retention.RetainUntilDate)
			} else {
				log.Printf("Object %s does not have object retention configured.\n", obj.key)
			}
		case ViewLegalHold:
			objChoice := scenario.questioner.AskChoice("Enter the number of the object to view:\n", objChoices)
			obj := objList[objChoice]
			legalHold, err := scenario.s3Actions.GetObjectLegalHold(ctx, obj.bucket, obj.key, obj.versionId)
			if err != nil {
				switch err.(type) {
				case *types.NoSuchKey:
					log.Printf("Can't get legal hold configuration for %s.\n", obj.key)
				default:
					panic(err)
				}
			} else if legalHold != nil {
				log.Printf("Object %s has legal hold %v.", obj.key, *legalHold)
			} else {
				log.Printf("Object %s does not have legal hold configured.", obj.key)
			}
		case Finish:
			log.Println("Let's clean up.")
		}
		log.Println(strings.Repeat("-", 88))
	}
}

type BucketKeyVersionId struct {
	bucket    string
	key       string
	versionId string
}

// GetAllObjects gets the object versions in the example S3 buckets and returns them in a flattened list.
func (scenario *ObjectLockScenario) GetAllObjects(ctx context.Context) []BucketKeyVersionId {
	var objectList []BucketKeyVersionId
	for _, info := range createInfo {
		bucket := scenario.resources.demoBuckets[info.name]
		versions, err := scenario.s3Actions.ListObjectVersions(ctx, bucket.name)
		if err != nil {
			switch err.(type) {
			case *types.NoSuchBucket:
				log.Printf("Couldn't get object versions for %s.\n", bucket.name)
			default:
				panic(err)
			}
		} else {
			for _, version := range versions {
				objectList = append(objectList,
					BucketKeyVersionId{bucket: bucket.name, key: *version.Key, versionId: *version.VersionId})
			}
		}
	}
	return objectList
}

// makeObjectChoiceList makes the object version list into a list of strings that are displayed
// as choices.
func (scenario *ObjectLockScenario) makeObjectChoiceList(bucketObjects []BucketKeyVersionId) []string {
	choices := make([]string, len(bucketObjects))
	for i := 0; i < len(bucketObjects); i++ {
		choices[i] = fmt.Sprintf("%s in %s with VersionId %s.",
			bucketObjects[i].key, bucketObjects[i].bucket, bucketObjects[i].versionId)
	}
	return choices
}

// Run runs the S3 Object Lock scenario.
func (scenario *ObjectLockScenario) Run(ctx context.Context) {
	defer func() {
		if r := recover(); r != nil {
			log.Println("Something went wrong with the demo.")
			_, isMock := scenario.questioner.(*demotools.MockQuestioner)
			if isMock || scenario.questioner.AskBool("Do you want to see the full error message (y/n)?", "y") {
				log.Println(r)
			}
			scenario.resources.Cleanup(ctx)
		}
	}()

	log.Println(strings.Repeat("-", 88))
	log.Println("Welcome to the Amazon S3 Object Lock Feature Scenario.")
	log.Println(strings.Repeat("-", 88))

	scenario.CreateBuckets(ctx)
	scenario.EnableLockOnBucket(ctx)
	scenario.SetDefaultRetentionPolicy(ctx)
	scenario.UploadTestObjects(ctx)
	scenario.SetObjectLockConfigurations(ctx)
	scenario.InteractWithObjects(ctx)

	scenario.resources.Cleanup(ctx)

	log.Println(strings.Repeat("-", 88))
	log.Println("Thanks for watching!")
	log.Println(strings.Repeat("-", 88))
}
```
定義包裝此範例使用之 S3 動作的結構。  

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"log"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// S3Actions wraps S3 service actions.
type S3Actions struct {
	S3Client  *s3.Client
	S3Manager *manager.Uploader
}



// CreateBucketWithLock creates a new S3 bucket with optional object locking enabled
// and waits for the bucket to exist before returning.
func (actor S3Actions) CreateBucketWithLock(ctx context.Context, bucket string, region string, enableObjectLock bool) (string, error) {
	input := &s3.CreateBucketInput{
		Bucket: aws.String(bucket),
		CreateBucketConfiguration: &types.CreateBucketConfiguration{
			LocationConstraint: types.BucketLocationConstraint(region),
		},
	}

	if enableObjectLock {
		input.ObjectLockEnabledForBucket = aws.Bool(true)
	}

	_, err := actor.S3Client.CreateBucket(ctx, input)
	if err != nil {
		var owned *types.BucketAlreadyOwnedByYou
		var exists *types.BucketAlreadyExists
		if errors.As(err, &owned) {
			log.Printf("You already own bucket %s.\n", bucket)
			err = owned
		} else if errors.As(err, &exists) {
			log.Printf("Bucket %s already exists.\n", bucket)
			err = exists
		}
	} else {
		err = s3.NewBucketExistsWaiter(actor.S3Client).Wait(
			ctx, &s3.HeadBucketInput{Bucket: aws.String(bucket)}, time.Minute)
		if err != nil {
			log.Printf("Failed attempt to wait for bucket %s to exist.\n", bucket)
		}
	}

	return bucket, err
}



// GetObjectLegalHold retrieves the legal hold status for an S3 object.
func (actor S3Actions) GetObjectLegalHold(ctx context.Context, bucket string, key string, versionId string) (*types.ObjectLockLegalHoldStatus, error) {
	var status *types.ObjectLockLegalHoldStatus
	input := &s3.GetObjectLegalHoldInput{
		Bucket:    aws.String(bucket),
		Key:       aws.String(key),
		VersionId: aws.String(versionId),
	}

	output, err := actor.S3Client.GetObjectLegalHold(ctx, input)
	if err != nil {
		var noSuchKeyErr *types.NoSuchKey
		var apiErr *smithy.GenericAPIError
		if errors.As(err, &noSuchKeyErr) {
			log.Printf("Object %s does not exist in bucket %s.\n", key, bucket)
			err = noSuchKeyErr
		} else if errors.As(err, &apiErr) {
			switch apiErr.ErrorCode() {
			case "NoSuchObjectLockConfiguration":
				log.Printf("Object %s does not have an object lock configuration.\n", key)
				err = nil
			case "InvalidRequest":
				log.Printf("Bucket %s does not have an object lock configuration.\n", bucket)
				err = nil
			}
		}
	} else {
		status = &output.LegalHold.Status
	}

	return status, err
}



// GetObjectLockConfiguration retrieves the object lock configuration for an S3 bucket.
func (actor S3Actions) GetObjectLockConfiguration(ctx context.Context, bucket string) (*types.ObjectLockConfiguration, error) {
	var lockConfig *types.ObjectLockConfiguration
	input := &s3.GetObjectLockConfigurationInput{
		Bucket: aws.String(bucket),
	}

	output, err := actor.S3Client.GetObjectLockConfiguration(ctx, input)
	if err != nil {
		var noBucket *types.NoSuchBucket
		var apiErr *smithy.GenericAPIError
		if errors.As(err, &noBucket) {
			log.Printf("Bucket %s does not exist.\n", bucket)
			err = noBucket
		} else if errors.As(err, &apiErr) && apiErr.ErrorCode() == "ObjectLockConfigurationNotFoundError" {
			log.Printf("Bucket %s does not have an object lock configuration.\n", bucket)
			err = nil
		}
	} else {
		lockConfig = output.ObjectLockConfiguration
	}

	return lockConfig, err
}



// GetObjectRetention retrieves the object retention configuration for an S3 object.
func (actor S3Actions) GetObjectRetention(ctx context.Context, bucket string, key string) (*types.ObjectLockRetention, error) {
	var retention *types.ObjectLockRetention
	input := &s3.GetObjectRetentionInput{
		Bucket: aws.String(bucket),
		Key:    aws.String(key),
	}

	output, err := actor.S3Client.GetObjectRetention(ctx, input)
	if err != nil {
		var noKey *types.NoSuchKey
		var apiErr *smithy.GenericAPIError
		if errors.As(err, &noKey) {
			log.Printf("Object %s does not exist in bucket %s.\n", key, bucket)
			err = noKey
		} else if errors.As(err, &apiErr) {
			switch apiErr.ErrorCode() {
			case "NoSuchObjectLockConfiguration":
				err = nil
			case "InvalidRequest":
				log.Printf("Bucket %s does not have locking enabled.", bucket)
				err = nil
			}
		}
	} else {
		retention = output.Retention
	}

	return retention, err
}



// PutObjectLegalHold sets the legal hold configuration for an S3 object.
func (actor S3Actions) PutObjectLegalHold(ctx context.Context, bucket string, key string, versionId string, legalHoldStatus types.ObjectLockLegalHoldStatus) error {
	input := &s3.PutObjectLegalHoldInput{
		Bucket: aws.String(bucket),
		Key:    aws.String(key),
		LegalHold: &types.ObjectLockLegalHold{
			Status: legalHoldStatus,
		},
	}
	if versionId != "" {
		input.VersionId = aws.String(versionId)
	}

	_, err := actor.S3Client.PutObjectLegalHold(ctx, input)
	if err != nil {
		var noKey *types.NoSuchKey
		if errors.As(err, &noKey) {
			log.Printf("Object %s does not exist in bucket %s.\n", key, bucket)
			err = noKey
		}
	}

	return err
}



// ModifyDefaultBucketRetention modifies the default retention period of an existing bucket.
func (actor S3Actions) ModifyDefaultBucketRetention(
	ctx context.Context, bucket string, lockMode types.ObjectLockEnabled, retentionPeriod int32, retentionMode types.ObjectLockRetentionMode) error {

	input := &s3.PutObjectLockConfigurationInput{
		Bucket: aws.String(bucket),
		ObjectLockConfiguration: &types.ObjectLockConfiguration{
			ObjectLockEnabled: lockMode,
			Rule: &types.ObjectLockRule{
				DefaultRetention: &types.DefaultRetention{
					Days: aws.Int32(retentionPeriod),
					Mode: retentionMode,
				},
			},
		},
	}
	_, err := actor.S3Client.PutObjectLockConfiguration(ctx, input)
	if err != nil {
		var noBucket *types.NoSuchBucket
		if errors.As(err, &noBucket) {
			log.Printf("Bucket %s does not exist.\n", bucket)
			err = noBucket
		}
	}

	return err
}



// EnableObjectLockOnBucket enables object locking on an existing bucket.
func (actor S3Actions) EnableObjectLockOnBucket(ctx context.Context, bucket string) error {
	// Versioning must be enabled on the bucket before object locking is enabled.
	verInput := &s3.PutBucketVersioningInput{
		Bucket: aws.String(bucket),
		VersioningConfiguration: &types.VersioningConfiguration{
			MFADelete: types.MFADeleteDisabled,
			Status:    types.BucketVersioningStatusEnabled,
		},
	}
	_, err := actor.S3Client.PutBucketVersioning(ctx, verInput)
	if err != nil {
		var noBucket *types.NoSuchBucket
		if errors.As(err, &noBucket) {
			log.Printf("Bucket %s does not exist.\n", bucket)
			err = noBucket
		}
		return err
	}

	input := &s3.PutObjectLockConfigurationInput{
		Bucket: aws.String(bucket),
		ObjectLockConfiguration: &types.ObjectLockConfiguration{
			ObjectLockEnabled: types.ObjectLockEnabledEnabled,
		},
	}
	_, err = actor.S3Client.PutObjectLockConfiguration(ctx, input)
	if err != nil {
		var noBucket *types.NoSuchBucket
		if errors.As(err, &noBucket) {
			log.Printf("Bucket %s does not exist.\n", bucket)
			err = noBucket
		}
	}

	return err
}



// PutObjectRetention sets the object retention configuration for an S3 object.
func (actor S3Actions) PutObjectRetention(ctx context.Context, bucket string, key string, retentionMode types.ObjectLockRetentionMode, retentionPeriodDays int32) error {
	input := &s3.PutObjectRetentionInput{
		Bucket: aws.String(bucket),
		Key:    aws.String(key),
		Retention: &types.ObjectLockRetention{
			Mode:            retentionMode,
			RetainUntilDate: aws.Time(time.Now().AddDate(0, 0, int(retentionPeriodDays))),
		},
		BypassGovernanceRetention: aws.Bool(true),
	}

	_, err := actor.S3Client.PutObjectRetention(ctx, input)
	if err != nil {
		var noKey *types.NoSuchKey
		if errors.As(err, &noKey) {
			log.Printf("Object %s does not exist in bucket %s.\n", key, bucket)
			err = noKey
		}
	}

	return err
}



// UploadObject uses the S3 upload manager to upload an object to a bucket.
func (actor S3Actions) UploadObject(ctx context.Context, bucket string, key string, contents string) (string, error) {
	var outKey string
	input := &s3.PutObjectInput{
		Bucket:            aws.String(bucket),
		Key:               aws.String(key),
		Body:              bytes.NewReader([]byte(contents)),
		ChecksumAlgorithm: types.ChecksumAlgorithmSha256,
	}
	output, err := actor.S3Manager.Upload(ctx, input)
	if err != nil {
		var noBucket *types.NoSuchBucket
		if errors.As(err, &noBucket) {
			log.Printf("Bucket %s does not exist.\n", bucket)
			err = noBucket
		}
	} else {
		err := s3.NewObjectExistsWaiter(actor.S3Client).Wait(ctx, &s3.HeadObjectInput{
			Bucket: aws.String(bucket),
			Key:    aws.String(key),
		}, time.Minute)
		if err != nil {
			log.Printf("Failed attempt to wait for object %s to exist in %s.\n", key, bucket)
		} else {
			outKey = *output.Key
		}
	}
	return outKey, err
}



// ListObjectVersions lists all versions of all objects in a bucket.
func (actor S3Actions) ListObjectVersions(ctx context.Context, bucket string) ([]types.ObjectVersion, error) {
	var err error
	var output *s3.ListObjectVersionsOutput
	var versions []types.ObjectVersion
	input := &s3.ListObjectVersionsInput{Bucket: aws.String(bucket)}
	versionPaginator := s3.NewListObjectVersionsPaginator(actor.S3Client, input)
	for versionPaginator.HasMorePages() {
		output, err = versionPaginator.NextPage(ctx)
		if err != nil {
			var noBucket *types.NoSuchBucket
			if errors.As(err, &noBucket) {
				log.Printf("Bucket %s does not exist.\n", bucket)
				err = noBucket
			}
			break
		} else {
			versions = append(versions, output.Versions...)
		}
	}
	return versions, err
}



// DeleteObject deletes an object from a bucket.
func (actor S3Actions) DeleteObject(ctx context.Context, bucket string, key string, versionId string, bypassGovernance bool) (bool, error) {
	deleted := false
	input := &s3.DeleteObjectInput{
		Bucket: aws.String(bucket),
		Key:    aws.String(key),
	}
	if versionId != "" {
		input.VersionId = aws.String(versionId)
	}
	if bypassGovernance {
		input.BypassGovernanceRetention = aws.Bool(true)
	}
	_, err := actor.S3Client.DeleteObject(ctx, input)
	if err != nil {
		var noKey *types.NoSuchKey
		var apiErr *smithy.GenericAPIError
		if errors.As(err, &noKey) {
			log.Printf("Object %s does not exist in %s.\n", key, bucket)
			err = noKey
		} else if errors.As(err, &apiErr) {
			switch apiErr.ErrorCode() {
			case "AccessDenied":
				log.Printf("Access denied: cannot delete object %s from %s.\n", key, bucket)
				err = nil
			case "InvalidArgument":
				if bypassGovernance {
					log.Printf("You cannot specify bypass governance on a bucket without lock enabled.")
					err = nil
				}
			}
		}
	} else {
		err = s3.NewObjectNotExistsWaiter(actor.S3Client).Wait(
			ctx, &s3.HeadObjectInput{Bucket: aws.String(bucket), Key: aws.String(key)}, time.Minute)
		if err != nil {
			log.Printf("Failed attempt to wait for object %s in bucket %s to be deleted.\n", key, bucket)
		} else {
			deleted = true
		}
	}
	return deleted, err
}



// DeleteObjects deletes a list of objects from a bucket.
func (actor S3Actions) DeleteObjects(ctx context.Context, bucket string, objects []types.ObjectIdentifier, bypassGovernance bool) error {
	if len(objects) == 0 {
		return nil
	}

	input := s3.DeleteObjectsInput{
		Bucket: aws.String(bucket),
		Delete: &types.Delete{
			Objects: objects,
			Quiet:   aws.Bool(true),
		},
	}
	if bypassGovernance {
		input.BypassGovernanceRetention = aws.Bool(true)
	}
	delOut, err := actor.S3Client.DeleteObjects(ctx, &input)
	if err != nil || len(delOut.Errors) > 0 {
		log.Printf("Error deleting objects from bucket %s.\n", bucket)
		if err != nil {
			var noBucket *types.NoSuchBucket
			if errors.As(err, &noBucket) {
				log.Printf("Bucket %s does not exist.\n", bucket)
				err = noBucket
			}
		} else if len(delOut.Errors) > 0 {
			for _, outErr := range delOut.Errors {
				log.Printf("%s: %s\n", *outErr.Key, *outErr.Message)
			}
			err = fmt.Errorf("%s", *delOut.Errors[0].Message)
		}
	} else {
		for _, delObjs := range delOut.Deleted {
			err = s3.NewObjectNotExistsWaiter(actor.S3Client).Wait(
				ctx, &s3.HeadObjectInput{Bucket: aws.String(bucket), Key: delObjs.Key}, time.Minute)
			if err != nil {
				log.Printf("Failed attempt to wait for object %s to be deleted.\n", *delObjs.Key)
			} else {
				log.Printf("Deleted %s.\n", *delObjs.Key)
			}
		}
	}
	return err
}
```
清除資源。  

```
import (
	"context"
	"log"
	"s3_object_lock/actions"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/awsdocs/aws-doc-sdk-examples/gov2/demotools"
)

// DemoBucket contains metadata for buckets used in this example.
type DemoBucket struct {
	name             string
	retentionEnabled bool
	objectKeys       []string
}

// Resources keeps track of AWS resources created during the ObjectLockScenario and handles
// cleanup when the scenario finishes.
type Resources struct {
	demoBuckets map[string]*DemoBucket

	s3Actions  *actions.S3Actions
	questioner demotools.IQuestioner
}

// init initializes objects in the Resources struct.
func (resources *Resources) init(s3Actions *actions.S3Actions, questioner demotools.IQuestioner) {
	resources.s3Actions = s3Actions
	resources.questioner = questioner
	resources.demoBuckets = map[string]*DemoBucket{}
}

// Cleanup deletes all AWS resources created during the ObjectLockScenario.
func (resources *Resources) Cleanup(ctx context.Context) {
	defer func() {
		if r := recover(); r != nil {
			log.Printf("Something went wrong during cleanup.\n%v\n", r)
			log.Println("Use the AWS Management Console to remove any remaining resources " +
				"that were created for this scenario.")
		}
	}()

	wantDelete := resources.questioner.AskBool("Do you want to remove all of the AWS resources that were created "+
		"during this demo (y/n)?", "y")
	if !wantDelete {
		log.Println("Be sure to remove resources when you're done with them to avoid unexpected charges!")
		return
	}

	log.Println("Removing objects from S3 buckets and deleting buckets...")
	resources.deleteBuckets(ctx)
	//resources.deleteRetentionObjects(resources.retentionBucket, resources.retentionObjects)

	log.Println("Cleanup complete.")
}

// deleteBuckets empties and then deletes all buckets created during the ObjectLockScenario.
func (resources *Resources) deleteBuckets(ctx context.Context) {
	for _, info := range createInfo {
		bucket := resources.demoBuckets[info.name]
		resources.deleteObjects(ctx, bucket)
		_, err := resources.s3Actions.S3Client.DeleteBucket(ctx, &s3.DeleteBucketInput{
			Bucket: aws.String(bucket.name),
		})
		if err != nil {
			panic(err)
		}
	}
	for _, info := range createInfo {
		bucket := resources.demoBuckets[info.name]
		err := s3.NewBucketNotExistsWaiter(resources.s3Actions.S3Client).Wait(
			ctx, &s3.HeadBucketInput{Bucket: aws.String(bucket.name)}, time.Minute)
		if err != nil {
			log.Printf("Failed attempt to wait for bucket %s to be deleted.\n", bucket.name)
		} else {
			log.Printf("Deleted %s.\n", bucket.name)
		}
	}
	resources.demoBuckets = map[string]*DemoBucket{}
}

// deleteObjects deletes all objects in the specified bucket.
func (resources *Resources) deleteObjects(ctx context.Context, bucket *DemoBucket) {
	lockConfig, err := resources.s3Actions.GetObjectLockConfiguration(ctx, bucket.name)
	if err != nil {
		panic(err)
	}
	versions, err := resources.s3Actions.ListObjectVersions(ctx, bucket.name)
	if err != nil {
		switch err.(type) {
		case *types.NoSuchBucket:
			log.Printf("No objects to get from %s.\n", bucket.name)
		default:
			panic(err)
		}
	}
	delObjects := make([]types.ObjectIdentifier, len(versions))
	for i, version := range versions {
		if lockConfig != nil && lockConfig.ObjectLockEnabled == types.ObjectLockEnabledEnabled {
			status, err := resources.s3Actions.GetObjectLegalHold(ctx, bucket.name, *version.Key, *version.VersionId)
			if err != nil {
				switch err.(type) {
				case *types.NoSuchKey:
					log.Printf("Couldn't determine legal hold status for %s in %s.\n", *version.Key, bucket.name)
				default:
					panic(err)
				}
			} else if status != nil && *status == types.ObjectLockLegalHoldStatusOn {
				err = resources.s3Actions.PutObjectLegalHold(ctx, bucket.name, *version.Key, *version.VersionId, types.ObjectLockLegalHoldStatusOff)
				if err != nil {
					switch err.(type) {
					case *types.NoSuchKey:
						log.Printf("Couldn't turn off legal hold for %s in %s.\n", *version.Key, bucket.name)
					default:
						panic(err)
					}
				}
			}
		}
		delObjects[i] = types.ObjectIdentifier{Key: version.Key, VersionId: version.VersionId}
	}
	err = resources.s3Actions.DeleteObjects(ctx, bucket.name, delObjects, bucket.retentionEnabled)
	if err != nil {
		switch err.(type) {
		case *types.NoSuchBucket:
			log.Println("Nothing to delete.")
		default:
			panic(err)
		}
	}
}
```
+ 如需 API 詳細資訊，請參閱《*適用於 Go 的 AWS SDK API 參考*》中的下列主題。
  + [GetObjectLegalHold](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.GetObjectLegalHold)
  + [GetObjectLockConfiguration](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.GetObjectLockConfiguration)
  + [GetObjectRetention](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.GetObjectRetention)
  + [PutObjectLegalHold](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.PutObjectLegalHold)
  + [PutObjectLockConfiguration](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.PutObjectLockConfiguration)
  + [PutObjectRetention](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#Client.PutObjectRetention)

### 上傳或下載大型檔案
<a name="s3_Scenario_UsingLargeFiles_go_2_topic"></a>

下列程式碼範例示範如何將大型檔案上傳至 Amazon S3，以及從中下載大型檔案。

如需詳細資訊，請參閱[使用分段上傳以上傳物件](https://docs.aws.amazon.com/AmazonS3/latest/userguide/mpu-upload-object.html)。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/gov2/s3#code-examples)中設定和執行。
建立使用上傳和下載管理員的函數，將資料分成數個部分，並同時傳輸。  

```
import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"io"
	"log"
	"os"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// BucketBasics encapsulates the Amazon Simple Storage Service (Amazon S3) actions
// used in the examples.
// It contains S3Client, an Amazon S3 service client that is used to perform bucket
// and object actions.
type BucketBasics struct {
	S3Client *s3.Client
}



// UploadLargeObject uses an upload manager to upload data to an object in a bucket.
// The upload manager breaks large data into parts and uploads the parts concurrently.
func (basics BucketBasics) UploadLargeObject(ctx context.Context, bucketName string, objectKey string, largeObject []byte) error {
	largeBuffer := bytes.NewReader(largeObject)
	var partMiBs int64 = 10
	uploader := manager.NewUploader(basics.S3Client, func(u *manager.Uploader) {
		u.PartSize = partMiBs * 1024 * 1024
	})
	_, err := uploader.Upload(ctx, &s3.PutObjectInput{
		Bucket: aws.String(bucketName),
		Key:    aws.String(objectKey),
		Body:   largeBuffer,
	})
	if err != nil {
		var apiErr smithy.APIError
		if errors.As(err, &apiErr) && apiErr.ErrorCode() == "EntityTooLarge" {
			log.Printf("Error while uploading object to %s. The object is too large.\n"+
				"The maximum size for a multipart upload is 5TB.", bucketName)
		} else {
			log.Printf("Couldn't upload large object to %v:%v. Here's why: %v\n",
				bucketName, objectKey, err)
		}
	} else {
		err = s3.NewObjectExistsWaiter(basics.S3Client).Wait(
			ctx, &s3.HeadObjectInput{Bucket: aws.String(bucketName), Key: aws.String(objectKey)}, time.Minute)
		if err != nil {
			log.Printf("Failed attempt to wait for object %s to exist.\n", objectKey)
		}
	}

	return err
}



// DownloadLargeObject uses a download manager to download an object from a bucket.
// The download manager gets the data in parts and writes them to a buffer until all of
// the data has been downloaded.
func (basics BucketBasics) DownloadLargeObject(ctx context.Context, bucketName string, objectKey string) ([]byte, error) {
	var partMiBs int64 = 10
	downloader := manager.NewDownloader(basics.S3Client, func(d *manager.Downloader) {
		d.PartSize = partMiBs * 1024 * 1024
	})
	buffer := manager.NewWriteAtBuffer([]byte{})
	_, err := downloader.Download(ctx, buffer, &s3.GetObjectInput{
		Bucket: aws.String(bucketName),
		Key:    aws.String(objectKey),
	})
	if err != nil {
		log.Printf("Couldn't download large object from %v:%v. Here's why: %v\n",
			bucketName, objectKey, err)
	}
	return buffer.Bytes(), err
}
```
執行互動式情境，示範如何在內容中使用上傳和下載管理員。  

```
import (
	"context"
	"crypto/rand"
	"log"
	"strings"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/awsdocs/aws-doc-sdk-examples/gov2/demotools"
	"github.com/awsdocs/aws-doc-sdk-examples/gov2/s3/actions"
)

// RunLargeObjectScenario is an interactive example that shows you how to use Amazon
// Simple Storage Service (Amazon S3) to upload and download large objects.
//
// 1. Create a bucket.
// 3. Upload a large object to the bucket by using an upload manager.
// 5. Download a large object by using a download manager.
// 8. Delete all objects in the bucket.
// 9. Delete the bucket.
//
// This example creates an Amazon S3 service client from the specified sdkConfig so that
// you can replace it with a mocked or stubbed config for unit testing.
//
// It uses a questioner from the `demotools` package to get input during the example.
// This package can be found in the ..\..\demotools folder of this repo.
func RunLargeObjectScenario(ctx context.Context, sdkConfig aws.Config, questioner demotools.IQuestioner) {
	defer func() {
		if r := recover(); r != nil {
			log.Println("Something went wrong with the demo.")
			_, isMock := questioner.(*demotools.MockQuestioner)
			if isMock || questioner.AskBool("Do you want to see the full error message (y/n)?", "y") {
				log.Println(r)
			}
		}
	}()

	log.Println(strings.Repeat("-", 88))
	log.Println("Welcome to the Amazon S3 large object demo.")
	log.Println(strings.Repeat("-", 88))

	s3Client := s3.NewFromConfig(sdkConfig)
	bucketBasics := actions.BucketBasics{S3Client: s3Client}

	bucketName := questioner.Ask("Let's create a bucket. Enter a name for your bucket:",
		demotools.NotEmpty{})
	bucketExists, err := bucketBasics.BucketExists(ctx, bucketName)
	if err != nil {
		panic(err)
	}
	if !bucketExists {
		err = bucketBasics.CreateBucket(ctx, bucketName, sdkConfig.Region)
		if err != nil {
			panic(err)
		} else {
			log.Println("Bucket created.")
		}
	}
	log.Println(strings.Repeat("-", 88))

	mibs := 30
	log.Printf("Let's create a slice of %v MiB of random bytes and upload it to your bucket. ", mibs)
	questioner.Ask("Press Enter when you're ready.")
	largeBytes := make([]byte, 1024*1024*mibs)
	_, _ = rand.Read(largeBytes)
	largeKey := "doc-example-large"
	log.Println("Uploading...")
	err = bucketBasics.UploadLargeObject(ctx, bucketName, largeKey, largeBytes)
	if err != nil {
		panic(err)
	}
	log.Printf("Uploaded %v MiB object as %v", mibs, largeKey)
	log.Println(strings.Repeat("-", 88))

	log.Printf("Let's download the %v MiB object.", mibs)
	questioner.Ask("Press Enter when you're ready.")
	log.Println("Downloading...")
	largeDownload, err := bucketBasics.DownloadLargeObject(ctx, bucketName, largeKey)
	if err != nil {
		panic(err)
	}
	log.Printf("Downloaded %v bytes.", len(largeDownload))
	log.Println(strings.Repeat("-", 88))

	if questioner.AskBool("Do you want to delete your bucket and all of its "+
		"contents? (y/n)", "y") {
		log.Println("Deleting object.")
		err = bucketBasics.DeleteObjects(ctx, bucketName, []string{largeKey})
		if err != nil {
			panic(err)
		}
		log.Println("Deleting bucket.")
		err = bucketBasics.DeleteBucket(ctx, bucketName)
		if err != nil {
			panic(err)
		}
	} else {
		log.Println("Okay. Don't forget to delete objects from your bucket to avoid charges.")
	}
	log.Println(strings.Repeat("-", 88))

	log.Println("Thanks for watching!")
	log.Println(strings.Repeat("-", 88))
}
```

## 無伺服器範例
<a name="serverless_examples"></a>

### 使用 Amazon S3 觸發條件調用 Lambda 函數
<a name="serverless_S3_Lambda_go_2_topic"></a>

下列程式碼範例示範如何實作 Lambda 函式，該函式接收透過上傳物件至 S3 儲存貯體時所觸發的事件。此函數會從事件參數擷取 S3 儲存貯體名稱和物件金鑰，並呼叫 Amazon S3 API 以擷取和記錄物件的內容類型。

**SDK for Go V2**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在[無伺服器範例](https://github.com/aws-samples/serverless-snippets/tree/main/integration-s3-to-lambda)儲存庫中設定和執行。
使用 Go 搭配 Lambda 來使用 S3 事件。  

```
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
package main

import (
	"context"
	"log"

	"github.com/aws/aws-lambda-go/events"
	"github.com/aws/aws-lambda-go/lambda"
	"github.com/aws/aws-sdk-go-v2/config"
	"github.com/aws/aws-sdk-go-v2/service/s3"
)

func handler(ctx context.Context, s3Event events.S3Event) error {
	sdkConfig, err := config.LoadDefaultConfig(ctx)
	if err != nil {
		log.Printf("failed to load default config: %s", err)
		return err
	}
	s3Client := s3.NewFromConfig(sdkConfig)

	for _, record := range s3Event.Records {
		bucket := record.S3.Bucket.Name
		key := record.S3.Object.URLDecodedKey
		headOutput, err := s3Client.HeadObject(ctx, &s3.HeadObjectInput{
			Bucket: &bucket,
			Key:    &key,
		})
		if err != nil {
			log.Printf("error getting head of object %s/%s: %s", bucket, key, err)
			return err
		}
		log.Printf("successfully retrieved %s/%s of type %s", bucket, key, *headOutput.ContentType)
	}

	return nil
}

func main() {
	lambda.Start(handler)
}
```