GetObject 搭配 a AWS SDK 或 CLI 使用

        /// <summary>
        /// Shows how to download an object from an Amazon S3 bucket to the
        /// local computer.
        /// </summary>
        /// <param name="client">An initialized Amazon S3 client object.</param>
        /// <param name="bucketName">The name of the bucket where the object is
        /// currently stored.</param>
        /// <param name="objectName">The name of the object to download.</param>
        /// <param name="filePath">The path, including filename, where the
        /// downloaded object will be stored.</param>
        /// <returns>A boolean value indicating the success or failure of the
        /// download process.</returns>
        public static async Task<bool> DownloadObjectFromBucketAsync(
            IAmazonS3 client,
            string bucketName,
            string objectName,
            string filePath)
        {
            // Create a GetObject request
            var request = new GetObjectRequest
            {
                BucketName = bucketName,
                Key = objectName,
            };

            // Issue request and remember to dispose of the response
            using GetObjectResponse response = await client.GetObjectAsync(request);

            try
            {
                // Save object to local file
                await response.WriteResponseStreamToFileAsync($"{filePath}\\{objectName}", true, CancellationToken.None);
                return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
            }
            catch (AmazonS3Exception ex)
            {
                Console.WriteLine($"Error saving {objectName}: {ex.Message}");
                return false;
            }
        }

###############################################################################
# function errecho
#
# This function outputs everything sent to it to STDERR (standard error output).
###############################################################################
function errecho() {
  printf "%s\n" "$*" 1>&2
}

###############################################################################
# function download_object_from_bucket
#
# This function downloads an object in a bucket to a file.
#
# Parameters:
#       $1 - The name of the bucket to download the object from.
#       $2 - The path and file name to store the downloaded bucket.
#       $3 - The key (name) of the object in the bucket.
#
# Returns:
#       0 - If successful.
#       1 - If it fails.
###############################################################################
function download_object_from_bucket() {
  local bucket_name=$1
  local destination_file_name=$2
  local object_name=$3
  local response

  response=$(aws s3api get-object \
    --bucket "$bucket_name" \
    --key "$object_name" \
    "$destination_file_name")

  # shellcheck disable=SC2181
  if [[ ${?} -ne 0 ]]; then
    errecho "ERROR: AWS reports put-object operation failed.\n$response"
    return 1
  fi
}

bool AwsDoc::S3::getObject(const Aws::String &objectKey,
                           const Aws::String &fromBucket,
                           const Aws::S3::S3ClientConfiguration &clientConfig) {
    Aws::S3::S3Client client(clientConfig);

    Aws::S3::Model::GetObjectRequest request;
    request.SetBucket(fromBucket);
    request.SetKey(objectKey);

    Aws::S3::Model::GetObjectOutcome outcome =
            client.GetObject(request);

    if (!outcome.IsSuccess()) {
        const Aws::S3::S3Error &err = outcome.GetError();
        std::cerr << "Error: getObject: " <<
                  err.GetExceptionName() << ": " << err.GetMessage() << std::endl;
    } else {
        std::cout << "Successfully retrieved '" << objectKey << "' from '"
                  << fromBucket << "'." << std::endl;
    }

    return outcome.IsSuccess();
}

下列範例使用 get-object命令從 Amazon S3 下載物件：

aws s3api get-object --bucket text-content --key dir/my_images.tar.bz2 my_images.tar.bz2

請注意，指定 Outfile 參數時沒有選項名稱，例如 "--outfile"。輸出檔案名稱必須是 命令中的最後一個參數。

以下範例示範使用 --range從物件下載特定位元組範圍。請注意，位元組範圍必須以 "bytes="：

aws s3api get-object --bucket text-content --key dir/my_data --range bytes=8888-9999 my_data_range

如需擷取物件的詳細資訊，請參閱 Amazon S3 開發人員指南中的取得物件。

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
}

使用 S3Client 將資料當作位元組陣列讀取。

    /**
     * Asynchronously retrieves the bytes of an object from an Amazon S3 bucket and writes them to a local file.
     *
     * @param bucketName the name of the S3 bucket containing the object
     * @param keyName    the key (or name) of the S3 object to retrieve
     * @param path       the local file path where the object's bytes will be written
     * @return a {@link CompletableFuture} that completes when the object bytes have been written to the local file
     */
    public CompletableFuture<Void> getObjectBytesAsync(String bucketName, String keyName, String path) {
        GetObjectRequest objectRequest = GetObjectRequest.builder()
            .key(keyName)
            .bucket(bucketName)
            .build();

        CompletableFuture<ResponseBytes<GetObjectResponse>> response = getAsyncClient().getObject(objectRequest, AsyncResponseTransformer.toBytes());
        return response.thenAccept(objectBytes -> {
            try {
                byte[] data = objectBytes.asByteArray();
                Path filePath = Paths.get(path);
                Files.write(filePath, data);
                logger.info("Successfully obtained bytes from an S3 object");
            } catch (IOException ex) {
                throw new RuntimeException("Failed to write data to file", ex);
            }
        }).whenComplete((resp, ex) -> {
            if (ex != null) {
                throw new RuntimeException("Failed to get object bytes from S3", ex);
            }
        });
    }

使用 S3TransferManager 將 S3 儲存貯體中的物件下載至本機檔案。檢視完整檔案並測試。

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import software.amazon.awssdk.core.sync.RequestBody;
import software.amazon.awssdk.transfer.s3.S3TransferManager;
import software.amazon.awssdk.transfer.s3.model.CompletedFileDownload;
import software.amazon.awssdk.transfer.s3.model.DownloadFileRequest;
import software.amazon.awssdk.transfer.s3.model.FileDownload;
import software.amazon.awssdk.transfer.s3.progress.LoggingTransferListener;

import java.io.IOException;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.UUID;

    public Long downloadFile(S3TransferManager transferManager, String bucketName,
                             String key, String downloadedFileWithPath) {
        DownloadFileRequest downloadFileRequest = DownloadFileRequest.builder()
                .getObjectRequest(b -> b.bucket(bucketName).key(key))
                .destination(Paths.get(downloadedFileWithPath))
                .build();

        FileDownload downloadFile = transferManager.downloadFile(downloadFileRequest);

        CompletedFileDownload downloadResult = downloadFile.completionFuture().join();
        logger.info("Content length [{}]", downloadResult.response().contentLength());
        return downloadResult.response().contentLength();
    }

使用 S3Client 讀取屬於某個物件的索引標籤。

import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.GetObjectTaggingRequest;
import software.amazon.awssdk.services.s3.model.GetObjectTaggingResponse;
import software.amazon.awssdk.services.s3.model.S3Exception;
import software.amazon.awssdk.services.s3.model.Tag;

import java.util.List;

/**
 * Before running this Java V2 code example, set up your development
 * environment, including your credentials.
 * <p>
 * For more information, see the following documentation topic:
 * <p>
 * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
 */

public class GetObjectTags {
    public static void main(String[] args) {
        final String usage = """

            Usage:
                <bucketName> <keyName>\s

            Where:
                bucketName - The Amazon S3 bucket name.\s
                keyName - A key name that represents the object.\s
            """;

        if (args.length != 2) {
            System.out.println(usage);
            System.exit(1);
        }

        String bucketName = args[0];
        String keyName = args[1];
        Region region = Region.US_EAST_1;
        S3Client s3 = S3Client.builder()
            .region(region)
            .build();

        listTags(s3, bucketName, keyName);
        s3.close();
    }

    /**
     * Lists the tags associated with an Amazon S3 object.
     *
     * @param s3 the S3Client object used to interact with the Amazon S3 service
     * @param bucketName the name of the S3 bucket that contains the object
     * @param keyName the key (name) of the S3 object
     */
    public static void listTags(S3Client s3, String bucketName, String keyName) {
        try {
            GetObjectTaggingRequest getTaggingRequest = GetObjectTaggingRequest
                .builder()
                .key(keyName)
                .bucket(bucketName)
                .build();

            GetObjectTaggingResponse tags = s3.getObjectTagging(getTaggingRequest);
            List<Tag> tagSet = tags.tagSet();
            for (Tag tag : tagSet) {
                System.out.println(tag.key());
                System.out.println(tag.value());
            }

        } catch (S3Exception e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }
}

使用 S3Client 取得物件的 URL。

import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.GetUrlRequest;
import software.amazon.awssdk.services.s3.model.S3Exception;

import java.net.URL;

/**
 * Before running this Java V2 code example, set up your development
 * environment, including your credentials.
 * <p>
 * For more information, see the following documentation topic:
 * <p>
 * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
 */

public class GetObjectUrl {
    public static void main(String[] args) {
        final String usage = """

            Usage:
                <bucketName> <keyName>\s

            Where:
                bucketName - The Amazon S3 bucket name.
                keyName - A key name that represents the object.\s
            """;

        if (args.length != 2) {
            System.out.println(usage);
            System.exit(1);
        }

        String bucketName = args[0];
        String keyName = args[1];
        Region region = Region.US_EAST_1;
        S3Client s3 = S3Client.builder()
            .region(region)
            .build();

        getURL(s3, bucketName, keyName);
        s3.close();
    }

    /**
     * Retrieves the URL for a specific object in an Amazon S3 bucket.
     *
     * @param s3 the S3Client object used to interact with the Amazon S3 service
     * @param bucketName the name of the S3 bucket where the object is stored
     * @param keyName the name of the object for which the URL should be retrieved
     * @throws S3Exception if there is an error retrieving the URL for the specified object
     */
    public static void getURL(S3Client s3, String bucketName, String keyName) {
        try {
            GetUrlRequest request = GetUrlRequest.builder()
                .bucket(bucketName)
                .key(keyName)
                .build();

            URL url = s3.utilities().getUrl(request);
            System.out.println("The URL for  " + keyName + " is " + url);

        } catch (S3Exception e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }
}

使用 S3Client 透過使用 S3Presigner 用戶端物件取得物件。

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.time.Duration;

import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.model.GetObjectRequest;
import software.amazon.awssdk.services.s3.model.S3Exception;
import software.amazon.awssdk.services.s3.presigner.model.GetObjectPresignRequest;
import software.amazon.awssdk.services.s3.presigner.model.PresignedGetObjectRequest;
import software.amazon.awssdk.services.s3.presigner.S3Presigner;
import software.amazon.awssdk.utils.IoUtils;

/**
 * Before running this Java V2 code example, set up your development
 * environment, including your credentials.
 * <p>
 * For more information, see the following documentation topic:
 * <p>
 * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
 */
public class GetObjectPresignedUrl {
    public static void main(String[] args) {
        final String USAGE = """

            Usage:
                <bucketName> <keyName>\s

            Where:
                bucketName - The Amazon S3 bucket name.\s
                keyName - A key name that represents a text file.\s
            """;

        if (args.length != 2) {
            System.out.println(USAGE);
            System.exit(1);
        }

        String bucketName = args[0];
        String keyName = args[1];
        Region region = Region.US_EAST_1;
        S3Presigner presigner = S3Presigner.builder()
            .region(region)
            .build();

        getPresignedUrl(presigner, bucketName, keyName);
        presigner.close();
    }

    /**
     * Generates a pre-signed URL for an Amazon S3 object.
     *
     * @param presigner The {@link S3Presigner} instance to use for generating the pre-signed URL.
     * @param bucketName The name of the Amazon S3 bucket where the object is stored.
     * @param keyName The key name (file name) of the object in the Amazon S3 bucket.
     *
     * @throws S3Exception If there is an error interacting with the Amazon S3 service.
     * @throws IOException If there is an error opening the HTTP connection or reading/writing the request/response.
     */
    public static void getPresignedUrl(S3Presigner presigner, String bucketName, String keyName) {
        try {
            GetObjectRequest getObjectRequest = GetObjectRequest.builder()
                .bucket(bucketName)
                .key(keyName)
                .build();

            GetObjectPresignRequest getObjectPresignRequest = GetObjectPresignRequest.builder()
                .signatureDuration(Duration.ofMinutes(60))
                .getObjectRequest(getObjectRequest)
                .build();

            PresignedGetObjectRequest presignedGetObjectRequest = presigner.presignGetObject(getObjectPresignRequest);
            String theUrl = presignedGetObjectRequest.url().toString();
            System.out.println("Presigned URL: " + theUrl);
            HttpURLConnection connection = (HttpURLConnection) presignedGetObjectRequest.url().openConnection();
            presignedGetObjectRequest.httpRequest().headers().forEach((header, values) -> {
                values.forEach(value -> {
                    connection.addRequestProperty(header, value);
                });
            });

            // Send any request payload that the service needs (not needed when
            // isBrowserExecutable is true).
            if (presignedGetObjectRequest.signedPayload().isPresent()) {
                connection.setDoOutput(true);

                try (InputStream signedPayload = presignedGetObjectRequest.signedPayload().get().asInputStream();
                     OutputStream httpOutputStream = connection.getOutputStream()) {
                    IoUtils.copy(signedPayload, httpOutputStream);
                }
            }

            // Download the result of executing the request.
            try (InputStream content = connection.getInputStream()) {
                System.out.println("Service returned response: ");
                IoUtils.copy(content, System.out);
            }

        } catch (S3Exception | IOException e) {
            e.getStackTrace();
        }
    }
}

使用 a ResponseTransformer 物件和 S3Client 取得物件。

import software.amazon.awssdk.core.ResponseBytes;
import software.amazon.awssdk.core.sync.ResponseTransformer;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.GetObjectRequest;
import software.amazon.awssdk.services.s3.model.S3Exception;
import software.amazon.awssdk.services.s3.model.GetObjectResponse;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;

/**
 * Before running this Java V2 code example, set up your development
 * environment, including your credentials.
 * <p>
 * For more information, see the following documentation topic:
 * <p>
 * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
 */

public class GetObjectData {
    public static void main(String[] args) {
        final String usage = """

            Usage:
                <bucketName> <keyName> <path>

            Where:
                bucketName - The Amazon S3 bucket name.\s
                keyName - The key name.\s
                path - The path where the file is written to.\s
            """;

        if (args.length != 3) {
            System.out.println(usage);
            System.exit(1);
        }

        String bucketName = args[0];
        String keyName = args[1];
        String path = args[2];
        Region region = Region.US_EAST_1;
        S3Client s3 = S3Client.builder()
            .region(region)
            .build();

        getObjectBytes(s3, bucketName, keyName, path);
        s3.close();
    }

    /**
     * Retrieves the bytes of an object stored in an Amazon S3 bucket and saves them to a local file.
     *
     * @param s3 The S3Client instance used to interact with the Amazon S3 service.
     * @param bucketName The name of the S3 bucket where the object is stored.
     * @param keyName The key (or name) of the S3 object.
     * @param path The local file path where the object's bytes will be saved.
     * @throws IOException If an I/O error occurs while writing the bytes to the local file.
     * @throws S3Exception If an error occurs while retrieving the object from the S3 bucket.
     */
    public static void getObjectBytes(S3Client s3, String bucketName, String keyName, String path) {
        try {
            GetObjectRequest objectRequest = GetObjectRequest
                .builder()
                .key(keyName)
                .bucket(bucketName)
                .build();

            ResponseBytes<GetObjectResponse> objectBytes = s3.getObject(objectRequest, ResponseTransformer.toBytes());
            byte[] data = objectBytes.asByteArray();

            // Write the data to a local file.
            File myFile = new File(path);
            OutputStream os = new FileOutputStream(myFile);
            os.write(data);
            System.out.println("Successfully obtained bytes from an S3 object");
            os.close();

        } catch (IOException ex) {
            ex.printStackTrace();
        } catch (S3Exception e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }
}

下載物件。

import {
  GetObjectCommand,
  NoSuchKey,
  S3Client,
  S3ServiceException,
} from "@aws-sdk/client-s3";

/**
 * Get a single object from a specified S3 bucket.
 * @param {{ bucketName: string, key: string }}
 */
export const main = async ({ bucketName, key }) => {
  const client = new S3Client({});

  try {
    const response = await client.send(
      new GetObjectCommand({
        Bucket: bucketName,
        Key: key,
      }),
    );
    // The Body object also has 'transformToByteArray' and 'transformToWebStream' methods.
    const str = await response.Body.transformToString();
    console.log(str);
  } catch (caught) {
    if (caught instanceof NoSuchKey) {
      console.error(
        `Error from S3 while getting object "${key}" from "${bucketName}". No such key exists.`,
      );
    } else if (caught instanceof S3ServiceException) {
      console.error(
        `Error from S3 while getting object from ${bucketName}.  ${caught.name}: ${caught.message}`,
      );
    } else {
      throw caught;
    }
  }
};

suspend fun getObjectBytes(
    bucketName: String,
    keyName: String,
    path: String,
) {
    val request =
        GetObjectRequest {
            key = keyName
            bucket = bucketName
        }

    S3Client { region = "us-east-1" }.use { s3 ->
        s3.getObject(request) { resp ->
            val myFile = File(path)
            resp.body?.writeToFile(myFile)
            println("Successfully read $keyName from $bucketName")
        }
    }
}

取得物件。

        $s3client = new Aws\S3\S3Client(['region' => 'us-west-2']);

        try {
            $file = $this->s3client->getObject([
                'Bucket' => $this->bucketName,
                'Key' => $fileName,
            ]);
            $body = $file->get('Body');
            $body->rewind();
            echo "Downloaded the file and it begins with: {$body->read(26)}.\n";
        } catch (Exception $exception) {
            echo "Failed to download $fileName from $this->bucketName with error: " . $exception->getMessage();
            exit("Please fix error with file downloading before continuing.");
        }

範例 1：此命令會從儲存貯體 "test-files" 擷取項目 "sample.txt"，並將其儲存至目前位置名為 "local-sample.txt" 的檔案。檔案 "local-sample.txt" 不必存在，即可呼叫此命令。

Read-S3Object -BucketName amzn-s3-demo-bucket -Key sample.txt -File local-sample.txt

範例 2：此命令會從儲存貯體 "test-files" 擷取虛擬目錄 "DIR"，並將其儲存至目前位置中名為 "Local-DIR" 的資料夾。呼叫此命令之前，資料夾「Local-DIR」不必存在。

Read-S3Object -BucketName amzn-s3-demo-bucket -KeyPrefix DIR -Folder Local-DIR

範例 3：將鍵以 '.json' 結尾的所有物件，從儲存貯體名稱中具有 'config' 的儲存貯體下載到指定資料夾中的檔案。物件金鑰用於設定檔案名稱。

Get-S3Bucket | ? { $_.BucketName -like '*config*' } | Get-S3Object | ? { $_.Key -like '*.json' } | Read-S3Object -Folder C:\ConfigObjects

class ObjectWrapper:
    """Encapsulates S3 object actions."""

    def __init__(self, s3_object):
        """
        :param s3_object: A Boto3 Object resource. This is a high-level resource in Boto3
                          that wraps object actions in a class-like structure.
        """
        self.object = s3_object
        self.key = self.object.key


    def get(self):
        """
        Gets the object.

        :return: The object data in bytes.
        """
        try:
            body = self.object.get()["Body"].read()
            logger.info(
                "Got object '%s' from bucket '%s'.",
                self.object.key,
                self.object.bucket_name,
            )
        except ClientError:
            logger.exception(
                "Couldn't get object '%s' from bucket '%s'.",
                self.object.key,
                self.object.bucket_name,
            )
            raise
        else:
            return body

使用條件式請求取得物件。

class S3ConditionalRequests:
    """Encapsulates S3 conditional request operations."""

    def __init__(self, s3_client):
        self.s3 = s3_client

    @classmethod
    def from_client(cls):
        """
        Instantiates this class from a Boto3 client.
        """
        s3_client = boto3.client("s3")
        return cls(s3_client)



    def get_object_conditional(
        self,
        object_key: str,
        source_bucket: str,
        condition_type: str,
        condition_value: str,
    ):
        """
        Retrieves an object from Amazon S3 with a conditional request.

        :param object_key: The key of the object to retrieve.
        :param source_bucket: The source bucket of the object.
        :param condition_type: The type of condition: 'IfMatch', 'IfNoneMatch', 'IfModifiedSince', 'IfUnmodifiedSince'.
        :param condition_value: The value to use for the condition.
        """
        try:
            response = self.s3.get_object(
                Bucket=source_bucket,
                Key=object_key,
                **{condition_type: condition_value},
            )
            sample_bytes = response["Body"].read(20)
            print(
                f"\tConditional read successful. Here are the first 20 bytes of the object:\n"
            )
            print(f"\t{sample_bytes}")
        except ClientError as e:
            error_code = e.response["Error"]["Code"]
            if error_code == "PreconditionFailed":
                print("\tConditional read failed: Precondition failed")
            elif error_code == "304":  # Not modified error code.
                print("\tConditional read failed: Object not modified")
            else:
                logger.error(f"Unexpected error: {error_code}")
                raise

取得物件。

require 'aws-sdk-s3'

# Wraps Amazon S3 object actions.
class ObjectGetWrapper
  attr_reader :object

  # @param object [Aws::S3::Object] An existing Amazon S3 object.
  def initialize(object)
    @object = object
  end

  # Gets the object directly to a file.
  #
  # @param target_path [String] The path to the file where the object is downloaded.
  # @return [Aws::S3::Types::GetObjectOutput, nil] The retrieved object data if successful; otherwise nil.
  def get_object(target_path)
    @object.get(response_target: target_path)
  rescue Aws::Errors::ServiceError => e
    puts "Couldn't get object #{@object.key}. Here's why: #{e.message}"
  end
end

# Example usage:
def run_demo
  bucket_name = "amzn-s3-demo-bucket"
  object_key = "my-object.txt"
  target_path = "my-object-as-file.txt"

  wrapper = ObjectGetWrapper.new(Aws::S3::Object.new(bucket_name, object_key))
  obj_data = wrapper.get_object(target_path)
  return unless obj_data

  puts "Object #{object_key} (#{obj_data.content_length} bytes} downloaded to #{target_path}."
end

run_demo if $PROGRAM_NAME == __FILE__

取得物件並報告其伺服器端的加密狀態。

require 'aws-sdk-s3'

# Wraps Amazon S3 object actions.
class ObjectGetEncryptionWrapper
  attr_reader :object

  # @param object [Aws::S3::Object] An existing Amazon S3 object.
  def initialize(object)
    @object = object
  end

  # Gets the object into memory.
  #
  # @return [Aws::S3::Types::GetObjectOutput, nil] The retrieved object data if successful; otherwise nil.
  def object
    @object.get
  rescue Aws::Errors::ServiceError => e
    puts "Couldn't get object #{@object.key}. Here's why: #{e.message}"
  end
end

# Example usage:
def run_demo
  bucket_name = "amzn-s3-demo-bucket"
  object_key = "my-object.txt"

  wrapper = ObjectGetEncryptionWrapper.new(Aws::S3::Object.new(bucket_name, object_key))
  obj_data = wrapper.get_object
  return unless obj_data

  encryption = obj_data.server_side_encryption.nil? ? 'no' : obj_data.server_side_encryption
  puts "Object #{object_key} uses #{encryption} encryption."
end

run_demo if $PROGRAM_NAME == __FILE__

async fn get_object(client: Client, opt: Opt) -> Result<usize, S3ExampleError> {
    trace!("bucket:      {}", opt.bucket);
    trace!("object:      {}", opt.object);
    trace!("destination: {}", opt.destination.display());

    let mut file = File::create(opt.destination.clone()).map_err(|err| {
        S3ExampleError::new(format!(
            "Failed to initialize file for saving S3 download: {err:?}"
        ))
    })?;

    let mut object = client
        .get_object()
        .bucket(opt.bucket)
        .key(opt.object)
        .send()
        .await?;

    let mut byte_count = 0_usize;
    while let Some(bytes) = object.body.try_next().await.map_err(|err| {
        S3ExampleError::new(format!("Failed to read from S3 download stream: {err:?}"))
    })? {
        let bytes_len = bytes.len();
        file.write_all(&bytes).map_err(|err| {
            S3ExampleError::new(format!(
                "Failed to write from S3 download stream to local file: {err:?}"
            ))
        })?;
        trace!("Intermediate write of {bytes_len}");
        byte_count += bytes_len;
    }

    Ok(byte_count)
}

    TRY.
        oo_result = lo_s3->getobject(           " oo_result is returned for testing purposes. "
                  iv_bucket = iv_bucket_name
                  iv_key = iv_object_key
               ).
        DATA(lv_object_data) = oo_result->get_body( ).
        MESSAGE 'Object retrieved from S3 bucket.' TYPE 'I'.
      CATCH /aws1/cx_s3_nosuchbucket.
        MESSAGE 'Bucket does not exist.' TYPE 'E'.
      CATCH /aws1/cx_s3_nosuchkey.
        MESSAGE 'Object key does not exist.' TYPE 'E'.
    ENDTRY.

import AWSS3

    public func downloadFile(bucket: String, key: String, to: String) async throws {
        let fileUrl = URL(fileURLWithPath: to).appendingPathComponent(key)

        let input = GetObjectInput(
            bucket: bucket,
            key: key
        )
        do {
            let output = try await client.getObject(input: input)

            guard let body = output.body else {
                throw HandlerError.getObjectBody("GetObjectInput missing body.")
            }

            guard let data = try await body.readData() else {
                throw HandlerError.readGetObjectBody("GetObjectInput unable to read data.")
            }

            try data.write(to: fileUrl)
        }
        catch {
            print("ERROR: ", dump(error, name: "Downloading a file."))
            throw error
        }
    }

import AWSS3

    public func readFile(bucket: String, key: String) async throws -> Data {
        let input = GetObjectInput(
            bucket: bucket,
            key: key
        )
        do {
            let output = try await client.getObject(input: input)
            
            guard let body = output.body else {
                throw HandlerError.getObjectBody("GetObjectInput missing body.")
            }

            guard let data = try await body.readData() else {
                throw HandlerError.readGetObjectBody("GetObjectInput unable to read data.")
            }

            return data
        }
        catch {
            print("ERROR: ", dump(error, name: "Reading a file."))
            throw error
        }
   }