SDK for Kotlin を使用した Amazon S3 の例

suspend fun main(args: Array<String>) {
    val usage = """
    Usage:
        <bucketName> <key> <objectPath> <savePath> <toBucket>

    Where:
        bucketName - The Amazon S3 bucket to create.
        key - The key to use.
        objectPath - The path where the file is located (for example, C:/AWS/book2.pdf).   
        savePath - The path where the file is saved after it's downloaded (for example, C:/AWS/book2.pdf).     
        toBucket - An Amazon S3 bucket to where an object is copied to (for example, C:/AWS/book2.pdf). 
        """

    if (args.size != 4) {
        println(usage)
        exitProcess(1)
    }

    val bucketName = args[0]
    val key = args[1]
    val objectPath = args[2]
    val savePath = args[3]
    val toBucket = args[4]

    // Create an Amazon S3 bucket.
    createBucket(bucketName)

    // Update a local file to the Amazon S3 bucket.
    putObject(bucketName, key, objectPath)

    // Download the object to another local file.
    getObjectFromMrap(bucketName, key, savePath)

    // List all objects located in the Amazon S3 bucket.
    listBucketObs(bucketName)

    // Copy the object to another Amazon S3 bucket
    copyBucketOb(bucketName, key, toBucket)

    // Delete the object from the Amazon S3 bucket.
    deleteBucketObs(bucketName, key)

    // Delete the Amazon S3 bucket.
    deleteBucket(bucketName)
    println("All Amazon S3 operations were successfully performed")
}

suspend fun createBucket(bucketName: String) {
    val request =
        CreateBucketRequest {
            bucket = bucketName
        }

    S3Client { region = "us-east-1" }.use { s3 ->
        s3.createBucket(request)
        println("$bucketName is ready")
    }
}

suspend fun putObject(
    bucketName: String,
    objectKey: String,
    objectPath: String,
) {
    val metadataVal = mutableMapOf<String, String>()
    metadataVal["myVal"] = "test"

    val request =
        PutObjectRequest {
            bucket = bucketName
            key = objectKey
            metadata = metadataVal
            this.body = Paths.get(objectPath).asByteStream()
        }

    S3Client { region = "us-east-1" }.use { s3 ->
        val response = s3.putObject(request)
        println("Tag information is ${response.eTag}")
    }
}

suspend fun getObjectFromMrap(
    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")
        }
    }
}

suspend fun listBucketObs(bucketName: String) {
    val request =
        ListObjectsRequest {
            bucket = bucketName
        }

    S3Client { region = "us-east-1" }.use { s3 ->

        val response = s3.listObjects(request)
        response.contents?.forEach { myObject ->
            println("The name of the key is ${myObject.key}")
            println("The owner is ${myObject.owner}")
        }
    }
}

suspend fun copyBucketOb(
    fromBucket: String,
    objectKey: String,
    toBucket: String,
) {
    var encodedUrl = ""
    try {
        encodedUrl = URLEncoder.encode("$fromBucket/$objectKey", StandardCharsets.UTF_8.toString())
    } catch (e: UnsupportedEncodingException) {
        println("URL could not be encoded: " + e.message)
    }

    val request =
        CopyObjectRequest {
            copySource = encodedUrl
            bucket = toBucket
            key = objectKey
        }
    S3Client { region = "us-east-1" }.use { s3 ->
        s3.copyObject(request)
    }
}

suspend fun deleteBucketObs(
    bucketName: String,
    objectName: String,
) {
    val objectId =
        ObjectIdentifier {
            key = objectName
        }

    val delOb =
        Delete {
            objects = listOf(objectId)
        }

    val request =
        DeleteObjectsRequest {
            bucket = bucketName
            delete = delOb
        }

    S3Client { region = "us-east-1" }.use { s3 ->
        s3.deleteObjects(request)
        println("$objectName was deleted from $bucketName")
    }
}

suspend fun deleteBucket(bucketName: String?) {
    val request =
        DeleteBucketRequest {
            bucket = bucketName
        }
    S3Client { region = "us-east-1" }.use { s3 ->
        s3.deleteBucket(request)
        println("The $bucketName was successfully deleted!")
    }
}

suspend fun copyBucketObject(
    fromBucket: String,
    objectKey: String,
    toBucket: String,
) {
    var encodedUrl = ""
    try {
        encodedUrl = URLEncoder.encode("$fromBucket/$objectKey", StandardCharsets.UTF_8.toString())
    } catch (e: UnsupportedEncodingException) {
        println("URL could not be encoded: " + e.message)
    }

    val request =
        CopyObjectRequest {
            copySource = encodedUrl
            bucket = toBucket
            key = objectKey
        }
    S3Client { region = "us-east-1" }.use { s3 ->
        s3.copyObject(request)
    }
}

suspend fun createNewBucket(bucketName: String) {
    val request =
        CreateBucketRequest {
            bucket = bucketName
        }

    S3Client { region = "us-east-1" }.use { s3 ->
        s3.createBucket(request)
        println("$bucketName is ready")
    }
}

us-west-2 リージョンにリクエストを送信するように S3 コントロールクライアントを設定します。

        suspend fun createS3ControlClient(): S3ControlClient {
            // Configure your S3ControlClient to send requests to US West (Oregon).
            val s3Control = S3ControlClient.fromEnvironment {
                region = "us-west-2"
            }
            return s3Control
        }

マルチリージョンアクセスポイントを作成します。

    suspend fun createMrap(
        s3Control: S3ControlClient,
        accountIdParam: String,
        bucketName1: String,
        bucketName2: String,
        mrapName: String,
    ): String {
        println("Creating MRAP ...")
        val createMrapResponse: CreateMultiRegionAccessPointResponse =
            s3Control.createMultiRegionAccessPoint {
                accountId = accountIdParam
                clientToken = UUID.randomUUID().toString()
                details {
                    name = mrapName
                    regions = listOf(
                        Region {
                            bucket = bucketName1
                        },
                        Region {
                            bucket = bucketName2
                        },
                    )
                }
            }
        val requestToken: String? = createMrapResponse.requestTokenArn

        // Use the request token to check for the status of the CreateMultiRegionAccessPoint operation.
        if (requestToken != null) {
            waitForSucceededStatus(s3Control, requestToken, accountIdParam)
            println("MRAP created")
        }

        val getMrapResponse =
            s3Control.getMultiRegionAccessPoint(
                input = GetMultiRegionAccessPointRequest {
                    accountId = accountIdParam
                    name = mrapName
                },
            )
        val mrapAlias = getMrapResponse.accessPoint?.alias
        return "arn:aws:s3::$accountIdParam:accesspoint/$mrapAlias"
    }

マルチリージョンアクセスポイントが使用可能になるまで待ちます。

        suspend fun waitForSucceededStatus(
            s3Control: S3ControlClient,
            requestToken: String,
            accountIdParam: String,
            timeBetweenChecks: Duration = 1.minutes,
        ) {
            var describeResponse: DescribeMultiRegionAccessPointOperationResponse
            describeResponse = s3Control.describeMultiRegionAccessPointOperation(
                input = DescribeMultiRegionAccessPointOperationRequest {
                    accountId = accountIdParam
                    requestTokenArn = requestToken
                },
            )

            var status: String? = describeResponse.asyncOperation?.requestStatus
            while (status != "SUCCEEDED") {
                delay(timeBetweenChecks)
                describeResponse = s3Control.describeMultiRegionAccessPointOperation(
                    input = DescribeMultiRegionAccessPointOperationRequest {
                        accountId = accountIdParam
                        requestTokenArn = requestToken
                    },
                )
                status = describeResponse.asyncOperation?.requestStatus
                println(status)
            }
        }

suspend fun deleteS3BucketPolicy(bucketName: String?) {
    val request =
        DeleteBucketPolicyRequest {
            bucket = bucketName
        }

    S3Client { region = "us-east-1" }.use { s3 ->
        s3.deleteBucketPolicy(request)
        println("Done!")
    }
}

suspend fun deleteBucketObjects(
    bucketName: String,
    objectName: String,
) {
    val objectId =
        ObjectIdentifier {
            key = objectName
        }

    val delOb =
        Delete {
            objects = listOf(objectId)
        }

    val request =
        DeleteObjectsRequest {
            bucket = bucketName
            delete = delOb
        }

    S3Client { region = "us-east-1" }.use { s3 ->
        s3.deleteObjects(request)
        println("$objectName was deleted from $bucketName")
    }
}

suspend fun getPolicy(bucketName: String): String? {
    println("Getting policy for bucket $bucketName")

    val request =
        GetBucketPolicyRequest {
            bucket = bucketName
        }

    S3Client { region = "us-east-1" }.use { s3 ->
        val policyRes = s3.getBucketPolicy(request)
        return policyRes.policy
    }
}

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")
        }
    }
}

suspend fun getBucketACL(
    objectKey: String,
    bucketName: String,
) {
    val request =
        GetObjectAclRequest {
            bucket = bucketName
            key = objectKey
        }

    S3Client { region = "us-east-1" }.use { s3 ->
        val response = s3.getObjectAcl(request)
        response.grants?.forEach { grant ->
            println("Grant permission is ${grant.permission}")
        }
    }
}

suspend fun listBucketObjects(bucketName: String) {
    val request =
        ListObjectsRequest {
            bucket = bucketName
        }

    S3Client { region = "us-east-1" }.use { s3 ->
        val response = s3.listObjects(request)
        response.contents?.forEach { myObject ->
            println("The name of the key is ${myObject.key}")
            println("The object is ${myObject.size?.let { calKb(it) }} KBs")
            println("The owner is ${myObject.owner}")
        }
    }
}

private fun calKb(intValue: Long): Long = intValue / 1024

suspend fun setBucketAcl(
    bucketName: String,
    idVal: String,
) {
    val myGrant =
        Grantee {
            id = idVal
            type = Type.CanonicalUser
        }

    val ownerGrant =
        Grant {
            grantee = myGrant
            permission = Permission.FullControl
        }

    val grantList = mutableListOf<Grant>()
    grantList.add(ownerGrant)

    val ownerOb =
        Owner {
            id = idVal
        }

    val acl =
        AccessControlPolicy {
            owner = ownerOb
            grants = grantList
        }

    val request =
        PutBucketAclRequest {
            bucket = bucketName
            accessControlPolicy = acl
        }

    S3Client { region = "us-east-1" }.use { s3 ->
        s3.putBucketAcl(request)
        println("An ACL was successfully set on $bucketName")
    }
}

suspend fun putS3Object(
    bucketName: String,
    objectKey: String,
    objectPath: String,
) {
    val metadataVal = mutableMapOf<String, String>()
    metadataVal["myVal"] = "test"

    val request =
        PutObjectRequest {
            bucket = bucketName
            key = objectKey
            metadata = metadataVal
            body = File(objectPath).asByteStream()
        }

    S3Client { region = "us-east-1" }.use { s3 ->
        val response = s3.putObject(request)
        println("Tag information is ${response.eTag}")
    }
}

署名GetObject付きリクエストを作成し、 URL を使用してオブジェクトをダウンロードします。

suspend fun getObjectPresigned(
    s3: S3Client,
    bucketName: String,
    keyName: String,
): String {
    // Create a GetObjectRequest.
    val unsignedRequest =
        GetObjectRequest {
            bucket = bucketName
            key = keyName
        }

    // Presign the GetObject request.
    val presignedRequest = s3.presignGetObject(unsignedRequest, 24.hours)

    // Use the URL from the presigned HttpRequest in a subsequent HTTP GET request to retrieve the object.
    val objectContents = URL(presignedRequest.url.toString()).readText()

    return objectContents
}

詳細オプションを使用して GetObject 署名済みリクエストを作成します。

suspend fun getObjectPresignedMoreOptions(
    s3: S3Client,
    bucketName: String,
    keyName: String,
): HttpRequest {
    // Create a GetObjectRequest.
    val unsignedRequest =
        GetObjectRequest {
            bucket = bucketName
            key = keyName
        }

    // Presign the GetObject request.
    val presignedRequest =
        s3.presignGetObject(unsignedRequest, signer = CrtAwsSigner) {
            signingDate = Instant.now() + 12.hours // Presigned request can be used 12 hours from now.
            algorithm = AwsSigningAlgorithm.SIGV4_ASYMMETRIC
            signatureType = AwsSignatureType.HTTP_REQUEST_VIA_QUERY_PARAMS
            expiresAfter = 8.hours // Presigned request expires 8 hours later.
        }
    return presignedRequest
}

PutObject の署名済みリクエストを作成し、それを使用してオブジェクトをアップロードします。

suspend fun putObjectPresigned(
    s3: S3Client,
    bucketName: String,
    keyName: String,
    content: String,
) {
    // Create a PutObjectRequest.
    val unsignedRequest =
        PutObjectRequest {
            bucket = bucketName
            key = keyName
        }

    // Presign the request.
    val presignedRequest = s3.presignPutObject(unsignedRequest, 24.hours)

    // Use the URL and any headers from the presigned HttpRequest in a subsequent HTTP PUT request to retrieve the object.
    // Create a PUT request using the OKHttpClient API.
    val putRequest =
        Request
            .Builder()
            .url(presignedRequest.url.toString())
            .apply {
                presignedRequest.headers.forEach { key, values ->
                    header(key, values.joinToString(", "))
                }
            }.put(content.toRequestBody())
            .build()

    val response = OkHttpClient().newCall(putRequest).execute()
    assert(response.isSuccessful)
}

Amazon Rekognition を使用して画像内のラベルを検出し、保存して後で取得できるようにする写真アセット管理アプリケーションの開発方法を示します。

完全なソースコードと、セットアップと実行の手順については、 GitHub「」の詳細な例を参照してください。

この例のソースについて詳しくは、AWS  コミュニティでブログ投稿を参照してください。

Amazon Rekognition Kotlin を使用してAmazon Rekognition を使用して Amazon Simple Storage Service (Amazon S3) バケットにあるイメージ内のオブジェクトをカテゴリ別に識別するアプリケーションAPIを作成する方法を示します。アプリは、Amazon Simple Email Service (Amazon ) を使用して、結果を含む E メール通知を管理者に送信しますSES。

完全なソースコードと、セットアップと実行の手順については、「」の詳細な例を参照してくださいGitHub。

非対称 Sigv4 (Sigv4a) 署名アルゴリズムを使用するように S3 クライアントを設定します。

        suspend fun createS3Client(): S3Client {
            // Configure your S3Client to use the Asymmetric Sigv4 (Sigv4a) signing algorithm.
            val sigV4AScheme = SigV4AsymmetricAuthScheme(CrtAwsSigner)
            val s3 = S3Client.fromEnvironment {
                authSchemes = listOf(sigV4AScheme)
            }
            return s3
        }

バケット名ARNの代わりにマルチリージョンアクセスポイントを使用して、オブジェクトを取得します。

    suspend fun getObjectFromMrap(
        s3: S3Client,
        mrapArn: String,
        keyName: String,
    ): String? {
        val request = GetObjectRequest {
            bucket = mrapArn // Use the ARN instead of the bucket name for object operations.
            key = keyName
        }

        var stringObj: String? = null
        s3.getObject(request) { resp ->
            stringObj = resp.body?.decodeToString()
            if (stringObj != null) {
                println("Successfully read $keyName from $mrapArn")
            }
        }
        return stringObj
    }