s3
Code examples
Explore code examples in the AWS SDK Code Examples Code Library.
Scenarios
Create a photo asset management application that lets users manage photos using labels
Detect objects in images with Amazon Rekognition using an AWS SDK
Get an Amazon S3 object from a Multi-Region Access Point by using an AWS SDK
Api
This module contains the Kotlin SDK client for Amazon Simple Storage Service.
Binary Data
Binary data (streams) are represented as a ByteStream. To supply a ByteStream there are several convenience functions including:
val req = PutObjectRequest {
...
body = ByteStream.fromFile(file)
// body = ByteStream.fromBytes(byteArray)
// body = ByteStream.fromString("string")
}Consuming a ByteStream similarly has easy ways to consume the stream:
s3.getObject(req) { resp -> {
// resp.body is a ByteStream instance
resp.body?.writeToFile(path)
// NOTE: both of these will consume the stream and buffer it entirely in-memory!
// resp.body?.toByteArray()
// resp.body?.decodeToString()
}See GetObjectResponse for more details.
Streaming Responses
Streaming responses are scoped to a block. Instead of returning the response directly, you must pass a lambda which is given access to the response (and the underlying stream). The result of the call is whatever the lambda returns.
val s3 = S3Client { ... }
val req = GetObjectRequest { ... }
val path = Paths.get("/tmp/download.txt")
val contentSize = s3.getObject(req) { resp ->
// resp is valid until the end of the block
// do not attempt to store or process the stream after the block returns
val rc = resp.body?.writeToFile(path)
rc
}
println("wrote $contentSize bytes to $path")This scoped response simplifies lifetime management for both the caller and the runtime.
See getObject for more details.