1769635097.md

applies_to	aws-sdk-rust
authors	ysaito1001
references	smithy-rs#1798 smithy-rs#4188
breaking	false
new_feature	false
bug_fix	true

Add full support for AWS chunked content encoding. AWS chunked content encoding enables streaming sigv4 for payloads without precomputing the sha256 of the entire payload. While this encoding was already used in S3's PutObject and UploadPart operations to support trailing checksums with non-chunked, unsigned streaming payloads, this release now splits streaming payloads into 64 KiB chunks by default (the last chunk may be smaller) and adds support for chunk signing (currently only activated for non-TLS requests).

If the default chunk size does not suit your use case, it can be configured via the service config:

// Custom chunk size
let config = aws_sdk_s3::Config::builder()
    .aws_chunked_encoding_chunk_size(Some(10240)) // 10 KiB chunks
    // other configurations
    .build();
let client = aws_sdk_s3::Client::from_conf(config);

// Disable chunking (buffers entire body in memory and sends it as one chunk)
let config = aws_sdk_s3::Config::builder()
    .aws_chunked_encoding_chunk_size(None)
    // other configurations
    .build();
let client = aws_sdk_s3::Client::from_conf(config);