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Ciro Spaciari 5d3f37d7ae feat(s3): add Content-Encoding header support for S3 uploads (#26149)
## Summary

Add support for setting the `Content-Encoding` header in S3 `.write()`
and `.writer()` calls, following the same pattern as
`Content-Disposition`.

This allows users to specify the encoding of uploaded content:

```typescript
// With .write()
await s3file.write("compressed data", { contentEncoding: "gzip" });

// With .writer()
const writer = s3file.writer({ contentEncoding: "gzip" });
writer.write("compressed data");
await writer.end();

// With bucket.write()
await bucket.write("key", data, { contentEncoding: "br" });
```

## Implementation

- Extended `SignedHeaders.Key` from 6 bits to 7 bits (64→128
combinations) to accommodate the new header
- Added `content_encoding` to `S3CredentialsWithOptions`, `SignOptions`,
and `SignResult` structs
- Updated `CanonicalRequest` format strings to include
`content-encoding` in AWS SigV4 signing
- Added `getContentEncoding()` method to `Headers` for fetch-based S3
uploads
- Expanded `_headers` array from 9 to 10 elements
- Pass `content_encoding` through all S3 upload paths (upload,
uploadStream, writableStream)

## Test plan

- Added tests for "should be able to set content-encoding" 
- Added tests for "should be able to set content-encoding in writer"
- Tests verify the Content-Encoding header is properly set on uploaded
objects via presigned URL fetch
- All 4 new tests pass with `bun bd test` and fail with
`USE_SYSTEM_BUN=1` (confirming the feature is new)

## Changelog

> Describe your changes in 1-2 sentences. These will be featured on
[bun.sh/blog](https://bun.sh/blog) and Bun's release notes.

Added `contentEncoding` option to S3 `.write()` and `.writer()` methods,
allowing users to set the `Content-Encoding` header when uploading
objects.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
2026-01-15 18:09:33 -08:00
..
2025-07-21 13:26:47 -07:00