fix(fixRequestBody): support content-encoding on request body

[robbtraister]

Description

The body-parser package supports the content-encoding header on the request (See here). When reconstructing the body for proxied requests that have already been parsed, we should respect the content-encoding header and preserve the original compression algorithm.

Motivation and Context

Without this patch, an encoded request will fail when the upstream server attempts to read it due to a mismatch between the compression algorithm reported and the actual payload received. An alternative approach would be to remove the content-encoding header from the proxied request, but this seems more appropriate.

How has this been tested?

I added a unit test to verify that the reconstructed body is encoded as expected.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[chimurai]

zlib.zstdCompressSync will throw in older Node versions:

Added in: v23.8.0, v22.15.0

https://nodejs.org/api/zlib.html#zlibzstdcompresssyncbuffer-options

Can you remove zstd support? since it is still experimental

[robbtraister]

sure thing. I noticed that body-parser only supports br, deflate, and gzip, but I thought might as well be more complete if possible. But I agree that better stability is more important.