Fixes server ignores request to gzip data

[rose2221]

What type of PR is this?

Bug fix

What does this PR do? Why is it needed?

This PR fixes an issue where the Prysm beacon chain server ignores the Accept-Encoding: gzip header in HTTP requests and always returns uncompressed JSON responses.

Fix Details:

• Updated middleware to properly respect the Accept-Encoding header.
• Ensured that responses are compressed when requested.
• Added error handling to prevent silent failures.

Which issue(s) does this PR fix?

Fixes #14593

Other Notes for Review

Acknowledgements

• [✅] I have read CONTRIBUTING.md.
• [✅] I have included a uniquely named changelog fragment file.
• [✅] I have added a description to this PR with sufficient context for reviewers to understand this PR.

[CLAassistant]

All committers have signed the CLA.

[rkapka]

Can you rename this to AcceptEncodingHeaderHandler because we already have AcceptHeaderHandler?

[rkapka]

Hey @rose2221 , thanks for the contribution! This PR only adds gzip to the blobs endpoint, but it would make much more sense to have support on all endpoints that return data. Which means all endpoint that use middleware.AcceptHeaderHandler.

Before merging the PR you will also have to sign the Contributor License Agreement and add a changelog file.

[rose2221]

Thank you, @rkapka, for your suggestions! I've implemented the requested changes. Let me know if there's anything else that needs adjustment. Also, should I add tests for this as well?

[rkapka]

Also, should I add tests for this as well?

That would be very helpful. Perhaps you could write a unit test where you:

• have a dummy handler that returns some value
• register the gzip middleware for this handler
• execute the handler and check that the returned data is NOT equal to the value that the handler returns (meaning that it got zipped - this is to prevent a scenario where nothing gets zipped and the next step does nothing, but the whole test passes)
• unzip the returned data and see that it's equal to the value returned from the handler

[rose2221]

Also, should I add tests for this as well?

That would be very helpful. Perhaps you could write a unit test where you:

• have a dummy handler that returns some value
• register the gzip middleware for this handler
• execute the handler and check that the returned data is NOT equal to the value that the handler returns (meaning that it got zipped - this is to prevent a scenario where nothing gets zipped and the next step does nothing, but the whole test passes)
• unzip the returned data and see that it's equal to the value returned from the handler

Thank you, I've implemented the test as suggested and I'm open to any further feedback. @rkapka