[HttpClient] Explain how to enable HTTP encoding ("Accept-Encoding" header)

[ThomasLandauer]

@nicolas-grekas Just noticed that (by default) HttpClient doesn't support compression. I think this should be emphasized more in the docs, since it's an easy (?) way to speed things up, isn't it?

https://symfony.com/doc/current/http_client.html#making-requests

HTTP compression and chunked transfer encoding are automatically enabled when both your PHP runtime and the remote server support them.

Some questions I'd like to expand on (but don't know the answers):

1. "HTTP compression" refers to an "Accept-Encoding" HTTP header being sent in the request?
2. How can I check what my PHP runtime supports?
3. If HttpClient comes to the conclusion that my PHP supports gzip and deflate, it will send?:

   Accept-Encoding: gzip, deflate

4. Since Transfer-Encoding is dead in HTTP/2, it's probably not so important to give more details about it?

[nicolas-grekas]

http compression is enabled by default if the php engine supports it.

[ThomasLandauer]

Yeah, I probably messed it up before - now accept-encoding: gzip is being sent by default. But I still can't figure out why? What needs to be present in phpinfo()? Or how would it be possible to disable it?

[nicolas-grekas]

compression is auto-enabled by curl when curl is compiled with it (see php --ri curl). Native http client checks with extension_loaded('zlib').

accept-encoding: identity disables compression

[ThomasLandauer]

Thanks - see #17218