[Frontend] add add_request_id middleware

[cjackal]

FIX #9593

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[github-actions]

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[cjackal]

It's a little vague where and how unit test should be written, suggestions are welcome.

[guoyuhong]

This X-Request-id seems not connected to request_id in create_chat_completion.

[cjackal]

Right, this id has nothing to do with chat request id(or request id of other OpenAI API response body). This behavior is consistent with OprnAI's current behavior, and you can recover this id like:

from openai import OpenAI

client = OpenAI(...)
response = client.chat.completions.create(...)
response._request_id

[guoyuhong]

Then, LGTM.

[simon-mo]

This makes sense to me given it's industry standard. It would be great to add comment about this as well. Thanks!

[cjackal]

@simon-mo Just have added an example using custom headers in the openai-compatible-server page (and sign-off), tell me if there's better spot to add comment about it.