DefaultBinder.Bind errors when POST request with empty body is sent

[yaziciahmet]

When a POST request is sent with an empty body, and Bind is called to bind param values, it fails with 415 unsupported media type.

I sent this request from browser and observed that Content-Length = 0 header is actually being sent, but on the server this header seems to be stripped out of headers, and ContentLength on the request object is set to -1, causing the request content length to be treated as unknown, and causing Bind method to fail.

I am aware I can just use c.Param or just sent an empty json etc. but this failing felt off so wanted to share it.

[Samar2170]

@yaziciahmet Can you share the entire request metadata and your handler function, I tried replicating this no json and content-length 0 and didn't 415 unsupported media.

[aldas]

If this happens with modern browser then inspect -> network tab and usually you can copy that request as CURL there. It would be much easier to guess anything about it with that info.

You can also see what c.Request().Header.Get("Content-Type") would return in your handler.

[aldas]

@vishr Is this "read one byte" proper solution? Especially in situation when we do not know when this happens properly (@yaziciahmet have not provided good example)

[vishr]

@aldas Let me revisit it, thanks.

[aldas]

That change replaces the request body (eq.Body = io.NopCloser(io.MultiReader(strings.NewReader(string(buf[:n])), req.Body))), but there are cases when user will add their own reader with specific behaviour. This was discussed two days ago in here #2641 (comment) so it could potentially interfere with these kind of situations.

[vishr]

Let me revert the change. Please keep an eye on the fixes that I am pushing - thank you!

[aldas]

could Claude do these through PRs? It would be easier to check them. Commiting directly to master branch is little bit sneaky of Claude.