BUG: lambdaurl.Wrap still does not add Content-Length headers?

[suntong]

Is your feature request related to a problem? Please describe. A clear and concise description of what the problem is.

Following https://github.com/aws/aws-lambda-go/issues/508,

The http.ResponseWriter implementation says the following thing about Content-Type header (and it actually has a note about Content-Length too).

If WriteHeader has not yet been called, Write calls WriteHeader(http.StatusOK) before writing the data. If the Header does not contain a Content-Type line, Write adds a Content-Type set to the result of passing the initial 512 bytes of written data to DetectContentType. Additionally, if the total size of all written data is under a few KB and there are no Flush calls, the Content-Length header is added automatically.

As of right now the lambdaurl.Wrap implementation completely misses this . . .

which get closed as a part of https://github.com/aws/aws-lambda-go/releases/tag/v1.42.0

However a quick search of Content-Length in the change log of https://github.com/aws/aws-lambda-go/compare/v1.41.0...v1.42.0

did not get any hits:

Are the Content-Length headers being added now?

Describe the solution you'd like

Add the Content-Length headers, properly.

Additional context

For a handler like:

                mux.HandleFunc("/hello", func(w http.ResponseWriter, r *http.Request) {
                    w.WriteHeader(200)
                    _, _ = w.Write([]byte("Hello World!"))
                })

I was able to get return from it if I try it locally, However, if using lambdaurl, I got empty returns, i.e., Content-Length: 0.

Please double-check. Thanks

[suntong]

Describe the solution you'd like

Add the Content-Length headers.

As the Content-Length header is not added by the lib. Ref: https://github.com/search?q=repo%3Aaws%2Faws-lambda-go+Content-Length&type=code

However, It seems to be more than that for a proper fix, as I tried to add the Content-Length headers myself but it has no effect at all:

    mux.HandleFunc("/hello", func(w http.ResponseWriter, r *http.Request) {
        w.Header().Set("Content-Length", "12") // len("Hello World!")
        w.WriteHeader(200)
        w.Write([]byte("Hello World!"))

    })