net/http: add possibility to debug response inside CheckRedirect

[kayrus]

Right now it is not possible to debug server response inside CheckRedirect function. It becomes annoying especially when you use HTTPS connection and can not figure out why your code doesn't work.

I suppose it should be like:

CheckRedirect func(req *Request, via []*Request, via_resp []*Response,) error

[minux]

The usual way to debug this kind of problem is to use a custom transport. modifying the type of the CheckRedirect field is not acceptable given the Go 1 API guarantee.

[kayrus]

Is it possible to implement new CheckRedirectResp?

[rakyll]

The canonical way to debug servers is to implement a RoundTripper that dumps the request and response. You can use httputil.DumpRequestOut and httputil.DumpResponse to dump the raw HTTP request and response.

http://golang.org/pkg/net/http/httputil/#DumpRequestOut
http://golang.org/pkg/net/http/httputil/#DumpResponse