Missing `Content-Length`

[ben221199]

Why isn't there a Content-Length header send in the response? It seems that many programs have problems with this.

btcd/rpcserver.go

Line 4559 in b7d0706

err = s.writeHTTPResponseHeaders(r, w.Header(), http.StatusOK, buf)

[Roasbeef]

It seems that many programs have problems with this.

Such as?

[shubhtrek]

Hi maintainers,

I'd like to fix the missing Content-Length header in RPC responses.

Plan: Set w.Header().Set("Content-Length", strconv.Itoa(len(body))) before writing headers.

Any objections? Happy to add a test.

[shubhtrek]

This handler uses hj.Hijack(), which takes control of the HTTP connection.
After that, data is written as a stream using *bufio.ReadWriter, so the response size isn’t known in advance.
Because of this, Content-Length can’t be set unless we first buffer the whole response.

[ben221199]

The fact that msg is known at line 4564 (see below), tells me that it is very easy to fix this issue:

btcd/rpcserver.go

Line 4564 in b7d0706

if _, err := buf.Write(msg); err != nil {

Isn't it possible to introduce a new parameter to writeHTTPResponseHeaders that passes len(msg)?

[shubhtrek]

Content-Length: Now explicitly set by buffering the JSON response before hijacking the connection. This fixes compatibility with standard HTTP clients.

Filter Extension: Included removeAddressStr to complete the filter API ported from dcrd.