Closed
Description
There's no way for Server handlers to set Trailer headers.
From a test I just wrote, with a work-around and TODO for Go 1.4:
ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
w.Header().Set("Connection", "close")
w.Header().Set("Trailer", "Server-Trailer-A, Server-Trailer-B")
w.Header().Add("Trailer", "Server-Trailer-C")
var decl []string
for k := range r.Trailer {
decl = append(decl, k)
}
sort.Strings(decl)
slurp, err := ioutil.ReadAll(r.Body)
if err != nil {
t.Errorf("Server reading request body: %v", err)
}
if string(slurp) != "foo" {
t.Errorf("Server read request body %q; want foo", slurp)
}
if r.Trailer == nil {
io.WriteString(w, "nil Trailer")
} else {
fmt.Fprintf(w, "decl: %v, vals: %s, %s",
decl,
r.Trailer.Get("Client-Trailer-A"),
r.Trailer.Get("Client-Trailer-B"))
}
// TODO: There's no way yet for the server to set trailers
// without hijacking, so do that for now, just to test the client.
// Later, in Go 1.4, it should be be implicit that any mutations
// to w.Header() after the initial write are the trailers to be
// sent, if and only if they were previously declared with
// w.Header().Set("Trailer", ..keys..)
w.(Flusher).Flush()
conn, buf, _ := w.(Hijacker).Hijack()
t := Header{}
t.Set("Server-Trailer-A", "valuea")
t.Set("Server-Trailer-C", "valuec") // skipping B
buf.WriteString("0\r\n") // eof
t.Write(buf)
buf.WriteString("\r\n") // end of trailers
buf.Flush()
conn.Close()