Function newTransferWriter

transfer.go:73–121

(r *http.Request)

}

func newTransferWriter(r *http.Request) (t *transferWriter, err error) {
	t = &transferWriter{}

	// Extract relevant fields
	atLeastHTTP11 := false
	if r.ContentLength != 0 && r.Body == nil {
		return nil, fmt.Errorf("http: Request.ContentLength=%d with nil Body", r.ContentLength)
	}
	t.Method = valueOrDefault(r.Method, "GET")
	t.Close = r.Close
	t.TransferEncoding = r.TransferEncoding
	t.Header = r.Header
	t.Trailer = r.Trailer
	t.Body = r.Body
	t.BodyCloser = r.Body
	t.ContentLength = outgoingLength(r)
	if t.ContentLength < 0 && len(t.TransferEncoding) == 0 && t.shouldSendChunkedRequestBody() {
		t.TransferEncoding = []string{"chunked"}
	}
	// If there's a body, conservatively flush the headers
	// to any bufio.Writer we're writing to, just in case
	// the server needs the headers early, before we copy
	// the body and possibly block. We make an exception
	// for the common standard library in-memory types,
	// though, to avoid unnecessary TCP packets on the
	// wire. (Issue 22088.)
	if t.ContentLength != 0 && !isKnownInMemoryReader(t.Body) {
		t.FlushHeaders = true
	}

	atLeastHTTP11 = true // Transport requests are always 1.1 or 2.0

	// Sanitize Body,ContentLength,TransferEncoding
	if !atLeastHTTP11 || t.Body == nil {
		t.TransferEncoding = nil
	}
	if chunked(t.TransferEncoding) {
		t.ContentLength = -1
	} else if t.Body == nil { // no chunking, no body
		t.ContentLength = 0
	}

	// Sanitize Trailer
	if !chunked(t.TransferEncoding) {
		t.Trailer = nil
	}

	return t, nil
}

// shouldSendChunkedRequestBody reports whether we should try to send a
// chunked request body to the server. In particular, the case we really