func handleCodeResponse()

in auth/login.go [146:191]
36 lines of code
5 McCabe index (conditional complexity)

func handleCodeResponse(ln net.Listener, stateCheck string) (string, error) {
	conn, err := ln.Accept()
	if err != nil {
		return "", err
	}

	srvConn := httputil.NewServerConn(conn, nil)
	defer srvConn.Close()

	req, err := srvConn.Read()
	if err != nil {
		return "", err
	}

	code := req.URL.Query().Get("code")
	state := req.URL.Query().Get("state")

	resp := &http.Response{
		StatusCode:    200,
		Proto:         "HTTP/1.1",
		ProtoMajor:    1,
		ProtoMinor:    1,
		Close:         true,
		ContentLength: -1, // designates unknown length
	}
	defer srvConn.Write(req, resp)

	// If the code couldn't be obtained, inform the user via the browser and
	// return an error.
	// TODO i18n?
	if code == "" {
		err := fmt.Errorf("Code not present in response: %s", req.URL.String())
		resp.Body = getResponseBody("ERROR: Authentication code not present in response.")
		return "", err
	}

	if state != stateCheck {
		err := fmt.Errorf("Invalid State")
		resp.StatusCode = 400
		resp.Body = getResponseBody("ERROR: State parameter is invalid.")
		return "", err
	}

	resp.Body = getResponseBody("Success! You may now close your browser.")
	return code, nil
}