Chapter 6 (sending/receiving message) of utility_client tutorial
This commit is contained in:
Peter Thorson
@@ -0,0 +1,336 @@
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/*
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* Copyright (c) 2014, Peter Thorson. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of the WebSocket++ Project nor the
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* names of its contributors may be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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// **NOTE:** This file is a snapshot of the WebSocket++ utility client tutorial.
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// Additional related material can be found in the tutorials/utility_client
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// directory of the WebSocket++ repository.
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#include <websocketpp/config/asio_no_tls_client.hpp>
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#include <websocketpp/client.hpp>
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#include <websocketpp/common/thread.hpp>
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#include <websocketpp/common/memory.hpp>
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#include <cstdlib>
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#include <iostream>
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#include <map>
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#include <string>
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#include <sstream>
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typedef websocketpp::client<websocketpp::config::asio_client> client;
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class connection_metadata {
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public:
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typedef websocketpp::lib::shared_ptr<connection_metadata> ptr;
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connection_metadata(int id, websocketpp::connection_hdl hdl, std::string uri)
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: m_id(id)
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, m_hdl(hdl)
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, m_status("Connecting")
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, m_uri(uri)
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, m_server("N/A")
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{}
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void on_open(client * c, websocketpp::connection_hdl hdl) {
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m_status = "Open";
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client::connection_ptr con = c->get_con_from_hdl(hdl);
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m_server = con->get_response_header("Server");
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}
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void on_fail(client * c, websocketpp::connection_hdl hdl) {
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m_status = "Failed";
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client::connection_ptr con = c->get_con_from_hdl(hdl);
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m_server = con->get_response_header("Server");
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m_error_reason = con->get_ec().message();
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}
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void on_close(client * c, websocketpp::connection_hdl hdl) {
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m_status = "Closed";
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client::connection_ptr con = c->get_con_from_hdl(hdl);
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std::stringstream s;
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s << "close code: " << con->get_remote_close_code() << " ("
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<< websocketpp::close::status::get_string(con->get_remote_close_code())
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<< "), close reason: " << con->get_remote_close_reason();
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m_error_reason = s.str();
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}
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void on_message(client * c, websocketpp::connection_hdl hdl, client::message_ptr msg) {
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if (msg->get_opcode() == websocketpp::frame::opcode::text) {
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m_messages.push_back("<< " + msg->get_payload());
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} else {
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m_messages.push_back("<< " + websocketpp::utility::to_hex(msg->get_payload()));
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}
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}
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websocketpp::connection_hdl get_hdl() const {
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return m_hdl;
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}
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int get_id() const {
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return m_id;
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}
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std::string get_status() const {
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return m_status;
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}
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void record_sent_message(std::string message) {
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m_messages.push_back(">> " + message);
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}
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friend std::ostream & operator<< (std::ostream & out, connection_metadata const & data);
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private:
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int m_id;
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websocketpp::connection_hdl m_hdl;
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std::string m_status;
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std::string m_uri;
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std::string m_server;
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std::string m_error_reason;
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std::vector<std::string> m_messages;
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};
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std::ostream & operator<< (std::ostream & out, connection_metadata const & data) {
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out << "> URI: " << data.m_uri << "\n"
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<< "> Status: " << data.m_status << "\n"
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<< "> Remote Server: " << (data.m_server.empty() ? "None Specified" : data.m_server) << "\n"
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<< "> Error/close reason: " << (data.m_error_reason.empty() ? "N/A" : data.m_error_reason) << "\n";
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out << "> Messages Processed: (" << data.m_messages.size() << ") \n";
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std::vector<std::string>::const_iterator it;
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for (it = data.m_messages.begin(); it != data.m_messages.end(); ++it) {
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out << *it << "\n";
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}
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return out;
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}
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class websocket_endpoint {
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public:
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websocket_endpoint () : m_next_id(0) {
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m_endpoint.clear_access_channels(websocketpp::log::alevel::all);
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m_endpoint.clear_error_channels(websocketpp::log::elevel::all);
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m_endpoint.init_asio();
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m_endpoint.start_perpetual();
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m_thread = websocketpp::lib::make_shared<websocketpp::lib::thread>(&client::run, &m_endpoint);
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}
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~websocket_endpoint() {
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m_endpoint.stop_perpetual();
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for (con_list::const_iterator it = m_connection_list.begin(); it != m_connection_list.end(); ++it) {
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if (it->second->get_status() != "Open") {
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// Only close open connections
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continue;
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}
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std::cout << "> Closing connection " << it->second->get_id() << std::endl;
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websocketpp::lib::error_code ec;
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m_endpoint.close(it->second->get_hdl(), websocketpp::close::status::going_away, "", ec);
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if (ec) {
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std::cout << "> Error closing connection " << it->second->get_id() << ": "
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<< ec.message() << std::endl;
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}
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}
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m_thread->join();
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}
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int connect(std::string const & uri) {
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websocketpp::lib::error_code ec;
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client::connection_ptr con = m_endpoint.get_connection(uri, ec);
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if (ec) {
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std::cout << "> Connect initialization error: " << ec.message() << std::endl;
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return -1;
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}
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int new_id = m_next_id++;
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connection_metadata::ptr metadata_ptr = websocketpp::lib::make_shared<connection_metadata>(new_id, con->get_handle(), uri);
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m_connection_list[new_id] = metadata_ptr;
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con->set_open_handler(websocketpp::lib::bind(
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&connection_metadata::on_open,
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metadata_ptr,
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&m_endpoint,
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websocketpp::lib::placeholders::_1
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));
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con->set_fail_handler(websocketpp::lib::bind(
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&connection_metadata::on_fail,
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metadata_ptr,
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&m_endpoint,
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websocketpp::lib::placeholders::_1
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));
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con->set_close_handler(websocketpp::lib::bind(
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&connection_metadata::on_close,
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metadata_ptr,
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&m_endpoint,
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websocketpp::lib::placeholders::_1
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));
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con->set_message_handler(websocketpp::lib::bind(
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&connection_metadata::on_message,
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metadata_ptr,
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&m_endpoint,
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websocketpp::lib::placeholders::_1,
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websocketpp::lib::placeholders::_2
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));
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m_endpoint.connect(con);
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return new_id;
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}
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void close(int id, websocketpp::close::status::value code, std::string reason) {
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websocketpp::lib::error_code ec;
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con_list::iterator metadata_it = m_connection_list.find(id);
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if (metadata_it == m_connection_list.end()) {
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std::cout << "> No connection found with id " << id << std::endl;
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return;
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}
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m_endpoint.close(metadata_it->second->get_hdl(), code, reason, ec);
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if (ec) {
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std::cout << "> Error initiating close: " << ec.message() << std::endl;
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}
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}
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void send(int id, std::string message) {
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websocketpp::lib::error_code ec;
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con_list::iterator metadata_it = m_connection_list.find(id);
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if (metadata_it == m_connection_list.end()) {
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std::cout << "> No connection found with id " << id << std::endl;
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return;
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}
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m_endpoint.send(metadata_it->second->get_hdl(), message, websocketpp::frame::opcode::text, ec);
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if (ec) {
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std::cout << "> Error sending message: " << ec.message() << std::endl;
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return;
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}
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metadata_it->second->record_sent_message(message);
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}
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connection_metadata::ptr get_metadata(int id) const {
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con_list::const_iterator metadata_it = m_connection_list.find(id);
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if (metadata_it == m_connection_list.end()) {
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return connection_metadata::ptr();
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} else {
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return metadata_it->second;
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}
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}
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private:
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typedef std::map<int,connection_metadata::ptr> con_list;
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client m_endpoint;
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websocketpp::lib::shared_ptr<websocketpp::lib::thread> m_thread;
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con_list m_connection_list;
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int m_next_id;
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};
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int main() {
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bool done = false;
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std::string input;
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websocket_endpoint endpoint;
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while (!done) {
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std::cout << "Enter Command: ";
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std::getline(std::cin, input);
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if (input == "quit") {
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done = true;
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} else if (input == "help") {
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std::cout
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<< "\nCommand List:\n"
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<< "connect <ws uri>\n"
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<< "send <connection id> <message>\n"
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<< "close <connection id> [<close code:default=1000>] [<close reason>]\n"
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<< "show <connection id>\n"
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<< "help: Display this help text\n"
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<< "quit: Exit the program\n"
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<< std::endl;
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} else if (input.substr(0,7) == "connect") {
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int id = endpoint.connect(input.substr(8));
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if (id != -1) {
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std::cout << "> Created connection with id " << id << std::endl;
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}
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} else if (input.substr(0,4) == "send") {
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std::stringstream ss(input);
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std::string cmd;
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int id;
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std::string message = "";
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ss >> cmd >> id;
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std::getline(ss,message);
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endpoint.send(id, message);
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} else if (input.substr(0,5) == "close") {
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std::stringstream ss(input);
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std::string cmd;
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int id;
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int close_code = websocketpp::close::status::normal;
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std::string reason = "";
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ss >> cmd >> id >> close_code;
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std::getline(ss,reason);
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endpoint.close(id, close_code, reason);
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} else if (input.substr(0,4) == "show") {
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int id = atoi(input.substr(5).c_str());
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connection_metadata::ptr metadata = endpoint.get_metadata(id);
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if (metadata) {
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std::cout << *metadata << std::endl;
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} else {
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std::cout << "> Unknown connection id " << id << std::endl;
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}
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} else {
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std::cout << "> Unrecognized Command" << std::endl;
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}
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}
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return 0;
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}
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/*
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clang++ -std=c++11 -stdlib=libc++ -I/Users/zaphoyd/software/websocketpp/ -I/Users/zaphoyd/software/boost_1_55_0/ -D_WEBSOCKETPP_CPP11_STL_ step4.cpp /Users/zaphoyd/software/boost_1_55_0/stage/lib/libboost_system.a
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clang++ -I/Users/zaphoyd/software/websocketpp/ -I/Users/zaphoyd/software/boost_1_55_0/ step4.cpp /Users/zaphoyd/software/boost_1_55_0/stage/lib/libboost_system.a /Users/zaphoyd/software/boost_1_55_0/stage/lib/libboost_thread.a /Users/zaphoyd/software/boost_1_55_0/stage/lib/libboost_random.a
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clang++ -std=c++11 -stdlib=libc++ -I/Users/zaphoyd/Documents/websocketpp/ -I/Users/zaphoyd/Documents/boost_1_53_0_libcpp/ -D_WEBSOCKETPP_CPP11_STL_ step4.cpp /Users/zaphoyd/Documents/boost_1_53_0_libcpp/stage/lib/libboost_system.a
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*/
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@@ -591,7 +591,7 @@ void close(int id, websocketpp::close::status::value code) {
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#### Add close option to the command loop and help message
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A close option is added to the command loop. It takes a connection ID and optionally a close code and a close reason. If no code is specified the default of 1000/Normal is used. If no reason is specified, none is sent. The `endpoint::send` method will do some error checking and abort the close request if you try and send an invalid code or a reason with invalid UTF8 formatting. Reason strings longer than 125 characters will be truncated.
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A close option is added to the command loop. It takes a connection ID and optionally a close code and a close reason. If no code is specified the default of 1000/Normal is used. If no reason is specified, none is sent. The `endpoint::close` method will do some error checking and abort the close request if you try and send an invalid code or a reason with invalid UTF8 formatting. Reason strings longer than 125 characters will be truncated.
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An entry is also added to the help system to describe how the new command may be used.
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@@ -654,7 +654,7 @@ Enter Command: close 0 1001 example message
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Enter Command: show 0
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> URI: ws://localhost:9002
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> Status: Closed
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> Remote Server: WebSocket++/0.3.0-alpha4
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> Remote Server: WebSocket++/0.4.0
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> Error/close reason: close code: 1001 (Going away), close reason: example message
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Enter Command: connect ws://localhost:9002
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> Created connection with id 1
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@@ -668,9 +668,138 @@ Enter Command: quit
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_Sending and receiving messages_
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- Sending a messages
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- terminology: WebSocket opcodes, text vs binary messages
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- Receiving a message
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> ###### Terminology: WebSocket message types (opcodes)
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> WebSocket messages have types indicated by their opcode. The protocol currently specifies two different opcodes for data messages, text and binary. Text messages represent UTF8 text and will be validated as such. Binary messages represent raw binary bytes and are passed through directly with no validation.
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>
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> WebSocket++ provides the values `websocketpp::frame::opcode::text` and `websocketpp::frame::opcode::binary` that can be used to direct how outgoing messages should be sent and to check how incoming messages are formatted.
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#### Sending Messages
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Messages are sent using `endpoint::send`. This is a thread safe method that may be called from anywhere to queue a message for sending on the specified connection. There are three send overloads for use with different scenarios.
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Each method takes a `connection_hdl` to indicate which connection to send the message on as well as a `frame::opcode::value` to indicate which opcode to label the message as. All overloads are also available with an exception free varient that fills in a a status/error code instead of throwing.
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The first overload, `connection_hdl hdl, std::string const & payload, frame::opcode::value op`, takes a `std::string`. The string contents are copied into an internal buffer and can be safely modified after calling send.
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The second overload, `connection_hdl hdl, void const * payload, size_t len, frame::opcode::value op`, takes a void * buffer and length. The buffer contents are copied and can be safely modified after calling send.
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The third overload, `connection_hdl hdl, message_ptr msg`, takes a WebSocket++ `message_ptr`. This overload allows a message to be constructed in place before the call to send. It also may allow a single message buffer to be sent multiple times, including to multiple connections, without copying. Whether or not this actually happens depends on other factors such as whether compression is enabled. The contents of the message buffer may not be safely modified after being sent.
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#### Add send method to `websocket_endpoint`
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Like the close method, send will start by looking up the given connection ID in the connection list. Next a send request is sent to the connection's handle with the specified WebSocket message and the text opcode. Finally, we record the sent message with our connection metadata object so later our show connection command can print a list of messages sent.
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```cpp
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void send(int id, std::string message) {
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websocketpp::lib::error_code ec;
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con_list::iterator metadata_it = m_connection_list.find(id);
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if (metadata_it == m_connection_list.end()) {
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std::cout << "> No connection found with id " << id << std::endl;
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return;
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}
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m_endpoint.send(metadata_it->second->get_hdl(), message, websocketpp::frame::opcode::text, ec);
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if (ec) {
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std::cout << "> Error sending message: " << ec.message() << std::endl;
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return;
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}
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metadata_it->second->record_sent_message(message);
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}
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```
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#### Add send option to the command loop and help message
|
||||
|
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A send option is added to the command loop. It takes a connection ID and a text message to send. An entry is also added to the help system to describe how the new command may be used.
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|
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```cpp
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else if (input.substr(0,4) == "send") {
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||||
std::stringstream ss(input);
|
||||
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||||
std::string cmd;
|
||||
int id;
|
||||
std::string message = "";
|
||||
|
||||
ss >> cmd >> id;
|
||||
std::getline(ss,message);
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|
||||
endpoint.send(id, message);
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}
|
||||
```
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||||
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#### Add glue to `connection_metadata` for storing sent messages
|
||||
|
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In order to store messages sent on this connection some code is added to `connection_metadata`. This includes a new data member `std::vector<std::string> m_messages` to keep track of all messages sent and received as well as a method for adding a sent message in that list:
|
||||
|
||||
```cpp
|
||||
void record_sent_message(std::string message) {
|
||||
m_messages.push_back(">> " + message);
|
||||
}
|
||||
```
|
||||
|
||||
Finally the connection metadata output operator is updated to also print a list of processed messages:
|
||||
|
||||
```cpp
|
||||
out << "> Messages Processed: (" << data.m_messages.size() << ") \n";
|
||||
|
||||
std::vector<std::string>::const_iterator it;
|
||||
for (it = data.m_messages.begin(); it != data.m_messages.end(); ++it) {
|
||||
out << *it << "\n";
|
||||
}
|
||||
```
|
||||
|
||||
#### Receiving Messages
|
||||
|
||||
Messages are received by registering a message handler. The message will be called once per message received and its signature is `void on_message(websocketpp::connection_hdl hdl, endpoint::message_ptr msg)`. The `connection_hdl`, like the similar parameter from the other handlers is a handle for the connection that the message was received on. The `message_ptr` is a pointer to an object that can be queried for the message payload, opcode, and other metadata. Note that the message_ptr type, as well as its underlying message type, is dependent on how your endpoint is configured and may be different for different configs.
|
||||
|
||||
#### Add a message handler to method to `connection_metadata`
|
||||
|
||||
The message receiving behave that we are implementing will be to collect all messages sent and received and to print them in order when the show connection command is run. The sent messages are already being added to that list. Now we add a message handler that pushes received messages to the list as well. Text messages are pushed as-is. Binary messages are first converted to printable hexadecimal format.
|
||||
|
||||
```cpp
|
||||
void on_message(client * c, websocketpp::connection_hdl hdl, client::message_ptr msg) {
|
||||
if (msg->get_opcode() == websocketpp::frame::opcode::text) {
|
||||
m_messages.push_back(msg->get_payload());
|
||||
} else {
|
||||
m_messages.push_back(websocketpp::utility::to_hex(msg->get_payload()));
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
In order to have this handler called when new messages are received we also register it with our connection. Note that unlike most other handlers, the message handler has two parameters and thus needs two placeholders.
|
||||
|
||||
```cpp
|
||||
con->set_message_handler(websocketpp::lib::bind(
|
||||
&connection_metadata::on_message,
|
||||
metadata_ptr,
|
||||
&m_endpoint,
|
||||
websocketpp::lib::placeholders::_1,
|
||||
websocketpp::lib::placeholders::_2
|
||||
));
|
||||
```
|
||||
|
||||
#### Build
|
||||
|
||||
There are no changes to the build instructions from step 5
|
||||
|
||||
#### Run
|
||||
|
||||
In this example run we are connecting to the WebSocket++ example echo_server. This server will repeat any message we send back to it. You can also try testing this with the echo server at `ws://echo.websocket.org` with similar results.
|
||||
|
||||
```
|
||||
Enter Command: connect ws://localhost:9002
|
||||
> Created connection with id 0
|
||||
Enter Command: send 0 example message
|
||||
Enter Command: show 0
|
||||
> URI: ws://localhost:9002
|
||||
> Status: Open
|
||||
> Remote Server: WebSocket++/0.4.0
|
||||
> Error/close reason: N/A
|
||||
> Messages Processed: (2)
|
||||
>> example message
|
||||
<< example message
|
||||
```
|
||||
|
||||
### Step 7
|
||||
|
||||
|
||||
Reference in New Issue
Block a user