feat: add support for Socket.IO v3

See also:

- https://github.com/socketio/engine.io-protocol#difference-between-v3-and-v4
- https://github.com/socketio/socket.io-protocol#difference-between-v5-and-v4

Author: darrachequesne

README.md

@@ -6,16 +6,24 @@ By virtue of being written in C++, this client works in several different platfo
 
 [![Clients with iPhone, QT, Console and web](https://cldup.com/ukvVVZmvYV.png)](https://github.com/socketio/socket.io-client-cpp/tree/master/examples)
 
+## Compatibility table
+
+| C++ Client version  | Socket.IO server version |
+| ------------------- | ------------------------ |
+| 2.x (`2.x` branch)  | 1.x / 2.x                |
+| 3.x (master branch) | 3.x                      |
+
 ## Features
 
 - 100% written in modern C++11
-- Compatible with socket.io 1.0+ protocol
 - Binary support
 - Automatic JSON encoding
 - Multiplex support
 - Similar API to the Socket.IO JS client
 - Cross platform
 
+Note: Only the WebSocket transport is currently implemented (no fallback to HTTP long-polling)
+
 ## Installation alternatives
 
 * [With CMAKE](./INSTALL.md#with-cmake)

src/internal/sio_client_impl.cpp

@@ -222,7 +222,7 @@ namespace sio
             } else {
                 ss<<uo.get_host();
             }
-            ss<<":"<<uo.get_port()<<"/socket.io/?EIO=3&transport=websocket";
+            ss<<":"<<uo.get_port()<<"/socket.io/?EIO=4&transport=websocket";
             if(m_sid.size()>0){
                 ss<<"&sid="<<m_sid;
             }
@@ -295,12 +295,6 @@ namespace sio
             lib::error_code ec;
             this->m_client.send(this->m_con, *payload, frame::opcode::text, ec);
         });
-        if(m_ping_timer)
-        {
-            asio::error_code e_code;
-            m_ping_timer->expires_from_now(milliseconds(m_ping_interval), e_code);
-            m_ping_timer->async_wait(std::bind(&client_impl::ping,this, std::placeholders::_1));
-        }
         if(!m_ping_timeout_timer)
         {
             m_ping_timeout_timer.reset(new asio::steady_timer(m_client.get_io_service()));
@@ -497,21 +491,21 @@ namespace sio
                 m_ping_timeout = 60000;
             }
 
-            m_ping_timer.reset(new asio::steady_timer(m_client.get_io_service()));
-            asio::error_code ec;
-            m_ping_timer->expires_from_now(milliseconds(m_ping_interval), ec);
-            if(ec)LOG("ec:"<<ec.message()<<endl){};
-            m_ping_timer->async_wait(std::bind(&client_impl::ping,this, std::placeholders::_1));
-            LOG("On handshake,sid:"<<m_sid<<",ping interval:"<<m_ping_interval<<",ping timeout"<<m_ping_timeout<<endl);
             return;
         }
 failed:
         //just close it.
         m_client.get_io_service().dispatch(std::bind(&client_impl::close_impl, this,close::status::policy_violation,"Handshake error"));
     }
 
-    void client_impl::on_pong()
+    void client_impl::on_ping()
     {
+        packet p(packet::frame_pong);
+        m_packet_mgr.encode(p, [&](bool /*isBin*/,shared_ptr<const string> payload)
+        {
+            this->m_client.send(this->m_con, *payload, frame::opcode::text);
+        });
+
         if(m_ping_timeout_timer)
         {
             m_ping_timeout_timer->cancel();
@@ -536,8 +530,8 @@ namespace sio
             //FIXME how to deal?
             this->close_impl(close::status::abnormal_close, "End by server");
             break;
-        case packet::frame_pong:
-            this->on_pong();
+        case packet::frame_ping:
+            this->on_ping();
             break;
 
         default:
@@ -560,11 +554,6 @@ namespace sio
             m_ping_timeout_timer->cancel(ec);
             m_ping_timeout_timer.reset();
         }
-        if(m_ping_timer)
-        {
-            m_ping_timer->cancel(ec);
-            m_ping_timer.reset();
-        }
     }
 
     void client_impl::reset_states()

src/internal/sio_client_impl.h

@@ -170,7 +170,7 @@ namespace sio
         //socketio callbacks
         void on_handshake(message::ptr const& message);
 
-        void on_pong();
+        void on_ping();
 
         void reset_states();
 
@@ -201,8 +201,6 @@ namespace sio
 
         packet_manager m_packet_mgr;
 
-        std::unique_ptr<asio::steady_timer> m_ping_timer;
-        
         std::unique_ptr<asio::steady_timer> m_ping_timeout_timer;
 
         std::unique_ptr<asio::steady_timer> m_reconn_timer;

src/internal/sio_packet.cpp

@@ -53,13 +53,7 @@ namespace sio
         Value numVal;
         numVal.SetInt((int)buffers.size());
         val.AddMember("num", numVal, doc.GetAllocator());
-        //FIXME can not avoid binary copy here.
-        shared_ptr<string> write_buffer = make_shared<string>();
-        write_buffer->reserve(msg.get_binary()->size()+1);
-        char frame_char = packet::frame_message;
-        write_buffer->append(&frame_char,1);
-        write_buffer->append(*(msg.get_binary()));
-        buffers.push_back(write_buffer);
+        buffers.push_back(msg.get_binary());
     }
 
     void accept_array_message(array_message const& msg,Value& val,Document& doc,vector<shared_ptr<const string> >& buffers)
@@ -253,7 +247,7 @@ namespace sio
     {
         if (_pending_buffers > 0) {
             assert(is_binary_message(buf_payload));//this is ensured by outside.
-            _buffers.push_back(std::make_shared<string>(buf_payload.data()+1,buf_payload.size()-1));
+            _buffers.push_back(std::make_shared<string>(buf_payload.data(),buf_payload.size()));
             _pending_buffers--;
             if (_pending_buffers == 0) {
 

src/sio_socket.cpp

@@ -269,10 +269,6 @@ namespace sio
     void socket::impl::send_connect()
     {
         NULL_GUARD(m_client);
-        if(m_nsp == "/")
-        {
-            return;
-        }
         packet p(packet::type_connect,m_nsp);
         m_client->send(p);
         m_connection_timer.reset(new asio::steady_timer(m_client->get_io_service()));

test/echo_server/index.js

@@ -1,19 +1,17 @@
 var port = 3000;
 
-var io = require('socket.io').listen(port);
+var io = require('socket.io')().listen(port);
 console.log("Listening on port " + port);
 
 /* Socket.IO events */
 io.on("connection", function(socket){
     console.log("new connection");
-    socket.on('test_text',function()
-    {
-        console.log("test text event received.");
+    socket.on('test_text', (...args) => {
+        console.log("test text event received.", args);
     });
 
-    socket.on('test_binary',function()
-    {
-       var args =Array.prototype.slice.call(arguments);
+    socket.on('test_binary', (...args) => {
+        console.log("test binary event received", args);
       if(args[0] instanceof Buffer)
       {
         console.log("test binary event received,binary length:"+ args[0].length);

test/echo_server/package-lock.json

@@ -1,8 +1,8 @@
 {
     "name": "echo_server",
-    "author":"Melo Yao",
-    "version":"0.0.0",
+    "author": "Melo Yao",
+    "version": "0.0.0",
     "dependencies": {
-        "socket.io": "1.*"
-  }
+        "socket.io": "^3.0.5"
+    }
 }

test/echo_server/package.json

@@ -118,16 +118,16 @@ TEST_CASE( "test_packet_accept_4" )
     int bin1Num = j["bin1"]["num"].get<int>();
     char numchar[] = {0,0};
     numchar[0] = bin1Num+'0';
-    CHECK(buffers[bin1Num]->length()==101);
+    CHECK(buffers[bin1Num]->length()==100);
     INFO("outputing payload bin1 num:" << numchar)
     CHECK(buffers[bin1Num]->at(50)==0);
-    CHECK(buffers[bin1Num]->at(0) == packet::frame_message);
+    CHECK(buffers[bin1Num]->at(0) == 0);
     int bin2Num = j["bin2"]["num"].get<int>();
     numchar[0] = bin2Num+'0';
-    CHECK(buffers[bin2Num]->length()==51);
+    CHECK(buffers[bin2Num]->length()==50);
     INFO("outputing payload bin2 num:" << numchar)
     CHECK(buffers[bin2Num]->at(25)==1);
-    CHECK(buffers[bin2Num]->at(0) == packet::frame_message);
+    CHECK(buffers[bin2Num]->at(0) == 1);
 }
 #endif
 
@@ -209,12 +209,11 @@ TEST_CASE( "test_packet_parse_4" )
     packet p;
     bool hasbin = p.parse("452-/nsp,101[\"bin_event\",[{\"_placeholder\":true,\"num\":1},{\"_placeholder\":true,\"num\":0},\"text\"]]");
     CHECK(hasbin);
-    char buf[101];
-    buf[0] = packet::frame_message;
-    memset(buf+1,0,100);
+    char buf[100];
+    memset(buf,0,100);
 
-    std::string bufstr(buf,101);
-    std::string bufstr2(buf,51);
+    std::string bufstr(buf,100);
+    std::string bufstr2(buf,50);
     CHECK(p.parse_buffer(bufstr));
     CHECK(!p.parse_buffer(bufstr2));