From 6ac3bdb94ada23609577c7761e6e7e4b576876a6 Mon Sep 17 00:00:00 2001
From: Benjamin Sergeant <bsergean@gmail.com>
Date: Thu, 3 Jan 2019 17:05:44 -0800
Subject: [PATCH] implement a max connections (default = 32) settings

---
 ixwebsocket/IXWebSocketServer.cpp | 25 ++++++++++++++++++++++++-
 ixwebsocket/IXWebSocketServer.h   | 11 ++++++++++-
 2 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/ixwebsocket/IXWebSocketServer.cpp b/ixwebsocket/IXWebSocketServer.cpp
index 549b03e0..3b56fd02 100644
--- a/ixwebsocket/IXWebSocketServer.cpp
+++ b/ixwebsocket/IXWebSocketServer.cpp
@@ -23,11 +23,16 @@ namespace ix
     const int WebSocketServer::kDefaultPort(8080);
     const std::string WebSocketServer::kDefaultHost("127.0.0.1");
     const int WebSocketServer::kDefaultTcpBacklog(5);
+    const size_t WebSocketServer::kDefaultMaxConnections(32);
 
-    WebSocketServer::WebSocketServer(int port, const std::string& host, int backlog) :
+    WebSocketServer::WebSocketServer(int port,
+                                     const std::string& host,
+                                     int backlog,
+                                     size_t maxConnections) :
         _port(port),
         _host(host),
         _backlog(backlog),
+        _maxConnections(maxConnections),
         _stop(false)
     {
 
@@ -194,6 +199,19 @@ namespace ix
                 continue;
             }
 
+            if (getConnectedClientsCount() >= _maxConnections)
+            {
+                std::stringstream ss;
+                ss << "WebSocketServer::run() reached max connections = "
+                   << _maxConnections << ". "
+                   << "Not accepting connection";
+                logError(ss.str());
+
+                ::close(clientFd);
+
+                continue;
+            }
+
             // Launch the handleConnection work asynchronously in its own thread.
             //
             // the destructor of a future returned by std::async blocks, 
@@ -252,4 +270,9 @@ namespace ix
         std::lock_guard<std::mutex> lock(_clientsMutex);
         return _clients;
     }
+
+    size_t WebSocketServer::getConnectedClientsCount()
+    {
+        return getClients().size();
+    }
 }
diff --git a/ixwebsocket/IXWebSocketServer.h b/ixwebsocket/IXWebSocketServer.h
index f3be5063..be3c4f34 100644
--- a/ixwebsocket/IXWebSocketServer.h
+++ b/ixwebsocket/IXWebSocketServer.h
@@ -4,6 +4,11 @@
  *  Copyright (c) 2018 Machine Zone, Inc. All rights reserved.
  */
 
+// TODO
+// pass to callback PATH
+// pass connection success too to callback
+//
+
 #pragma once
 
 #include <utility> // pair
@@ -25,7 +30,8 @@ namespace ix
     public:
         WebSocketServer(int port = WebSocketServer::kDefaultPort,
                         const std::string& host = WebSocketServer::kDefaultHost,
-                        int backlog = WebSocketServer::kDefaultTcpBacklog);
+                        int backlog = WebSocketServer::kDefaultTcpBacklog,
+                        size_t maxConnections = WebSocketServer::kDefaultMaxConnections);
         virtual ~WebSocketServer();
 
         void setOnConnectionCallback(const OnConnectionCallback& callback);
@@ -43,6 +49,7 @@ namespace ix
         int _port;
         std::string _host;
         int _backlog;
+        size_t _maxConnections;
 
         OnConnectionCallback _onConnectionCallback;
 
@@ -63,10 +70,12 @@ namespace ix
         const static int kDefaultPort;
         const static std::string kDefaultHost;
         const static int kDefaultTcpBacklog;
+        const static size_t kDefaultMaxConnections;
 
         // Methods
         void run();
         void handleConnection(int fd);
+        size_t getConnectedClientsCount();
 
         // Logging
         void logError(const std::string& str);