From 0e3b79dc8815a7c5bf13d5f5f624acb4d9a51d2d Mon Sep 17 00:00:00 2001
From: ethanglide <ecook2489@gmail.com>
Date: Tue, 9 Jul 2024 15:04:47 -0400
Subject: [PATCH] Improve socket connection style

Previously, a new socket was being opened and closed on every call. Now, there is one socket per client which is used continuously until the connection closes.
---
 cpp-console-game/main.cpp |  4 +--
 eRPC/Client.cpp           | 20 +++++----------
 eRPC/Client.hpp           |  3 ---
 eRPC/Server.cpp           | 53 ++++++++++++++++++++++++++++-----------
 eRPC/Server.hpp           |  7 +++++-
 5 files changed, 53 insertions(+), 34 deletions(-)

diff --git a/cpp-console-game/main.cpp b/cpp-console-game/main.cpp
index 86f039c..2e10423 100644
--- a/cpp-console-game/main.cpp
+++ b/cpp-console-game/main.cpp
@@ -72,7 +72,7 @@ std::pair<bool, std::string> echo(std::vector<std::string> args)
 
   std::cout << std::endl;
 
-  return {true, "Echo Successful"};
+  return {true, ""};
 }
 
 int main(int argc, char **argv)
@@ -101,7 +101,7 @@ int main(int argc, char **argv)
     client.call("echo", {"Hello", "World"});
     client.call("movePlayer", {"1", "5", "5"});
     client.call("movePlayer", {"1", "6", "6"});
-    auto ret = client.call("echol", {"Goodbye", "World"});
+    auto ret = client.call("echo", {"Goodbye", "World"});
 
     std::cout << "Result: " << ret << std::endl;
   }
diff --git a/eRPC/Client.cpp b/eRPC/Client.cpp
index 542b929..6ac7f47 100644
--- a/eRPC/Client.cpp
+++ b/eRPC/Client.cpp
@@ -6,7 +6,6 @@
 #include <arpa/inet.h>
 #include <stdexcept>
 #include <unistd.h>
-#include <iostream>
 
 int msgIdCounter = 0;
 
@@ -24,15 +23,7 @@ namespace eRPC
     }
 
     this->serverAddress = serverAddress;
-  }
 
-  Client::~Client()
-  {
-    closeConnection();
-  }
-
-  void Client::openConnection()
-  {
     if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
     {
       throw std::runtime_error("Failed to create socket");
@@ -44,16 +35,19 @@ namespace eRPC
     }
   }
 
-  void Client::closeConnection()
+  Client::~Client()
   {
+    Request request(msgIdCounter++, "disconnect", {});
+
+    auto serialized = request.serialize();
+    write(sockfd, serialized.c_str(), serialized.size() + 1);
+
     close(sockfd);
     sockfd = -1;
   }
 
   std::string Client::call(std::string method, std::vector<std::string> params)
   {
-    Client::openConnection();
-
     Request request(msgIdCounter++, method, params);
     auto serialized = request.serialize();
     write(sockfd, serialized.c_str(), serialized.size() + 1);
@@ -61,8 +55,6 @@ namespace eRPC
     char buffer[1024] = {0};
     read(sockfd, buffer, 1024);
 
-    Client::closeConnection();
-
     Response response(buffer);
 
     if (!response.isOk())
diff --git a/eRPC/Client.hpp b/eRPC/Client.hpp
index 9b4d2ff..bcbd5e2 100644
--- a/eRPC/Client.hpp
+++ b/eRPC/Client.hpp
@@ -17,9 +17,6 @@ namespace eRPC
   private:
     int sockfd;
     sockaddr_in serverAddress;
-
-    void openConnection();
-    void closeConnection();
   };
 }
 
diff --git a/eRPC/Server.cpp b/eRPC/Server.cpp
index 32cd4e6..c707905 100644
--- a/eRPC/Server.cpp
+++ b/eRPC/Server.cpp
@@ -7,6 +7,7 @@
 #include <stdexcept>
 #include <unistd.h>
 #include <memory>
+#include <thread>
 
 namespace eRPC
 {
@@ -50,11 +51,47 @@ namespace eRPC
     while (running)
     {
       auto connfd = accept(sockfd, (sockaddr *)NULL, NULL);
+      if (connfd < 0)
+      {
+        throw std::runtime_error("Failed to accept connection");
+      }
 
+      // Start a new thread to serve the client
+      std::thread(&Server::serveClient, this, connfd).detach();
+    }
+
+    close(sockfd);
+  }
+
+  void Server::stop()
+  {
+    running = false;
+  }
+
+  void Server::bindMethod(std::string method, std::function<std::pair<bool, std::string>(std::vector<std::string>)> callback)
+  {
+    methods[method] = callback;
+  }
+
+  void Server::serveClient(int connfd)
+  {
+    while (true)
+    {
       char buffer[1024] = {0};
-      read(connfd, buffer, 1024);
+      if (read(connfd, buffer, 1024) <= 0)
+      {
+        break;
+      }
+
+      // Parse the request
       Request request(buffer);
 
+      if (request.getMethod() == "disconnect")
+      {
+        break;
+      }
+
+      // Call the method if it exists to generate a response
       std::unique_ptr<Response> response;
       if (methods.find(request.getMethod()) != methods.end())
       {
@@ -76,20 +113,8 @@ namespace eRPC
 
       auto serialized = response->serialize();
       write(connfd, serialized.c_str(), serialized.size() + 1);
-
-      close(connfd);
     }
 
-    close(sockfd);
-  }
-
-  void Server::stop()
-  {
-    running = false;
-  }
-
-  void Server::bindMethod(std::string method, std::function<std::pair<bool, std::string>(std::vector<std::string>)> callback)
-  {
-    methods[method] = callback;
+    close(connfd);
   }
 }
\ No newline at end of file
diff --git a/eRPC/Server.hpp b/eRPC/Server.hpp
index d3a6858..0e5b2bd 100644
--- a/eRPC/Server.hpp
+++ b/eRPC/Server.hpp
@@ -21,7 +21,7 @@ namespace eRPC
     ~Server();
 
     /**
-     * Start the server loop.
+     * Start the server loop. This will block until the server is stopped.
      */
     void start();
 
@@ -39,6 +39,11 @@ namespace eRPC
     int sockfd;
     bool running;
     std::unordered_map<std::string, std::function<std::pair<bool, std::string>(std::vector<std::string>)>> methods;
+
+    /**
+     * Keep a socket open and serve a client until they disconnect.
+     */
+    void serveClient(int connfd);
   };
 }