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| 1 | +#pragma once |
| 2 | + |
| 3 | +#include <arpa/inet.h> |
| 4 | +#include <netinet/in.h> |
| 5 | +#include <sys/socket.h> |
| 6 | +#include <unistd.h> |
| 7 | + |
| 8 | +#include <cstring> |
| 9 | +#include <sstream> |
| 10 | +#include <stdexcept> |
| 11 | +#include <string> |
| 12 | +#include <thread> |
| 13 | + |
| 14 | +/** |
| 15 | + * @class EchoServer |
| 16 | + * A simple HTTP echo server for testing purposes |
| 17 | + * Listens on a TCP socket and echoes back the received HTTP request |
| 18 | + */ |
| 19 | +class EchoServer { |
| 20 | + private: |
| 21 | + int _serverSocket{-1}; |
| 22 | + int _port; |
| 23 | + std::jthread _serverThread; |
| 24 | + |
| 25 | + /** |
| 26 | + * Server loop that handles incoming connections |
| 27 | + * @param[in] stopToken Stop token for cooperative cancellation |
| 28 | + */ |
| 29 | + void serverLoop(std::stop_token stopToken) |
| 30 | + { |
| 31 | + while (!stopToken.stop_requested()) |
| 32 | + { |
| 33 | + // Accept incoming connection |
| 34 | + sockaddr_in clientAddr{}; |
| 35 | + socklen_t clientAddrLen = sizeof(clientAddr); |
| 36 | + int clientSocket = accept(_serverSocket, reinterpret_cast<sockaddr *>(&clientAddr), &clientAddrLen); |
| 37 | + |
| 38 | + if (clientSocket < 0) |
| 39 | + { |
| 40 | + if (!stopToken.stop_requested()) |
| 41 | + { |
| 42 | + continue; |
| 43 | + } |
| 44 | + break; |
| 45 | + } |
| 46 | + |
| 47 | + // Read the HTTP request |
| 48 | + char buffer[4096] = {0}; |
| 49 | + ssize_t bytesRead = recv(clientSocket, buffer, sizeof(buffer) - 1, 0); |
| 50 | + |
| 51 | + if (bytesRead > 0) |
| 52 | + { |
| 53 | + // Use explicit length constructor to ensure exact byte count |
| 54 | + std::string request(buffer, bytesRead); |
| 55 | + |
| 56 | + // Extract only the body from the HTTP request |
| 57 | + // HTTP headers end with "\r\n\r\n", body starts after that |
| 58 | + std::string body; |
| 59 | + size_t bodyStart = request.find("\r\n\r\n"); |
| 60 | + if (bodyStart != std::string::npos) |
| 61 | + { |
| 62 | + body = request.substr(bodyStart + 4); // +4 to skip "\r\n\r\n" |
| 63 | + } |
| 64 | + |
| 65 | + // Build HTTP response with echoed body content |
| 66 | + std::ostringstream response; |
| 67 | + response << "HTTP/1.1 200 OK\r\n"; |
| 68 | + response << "Content-Type: text/plain\r\n"; |
| 69 | + response << "Content-Length: " << body.length() << "\r\n"; |
| 70 | + response << "Connection: close\r\n"; |
| 71 | + response << "\r\n"; |
| 72 | + response << body; |
| 73 | + |
| 74 | + // Send response |
| 75 | + std::string responseStr = response.str(); |
| 76 | + send(clientSocket, responseStr.c_str(), responseStr.length(), 0); |
| 77 | + } |
| 78 | + |
| 79 | + close(clientSocket); |
| 80 | + } |
| 81 | + } |
| 82 | + |
| 83 | + public: |
| 84 | + /** |
| 85 | + * Constructs a new EchoServer object and starts listening |
| 86 | + * @param[in] port The port to listen on |
| 87 | + * @throws std::runtime_error if server fails to start |
| 88 | + */ |
| 89 | + explicit EchoServer(int port) : _port(port) |
| 90 | + { |
| 91 | + _serverSocket = socket(AF_INET, SOCK_STREAM, 0); |
| 92 | + if (_serverSocket < 0) |
| 93 | + { |
| 94 | + throw std::runtime_error("Failed to create socket"); |
| 95 | + } |
| 96 | + |
| 97 | + int opt = 1; |
| 98 | + if (setsockopt(_serverSocket, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) < 0) |
| 99 | + { |
| 100 | + close(_serverSocket); |
| 101 | + throw std::runtime_error("Failed to set socket options"); |
| 102 | + } |
| 103 | + |
| 104 | + sockaddr_in serverAddr{}; |
| 105 | + serverAddr.sin_family = AF_INET; |
| 106 | + serverAddr.sin_addr.s_addr = INADDR_ANY; |
| 107 | + serverAddr.sin_port = htons(_port); |
| 108 | + |
| 109 | + if (bind(_serverSocket, reinterpret_cast<sockaddr *>(&serverAddr), sizeof(serverAddr)) < 0) |
| 110 | + { |
| 111 | + close(_serverSocket); |
| 112 | + throw std::runtime_error("Failed to bind socket to port"); |
| 113 | + } |
| 114 | + |
| 115 | + if (listen(_serverSocket, 5) < 0) |
| 116 | + { |
| 117 | + close(_serverSocket); |
| 118 | + throw std::runtime_error("Failed to listen on socket"); |
| 119 | + } |
| 120 | + |
| 121 | + // Start server thread |
| 122 | + _serverThread = std::jthread(&EchoServer::serverLoop, this); |
| 123 | + } |
| 124 | + |
| 125 | + /** |
| 126 | + * Gets the port number |
| 127 | + * @return The port number the server is listening on |
| 128 | + */ |
| 129 | + [[nodiscard]] int getPort() const { return _port; } |
| 130 | + |
| 131 | + /// Destructor - stops the server and cleans up |
| 132 | + ~EchoServer() |
| 133 | + { |
| 134 | + _serverThread.request_stop(); |
| 135 | + if (_serverSocket >= 0) |
| 136 | + { |
| 137 | + shutdown(_serverSocket, SHUT_RDWR); |
| 138 | + close(_serverSocket); |
| 139 | + _serverSocket = -1; |
| 140 | + } |
| 141 | + } |
| 142 | + |
| 143 | + /// Deleted copy constructor |
| 144 | + EchoServer(const EchoServer &) = delete; |
| 145 | + |
| 146 | + /// Deleted copy assignment operator |
| 147 | + EchoServer &operator=(const EchoServer &) = delete; |
| 148 | + |
| 149 | + /// Deleted move constructor |
| 150 | + EchoServer(EchoServer &&) = delete; |
| 151 | + |
| 152 | + /// Deleted move assignment operator |
| 153 | + EchoServer &operator=(EchoServer &&) = delete; |
| 154 | +}; |
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