104 lines
4.6 KiB
C++
104 lines
4.6 KiB
C++
#include "SimpleClient.h"
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#include <iostream>
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#include <stdexcept>
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// 1. THE CONSTRUCTOR (Birth)
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// We initialize the socket to INVALID. We haven't bought a telephone yet.
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SimpleClient::SimpleClient() : clientSocket(INVALID_SOCKET) {}
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// 2. THE DESTRUCTOR (Cleanup)
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// When the Client object is destroyed, we must hang up the phone.
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SimpleClient::~SimpleClient() {
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if (clientSocket != INVALID_SOCKET) {
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CLOSE_SOCKET(clientSocket);
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}
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}
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// 3. THE CONNECT METHOD (The Dialing Algorithm)
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bool SimpleClient::connectTo(const std::string& ip, int port) {
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// =========================================================================
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// STEP 1: CREATE THE SOCKET (Buying the physical telephone)
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// =========================================================================
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// Just like the server, we need a physical socket to communicate.
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// AF_INET = IPv4, SOCK_STREAM = Reliable TCP connection.
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clientSocket = socket(AF_INET, SOCK_STREAM, 0);
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if (clientSocket == INVALID_SOCKET) {
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std::cerr << "❌ Failed to create client socket!\n";
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return false;
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}
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// =========================================================================
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// STEP 2: SETUP THE ADDRESS (Looking up the phone number)
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// =========================================================================
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// We need to tell the OS *who* we want to call.
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sockaddr_in serverAddr{};
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serverAddr.sin_family = AF_INET; // IPv4
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serverAddr.sin_port = htons(port); // The port number (e.g., 8080)
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// inet_pton = "Internet Presentation to Network"
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// It converts the human-readable text "127.0.0.1" into the 32-bit binary
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// number that the computer's network card actually understands.
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if (inet_pton(AF_INET, ip.c_str(), &serverAddr.sin_addr) <= 0) {
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std::cerr << "❌ Invalid IP address format!\n";
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return false;
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}
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// =========================================================================
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// STEP 3: CONNECT (Dialing the number and waiting for an answer)
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// =========================================================================
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// This function BLOCKS (pauses) the program here until the server picks up.
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// If the server isn't running, or the port is wrong, this will fail.
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if (connect(clientSocket, reinterpret_cast<sockaddr*>(&serverAddr), sizeof(serverAddr)) == SOCKET_ERROR) {
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std::cerr << "❌ Failed to connect to server at " << ip << ":" << port << "\n";
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return false; // We couldn't get through, so we return false.
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}
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// If we reach here, the connection is successful! The line is open.
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return true;
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}
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// 4. THE TALK METHOD (The Conversation Algorithm)
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void SimpleClient::talk(const std::string& message) const {
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// Safety check: Don't try to talk if we aren't connected!
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if (clientSocket == INVALID_SOCKET) {
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std::cerr << "⚠️ Cannot talk: Not connected to a server.\n";
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return;
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}
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std::cout << "📤 Sending: " << message;
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// =========================================================================
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// STEP 4: SEND (Speaking into the microphone)
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// =========================================================================
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// We push our text message out through the open connection.
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// We cast the length to 'int' to satisfy Windows, and it's perfectly safe
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// because our messages are small.
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send(clientSocket, message.c_str(), static_cast<int>(message.length()), 0);
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// =========================================================================
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// STEP 5: RECV (Listening for the echo)
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// =========================================================================
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char buffer[1025]; // Our listening box (1024 data + 1 for '\0')
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// We BLOCK (wait) here until the server sends data back to us.
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// We read up to 1024 bytes, leaving 1 byte for the stop-sign.
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auto bytesReceived = recv(clientSocket, buffer, sizeof(buffer) - 1, 0);
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if (bytesReceived > 0) {
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// Convert to safe size_t for array indexing
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const auto len = static_cast<size_t>(bytesReceived);
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// Add the invisible C-string stop-sign
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buffer[len] = '\0';
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std::cout << "📥 Server echoed back: " << buffer << "\n";
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} else {
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// If bytesReceived is 0, the server hung up on us politely.
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// If < 0, the connection broke.
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std::cerr << "⚠️ Server disconnected or error occurred while waiting for echo.\n";
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}
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}
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// Note: We do NOT call CLOSE_SOCKET() here.
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// We want to keep the line open so the user can call talk() multiple times!
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// The destructor (~EchoClient) will handle the final hang-up.
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