web-service-c.cpp

#include <sys/socket.h> // For socket functions
#include <netinet/in.h> // For sockaddr_in
#include <cstdlib> // For exit() and EXIT_FAILURE
#include <iostream> // For cout
#include <unistd.h> // For read

// Compile: `g++ main.cpp -o web-service-c`
// Usage: `telnet localhost 8002`
int main() {
    // Create a socket (IPv4, TCP)
    int sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd == -1) {
        std::cout << "Failed to create socket. errno: " << errno << std::endl;
        exit(EXIT_FAILURE);
    }

    // Listen to port 8002 on any address
    sockaddr_in sockaddr;
    sockaddr.sin_family = AF_INET;
    sockaddr.sin_addr.s_addr = INADDR_ANY;
    sockaddr.sin_port = htons(8002);
    if (bind(sockfd, (struct sockaddr*)&sockaddr, sizeof(sockaddr)) < 0) {
        std::cout << "Failed to bind to port 8002. errno: " << errno << std::endl;
        exit(EXIT_FAILURE);
    }

    // Start listening. Hold at most 10 connections in the queue
    if (listen(sockfd, 10) < 0) {
        std::cout << "Failed to listen on socket. errno: " << errno << std::endl;
        exit(EXIT_FAILURE);
    }

    // Grab a connection from the queue
    auto addrlen = sizeof(sockaddr);
    int connection = accept(sockfd, (struct sockaddr*)&sockaddr, (socklen_t*)&addrlen);
    if (connection < 0) {
        std::cout << "Failed to grab connection. errno: " << errno << std::endl;
        exit(EXIT_FAILURE);
    }

    // Read from the connection
    char buffer[100];
    auto bytesRead = read(connection, buffer, 100);
    std::cout << "The message was: " << buffer;

    // Send a message to the connection
    std::string response = "Good talking to you\n";
    send(connection, response.c_str(), response.size(), 0);

    // Close the connections
    close(connection);
    close(sockfd);
}