How do I properly get the c++ server code to access the web browser?

Question

The following is the code I've done with the message, but for some reason I keep getting a message saying "Problem connecting to the socket! Sorry!!" followed by this GET message:

Server says:
GET / HTTP/1.1
Host: 006010fb-d2cb-4a56-9e26-21bf35548134.id.replitusercontent.com
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.190 Safari/537.36
Accept: text/html,application/xhtml+xml,apP�s� 

Can anyone look over this and tell me what I'm missing/doing wrong? This is my first time doing server/client coding.

/**
 * @brief Main function of the program. It is called like this "program <port> <encryptedMessage>",
 * where <port> means the address of the webserver and <encryptedMessage> is the message to show
 * 
 * @param argc number of arguments
 * @param argv pointer to arguments
 * @return int 0 if everything is ok
 */
 
//Basic TCP Client: socket() creation > connect() > receive() > display > close

#include <stdio.h>          //Standard library
#include <stdlib.h>         //Standard library
#include <sys/socket.h>     //API and definitions for the sockets
#include <sys/types.h>      //more definitions
#include <netinet/in.h>     //Structures to store address information
#include <unistd.h>         //close function
#include <string.h>  
#define PORT 8080

int main()
{
    char tcp_server_message[256] = " Hello, I am the TCP Server you successfully connected to!! \n\n               Bye Bye!!!\n\n";
    //create the server socket
    int tcp_server_socket;                                  //variable for the socket descriptor
    tcp_server_socket = socket(AF_INET, SOCK_STREAM, 0);    //calling the socket function. Params: Domain of the socket (Internet in this case), type of socket stream (TCP), Protocol (default, 0 for TCP)

    //creating the TCP socket
    int tcp_client_socket;                                    //Socket descriptor
    tcp_client_socket = socket(AF_INET, SOCK_STREAM, 0);      //Calling the socket function - args: socket domain, socket stream type, TCP protocol (default)

    //specify address and port of the remote socket
    struct sockaddr_in tcp_server_address;             //declaring a structure for the address
    tcp_server_address.sin_family = AF_INET;           //Structure Fields' definition: Sets the address family of the address the client would connect to
    tcp_server_address.sin_port = htons(PORT);        //Specify and pass the port number to connect - converting in right network byte order
    tcp_server_address.sin_addr.s_addr = INADDR_ANY;   //Connecting to 0.0.0.0
    
    // binding the socket to the IP address and port
    bind(tcp_server_socket, (struct sockaddr *) &tcp_server_address, sizeof(tcp_server_address));  //Params: which socket, cast for server address, its size

    //listen for simultaneous connections
    listen(tcp_server_socket, 5);  //which socket, how many connections
    // server socket to interact with client, structure like before - if you know - else NULL for local connection
    tcp_client_socket = accept(tcp_server_socket, NULL, NULL);
    
    //send data stream
    send(tcp_client_socket, tcp_server_message, strlen(tcp_server_message), 0);  // send where, what, how much, flags (optional)
    //connecting to the remote socket
    int connection_status = connect(tcp_client_socket, (struct sockaddr *) &tcp_server_address, sizeof(tcp_server_address)); //params: which socket, cast for address to the specific structure type, size of address
    if (connection_status == -1)
    {   //return value of 0 means all okay, -1 means a problem
        printf(" Problem connecting to the socket! Sorry!! \n");
    }
    char tcp_server_response[256];
    recv(tcp_client_socket, &tcp_server_response, sizeof(tcp_server_response), 0);   // params: where (socket), what (string), how much - size of the server response, flags (0)

    //Output, as received from Server
    printf("\n\n Server says: %s \n", tcp_server_response);

    //closing the socket
    close(tcp_client_socket);

    return 0;
}

run.bash

#!/bin/bash
# DO NOT MODIFY THIS FILE

# This script compiles and runs the webserver.

c++ -o src/serveMessage src/main.cpp

src/serveMessage 8080 "We will meet at midnight"

Answer 1

You need to separate the program into a server part and a client part. Perform the server program first and make it listening to the client's access. And then perform the client program. This is the server part (Server.cpp).

    :
    :
int main()
{
    char tcp_server_message[256] = " Hello, I am the TCP Server you successfully connected to!! \n\n               Bye Bye!!!\n\n";
    
    //create the server socket
    int tcp_server_socket;                                  //variable for the socket descriptor
    tcp_server_socket = socket(AF_INET, SOCK_STREAM, 0);    //calling the socket function. Params: Domain of the socket (Internet in this case), type of socket stream (TCP), Protocol (default, 0 for TCP)

    //creating the TCP socket
    int tcp_client_socket;                                    //Socket descriptor
    //tcp_client_socket = socket(AF_INET, SOCK_STREAM, 0);      //Calling the socket function - args: socket domain, socket stream type, TCP protocol (default)

    //specify address and port of the remote socket
    struct sockaddr_in tcp_server_address;             //declaring a structure for the address
    tcp_server_address.sin_family = AF_INET;           //Structure Fields' definition: Sets the address family of the address the client would connect to
    tcp_server_address.sin_port = htons(PORT);        //Specify and pass the port number to connect - converting in right network byte order
    tcp_server_address.sin_addr.s_addr = INADDR_ANY;   //Connecting to 0.0.0.0
             

    // binding the socket to the IP address and 
    //Params: which socket, cast for server address, its size        
    if (bind(tcp_server_socket, (struct sockaddr *) &tcp_server_address, sizeof(tcp_server_address)) < 0)
    {
        printf("Error binding\n");
    } 
    else
    {
        printf("Bind successfully!\n");
    }

    //listen for simultaneous connections
    if(listen(tcp_server_socket, 5) < 0) {      // listen for incoming connections
        printf("Error listening\n");
    }    
    else
    {
        printf("Success in listening\n");
    }

    // server socket to interact with client, structure like before - if you know - else NULL for local connection
    if((tcp_client_socket=accept(tcp_server_socket, NULL, NULL)) < 0) { // accept one
        printf("Error accepting\n");
    }    
    else
    {
        printf("Success in accepting\n");
        //send data stream
        send(tcp_client_socket, tcp_server_message, strlen(tcp_server_message), 0);  // send where, what, how much, flags (optional)            
    }
 
    //closing the socket
    close(tcp_server_socket);

    return 0;
}

This is the client part (Client.cpp).

:
:

int main()
{
    //creating the TCP socket
    int tcp_client_socket;                                    //Socket descriptor
    tcp_client_socket = socket(AF_INET, SOCK_STREAM, 0);      //Calling the socket function - args: socket domain, socket stream type, TCP protocol (default)

    //specify address and port of the remote socket
    struct sockaddr_in tcp_server_address;             //declaring a structure for the address
    tcp_server_address.sin_family = AF_INET;           //Structure Fields' definition: Sets the address family of the address the client would connect to
    tcp_server_address.sin_port = htons(PORT);        //Specify and pass the port number to connect - converting in right network byte order
    tcp_server_address.sin_addr.s_addr = INADDR_ANY;   //Connecting to 0.0.0.0
             
    //connecting to the remote socket
    int connection_status = connect(tcp_client_socket, (struct sockaddr *) &tcp_server_address, sizeof(tcp_server_address)); //params: which socket, cast for address to the specific structure type, size of address
    if (connection_status == -1)
    {   //return value of 0 means all okay, -1 means a problem
        printf(" Problem connecting to the socket! Sorry!! \n");
    }
    else
    {
        char tcp_server_response[256];
        recv(tcp_client_socket, &tcp_server_response, sizeof(tcp_server_response), 0);   // params: where (socket), what (string), how much - size of the server response, flags (0)

        //Output, as received from Server
        printf("\n\n Server says: %s \n", tcp_server_response);
    }    
 
    //closing the socket
    close(tcp_client_socket);

    return 0;
}

Answer 2

You forgot to bind your client socket. tcp_client_socket has been initialize with socket() but not yet bound. Typically you bind to 0 IP and 0 port for outbound, and HTTP doesn't say otherwise so that's what you do.