Programming Forums > Application Development > C++

LOI Kratong · Jun 30th, 2006, 10:30 AM

I know about sockets, I've created a chat program, so don't just point me to the door!

I'm trying to make a program to download a file, but I'm not having much luck, and google is being a evil, and not showing me the good stuff.

Does anyone know how I can connect to a website on port 80 and download the file which has been pointed to?

Cheers!

Wizard1988 · Jun 30th, 2006, 10:35 AM

You might need to look into HTTP Headers.

You can connect but the server won't know what you want it to do unless you tell it to.

nnxion · Jun 30th, 2006, 10:36 AM

What's there not to understand? Just go to the link (with HTTP, duh?) and receive the information and write it to a file.

Edit: Here's a link you can play with. It contains a super small and simple client at the end.

LOI Kratong · Jun 30th, 2006, 10:37 AM

I can't seem to recive the information, I'm sure I've had it working before, but my brain doesn't seem to want to actually work at the minute!

Wizard1988 · Jun 30th, 2006, 10:41 AM

This should help you http://www.perlfect.com/articles/http.shtml

LOI Kratong · Jun 30th, 2006, 10:52 AM

Thanks, that did help clear a bit up.

Can anyone see any problems with this code?

(Toggle Plain Text)

#include <stdio.h>
#include <iostream>
#include "winsock2.h"

using namespace std;

int main() {

    // Initialize Winsock.
    WSADATA wsaData;
    int iResult = WSAStartup( MAKEWORD(2,2), &wsaData );
    if ( iResult != NO_ERROR )
        cout << "Error at WSAStartup()\n";

    // Create a socket.
    SOCKET m_socket;
    m_socket = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP );

    if ( m_socket == INVALID_SOCKET ) {
        cout << "Error at socket(): \n" << WSAGetLastError();
        WSACleanup();
        return 0;
    }

    // Connect to a server.
    sockaddr_in server;

    server.sin_family = AF_INET;
    server.sin_addr.s_addr = inet_addr( "64.233.167.99" ); //google.com
    server.sin_port = htons( 80 );

    if ( connect( m_socket, (SOCKADDR*) &server, sizeof(server) ) == SOCKET_ERROR) {
        cout << "Failed to connect.\n";
        WSACleanup();
        return 0;
    }

    // Send and receive data.
    int bytesSent;
    int bytesRecv = SOCKET_ERROR;
    char sendbuf[32] = "GET /imghp HTTP/1.0"; //get google image search
    char recvbuf[32] = "";
    
    bytesSent = send( m_socket, sendbuf, strlen(sendbuf), 0 );
    
    while( bytesRecv == SOCKET_ERROR ) {
       bytesRecv = recv( m_socket, recvbuf, 32, 0 );
       cout << recvbuf;
       if ( bytesRecv == 0 || bytesRecv == WSAECONNRESET ) {
           cout << "Connection Closed.\n";
           break;
        }
        if (bytesRecv < 0)
            return 0;
    }
    if (bytesSent == -1)
    {
           return 0;
    }
    system ("PAUSE");
    return 0;
    }

It just hangs at a black screen!

Wizard1988 · Jun 30th, 2006, 11:00 AM

It sends the header to the site. There must be something wrong with the formatting of the request.

LOI Kratong · Jun 30th, 2006, 11:02 AM

If you look at the website you gave me, this is what the request ought to be sent as, if I'm reading it right...

Wizard1988 · Jun 30th, 2006, 11:21 AM

I somewhat got it to work

(Toggle Plain Text)

#include <stdio.h>
#include <iostream>
#include "winsock2.h"

using namespace std;

int main() {

    // Initialize Winsock.
    WSADATA wsaData;
    int iResult = WSAStartup( MAKEWORD(2,2), &wsaData );
    if ( iResult != NO_ERROR )
        cout << "Error at WSAStartup()\n";

    // Create a socket.
    SOCKET m_socket;
    m_socket = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP );

    if ( m_socket == INVALID_SOCKET ) {
        cout << "Error at socket(): \n" << WSAGetLastError();
        WSACleanup();
        return 0;
    }

    // Connect to a server.
    sockaddr_in server;

    server.sin_family = AF_INET;
    server.sin_addr.s_addr = inet_addr( "64.233.167.99" ); //google.com
    server.sin_port = htons( 80 );

    if ( connect( m_socket, (SOCKADDR*) &server, sizeof(server) ) == SOCKET_ERROR) {
        cout << "Failed to connect.\n";
        WSACleanup();
        return 0;
    }
	cout << "After connecting" << endl;

    // Send and receive data.
    int bytesSent;
    int bytesRecv = SOCKET_ERROR;
    char sendbuf[32] = "GET /index.html HTTP/1.1\n\n"; //get google image search
    char recvbuf[32] = "";
    
    bytesSent = send( m_socket, sendbuf, strlen(sendbuf), 0 );

	cout << "After connecting" << endl;
    
    while( bytesRecv == SOCKET_ERROR ) {
       bytesRecv = recv( m_socket, recvbuf, 32, 0 );
       cout << recvbuf;
       if ( bytesRecv == 0 || bytesRecv == WSAECONNRESET ) {
           cout << "Connection Closed.\n";
           break;
        }
        if (bytesRecv < 0)
            return 0;
    }
    if (bytesSent == -1)
    {
           return 0;
    }
    system ("PAUSE");
    return 0;
    }

LOI Kratong · Jun 30th, 2006, 11:44 AM

Got it to work in what sense? I tried compiling a slightly modified version:

(Toggle Plain Text)

#include <stdio.h>
#include <iostream>
#include "winsock2.h"

using namespace std;

int main() {

    // Initialize Winsock.
    WSADATA wsaData;
    int iResult = WSAStartup( MAKEWORD(2,2), &wsaData );
    if ( iResult != NO_ERROR )
        cout << "Error at WSAStartup()\n";

    // Create a socket.
    SOCKET m_socket;
    m_socket = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP );

    if ( m_socket == INVALID_SOCKET ) {
        cout << "Error at socket(): \n" << WSAGetLastError();
        WSACleanup();
        return 0;
    }

    // Connect to a server.
    sockaddr_in server;

    server.sin_family = AF_INET;
    server.sin_addr.s_addr = inet_addr( "64.233.167.99" ); //google.com
    server.sin_port = htons( 80 );

    if ( connect( m_socket, (SOCKADDR*) &server, sizeof(server) ) == SOCKET_ERROR) {
        cout << "Failed to connect.\n";
        WSACleanup();
        return 0;
    }
	cout << "After connecting" << endl;

    // Send and receive data.
    int bytesSent;
    int bytesRecv = SOCKET_ERROR;
    char sendbuf[32] = "GET /index.html HTTP/1.1\n\n"; //get google image search
    char recvbuf[32] = "";
    
    bytesSent = send( m_socket, sendbuf, strlen(sendbuf), 0 );
    cout << "Bytes Sent: " << bytesSent << "\n";
    cout << "After connecting" << endl;
    
    while( bytesRecv == SOCKET_ERROR ) {
       bytesRecv = recv( m_socket, recvbuf, 32, 0 );
       cout << "Bytes Received: " << bytesRecv << "\n";
       if ( bytesRecv == 0 || bytesRecv == WSAECONNRESET ) {
           cout << "Connection Closed.\n";
           break;
        }
        if (bytesRecv < 0)
            return 0;
    }
    if (bytesSent == -1)
    {
           return 0;
    }
    system ("PAUSE");
    return 0;
    }

And the output is:

(Toggle Plain Text)

After connecting
Bytes Sent: 26
After connecting
Bytes Received: 0
Connection Closed.

What did you get?

Jun 30th, 2006, 10:30 AM	#1
LOI Kratong Professional Programmer Join Date: May 2005 Location: Woo - Boot Sector! Posts: 294 Rep Power: 4	Creating a file downloader I know about sockets, I've created a chat program, so don't just point me to the door! I'm trying to make a program to download a file, but I'm not having much luck, and google is being a evil, and not showing me the good stuff. Does anyone know how I can connect to a website on port 80 and download the file which has been pointed to? Cheers! __________________ www.heldtogether.co.uk

Jun 30th, 2006, 10:36 AM	#3
nnxion Programming Guru Join Date: Jun 2005 Location: elemental plane Posts: 1,429 Rep Power: 5	What's there not to understand? Just go to the link (with HTTP, duh?) and receive the information and write it to a file. Edit: Here's a link you can play with. It contains a super small and simple client at the end. __________________ "Employ your time in improving yourself by other men's writings, so that you shall gain easily what others have labored hard for." -- Socrates Last edited by nnxion; Jun 30th, 2006 at 10:46 AM.

Jun 30th, 2006, 10:37 AM	#4
LOI Kratong Professional Programmer Join Date: May 2005 Location: Woo - Boot Sector! Posts: 294 Rep Power: 4	I can't seem to recive the information, I'm sure I've had it working before, but my brain doesn't seem to want to actually work at the minute! __________________ www.heldtogether.co.uk

Jun 30th, 2006, 10:52 AM	#6
LOI Kratong Professional Programmer Join Date: May 2005 Location: Woo - Boot Sector! Posts: 294 Rep Power: 4	Thanks, that did help clear a bit up. Can anyone see any problems with this code? (Toggle Plain Text) #include <stdio.h> #include <iostream> #include "winsock2.h" using namespace std; int main() { // Initialize Winsock. WSADATA wsaData; int iResult = WSAStartup( MAKEWORD(2,2), &wsaData ); if ( iResult != NO_ERROR ) cout << "Error at WSAStartup()\n"; // Create a socket. SOCKET m_socket; m_socket = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP ); if ( m_socket == INVALID_SOCKET ) { cout << "Error at socket(): \n" << WSAGetLastError(); WSACleanup(); return 0; } // Connect to a server. sockaddr_in server; server.sin_family = AF_INET; server.sin_addr.s_addr = inet_addr( "64.233.167.99" ); //google.com server.sin_port = htons( 80 ); if ( connect( m_socket, (SOCKADDR) &server, sizeof(server) ) == SOCKET_ERROR) { cout << "Failed to connect.\n"; WSACleanup(); return 0; } // Send and receive data. int bytesSent; int bytesRecv = SOCKET_ERROR; char sendbuf[32] = "GET /imghp HTTP/1.0"; //get google image search char recvbuf[32] = ""; bytesSent = send( m_socket, sendbuf, strlen(sendbuf), 0 ); while( bytesRecv == SOCKET_ERROR ) { bytesRecv = recv( m_socket, recvbuf, 32, 0 ); cout << recvbuf; if ( bytesRecv == 0 \|\| bytesRecv == WSAECONNRESET ) { cout << "Connection Closed.\n"; break; } if (bytesRecv < 0) return 0; } if (bytesSent == -1) { return 0; } system ("PAUSE"); return 0; } #include <stdio.h> #include <iostream> #include "winsock2.h" using namespace std; int main() { // Initialize Winsock. WSADATA wsaData; int iResult = WSAStartup( MAKEWORD(2,2), &wsaData ); if ( iResult != NO_ERROR ) cout << "Error at WSAStartup()\n"; // Create a socket. SOCKET m_socket; m_socket = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP ); if ( m_socket == INVALID_SOCKET ) { cout << "Error at socket(): \n" << WSAGetLastError(); WSACleanup(); return 0; } // Connect to a server. sockaddr_in server; server.sin_family = AF_INET; server.sin_addr.s_addr = inet_addr( "64.233.167.99" ); //google.com server.sin_port = htons( 80 ); if ( connect( m_socket, (SOCKADDR) &server, sizeof(server) ) == SOCKET_ERROR) { cout << "Failed to connect.\n"; WSACleanup(); return 0; } // Send and receive data. int bytesSent; int bytesRecv = SOCKET_ERROR; char sendbuf[32] = "GET /imghp HTTP/1.0"; //get google image search char recvbuf[32] = ""; bytesSent = send( m_socket, sendbuf, strlen(sendbuf), 0 ); while( bytesRecv == SOCKET_ERROR ) { bytesRecv = recv( m_socket, recvbuf, 32, 0 ); cout << recvbuf; if ( bytesRecv == 0 \|\| bytesRecv == WSAECONNRESET ) { cout << "Connection Closed.\n"; break; } if (bytesRecv < 0) return 0; } if (bytesSent == -1) { return 0; } system ("PAUSE"); return 0; } It just hangs at a black screen! __________________ www.heldtogether.co.uk

Jun 30th, 2006, 11:02 AM	#8
LOI Kratong Professional Programmer Join Date: May 2005 Location: Woo - Boot Sector! Posts: 294 Rep Power: 4	If you look at the website you gave me, this is what the request ought to be sent as, if I'm reading it right... __________________ www.heldtogether.co.uk

Jun 30th, 2006, 10:35 AM	#2
Wizard1988 Professional Programmer Join Date: Oct 2005 Location: Chitown Posts: 417 Rep Power: 4	You might need to look into HTTP Headers. You can connect but the server won't know what you want it to do unless you tell it to.

Jun 30th, 2006, 10:41 AM	#5
Wizard1988 Professional Programmer Join Date: Oct 2005 Location: Chitown Posts: 417 Rep Power: 4	This should help you http://www.perlfect.com/articles/http.shtml

Jun 30th, 2006, 11:00 AM	#7
Wizard1988 Professional Programmer Join Date: Oct 2005 Location: Chitown Posts: 417 Rep Power: 4	It sends the header to the site. There must be something wrong with the formatting of the request.

Jun 30th, 2006, 11:21 AM	#9
Wizard1988 Professional Programmer Join Date: Oct 2005 Location: Chitown Posts: 417 Rep Power: 4	I somewhat got it to work (Toggle Plain Text) #include <stdio.h> #include <iostream> #include "winsock2.h" using namespace std; int main() { // Initialize Winsock. WSADATA wsaData; int iResult = WSAStartup( MAKEWORD(2,2), &wsaData ); if ( iResult != NO_ERROR ) cout << "Error at WSAStartup()\n"; // Create a socket. SOCKET m_socket; m_socket = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP ); if ( m_socket == INVALID_SOCKET ) { cout << "Error at socket(): \n" << WSAGetLastError(); WSACleanup(); return 0; } // Connect to a server. sockaddr_in server; server.sin_family = AF_INET; server.sin_addr.s_addr = inet_addr( "64.233.167.99" ); //google.com server.sin_port = htons( 80 ); if ( connect( m_socket, (SOCKADDR) &server, sizeof(server) ) == SOCKET_ERROR) { cout << "Failed to connect.\n"; WSACleanup(); return 0; } cout << "After connecting" << endl; // Send and receive data. int bytesSent; int bytesRecv = SOCKET_ERROR; char sendbuf[32] = "GET /index.html HTTP/1.1\n\n"; //get google image search char recvbuf[32] = ""; bytesSent = send( m_socket, sendbuf, strlen(sendbuf), 0 ); cout << "After connecting" << endl; while( bytesRecv == SOCKET_ERROR ) { bytesRecv = recv( m_socket, recvbuf, 32, 0 ); cout << recvbuf; if ( bytesRecv == 0 \|\| bytesRecv == WSAECONNRESET ) { cout << "Connection Closed.\n"; break; } if (bytesRecv < 0) return 0; } if (bytesSent == -1) { return 0; } system ("PAUSE"); return 0; } #include <stdio.h> #include <iostream> #include "winsock2.h" using namespace std; int main() { // Initialize Winsock. WSADATA wsaData; int iResult = WSAStartup( MAKEWORD(2,2), &wsaData ); if ( iResult != NO_ERROR ) cout << "Error at WSAStartup()\n"; // Create a socket. SOCKET m_socket; m_socket = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP ); if ( m_socket == INVALID_SOCKET ) { cout << "Error at socket(): \n" << WSAGetLastError(); WSACleanup(); return 0; } // Connect to a server. sockaddr_in server; server.sin_family = AF_INET; server.sin_addr.s_addr = inet_addr( "64.233.167.99" ); //google.com server.sin_port = htons( 80 ); if ( connect( m_socket, (SOCKADDR) &server, sizeof(server) ) == SOCKET_ERROR) { cout << "Failed to connect.\n"; WSACleanup(); return 0; } cout << "After connecting" << endl; // Send and receive data. int bytesSent; int bytesRecv = SOCKET_ERROR; char sendbuf[32] = "GET /index.html HTTP/1.1\n\n"; //get google image search char recvbuf[32] = ""; bytesSent = send( m_socket, sendbuf, strlen(sendbuf), 0 ); cout << "After connecting" << endl; while( bytesRecv == SOCKET_ERROR ) { bytesRecv = recv( m_socket, recvbuf, 32, 0 ); cout << recvbuf; if ( bytesRecv == 0 \|\| bytesRecv == WSAECONNRESET ) { cout << "Connection Closed.\n"; break; } if (bytesRecv < 0) return 0; } if (bytesSent == -1) { return 0; } system ("PAUSE"); return 0; }

Jun 30th, 2006, 11:44 AM	#10
LOI Kratong Professional Programmer Join Date: May 2005 Location: Woo - Boot Sector! Posts: 294 Rep Power: 4	Got it to work in what sense? I tried compiling a slightly modified version: (Toggle Plain Text) #include <stdio.h> #include <iostream> #include "winsock2.h" using namespace std; int main() { // Initialize Winsock. WSADATA wsaData; int iResult = WSAStartup( MAKEWORD(2,2), &wsaData ); if ( iResult != NO_ERROR ) cout << "Error at WSAStartup()\n"; // Create a socket. SOCKET m_socket; m_socket = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP ); if ( m_socket == INVALID_SOCKET ) { cout << "Error at socket(): \n" << WSAGetLastError(); WSACleanup(); return 0; } // Connect to a server. sockaddr_in server; server.sin_family = AF_INET; server.sin_addr.s_addr = inet_addr( "64.233.167.99" ); //google.com server.sin_port = htons( 80 ); if ( connect( m_socket, (SOCKADDR) &server, sizeof(server) ) == SOCKET_ERROR) { cout << "Failed to connect.\n"; WSACleanup(); return 0; } cout << "After connecting" << endl; // Send and receive data. int bytesSent; int bytesRecv = SOCKET_ERROR; char sendbuf[32] = "GET /index.html HTTP/1.1\n\n"; //get google image search char recvbuf[32] = ""; bytesSent = send( m_socket, sendbuf, strlen(sendbuf), 0 ); cout << "Bytes Sent: " << bytesSent << "\n"; cout << "After connecting" << endl; while( bytesRecv == SOCKET_ERROR ) { bytesRecv = recv( m_socket, recvbuf, 32, 0 ); cout << "Bytes Received: " << bytesRecv << "\n"; if ( bytesRecv == 0 \|\| bytesRecv == WSAECONNRESET ) { cout << "Connection Closed.\n"; break; } if (bytesRecv < 0) return 0; } if (bytesSent == -1) { return 0; } system ("PAUSE"); return 0; } #include <stdio.h> #include <iostream> #include "winsock2.h" using namespace std; int main() { // Initialize Winsock. WSADATA wsaData; int iResult = WSAStartup( MAKEWORD(2,2), &wsaData ); if ( iResult != NO_ERROR ) cout << "Error at WSAStartup()\n"; // Create a socket. SOCKET m_socket; m_socket = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP ); if ( m_socket == INVALID_SOCKET ) { cout << "Error at socket(): \n" << WSAGetLastError(); WSACleanup(); return 0; } // Connect to a server. sockaddr_in server; server.sin_family = AF_INET; server.sin_addr.s_addr = inet_addr( "64.233.167.99" ); //google.com server.sin_port = htons( 80 ); if ( connect( m_socket, (SOCKADDR) &server, sizeof(server) ) == SOCKET_ERROR) { cout << "Failed to connect.\n"; WSACleanup(); return 0; } cout << "After connecting" << endl; // Send and receive data. int bytesSent; int bytesRecv = SOCKET_ERROR; char sendbuf[32] = "GET /index.html HTTP/1.1\n\n"; //get google image search char recvbuf[32] = ""; bytesSent = send( m_socket, sendbuf, strlen(sendbuf), 0 ); cout << "Bytes Sent: " << bytesSent << "\n"; cout << "After connecting" << endl; while( bytesRecv == SOCKET_ERROR ) { bytesRecv = recv( m_socket, recvbuf, 32, 0 ); cout << "Bytes Received: " << bytesRecv << "\n"; if ( bytesRecv == 0 \|\| bytesRecv == WSAECONNRESET ) { cout << "Connection Closed.\n"; break; } if (bytesRecv < 0) return 0; } if (bytesSent == -1) { return 0; } system ("PAUSE"); return 0; } And the output is: (Toggle Plain Text) After connecting Bytes Sent: 26 After connecting Bytes Received: 0 Connection Closed. After connecting Bytes Sent: 26 After connecting Bytes Received: 0 Connection Closed. What did you get? __________________ www.heldtogether.co.uk

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Programming Forums > Application Development > C++

Creating a file downloader