Program is hanging

This is a discussion on Program is hanging within the Networking/Device Communication forums, part of the General Programming Boards category; Hello all, I am trying to make a program to get html code from a web site. I have this ...

  1. #1
    Or working on it anyways mramazing's Avatar
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    Program is hanging

    Hello all,
    I am trying to make a program to get html code from a web site. I have this code which is partly taken from another example i found on the internet. My problem is that when i run the program it hangs... for 10 min. I just cancelled it after that.

    Can anyone tell me why the program is hanging or if maybe something in my code is wrong?

    Code:
    #include <iostream>
    #include <windows.h>
    #include <winsock2.h>
    #include <string>
    using namespace std;
    
    int main()
    {
        WSADATA wsaData;
        WORD version;
        int error;
        
        version = MAKEWORD(2, 0);
        
        error = WSAStartup(version, &wsaData);
        
        if(error != 0)
        {
            return FALSE;
        }
        
        if( LOBYTE(wsaData.wVersion) != 2 || HIBYTE(wsaData.wVersion) != 0) 
        {
            WSACleanup();
            return FALSE;
        }
        
        cout << "Winsock initialized" << endl;
        
        SOCKET client;
        client = socket(AF_INET, SOCK_STREAM, 0);
        
        if(client == INVALID_SOCKET)
        {
            cout << "Socket init failed" << endl;
            
            fflush(stdin);
            cin.get();
            WSACleanup();
            return FALSE;
        }
        
        sockaddr_in sockin;
        sockin.sin_port = htons(80);
        sockin.sin_addr.s_addr = inet_addr("216.239.136.165");
        sockin.sin_family = AF_INET;
        
        if(connect(client, (sockaddr*)&sockin, sizeof(sockin)) == SOCKET_ERROR)
        {
            cout << "Connection failed: " << WSAGetLastError();
            fflush(stdin);
            cin.get();
            WSACleanup();
            
            return FALSE;
        }
        else
        {
            cout << "Connection made to 216.239.136.165" << endl;
        }
        cout << "---------------------------" << endl;
        
        char buffer[1024];
        
        /*for(int i = 0; i < 1024; i++)
        {
            buffer[i] = '\0';
        }*/
        
        char welcome[] = "GET / HTTP/1.1\r\n";
        strcat(welcome, "Host: asdf.com\r\n");
        strcat(welcome, "Connection: close\r\n");
        //strcat(welcome, "Accept: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,/;q=0.5\r\n");
        //strcat(welcome, "Accept-Language: fr,fr-fr;q=0.8,en-us;q=0.5,en;q=0.3\r\n");
        //strcat(welcome, "Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7\r\n");
        //strcat(welcome, "User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; fr; rv:1.8.1.3) Gecko/20070309 Firefox/2.0.0.3\r\n");
        //strcat(welcome, "Referer: http://pozzyx.net/\r\n");
        strcat(welcome, "\r\n");
        
        cout << "Request:: " << endl << welcome << endl;    
        
        send(client, welcome, sizeof(welcome), 0);
        
        string Source = "";
        
        int i = 0;
        do
        {
            i = recv(client, buffer, sizeof(buffer), 0);
            Source += buffer;
            
        }while (i != 0);
        
        cout << Source << endl;
        
        cout << endl << "Done." << endl;
        
        WSACleanup();
        fflush(stdin);
        cin.get();
    }
    -- Will you show me how to c++?

  2. #2
    Guest Sebastiani's Avatar
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    Location
    Waterloo, Texas
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    5,701
    // char welcome[] = "GET / HTTP/1.1\r\n";

    There isn't nearly enough room in there to fit all of your data. Suggestion: store it in an std::string.

    // i = recv(client, buffer, sizeof(buffer), 0);

    recv is going to return either the number of bytes read (could be zero!), or SOCKET_ERROR (which is normally defined as -1). So the typical strategy is to recv until the buffer is partially filled, or an error occurs. Don't forget to null terminate the buffer - recv will not do this for you!
    Code:
    bool flip(bool value)
    {
        return std::pow(std::exp(1), std::complex<float>(0, 1) 
        * std::complex<float>(std::atan(1)*(1 << (value + 2))))
        .real() < 0;
    }

  3. #3
    Registered User slingerland3g's Avatar
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    Seattle
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    Also in troubleshooting such matters are you able to run WireShark perhaps from your Windows client to see how you are actually connecting and insuring you are getting data back? WireShark is a free app for Windows. I use tcpdump on my Linux distros. When writing network apps, there may be nothing wrong with your code at all and now you may have to troubleshoot why something is not working on the network. WireShark can give you a ton of data as far as payload size and such.

  4. #4
    Or working on it anyways mramazing's Avatar
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    Thank you guys. I have wireshark but didnt even think to use it last night it was so late. I will try both ideas and get back to you in a few. Thank you again!
    -- Will you show me how to c++?

  5. #5
    Or working on it anyways mramazing's Avatar
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    So this worked...
    Code:
        string welcome = "GET /about/sites.html HTTP/1.1\r\n";
        welcome += "Host: www.craigslist.org\r\n";
        welcome += "Connection: close\r\n";
        welcome += "\r\n";
    but this did not...
    Code:
        char welcome[] = "GET /about/sites.html HTTP/1.1\r\n";
        strcat(welcome, "Host: www.craigslist.org\r\n");
        strcat(welcome, "Connection: close\r\n");
        strcat(welcome, "\r\n");
    how come?
    -- Will you show me how to c++?

  6. #6
    Or working on it anyways mramazing's Avatar
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    Well it works now. Thank you guys alot. The problem was what i think you said Sebastiani... there wasnt enough room in the request array. So what instead of having

    Code:
    char welcome[] = "GET / HTTP/1.1";
    strcat(welcome, "Host: www.craigslist.org");
    I needed:
    Code:
    char welcome[4098] = "GET / HTTP/1.1";
    strcat(welcome, "Host: www.craigslist.org");
    I was concatenating past the end of my array.
    -- Will you show me how to c++?

  7. #7
    Registered User
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    Sydney, Australia
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    You could of just done:

    Code:
    char welcome[] = "GET /about/sites.html HTTP/1.1\r\n"
                    "Host: www.craigslist.org\r\n"
                    "Connection: close\r\n"
                    "\r\n";

  8. #8
    Or working on it anyways mramazing's Avatar
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    Haha, yes you are right. I cant believe i didnt think of that. Thank you
    -- Will you show me how to c++?

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