Socket web browser

This is a discussion on Socket web browser within the Networking/Device Communication forums, part of the General Programming Boards category; I am trying to create a simple web browser, but I have not found any tutorials. I have read a ...

  1. #1
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    Socket web browser

    I am trying to create a simple web browser, but I have not found any tutorials. I have read a socket tutorial (but it is not on creating a web browser), and the code I give below is what I have come with. I do not know why it does not work at all. It kind of stops at the receive part. I used a packet sniffer and saw that I was sending some data to the site address, but I am not getting the webpage HTML code back. Can somebody tell me what I am doing wrong?

    Code:
    #include <stdio.h>
    #include <stdlib.h>
    #include <errno.h>
    #include <winsock.h>
    
    WSADATA wsaData;
    char buf[100];
    int socketsrc, bytesRecv, bytesSent;
    struct sockaddr_in dest_addr;
    struct hostent *h;
    char *msg = "GET / HTTP/1.1";
    
    int main(int argc, char *argv[])
    {
        if (WSAStartup(MAKEWORD(1, 1), &wsaData) != 0)
    {
        fprintf(stderr, "WSAStartup failed.\n");
        exit(1);
        }
        if ((socketsrc = socket(AF_INET, SOCK_STREAM, 0)) == -1)
        {
         perror("socket");
         exit(1);
         }
        printf("\nsuccess: socket");
    
         if (argc != 2) { // error check the command line
         fprintf(stderr,"usage: getip address\n");
         exit(1);
         }
         if ((h=gethostbyname(argv[1])) == NULL) { // get the host info
         printf("\nNo Host for %s", argv[1]);
         exit(1);
         }
        printf("\nsuccess: hostname");
        dest_addr.sin_family = AF_INET; // host byte order
        dest_addr.sin_port = htons(80); // short, network byte order
        dest_addr.sin_addr.s_addr = inet_addr("216.239.57.99");
        memset(&(dest_addr.sin_zero), 0, 8); // zero the rest of the struct
        
        if (connect(socketsrc, (struct sockaddr *)&dest_addr,
        sizeof(struct sockaddr)) == -1) {
        perror("connect");
        exit(1);
        }
        printf("\nsuccess: connect");
            
        bytesSent = send(socketsrc, msg, strlen(msg), 0);
        printf( "\nBytes Sent: %d", bytesSent );
    
        //and this is where I think the program just stops
    
        while((bytesRecv = recv( socketsrc, buf, 99, 0 )) != -1 ) {
          if ( bytesRecv == 0) {
           printf( "\nConnection Closed.");
           break;
          }
        printf( "\nBytes Recv: %d", bytesRecv );
        }
    
        printf("\nsuccess: recieve");
        closesocket(socketsrc);
    
        WSACleanup();
        return 0;
    }

  2. #2
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    Moved to the Networking Board.

  3. #3
    Registered User Tonto's Avatar
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    Perhaps your request (char* msg) should be more like "GET / HTTP/1.1\r\nHost: www.thesitehere.com\r\n\r\n" at a bare minimum. \r\n is a crlf (google), like pressing enter in a telnet/ssh client. Otherwise this looks pretty clean. I am pretty fond of this tutorial for your basic winsock blocking client (C++): http://madwizard.org/view.php?page=t...pter6&lang=cpp whereas your code is pure C off MSDN Hope changing your HTTP request works! Also, the strings you recv from your socket are not null-terminated (don't want 00 lying about image data). If you wish to print them, you might for instance:

    Code:
    	recvBuffer[iRet] = 0x00;
    	std::cout << recvBuffer;
    Lines up so perfectly.

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    Smile

    Wow! Thanks, now I am finally getting some results!
    I didn't even know I was just writing in pure C -.-

    Unfortunately, since I am kind of a beginner to C, I do not really understand your code. I can hardly even understand my code Well like I can tell what the second line does, which is display the string, but I do not know what 0x00 means, and not even how to get the string from the recv().

    I am improving though, at least I hope so. I will try to follow the tutorial that you suggested, since it seems that it is what I am trying to do. Maybe I will be able to understand all this stuff soon.

    Thanks for the quick reply!

    I also have a really really noob question:
    How do I get the cin and cout to work? It just says that it is undeclared...

    I am trying to use this code:
    Code:
    cout<<Starting Up;
    but this doesn't work either
    Code:
    std::cout<<Starting Up;
    I think you can already tell I do not know too much about c++.
    I've been too spoiled by PHP.. -.-
    Plus I never used classes in PHP cause I never found any use for them.

    I hope I haven't scared you away with so many questions
    The only things I think I need is why cout doesn't work and what recvBuffer[iRet] = 0x00 is. I will try to figure out the rest with the tutorial you gave.

    Many Thanks!

  5. #5
    Registered User Tonto's Avatar
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    '\0' == 0 == 0x00 == \x00 == \000 It is all exactly the same. I chose 0x00 to make it line up nicely and make it look cool. I was very into that. To use cout in your app, you would #include <iostream>. C++ headers do not end in a .h Check out this brief tutorial: http://cplus.about.com/od/beginnerct.../aa022302a.htm but don't feel obligated to throw yourself into C++, if you're comfortable (or somewhat more so) with C at the time-being.
    Last edited by Tonto; 09-21-2005 at 11:19 PM.

  6. #6
    C++ Enthusiast jmd15's Avatar
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    Quote Originally Posted by digitaltsai
    Code:
    cout<<Starting Up;
    How can "Starting Up" be a single variable? That isn't a legal variable name, notice the space in between. If it is two different variables you need to add an extra "<<" in between the two names. Maybe that's why that "cout" code wasn't working?
    Try something like this:
    Code:
    cout<<Starting_Up;
    //or if they are two variables try this
    cout<<Starting<<Up;
    Just wanted to point that out.
    Trinity: "Neo... nobody has ever done this before."
    Neo: "That's why it's going to work."
    c9915ec6c1f3b876ddf38514adbb94f0

  7. #7
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    O bleh.
    I meant to put quotes around that
    the include iostream works!
    I don't see why we need to include all these files. Why not just include like one file that is a combination of everything?

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    How do I set the temporary buffer in the receive to be the size of the incoming data?
    [edit]
    Nevermind, figured that it doesn't matter

    Now I just have to figure out why the last buffer is so weird...
    Last edited by digitaltsai; 09-22-2005 at 09:31 PM.

  9. #9
    C++ Enthusiast jmd15's Avatar
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    How is it weird, and what are you storing into it? Which buffer are you talking about?
    Trinity: "Neo... nobody has ever done this before."
    Neo: "That's why it's going to work."
    c9915ec6c1f3b876ddf38514adbb94f0

  10. #10
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    buffer of the recv
    It give me back the correct stuff, then a 0, then repeats part of the correct stuff again. <-all this is in the last buffer

  11. #11
    Registered User Tonto's Avatar
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    Might we see the new code you're using? We're not psychic!

  12. #12
    C++ Enthusiast jmd15's Avatar
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    Well have you tried clearing that buffer's memory? Maybe it's just appending it each time it receives. That's my best guess without code to look at.
    Trinity: "Neo... nobody has ever done this before."
    Neo: "That's why it's going to work."
    c9915ec6c1f3b876ddf38514adbb94f0

  13. #13
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    I found the problem!
    This is kind of dumb, since Tonto made a statement about the recv buffer not being null-terminated. I did not know what a string not being null-terminated meant before so I thought he meant something about the while loop never ending since it will never receive NULL. Now that you are thoroughly confused about what I was saying, here was my problem:
    Code:
    buf[bytesRecv] == 0;
    Here is my code if someone finds this thread and wants to create something to get the HTML from a site:
    http://lelements.net/files/gethtml.txt
    *Use at your own risk, just because it works for me doesn't mean it works for you.

    How would I read the individual bytes of the buffer I receive in HEX?
    How would I send a packet in HEX also?

    Thanks for all your helps!

  14. #14
    C++ Enthusiast jmd15's Avatar
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    Do you mean bytes or characters? Like you receive a buffer full of different characters and want to pick out a single one, is that what you mean?
    Trinity: "Neo... nobody has ever done this before."
    Neo: "That's why it's going to work."
    c9915ec6c1f3b876ddf38514adbb94f0

  15. #15
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    Please, If you are a beginner at C, then don't attempt to write this. You started out by saying there are no tutorials on building web browsers. This is true because writing a web browser is increidbly complex. If you are capable of writing a web browser then you don't need a tutorial.
    Sockets also have zero to do with C. If you are new to C then you shouldn't be writing a socket application. Learn the language first, then learn third party things, such as sockets.
    By this point you are ready to say to me: I've started this application and have made some headway in this program. After I finish this I'll go back and learn C properly. Besides, I learn things better by jumping in over my head.
    My response to that? Bull. Without a strong grasp of C you are just going to be asking a lot of annoying questions to get yoru program to work. Such as:
    How would I read the individual bytes of the buffer I receive in HEX?
    How would I send a packet in HEX also?
    These questions are silly.
    Go learn C, come back later. I know you don't want to hear that but hey, that's life, deal with it.

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