CODEWITHSUNDEEP
csocketshttpdownload
Pawan Chaurasiya
Pawan Chaurasiya

Reputation: 901

How can I download a file using C Socket Programming

How can i make a program like internet download manager to download a file of given link from internet. Could use socket programming C to download a file from internet.

Your help will be appreciated. Thanks.

Upvotes: 3

Views: 22851

Answers (2)

Pawan Chaurasiya
Pawan Chaurasiya

Reputation: 901

#include<stdio.h>
#include<string.h>    
#include<sys/socket.h>
#include<arpa/inet.h>

// www.axmag.com/download/pdfurl-guide.pdf
int main(int argc , char *argv[])
{
    int socket_desc;

    char *message;
    char server_reply[10000];
    char *filename = "file.pdf";
    int total_len = 0;
    int file_len = 99352;

    int len; 

    FILE *file = NULL;
    struct sockaddr_in server;

    //Create socket
    socket_desc = socket(AF_INET , SOCK_STREAM , 0);
    if (socket_desc == -1)
    {
        printf("Could not create socket");
    }

    server.sin_addr.s_addr = inet_addr("198.11.181.184");
    server.sin_family = AF_INET;
    server.sin_port = htons( 80 );

    //Connect to remote server
    if (connect(socket_desc , (struct sockaddr *)&server , sizeof(server)) < 0)
    {
        puts("connect error");
        return 1;
    }

    puts("Connected\n");

    //Send request
    message = "GET /download/pdfurl-guide.pdf HTTP/1.1\r\nHost: www.axmag.com\r\n\r\n Connection: keep-alive\r\n\r\n Keep-Alive: 300\r\n";

    if( send(socket_desc , message , strlen(message) , 0) < 0)
    {
        puts("Send failed");
        return 1;
    }

    puts("Data Send\n"); 

    remove(filename);
    file = fopen(filename, "ab");

    if(file == NULL){
        printf("File could not opened");
    }   

    while(1)
    {
        int received_len = recv(socket_desc, server_reply , sizeof server_reply , 0);

        if( received_len < 0 ){
            puts("recv failed");
            break;
        }

        total_len += received_len;

        //puts(server_reply);   
        fwrite(server_reply , received_len , 1, file);

        printf("\nReceived byte size = %d\nTotal lenght = %d", received_len, total_len);

        if( total_len >= file_len ){
            break;
        }   
    }

    puts("Reply received\n");

    fclose(file);

    return 0;
}

Upvotes: 5

alk
alk

Reputation: 70883

  1. Create a socket using socket()
  2. Call connect() on it.
  3. Send a GET /path/filename HTTP/1.0\r\n\r\n request using either send() or write() properly.
  4. Receive the response using either recv() or read() properly.
  5. Parse the response to find out if the request succeeded and what format the file data is being sent as.
  6. Receive the file data, if present, using either recv() or read().
  7. Close the socket using close().

Further readings:

Upvotes: 11

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