Uploading file to a server

[starter08]

Hi,
I have a C++ function which sends a post request to a server for uploading a file.
I have also written a server side cgi to receive the data and create the file in a specified directory.
The server side cgi creates a file, however it is blank, I don't see any errors in the log files (apache2/error.log)
Below is my server side script

!/usr/bin/perl -wT
 
use strict;
use CGI;
use CGI::Carp qw ( fatalsToBrowser );
use File::Basename;
 
$CGI::POST_MAX = 10240 * 5000;
my $safe_filename_characters = "a-zA-Z0-9_.-";
my $upload_dir = "/usr/local/web/upload";
 
my $query = new CGI;
my $filename = $query->param("flat_file");
#my $email_address = $query->param("email_address");
 
if ( !$filename )
{
 print $query->header ( );
 print "There was a problem uploading your file (try a smaller file).";
 exit;
}
 
my ( $name, $path, $extension ) = fileparse ( $filename, '\..*' );
$filename = $name . $extension;
$filename =~ tr/ /_/;
$filename =~ s/[^$safe_filename_characters]//g;
 
if ( $filename =~ /^([$safe_filename_characters]+)$/ )
{
 $filename = $1;
}
else
{
 die "Filename contains invalid characters";
}
 
my $upload_filehandle = $query->upload("flat_file");
 
open ( UPLOADFILE, ">$upload_dir/$filename" ) or die "$!";
binmode UPLOADFILE;
 
while ( <$upload_filehandle> )
{
 print UPLOADFILE;
}
 
close UPLOADFILE;
 
print $query->header ( ); 
 

Appreciate if anybody can point out what I am doing wrong in the script.
I can post my C++ code also if needed, it's a bit longer so I am not posting it right now.

Thanks,

[numberwhun]

You have:

print UPOADFILE;
 

but you aren't telling it what to print. If you want to use the default variable, then put it in there, like so:

print UPOADFILE ("$_\n");
 

Regards,

Jeff

[starter08]

You have:

print UPOADFILE;
 

but you aren't telling it what to print. If you want to use the default variable, then put it in there, like so:

print UPOADFILE ("$_\n");
 

Regards,

Jeff

Hi jeff,
Thanks for the quick reply, I modified the script as per your suggestion, still the uploaded file is blank.
Thanks,
Mohit

[KevinADC]

what is the enctype of the <form> tag?

[starter08]

what is the enctype of the <form> tag?

Here is my C++ code which sends a post request to the server for file upload. I am using Content-Disposition: multipart/form-data

int Send_to_DB_via_HTTP(char* Traveller_output_buffer, unsigned data_len, string fileName, string servIP, string url)
{
 
     int sock;                          /*  Socket descriptor */
        struct sockaddr_in echoServAddr;   /*  server address */
        unsigned short echoServPort;       /*  server port */
        //char *servIP;                      /*  Server IP address (dotted quad) */
    //char *url;
        char *echoString;                  /*  String to send to echo server */
        char echoBuffer[RCVBUFSIZE];       /* Buffer for echo string */
        unsigned int echoStringLen;        /* Length of string to echo */
        int bytesRcvd, totalBytesRcvd;     /* Bytes read in single recv()
                                                   and total bytes read */
    int                         first_form_len=0;
        int                         second_form_len=0;
    unsigned             count = 0;
    int    count1 = 0;
    int    count2 = 0;
    char buf[2000];
    int n;
    const char *m_servIP;
    const char *m_url;
    m_servIP = servIP.c_str();
    m_url = url.c_str();
    //servIP = "192.168.2.20";
    echoServPort = 80;
    //url = "http://tewaris.dyndns.org/";
 
     /*Create a reliable, stream socket using TCP */
 
    if ((sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
          cout << " socket () failed" << endl;
 
    /* Construct the server address structure */
 
    memset(&echoServAddr, 0, sizeof(echoServAddr));         /* Zero out structure */
    echoServAddr.sin_family         = PF_INET;              /* Internet address family */
    echoServAddr.sin_addr.s_addr = inet_addr(m_servIP);       /* Server IP address */
    echoServAddr.sin_port           = htons(echoServPort); /* Server port */
 
    /* Establish the connection to the echo server */
    int k;
    k = connect(sock, (struct sockaddr *) &echoServAddr, sizeof(echoServAddr));
    //cout << k << endl;
    //if (connect(sock, (struct sockaddr *) &echoServAddr, sizeof(echoServAddr)) < 0)
    if (k < 0)
    {
          cout<< "Error Connecting to " << servIP << endl;
    return -1;
    }
    else
     cout << "Connection Successfull to " << servIP << endl;
 
     //Start the form off with the boundary string
 
    first_form_len += snprintf(
                        &buffer1[first_form_len],
                        sizeof(buffer1) - first_form_len,
                        "%s%s\r\n",
                        "--",BOUNDARY_STRING );
    //Some random filename - must end in .dat because web server checks
    //This is the data portion of the form - the flat file will be sent in this section
    first_form_len += snprintf(
                        &buffer1[first_form_len],
                        sizeof(buffer1) - first_form_len,
                        "Content-Disposition: form-data; name=\"flat_file\"; filename=\"travellerdata.dat\"\r\n" );
 
    first_form_len += snprintf(
                        &buffer1[first_form_len],
                        sizeof(buffer1) - first_form_len,
                        "Content-Type: text/plain\r\n\r\n" );
 
 
    //Prepare the ending part of the form-data - this follows the flat file contents
 
 
    //Start the form off with the boundary string
    second_form_len += snprintf(
                        &buffer1[first_form_len+second_form_len],
                        sizeof(buffer1) - (first_form_len+second_form_len),
                        "%s%s\r\n",
                        "--",BOUNDARY_STRING );
    //Not sure why they have this hidden field, but we need to include it or else
    //the web server will reject
    //char system_serial_number[SERIAL_NUMBER_MAX_STRING_LENGTH+1];
    //Get_serial_number_string( system_serial_number, sizeof(system_serial_number) );
    second_form_len += snprintf(
                        &buffer1[(first_form_len+second_form_len)],
                        sizeof(buffer1) - (first_form_len+second_form_len),
                        "Content-Disposition: form-data; name=\"filename\"\r\n\r\n%s_auto_end\r\n",
                        syssn_no );
 
    //End of multi-part form
    second_form_len += snprintf(
                        &buffer1[(first_form_len+second_form_len)],
                        sizeof(buffer1) - (first_form_len+second_form_len),
                        "%s%s%s\r\n",
                        "--",BOUNDARY_STRING,"--" );
 
 
    // Put together the headers for HTTP POST
    count = snprintf(
                       &buffer[0],
                       sizeof(buffer),
                       "POST %s HTTP/1.1\r\n",
                       m_url);
    /*count = snprintf(
                       &buffer[0],
                       sizeof(buffer),
                       "Connection: %s Keep-Alive\r\n",
                       "");*/
    count += snprintf(
                        &buffer[count],
                        sizeof(buffer) - count,
                        "Accept-Language: en-us\r\n" );
    count += snprintf(
                        &buffer[count],
                        sizeof(buffer) - count,
                        "Content-Type: multipart/form-data; boundary=%s\r\n",
                        BOUNDARY_STRING);
 
 
    count += snprintf(
                        &buffer[count],
                        sizeof(buffer) - count,
                        "User-Agent: Mozilla/3.01 (compatible)\r\n");
    count += snprintf(
                        &buffer[count],
                        sizeof(buffer) - count,
                        "Host: %s\r\n",
                        m_servIP);
 
 
    count += snprintf(
                        &buffer[count],
                        sizeof(buffer) - count,
                        "Pragma: no-cache\r\n" );
    count += snprintf(
                        &buffer[count],
                        sizeof(buffer) - count,
                        "Content-Length: %d\r\n",
                        data_len+first_form_len+second_form_len );
    count += snprintf(
                        &buffer[count],
                        sizeof(buffer) - count,
                        "Connection: Keep-Alive\r\n" );
    count += snprintf(
                        &buffer[count],
                        sizeof(buffer) - count,
                        "\r\n" );
    //cout << buffer << endl;
   count1 += snprintf(
            &buffer2[count1],
            sizeof(buffer2) - count1,
            "%s%s\r\n",
                        "--",BOUNDARY_STRING);
 
   count1 += snprintf(
            &buffer2[count1],
            sizeof(buffer2) - count1,
            "Content-Disposition: multipart/form-data; name=\"flat_file\";filename=\"travellerdata.dat\"\r\n",
            "\r\n");
   count1 += snprintf(
            &buffer2[count1],
            sizeof(buffer2) - count1,
            "Content-Type: text/plain\r\n");
   count1 += snprintf(
            &buffer2[count1],
            sizeof(buffer2) - count1,
            "Content-Length: %d\r\n", data_len+count1);
   count2 += snprintf(
            &buffer3[count2],
            sizeof(buffer3) - (count1+count2),
            "%s%s%s\r\n",
            "--",BOUNDARY_STRING, "--");
 
    string status;
 
    cout << "Sending Post Headers" << endl<< buffer << endl << "End Post Headers" << endl;
 
    //Send the "POST" header to the HTTP server.
    if (send(sock, buffer, count, 0) == -1) {
 
        //status = perror("send");
        cout << "Stats Worker: received socket error %d on header send\n" << endl;
        return -1;
    }
    /*else
    {
        cout << "data Sent" << endl;
    }*/
 
    cout << "Now Sending first part of the form data BUFFER1" << endl << buffer1 << endl<< "End First Part"<< endl;
 
 
 
    if (send(sock, buffer1, first_form_len, 0) == -1) {
 
        //status = CK_Get_last_error();
        cout << "Stats Worker: received socket error on header send\n" << endl;
        return -1;
    }
    cout << "Sending start boundary string " << endl << buffer2 << endl;
    if (send(sock, buffer2, count1, 0) == -1) {
 
        //status = perror("send");
        cout << "Stats Worker: received socket error %d on header send\n" << endl;
        return -1;
    }
    cout << "Now Sending file " << Traveller_output_buffer << endl;
    //Now send the flat file
    if (send(sock, Traveller_output_buffer, data_len, 0) == -1) {
 
        //status = CK_Get_last_error();
 
        cout << "Stats Worker: received socket error %d on message send\n" << endl;
        return -1;
    }
    cout << "Sending ending boundary string " << endl << buffer3 << endl;
    if (send(sock, buffer3, count2, 0) == -1) {
 
        //status = perror("send");
        cout << "Stats Worker: received socket error %d on header send\n" << endl;
        return -1;
    }
    /*cout << "Sending Last part of the form data" <<  endl << buffer1+first_form_len << endl;
 
    //Send the last part of the form data to the HTTP server.
    if (send(sock, buffer1+first_form_len, second_form_len, 0) == -1) {
 
        //status = CK_Get_last_error();
        cout << "Stats Worker: received socket error %d on header send\n" << endl;
        return -1;
    }*/
    /*else
    {
        cout << "Data has been Sent Successfully" << endl;
    }*/
 
    //Receive server response
    //cout << "Buffer = " << buf << endl;
    n = recv(sock, buf, 2000, 0);
    //cout << "Server Response is " << endl << buf << endl;
    if(n < 0)
    {
        cout << "Upload Failed" << endl;
        return -1;
    }
 
    // Make sure this is a HTTP header
    if (!strstr(buf, "HTTP")) {
 
        cout << "Stats Worker: response doesn't contain HTTP\n";
        return -1;
    }
 
    if (n < 0) {
 
        cout << "Stats Worker: response status is " << n;
        return -1;
    }
 
        // while (n > 0) {
     //printf(buf);
            if(!strstr(buf, Successful_Upload))
         {
        cout << "Traveller Upload Failed. Server Responded " << buf;
        return -1;
        }
         else
        {
         cout << "Traveller Upload Successfull. \n Server Response is \n" << buf;
         //return 0;
        }
            //n = recv(sock, buf, 10480, 0);
         //}
 
//close(sock);
}
 

Appreciate any help.
Thanks

[KevinADC]

I don't know C++. If you are using the correct enctype and the POST method and you are getting no error messages when running the script it is most likely a server issue. Try using a differnt directy to write the file to.

[KevinADC]

Are you uploading a file smaller than the post max setting?

$CGI::POST_MAX = 10240 * 5000;

5 megabytes in this case.

[starter08]

Are you uploading a file smaller than the post max setting?

$CGI::POST_MAX = 10240 * 5000;

5 megabytes in this case.

Hi,
Thanks for replying. Yes I am uploading just a 2 megabytes file and it's always going to be this size.
Thanks,

[KevinADC]

try writing to a different directory.

[starter08]

try writing to a different directory.

Hi Kevin,
Thanks for all the suggestions. I tried writing to a different directories however no success, still the uploaded file is blank.
I think maybe there is something wrong or missing in my C++ code.
I will try some C++ forums.
Though thanks for all your suggestions.
Thanks,
Mohit

[eWish]

Not sure if this will help, but you could look at an article that was written by a member on how to upload files. Are you trying to upload a text file or image?

You might compare your code.

Just a thought. Also, I suppose that your problem could be coming from the C++.

--Kevin

[starter08]

Not sure if this will help, but you could look at an article that was written by a member on how to upload files. Are you trying to upload a text file or image?

You might compare your code.

Just a thought. Also, I suppose that your problem could be coming from the C++.

--Kevin

Hi Kevin,
Thanks for the reply. I am trying to upload a text file. I already read the article you have pointed to.
Still I am getting a blank file. It seems like the cgi script is not seeing the file data that I am sending through the socket.
Thanks,
Mohit