WinSock protocol

I am trying to build a script for testing a python based desktop application which sends files to the server.

I have created the script after recording the actual application.

How can I send the contents of different file to the server (instead of sending the same data while recording) each iteration.

The code for init is 

/*********************************************************************
 * Created by Windows Sockets Recorder
 *
 * Created on: Thu Jan 29 02:22:11
 *********************************************************************/

#include "lrs.h"
#define SEEK_SET 0 /* beginning of file. */
#define SEEK_CUR 1 /* current position. */
#define SEEK_END 3726

vuser_init()
{
    char *recvbuf;
     int recvlen=0;
    int rc;
    lrs_startup(257);
    
    lr_start_transaction("VV_01_AMT_000_Conn_socket");

   rc=lrs_create_socket("socket0", "TCP", "RemoteHost=am-us-tos-vvsit.hughestelematics.net:15557",  LrsLastArg);
   
    if (rc != 0 ) 
    {
        lr_output_message("%s","Unable to connect to host");
        lr_end_transaction("VV_01_AMT_000_Conn_socket", LR_FAIL);
        return 0;
    }
    
    lrs_send("socket0", "buf0", LrsLastArg);

    lrs_receive("socket0", "buf1", LrsLastArg);
    
    lrs_get_last_received_buffer("socket0",&recvbuf,&recvlen);
    
    if(recvlen==53)
    {
        lr_output_message("%s","Unable to connect to host");
         lr_end_transaction("VV_01_AMT_000_Conn_socket", LR_FAIL);
        return 0;
    }
    
    lr_end_transaction("VV_01_AMT_000_Conn_socket", LR_AUTO);
     

    return 0;
}

for Action is

/*********************************************************************
 * Created by Windows Sockets Recorder
 *
 * Created on: Thu Jan 29 02:22:11
 *********************************************************************/

#include "lrs.h"


Action()
{
    char *recvbuf;
     int recvlen=0;
     int rc=0;
    char filename[100];
    char *file_contents;
    int input_file_size;
    long packetFile;
//    strcpy(filename,lr_eval_string("{P_FileName}"));
//    packetFile= fopen(filename,"rb+");
//    if( packetFile == NULL )
//    {
//      lr_output_message("Error while opening the file.\n");
//    }
//    file_contents = (char*)malloc(3726 * (sizeof(char)));
//    fread(file_contents, sizeof(char), 3726, packetFile);
//    fclose(packetFile);
    
//    lr_output_message("%s",file_contents);

        

   lr_start_transaction("VV_01_AMT_010_SendPacket");
   
//    lrs_set_send_buffer("socket0",file_contents,3726);
//    rc=lrs_length_send("socket0", "buf2",0,"Encoding=0",LrsLastArg);
    rc=lrs_send("socket0", "buf2", LrsLastArg);
    
 
    
    if(rc==WSAECONNRESET || rc==WSAECONNABORTED)
    {
        lr_stop_transaction("VV_01_AMT_010_SendPacket");
        lr_output_message("Connection Lost midway trying to reconnect Error=%d",rc);
        ConnectHost();
        lr_resume_transaction("VV_01_AMT_010_SendPacket");
//        lrs_set_send_buffer("socket0",file_contents,3726);
        rc=lrs_send("socket0", "buf2", LrsLastArg);
    }
    
       rc=lrs_receive("socket0", "buf3", LrsLastArg);
    
    lrs_get_last_received_buffer("socket0",&recvbuf,&recvlen);
    
    if(recvlen>=15)
    {
        lr_output_message("Received Buffer = %s",recvbuf);
        lr_end_transaction("VV_01_AMT_010_SendPacket", LR_PASS);
    }
     else
     {
         lr_error_message("Unable to send packet Error =%d",rc);
         lr_end_transaction("VV_01_AMT_010_SendPacket", LR_FAIL);
     }


//    lr_think_time(300);
    
    return 0;
}

the above line in orange sends the recorded data(i.e. a file data).

How can we send custom data from specified file??