//===================================================== file = httpget3.c =====
//=  A client program to connect to a Web server and do HTTP GETs             =
//=   - Does NUM_GET parallel GETs and does not output the response           =
//=============================================================================
//=  Notes:                                                                   =
//=    1) This program compiles for Winsock only as it uses threads.          =
//=    2) This program hardwires the IP address of www.grad.csee.usf in the   =
//=       #define IP_ADDR and hardwires the GET request string into           =
//=       #define GET_STRING.                                                 =
//=---------------------------------------------------------------------------=
//=  Output from an execution (hardwired to get Christensen homepage):        =
//=                                                                           =
//=    Start of httpget3.c                                                    =
//=    End of httpget3.c                                                      =
//=---------------------------------------------------------------------------=
//=  Build: bcc32 httpget3.c, cl httpget3.c wsock32.lib,                      =
//=---------------------------------------------------------------------------=
//=  Execute: httpget3                                                        =
//=---------------------------------------------------------------------------=
//=  History:  KJC (01/04/01) - Genesis (from httpget2.c)                     =
//=============================================================================

//----- Include files ---------------------------------------------------------
#include <stdio.h>          // Needed for printf()
#include <stdlib.h>         // Needed for exit()
#include <string.h>         // Needed for strcpy() and strlen()
#include <windows.h>        // Needed for all Winsock stuff
#include <process.h>        // Needed for _beginthread() and _endthread()

//----- Defines ---------------------------------------------------------------
#define  BUF_SIZE            4096     // Buffer size
#define  PORT_NUM              80     // Web servers are at port 80
#define  NUM_GET               10     // Number of serial GETs to do
#define  IP_ADDR    "131.247.3.1" // IP address of www.csee.usf.edu
#define  GET_STRING "GET /~christen/index.html HTTP/1.0\n\n"  // GET string

//----- Globals -------------------------------------------------------------
int Count;                            // Global thread counter

//----- Function prototypes -------------------------------------------------
void do_get(void *in_arg);            // Thread function to do a GET

//===== Main program ==========================================================
void main(void)
{
  WORD wVersionRequested = MAKEWORD(1,1);    // Stuff for WSA functions
  WSADATA wsaData;                           // Stuff for WSA functions
  unsigned int         retcode;              // Return code
  unsigned int         i;                    // Loop counter

  // This stuff initializes winsock
  WSAStartup(wVersionRequested, &wsaData);

  // Output start message and do NUM_GET GETs
  printf("Start of httpget3.c \n");
  Count = 0;
  for (i=0; i<NUM_GET; i++)
  {
    Count++;
    if (_beginthread(do_get, 4096, (void *)i) < 0)
    {
      printf("ERROR - Unable to create thread \n");
      exit(1);
    }
  }

  // Wait for all threads to finish
  while(Count);

  // Output end message
  printf("End of httpget3.c \n");

  // This stuff cleans-up winsock
  WSACleanup();
}

//===========================================================================
//=  Thread function to do a get                                            =
//===========================================================================
void do_get(void *in_arg)
{
  unsigned int         server_s;             // Server socket descriptor
  struct sockaddr_in   server_addr;          // Server Internet address
  char                 out_buf[BUF_SIZE];    // Output buffer for GET request
  char                 in_buf[BUF_SIZE];     // Input buffer for response
  unsigned int         retcode;              // Return code
  unsigned int         i;                    // Loop counter

  // Create a socket
  server_s = socket(AF_INET, SOCK_STREAM, 0);

  // Fill-in the Web server socket's address information
  server_addr.sin_family = AF_INET;                 // Address family to use
  server_addr.sin_port = htons(PORT_NUM);           // Port num to use
  server_addr.sin_addr.s_addr = inet_addr(IP_ADDR); // IP address to use

  // Do a connect (connect() blocks)
  retcode = connect(server_s, (struct sockaddr *)&server_addr,
                    sizeof(server_addr));
  if (retcode != 0)
  {
    Count--;
    printf("ERROR - connect() failed \n");
    _endthread();
    exit(1);
  }

  // Send a GET to the Web server
  strcpy(out_buf, GET_STRING);
  send(server_s, out_buf, strlen(out_buf), 0);

  // Receive from the Web server
  //  - The return code from recv() is the number of bytes received
  retcode = recv(server_s, in_buf, BUF_SIZE, 0);
  while ((retcode > 0) || (retcode == -1))
  {
    if (retcode == -1)
    {
      Count--;
      printf("ERROR - recv() failed \n");
      _endthread();
      exit(1);
    }
    retcode = recv(server_s, in_buf, BUF_SIZE, 0);
  }

  // Decrement for a completed thread
  Count--;

  // Close all open sockets and end the thread
  closesocket(server_s);
  _endthread();
}