/**************************************************************************
*   Persistent CGI Example                                                *
***************************************************************************
*                                                                         *
*  Request this program with following URL:                               *
*  http://hostname:port/cgi-bin/persistc.pgm?bin=1                        *
*                                                                         *
*  This is a demo to demonstrate the capabilities of Persistent CGI on    *
*  the AS/400 platform.  Persistent CGI is an extension to the CGI        *
*  interface that allows a CGI program to remain active across multiple   *
*  browser requests and maintain a session with that browser client.      *
*  This allows files to be left open, the state to be maintained, and     *
*  long running database transactions to be committed or rolled-back      *
*  based on end-user input.  The AS/400 CGI program must be written using *
*  named activation groups which allows the program to remain active      *
*  after returning to the server.  The CGI program notifies the server    *
*  it wants to remain persistent using the "Accept-HTSession" CGI header  *
*  as the first header it returns.  This header defines the session ID    *
*  associated with this instance of the CGI program and is not returned   *
*  to the browser.  Subsequent URL requests to this program must contain  *
*  the session ID as the first parameter after the program name.  The     *
*  server uses this ID to route the request to the specific instance of   *
*  the CGI program.  The CGI program should regenerate this session ID    *
*  for each request.  It is strongly recommended that you use Secure      *
*  Sockets Layer (SSL) for persistent and secure business transaction     *
*  processing.                                                            *
*                                                                         *
*  To create a unique HTSession we combine the process id, which should   *
*  be unique already, with a random number.  For demonstration purposes   *
*  this will be a sufficiently unique Session Id.                         *
*                                                                         *
**************************************************************************/


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
/* System API used to create unique session id */
#include <sys/types.h>
#include <unistd.h>
#define BUFSIZE 1024
unsigned int MAXINPUT = BUFSIZE; /* Maximum input data.*/

int static count = 1;
pid_t static processId = -1;
int static randnum = -1;

int main()
{
char *pt;
char carac[2] = " ";
int bin = 1;
char * sessionId;
char localId[30];

stdin = fopen("stdin", "r");
stdout = fopen("stdout", "w");
stderr = fopen("stderr", "w");

/* get a unique session handle */
if((sessionId = getenv("UNIQUE_ID")) == NULL)
{
    processId = getpid();
    srand((unsigned int)time(NULL));
    randnum = rand();
    sessionId = localId;
    sprintf(sessionId,"%d",(processId + randnum));
}
pt = getenv("QUERY_STRING");
bin = 1;                /* initialize bin to 1 */
if(*pt != '\0')         /* Request without QUERY_STRING uses bin=1 */
{
    carac[0] = pt[4];   /* get 5th char in QUERY_STRING */
    bin=atoi(carac);
}
/*******************************************************************/
/* The following resets the static variable (count) after a timeout*/
/* occurs.  This insures a user always goes back to the initial    */
/* html if his previous persistent session times out               */
/*******************************************************************/
 if (count == 1) /* if the state is initial */  
   bin=1; /* go back to the first form */  
     
/*******************************************************************/
/* Determine which html page to present to the user based on the   */
/* bin value returned from the browser                             */
/*******************************************************************/                                             
if(bin == 1)
{
printf("Accept-HTSession: %s\n", sessionId);
printf("HTTimeout: 1\n");
printf("Content-type: text/html \n\n");
printf("<html><title>Test persistent CGI</title><body>");
printf("<h2> The first form</h2>");
printf("Count: %i",count);
printf("<form action=\"/cgi-bin/persistc.pgm/%s\" ", sessionId);
printf("method=\"GET\"> ");
printf("<input type=HIDDEN NAME=BIN VALUE=2>");
printf("<h2>Start Persistent CGI session</h2>");
printf("<input type=submit value=Execute>");
printf("</form>");
printf("<p><h2>While clicking 'Finish' will end the persistent cgi session ");
printf("after the response has been returned.</h2>");
printf("<form action=\"/cgi-bin/persistc.pgm/%s\" ", sessionId);
printf("method=\"GET\"> ");
printf("<input type=HIDDEN NAME=BIN VALUE=6>");
printf("<input type=submit value=Finish>");
printf("</form> </body></html>");
count++;
}
if(bin == 2)
{
printf("Accept-HTSession: %s\n", sessionId);
printf("Content-type: text/html \n\n");
printf("<html><title> Test persistent CGI</title><body>");
printf("<h2> The second form</h2>");
printf("Count: %i",count);
printf("<form action=\"/cgi-bin/persistc.pgm/%s\" ", sessionId);
printf("method=\"GET\"> ");
printf("<input type=HIDDEN NAME=BIN VALUE=3>");
printf("<h2>Persistent CGI is working if count=2</h2>");
printf("<input type=submit value=Execute>");
printf("</form>");
printf("<p><h2>While clicking 'Finish' will end the persistent cgi session ");
printf("after the response has been returned.</h2>");
printf("<form action=\"/cgi-bin/persistc.pgm/%s\" ", sessionId);
printf("method=\"GET\"> ");
printf("<input type=HIDDEN NAME=BIN VALUE=6>");
printf("<input type=submit value=Finish>");
printf("</form> </body></html>");
count++;
}
if(bin == 3)
{
printf("Accept-HTSession: %s\n", sessionId);
printf("Content-type: text/html \n\n");
printf("<html><title> Test persistent CGI</title><body>");
printf("<h2> The third form</h2>");
printf("Count: %i",count);
printf("<form action=\"/cgi-bin/persistc.pgm/%s\" ", sessionId);
printf("method=\"GET\"> ");
printf("<h2>Persistent CGI is working if count=3</h2>");
printf("<input type=HIDDEN NAME=BIN VALUE=4>");
printf("<input type=submit value=Execute>");
printf("</form>");
printf("<p><h2>While clicking 'Finish' will end the persistent cgi session ");
printf("after the response has been returned.</h2>");
printf("<form action=\"/cgi-bin/persistc.pgm/%s\" ", sessionId);
printf("method=\"GET\"> ");
printf("<input type=HIDDEN NAME=BIN VALUE=6>");
printf("<input type=submit value=Finish>");
printf("</form> </body></html>");
count++;
}
if(bin == 4)
{
printf("Accept-HTSession: %s\n", sessionId);
printf("Content-type: text/html \n\n");
printf("<html><title> Test persistent CGI</title><body>");
printf("<h2> The fourth form</h2>");
printf("Count: %i",count);
printf("<h2>Persistent CGI is working if count=4");
printf("<br>Clicking 'Next' will continue to increment the counter");
printf(" in our persistent session</h2>");
printf("<form action=\"/cgi-bin/persistc.pgm/%s\" ", sessionId);
printf("method=\"GET\"> ");
printf("<input type=HIDDEN NAME=BIN VALUE=5>");
printf("<input type=submit value=Next>");
printf("</form>");
printf("<p><h2>While clicking 'Finish' will end the persistent cgi session ");
printf("after the response has been returned.</h2>");
printf("<form action=\"/cgi-bin/persistc.pgm/%s\" ", sessionId);
printf("method=\"GET\"> ");
printf("<input type=HIDDEN NAME=BIN VALUE=6>");
printf("<input type=submit value=Finish>");
printf("</form> </body></html>");
count++;
}
if(bin == 5)
{
printf("Accept-HTSession: %s\n", sessionId);
printf("Content-type: text/html \n\n");
printf("<html><title> Test persistent CGI</title><body>");
printf("<form action=\"/cgi-bin/persistc.pgm/%s\" ", sessionId);
printf("method=\"GET\"> ");
printf("<h2> The fifth form</h2>");
printf("Count: %i",count);
printf("<h2>Persistent CGI is working if count=5");
printf("<p>Clicking 'Finish' will end the persistent cgi session ");
printf("after the response has been returned.</h2>");
printf("<input type=HIDDEN NAME=BIN VALUE=6>");
printf("<input type=submit value=Finish>");
printf("</form></body></html>");
count++;
}
if(bin == 6)
{
printf("Content-type: text/html \n\n");
printf("<html><title> Test persistent CGI</title><body>");
printf("<h2> The Persistent CGI session is completed.<p> The next");
printf(" request for this program will reset the counter to 1. </h2><p>");
printf("<h2>Click 'Again' to start a new Persistent CGI session.</h2>");
printf("<form action=\"/cgi-bin/persistc.pgm\" ");
printf("method=\"GET\"> ");
printf("<input type=HIDDEN NAME=BIN VALUE=1>");
printf("<input type=submit value=Again>");
printf("</form></body></html>");
count = 1; /* need to reset count */
}
fflush(stdout);
fflush(stderr);
fclose(stdout);
fclose(stdin);
fclose(stderr);
return 0;
}