Sending out holding pages before final result page

Sticky fields and session example from a Well House Consultants training course
More on Sticky fields and session [link]

This example is described in the following article(s):
• Automating access to a page obscured behind a holding page - [link]

If you're searching for a page where you can try this code, select here

Source code: dozen.php Module: H301


<?php

/* This script shows one of several methods that a server can
use to provide intermediate "please wait" pages back to a browser.

On first request, a cookie is send out together with a page which
includes a refresh header.   The client keeps asking for the page
at the interval speciied each time in the refresh header, until
the final result is presented.  When the final result is sent out,
it does NOT include a refresh header and it deletes the cookie by
resetting it with a negative time. */

if ($_COOKIE[colin]) {
        # Second and subsequent time through
        $elapsed = time () - $_COOKIE[colin] ;
        #  -- See how background processing is doing here  --
} else {
        # First time through / arrival at this page

        # We are very crudely setting cookie value to start time
        # in this demo so that we can check the time without
        # having to set up temporary files, etc. Would probably
        # be a good idea to use PHP's sessions in a live
        # application, but I wanted to show the principles here.

        $elapsed = 0;
        setcookie("colin",time());
        #  -- Start off background processing here --
}

/* Have we reached the end of the processing?  (In this test program
we are simply waiting 20 seconds but with a live program we would be
testing the status returned from the background process */

if ($elapsed < 20) {
        # We're sending (another) "please wait" page
        $mh = '<meta http-equiv="Refresh" content="5; URL=/demo/dozen.php">';
        $report = "%start% Running ... $elapsed seconds gone %end%";
} else {
        # We're sending final result - NO refresh headed
        # And a backward timed cookie to clear out the browser
        $mh = '';
        setcookie("colin","zz_cancel",time()-360000);
        $sayvalend = `uptime`;
        $report = "%start% Completed ... \n$sayvalend %end%";
} ?>
<html>
<head>
<title>Waiting for a result and keeping the user amused</title>
<?= $mh ?>
</head>
<body>
<h1>This is something I needs to thinks about ...</h1>

<b><?= $report ?></b><br>
</body>
</html>

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This module and example are covered on our public PHP Techniques course. If you have a group of three or more trainees who need to learn the subject, we can also arrange a private or on site course for you.

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Other Examples

This example comes from our "Sticky fields and session" training module. You'll find a description of the topic and some other closely related examples on the "Sticky fields and session" module index page.

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