Progressbar

• This is a demo module which implements a progress bar
• This demo simulates a slowish function by iterating over a sleep statement
• On each iteration the progress is updated in the database
• If the user has javascript it will attach an action to the 'start' link - calling the work function via ajax

Note: A demonstration of this module can be found at:
http://www.practicalweb.co.uk/progresbardemo

$.get does the magic bit

$.get(url, params, callback)

Load a remote page using an HTTP GET request.

Parameters

* url (String): The URL of the page to load.
* params (Map): (optional) Key/value pairs that will be sent to the server.
* callback (Function): (optional) A function to be executed whenever the data is loaded successfully.

see http://visualjquery.com/1.1.2.html for more detail

in this case

• the uri is progresbardemo/work_ajax
• there are no params to pass
• the callback is a function that prepares to add the result of the 'work' function to the page and stop the progressbar when the ajax call completes.

After starting the ajax call the javascript then sets up a monitor which periodically calls /progresbardemo/monitor

If the user doesn't have javascript enabled the link takes them to progresbardemo/work - performing the same function but without a progressbar to keep them entertained.

<?php
/**
* page callback for javascript
*
* Normally I'd just include a javascript file
* but I wanted to put all the code in one file for this demo
*
*/
function progresbardemo_javascript() {

    $content = '
if (Drupal.jsEnabled) {
  $(document).ready(function() {
    $("#clickme").click(function() {
      titlediv = $("#clickme").parent();
      pb = new Drupal.progressBar(\'myProgressBar\');
      $(pb.element).appendTo("#progress");
      pb.setProgress("0", "processing...");
      uri = \'/progresbardemo/work_ajax\';
      $.get(uri , \'\', function(data) {
        $("#fillme").empty();
        $("#fillme").append(data);
        pb.stopMonitoring();
          pb.setProgress("100", "done");
      });
      pb.startMonitoring(\'/progresbardemo/monitor\', 1000);
      return false;
    })
  })
}
    ';

    header("Content-type: text/javascript");
    print $content;
    exit();
}

/**
* Page callback for the demo start page
*
* @return html output
*/
function progresbardemo_page() {


    drupal_add_js('misc/progress.js');
    drupal_add_js('progresbardemo/javascript');
    $output .= '<h2>Progress Bar Demo</h2>';
    $output .= '<div><p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'. l('Start', 'progresbardemo/work', array('id' => 'clickme')) .'</p></div>';
    $output .= '<div id="fillme"></div>';
    $output .= '<div id="progress"></div>';
   
    return $output;
}

/**
* Do the work
* This function can be called directly as a menu callback where it will provide the page content
* Or via the ajax callback function
*
* @return html content
*/
function progresbardemo_work() {
   
    $progres = 0;
    db_query("insert into {variable} (name, value) values ('progresbardemo_progres', '%s')", $progres);
    define('PERCENT', 100);
    define('STEPS', 20);
    while ($progres < PERCENT) {
     sleep(1);
     $progres += (PERCENT / STEPS);
     db_query("update {variable} set value = '%s' where name = 'progresbardemo_progres'", $progres);
    }
    db_query("delete from {variable} where name='progresbardemo_progres'");
    return "<p>all done</p>";
}

/**
* Do the task - called in ajax context - return the result without the page wrapper
*/
function progresbardemo_work_ajax() {
    print progresbardemo_work();
    exit();

}
/**
* called by the ajax monitor
*/
function progresbardemo_monitor() {
    $progres = (int) db_result(db_query("select value from {variable}  where name='progresbardemo_progres'"));
   
    print drupal_to_js(array('status' => TRUE, 'percentage' => $progres, 'message' => "working... $progres"));
    exit();
}






/**
* define the menu
* implementation of hook_menu
*
* @return menu array
*/

function progresbardemo_menu($may_cache) {
    $items = array();

    if (!$may_cache) {

        $items[] =  array(
                    'type'          => MENU_NORMAL_ITEM,
                    'title'             => t("Progress Bar Demo"),
                    'path'          => 'progresbardemo',
                    'callback'  => 'progresbardemo_page',
                    'access'        => TRUE
        );

        $items[] =  array(
                    'type'          => MENU_CALLBACK,
                    'path'          => 'progresbardemo/work',
                    'callback'  => 'progresbardemo_work',
                    'access'        => TRUE
        );

        $items[] =  array(
                    'type'          => MENU_CALLBACK,
                    'path'          => 'progresbardemo/work_ajax',
                    'callback'  => 'progresbardemo_work_ajax',
                    'access'        => TRUE
        );

        $items[] =  array(
                    'type'          => MENU_CALLBACK,
                    'path'          => 'progresbardemo/monitor',
                    'callback'  => 'progresbardemo_monitor',
                    'access'        => TRUE
        );

        $items[] =  array(
                    'type'          => MENU_CALLBACK,
                    'path'          => 'progresbardemo/javascript',
                    'callback'  => 'progresbardemo_javascript',
                    'access'        => TRUE
        );
    }
    return $items;
}
?>