Chat

• AJAX technology is used to smoothly refresh (no flicker) and display the chat and nickname zone.
• 
  

I have yet to come accross truly browser independent AJAX.of complex applications. For example the Google AJAX based tools (Docs and Spreadsheets) work with Firefox and IE but not with other browsers, same with Zoho office. However a minimalist approach to AJAX, i.e. just using it where it brings overwhealming benefit (e.g. the refresh you mention) might make sense.

• Bandwidth is preserved because the server never transmits the same data twice, only new messages are transmitted.

AJAX can provide a performance benefit in that only new information is displayed in the browser rather than a total refresh of the contents.

• No problems with firewalls

There seems to be no connection between the use of AJAX and firewalls. One of the benefits of the moodle chat approach is because it uses plain HTTP it will generally work through any firewall. If plain HTTP wont get through then generally the users won't be able to browser the web.


I don't mean to be overly negative, it is just that I have ten years of dissapointment and frustration with Javascript so I am very, very cautious when it is suggested and AJAX is a JavaScript based technology. Having said that I have switched to doing all my primary writing in the Google docs module and absolutely love the Google HTML chat system. Bear in mind that those Google folks are very, very smart. Ok OK so are the moodle folks (grins).

Marcus

We really had trouble with moodle chat so I hacked together phpfreechat.  Here is what I did. Take it for what it is worth (which isn't much).  I did this about 6 months ago so I may be missing something.

moodle/mod/chat/phpchatfree/index.php

add to the top of the file (don't leave any spaces before or after <? ?>

<?php
require_once('../../../config.php');
$chatid = $_GET['id'];
$groupid = optional_param('groupid', 0, PARAM_INT); //only for teachers
if (!$chat = get_record('chat', 'id', $id)) {
error('Could not find that chat room!');
exit;
}

if (!$course = get_record('course', 'id', $chat->course)) {
error('Could not find the course this belongs to!');
exit;
}

/// Check to see if groups are being used here
if ($groupmode = groupmode($course, $cm)) { // Groups are being used
if ($groupid = get_and_set_current_group($course, $groupmode, $groupid)) {
if (!$group = get_record('groups', 'id', $groupid)) {
error("That group (id $groupid) doesn't exist!");
}

$groupname = ': '.$group->name;
} else {
$groupname = ': '.get_string('allparticipants');
}

} else {
$groupid = 0;
$groupname = '';
}

$strchat = get_string('modulename', 'chat'); // must be before current_language() in chat_login_user() to force course language!!!
$userid=$USER->id; // Set the user id for Moodle
global $chatid, $userid, $groupid;
// END MOODLE - Don't leave any space between the php indicators below or you will receive xhmtl error
?>

Then in the params for phpfreechat in the same index.php file, add
$params["serverid"] = $_GET['id']; // use moodle id for chat
You can also make the $USER->firstname and $USER->lastname variable from moodle the user name in phpchatfree if you like.  Something like
$params["nick"] = $USER->firstname.' '.$USER->lastname;

It would be nice to add something that checks if the user entering the chat is an admin or teacher and adding "$params["isadmin"] = true;" if they are.  I am currently just hacking this by using an array $admin_users:

$admin_users[0]='Jane Doe';
$admin_users[1]='John Smith';
foreach ($admin_users as $value) {
  IF($value=="$USER->firstname $USER->lastname")
   $params["isadmin"] = true; // just for debug ;)
  }
}

----------------------------------------------------------------

in file moodle/mod/chat/phpchatfree/src/containers/file.class.php in the setMeta function below
// store the value in the memory cache
//@todo
// $this->_meta[$enc_type][$enc_subtype][$enc_key] = $value;

add the following so that it stores the messages in the moodle chat_messages table.

// MOODLE
 IF($group=='channelid-to-msg'){

 $pos1 = stripos($leafvalue,'send')+5;
 $moodleleafvalue = substr("$leafvalue", $pos1);
                $msg = &New stdClass;
                $msg->chatid    = $GLOBALS[chatid];
                $msg->userid    = $GLOBALS[userid];
                $msg->groupid   = $GLOBALS[groupid];
                $msg->system    = 0;
                //$msg->message   = addslashes($leafvalue); // have to undo the browser's encoding
                $msg->message   = addslashes($moodleleafvalue); // have to undo the browser's encoding

                $msg->timestamp = time();

                // Commit to DB
                insert_record('chat_messages', $msg, false);  // Moodle function
 }elseif($group=='nickid-to-metadata' && $leaf=='nick'){
          $msg = &New stdClass;
                $msg->chatid    = $GLOBALS[chatid];
                $msg->userid    = $GLOBALS[userid];
                $msg->groupid   = $GLOBALS[groupid];
                $msg->system    = 0;
                $msg->message   = 'enter';
                $msg->timestamp = time();

                // Commit to DB
                insert_record('chat_messages', $msg, false);

 }
//END MOODLE

--------------------------------------------------------------------

Lastly, in moodle/mod/chat/view.php look for
link_to_popup_window ("/mod/chat/gui_$CFG->chat_method/index.php?id=$chat->id$groupparam","chat$course->id$chat->id$groupparam", "$strenterchat", 500, 700, get_string('modulename', 'chat'));

and comment it out and add it with

link_to_popup_window ("/mod/chat/phpchatfree/?id=$chat->id$groupparam","chat$course->id$chat->id$groupparam", "$strenterchat", 700, 700, get_string('modulename', 'chat'));

I think I included everything here.  This is a pretty bad hack but it will probably work ok if you need something quick.