How To Build A Real-Time Commenting System - Practical JavaScript Techniques - page 112

user information for presence channels . We just want to use the basic event triggering

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functionality in the post_comment.php file so we need to download the Pusher PHP library 25
( direct zip file download ) .

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Once you've downloaded this zip file, unzip it into the directory along with your other files. Your
file structure will now look something like this:

•

index.php

•

css (dir)

•

images (dir)

•

post_comment.php

•

pusher_config.php

•

Persistence.php

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squeeks-Pusher-PHP (dir) including lib (dir) with Pusher.php

An event can be triggering in just a few lines of code:

<?php
require ( 'squeeks-Pusher-PHP/lib/Pusher.php' );
require ( 'pusher_config.php' );

$pusher = new Pusher ( APP_KEY , APP_SECRET , APP_ID );
$pusher -& gt ; trigger ( 'comments-1' , 'new_comment' , array (
"comment_post_ID" =& gt ; 1 ,
"date" =& gt ; "Tue, 21 Feb 2012 18:33:03 +0000" ,
"comment" =& gt ; "The realtime Web rocks!" ,
"comment_author" =& gt ; "Phil Leggetter"

));
?>

However, we need to apply a some additional logic before we trigger the event:

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Check that the comment was added.

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Extract the unique comment identifier from the $added array.