[php] Compression | Output Buffer control

[litewarez]

Heya guys, I just built this small tool so you can add into your sites to compress your content and and modify it to save bandwidth.

How it works:
This class will watch your script so when your echoing content it will do some modifications and can also take your own modifications aswell

The Class:

<?php
class OutputBuffer
{
    private $callbacks = array(); //Holder for callbacks
    private $content;
    
    function __construct()
    {
        ob_start(array($this,'handler'));
    }
    
    function addCallback($name,$item)
    {
        if(is_callable($item))
        {
            $this->callbacks[$name] = $item;
            return true;
        }
        return false;
    }
    
    function handler($contents,$bitAtchion = null)
    {
        if($bitAtchion & PHP_OUTPUT_HANDLER_START)
        {
            $this->content = ''; //A New Buffer
        }
        
        if($bitAtchion & PHP_OUTPUT_HANDLER_CONT)
        {
            $this->content .= $contents;
        }
        
        if($bitAtchion & PHP_OUTPUT_HANDLER_END)
        {
            $this->content .= $contents;
            //AS this is a final request we want to run the callbacks
            foreach($this->callbacks as $this->callback)
            {
                try
                {
                    $this->content = call_user_func($this->callback,$this->content);
                } catch(Exception $e){}
            }
            return $this->_compress($this->content); //Compress and push out
        }
        return $this->content;
    }
    
    function _compress($string)
    {
        if(headers_sent() || function_exists('gzencode') === false)
        {
            return $string; //Cant compress
        }
        
        $ctype = strpos($_SERVER["HTTP_ACCEPT_ENCODING"], 'x-gzip') ? 'x-gzip' : strpos($_SERVER["HTTP_ACCEPT_ENCODING"], 'gzip') ? 'gzip' : false;
        
        if($ctype !== false)
        {
             header('Content-Encoding: '.$ctype);
             return gzencode($string);
        }
        
        return $string;
    }
}
?>

Usage:
If you already have the function ob_start() in your script then replace with the code below, otherwise add the code below before your session_start() or at the very start of your script.

include 'OutputBuffer.php';
$buffer = new OutputBuffer(); 

This will now compress your source before it gets to the user.

Adding Callbacks:
You can add your own custom callbacks to modify the end content such as rudes whitespace, add timestamps etc etc.

Example of callback:

function addTimeStamp($content)
{
    return $content . '<!--' . time() . '-->';
} 

As you can see the above is a function that returns the in-putted string but adds a html comment to the end with the time-stamp within it.

You can add it to your Output Controller like so:

$buffer->addCallback('timestamp','addTimeStamp'); 

the params for the addCallback method are

addCallback( string $name[, mixed $callback]])

You can also add methods from objects by passing an array of the object adn the method

Example:

$buffer->addCallback('tidyHtml',array($object,'method')); 

heres another example that you can use to compress whitespace in your html source.

function _trimwhitespace($source)
{
    // Pull out the script blocks
    preg_match_all("!<script[^>]*?>.*?</script>!is", $source, $match);
    $_script_blocks = $match[0];
    $source = preg_replace("!<script[^>]*?>.*?</script>!is",'@@@FILTER_TRIM_SCRIPT@@@', $source);

    // Pull out the pre blocks
    preg_match_all("!<pre[^>]*?>.*?</pre>!is", $source, $match);
    $_pre_blocks = $match[0];
    $source = preg_replace("!<pre[^>]*?>.*?</pre>!is",'@@@FILTER_TRIM_PRE@@@', $source);
    
    // Pull out the textarea blocks
    preg_match_all("!<textarea[^>]*?>.*?</textarea>!is", $source, $match);
    $_textarea_blocks = $match[0];
    $source = preg_replace("!<textarea[^>]*?>.*?</textarea>!is",'@@@FILTER_TRIM_TEXTAREA@@@', $source);

    // remove all leading spaces, tabs and carriage returns NOT
    // preceeded by a php close tag.
    $source = trim(preg_replace('/((?<!\?>)\n)[\s]+/m', '\1', $source));

    // replace textarea blocks
    _outputfilter_trimwhitespace_replace("@@@FILTER_TRIM_TEXTAREA@@@",$_textarea_blocks, $source);

    // replace pre blocks
    _outputfilter_trimwhitespace_replace("@@@FILTER_TRIM_PRE@@@",$_pre_blocks, $source);

    // replace script blocks
    _outputfilter_trimwhitespace_replace("@@@FILTER_TRIM_SCRIPT@@@",$_script_blocks, $source);

    return $source;
}

//HELPER FUNCTION, NEEDED ABOVE.
function _outputfilter_trimwhitespace_replace($search_str, $replace, &$subject)
{
    $_len = strlen($search_str);
    $_pos = 0;
    for ($_i=0, $_count=count($replace); $_i<$_count; $_i++)
        if (($_pos=strpos($subject, $search_str, $_pos))!==false)
            $subject = substr_replace($subject, $replace[$_i], $_pos, $_len);
        else
            break;
} 

and then you can just keep this in a seperate file and include it and then add the callback like so

$buffer->addCallback('trim_white_space','_trimwhitespace'); 

this will change the following code:

<html>
    <head>
        <title>my Website</title>
    </head>
    <body>
       <p>.....</p>
    </body>
</html>

Into:

<html><head><title>my Website</title></head><body><p>.....</p></body></html>

Now all your html will be compress like Litewarez and Katz.

P.S, The above function was taken from a smarty plugin and slightly modified

litewarez Reviewed by litewarez on 2nd Jul 2010. [php] Compression | Output Buffer control Heya guys, I just built this small tool so you can add into your sites to compress your content and and modify it to save bandwidth. How it works: This class will watch your script so when your echoing content it will do some modifications and can also take your own modifications aswell The Class: <?php class OutputBuffer { Rating: 5