Compress Magento HTML Code - php

Question

I'm trying to compress HTML code generated by Magento with this:
Observer.php
public function alterOutput($observer)
{
$lib_path = Mage::getBaseDir('lib').'/Razorphyn/html_compressor.php';
include_once($lib_path);
//Retrieve html body
$response = $observer->getResponse();
$html = $response->getBody();
$html=html_compress($html);
//Send Response
$response->setBody($html);
}
html_compressor.php:
function html_compress($string){
global $idarray;
$idarray=array();
//Replace PRE and TEXTAREA tags
$search=array(
'#(<)\s*?(pre\b[^>]*?)(>)([\s\S]*?)(<)\s*(/\s*?pre\s*?)(>)#', //Find PRE Tag
'#(<)\s*?(textarea\b[^>]*?)(>)([\s\S]*?)(<)\s*?(/\s*?textarea\s*?)(>)#' //Find TEXTAREA
);
$string=preg_replace_callback($search,
function($m){
$id='<!['.uniqid().']!>';
global $idarray;
$idarray[]=array($id,$m[0]);
return $id;
},
$string
);
//Remove blank useless space
$search = array(
'#( |\t|\f)+#', // Shorten multiple whitespace sequences
'#(^[\r\n]*|[\r\n]+)[\s\t]*[\r\n]+#', //Remove blank lines
'#^(\s)+|( |\t|\0|\r\n)+$#' //Trim Lines
);
$replace = array(' ',"\\1",'');
$string = preg_replace($search, $replace, $string);
//Replace IE COMMENTS, SCRIPT, STYLE and CDATA tags
$search=array(
'#<!--\[if\s(?:[^<]+|<(?!!\[endif\]-->))*<!\[endif\]-->#', //Find IE Comments
'#(<)\s*?(script\b[^>]*?)(>)([\s\S]*?)(<)\s*?(/\s*?script\s*?)(>)#', //Find SCRIPT Tag
'#(<)\s*?(style\b[^>]*?)(>)([\s\S]*?)(<)\s*?(/\s*?style\s*?)(>)#', //Find STYLE Tag
'#(//<!\[CDATA\[([\s\S]*?)//]]>)#', //Find commented CDATA
'#(<!\[CDATA\[([\s\S]*?)]]>)#' //Find CDATA
);
$string=preg_replace_callback($search,
function($m){
$id='<!['.uniqid().']!>';
global $idarray;
$idarray[]=array($id,$m[0]);
return $id;
},
$string
);
//Remove blank useless space
$search = array(
'#(class|id|value|alt|href|src|style|title)=(\'\s*?\'|"\s*?")#', //Remove empty attribute
'#<!--([\s\S]*?)-->#', // Strip comments except IE
'#[\r\n|\n|\r]#', // Strip break line
'#[ |\t|\f]+#', // Shorten multiple whitespace sequences
'#(^[\r\n]*|[\r\n]+)[\s\t]*[\r\n]+#', //Remove blank lines
'#^(\s)+|( |\t|\0|\r\n)+$#' //Trim Lines
);
$replace = array(' ','',' ',' ',"\\1",'');
$string = preg_replace($search, $replace, $string);
//Replace unique id with original tag
$c=count($idarray);
for($i=0;$i<$c;$i++){
$string = str_replace($idarray[$i][0], "\n".$idarray[$i][1]."\n", $string);
}
return $string;
}
My main concers are two:
Is this a heavy(or good) solution?
Is there a way to optimize this?
Has it really got sense to compress a Magento HTML page(taken resource and time vs real benefit)?

Answer 1

I will not comment or review your code. Deciphering regexes (in any flavor) is not my favorite hobby.
Yes, compressing HTML makes sense if you aim to provide professional services.
If I look at a HTML code of someone's site with lots of nonsense blank spaces and user-useless comments inside and the site disrespects Google's PageSpeed Insights Rules and does not help in making the web faster and eco-friendly then it says to me: be aware, don't trust, certainly don't give them your credit card number
My advice:
read answers to this question: Stack Overflow: HTML minification?
read other developer's code, this is the one I use: https://github.com/kangax/html-minifier
benchmark, e.g. run Google Chrome > Developer tools > Audits
test a lot if your minifier does not unintentionally destroy the pages

Answer 2

There is really no point in doing this if you have gzip compression (and you should have it) enabled. It's a waste of CPU cycles really. You should rather focus on image optimization, reducing number of http requests and setting proper cache headers.