[wp-trac] [WordPress Trac] #58285: New filter hook for filtering whole HTML before final output

[WordPress Trac]

#58285: New filter hook for filtering whole HTML before final output
-----------------------------+-----------------------------
 Reporter:  kubiq            |      Owner:  (none)
     Type:  feature request  |     Status:  new
 Priority:  normal           |  Milestone:  Awaiting Review
Component:  General          |    Version:  6.2
 Severity:  normal           |   Keywords:
  Focuses:  performance      |
-----------------------------+-----------------------------
 Let's say I have 1 cache plugin that is great in cache but has no or bad
 CSS and JS combining and minification options, so I have another plugin to
 do that... than I have another plugin that is removing some unnecessary
 styles and scripts from HTML on some pages and then I have another one
 that fixes some width, height, loading, alt attributes...

 These plugins use their own {{{ob_starts}}} again and again, flushing,
 etc... some of them use some preg_match and replaces, some use domdocument
 parser and then the website is very slow for administrator or on first
 load before cache are created.

 Currently, most cache, optimizing, assets plugins do something like this
 {{{#!php
 <?php
 add_action( 'init', function(){
         ob_start( 'my_magic_function' );
 }, -1 );

 function my_magic_function( $html ){
         // preg_replaces
         // maybe domdocument parsing
         return $html;
 }
 }}}

 and this is done again and again by every such-a-plugin

 That's why I think it should be part of the core and I imagine something
 like this:
 {{{#!php
 <?php
 add_action( 'init', function(){
         if( apply_filters( 'wp_enable_final_html_filtering', false ) ){
                 ob_start( 'default_wp_ob_handler' );
         }
 }, -1 );

 function default_wp_ob_handler( $html ){
         $dom = false;
         if( apply_filters( 'wp_enable_final_html_dom', false ) ){
                 $dom = new DOMDocument();
                 $dom->loadHTML( $html );
                 $dom = apply_filters( 'wp_filter_final_html_dom', $dom );
                 $html = $dom->saveHTML();
         }
         return apply_filters( 'wp_filter_final_html', $html );
 }
 }}}

 so then plugin developers can easily access html or DOM and change it
 without the need to use ob_starts and flushes and parsers again and again,
 eg.:

 {{{#!php
 <?php
 add_filter( 'wp_enable_final_html_filtering', '__return_true' );
 add_filter( 'wp_filter_final_html', function( $html ){
         // preg_mathces and replacements
         return $html;
 });

 // or if you need work with DOM structure

 add_filter( 'wp_enable_final_html_filtering', '__return_true' );
 add_filter( 'wp_filter_final_html_dom', function( $dom ){
         // xpath searches and replacements
         return $dom;
 }, 10, 2 );
 }}}

 This can improve loading performance for admin users, or on the first load
 of page before cache is created, it will be more consistent and all cache
 and optimizing plugins can use these hooks easily then.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/58285>
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