Get entire page content (generated HTML in browser)

Question

I'm looking for a filter that provides the full page generated in WordPress - including the head section with meta tags, body, styling and dynamic content. the_content() and the_excerpt() do work only for the dynamic part and the request filter seems to work only for SQL queries (or not)?

I would like to filter some data in the entire page in all links or buttons. How can I do this?

Answer 1

You can use output buffering to accomplish this.

Add a high priority hook directly before the template is rendered:

add_action('template_redirect', 'foo_buffer_go', 0);
function foo_buffer_go(){
    ob_start('foo_buffer_callback');
}

Add a shutdown hook with an extremely low priority.

add_action('shutdown', 'foo_buffer_stop', 1000);
function foo_buffer_stop(){
    ob_end_flush();
}

Inside your callback, you manipulate the rendered HTML.

function foo_buffer_callback($buffer){
  //Do something with the buffer (HTML)
  return $buffer;
}

You may download this as a plugin here: http://3-3.me/B9lK

1. Enable the plugin
2. Visit the site and it will be rendered as "Foo Bar" which means you are capturing the entirety of the generated HTML

Answer 2

Slight change to @BrianFegter's code so the output buffer is closed only if it was opened. This has the benefit of being able to conditionally decide whether to filter or not.

if ($want_to_modify_content) {
    add_action('template_redirect', 'YOURPLUGIN_buffer_start', 0);
}
function YOURPLUGIN_buffer_start() {
    add_action('shutdown', 'YOURPLUGIN_buffer_stop', PHP_INT_MAX);
    ob_start('YOURPLUGIN_modify_content'); 
}
function YOURPLUGIN_buffer_stop() {
    ob_end_flush();
}
function YOURPLUGIN_modify_content($content) {
    //modify $content
    return $content;
}

Answer 3

You can use HTTP API to get the content of the post URL.