README.MD

Combine, Minify and Inline CSS In WordPress, in the correct order

Installation

Use copypasta to add to a sub-dir of mu-plugins or use Composer:

  "require": {
    "shelob9/css-inliner" : "*"
  }

and

  "repositories": [
    {
      "type": "vcs",
      "url": "https://gist.github.com/Shelob9/4abd39c57e31c1a37d689118236be729.git"
    }
  ]

Example Usage:

In your main mu-plugin or whatever

  add_action( 'init', function(){
    if( ! is_admin() && ! wp_doing_ajax() ){
      include  WP_CONTENT_DIR  . '/mu-plugins/css-inliner/init.php';

      add_filter( 'josh_css_minifier_styles', function(){
        return [
          'tm_clicktotweet',
          'edd-styles',
          'edd_acp_frontend_css',
          'edd-sl-styles',
          'edd-recurring',
        ];

      });
    }
  });

composer.json

{
  "name": "shelob9/css-inliner",
  "license": "GPL v2+",
  "type": "wordpress-muplugin",
  "repositories": [
    {
      "type": "composer",
      "url": "http://wpackagist.org"
    }
  ],
  "require": {
  	"composer/installers" : "~1.0"
  }
}

css-inliner.php

<?php
class Josh_CSS_Inliner {

	protected $styles;

	protected $prepared;
	public function __construct( array $styles = array() )
	{
		$this->styles = $styles;
		if( ! empty( $this->styles ) ){
			$this->set_prepared();
			if( ! empty( $this->prepared ) ){
				add_action( 'wp_head', [ $this, 'wp_head' ] );
			}
		}
	}

	public function  wp_head()
	{
		printf( "<style id='%s-inline-css' class='cfdc-inlined' type='text/css'>\n%s\n</style>\n", esc_attr( $this->cache_key() ), $this->prepared );
	}

	protected function cache_key() : string
	{
		return md5( implode( ',', array_values( $this->styles ) ) );

	}


	protected function set_prepared()
	{
		$key = $this->cache_key();
		if( ! empty( $_prepared = get_transient( $key ) ) ){
			$this->prepared = $_prepared;
		}else{
			$this->prepared = $this->process();
			set_transient( $key, $this->prepared, WEEK_IN_SECONDS );
		}


	}

	protected function process() : string
	{
		global  $wp_styles;
		foreach ( $this->styles as $style ){
			$key = array_search( $style, $wp_styles->queue );
			if( false !== $key ){
				$ordered[ $key ] =  str_replace( WP_CONTENT_URL, untrailingslashit( WP_CONTENT_DIR ), $wp_styles->registered[ $style ]->src );
				unset( $wp_styles->queue[ $key ] );
				unset( $wp_styles->registered[ $style ] );
			}

		}

		ksort( $ordered );


		ob_start();
		foreach ( $ordered as $path ){
			if( file_exists( $path ) ){
				include  $path;
			}

		}
		$concat = ob_get_clean();
		if( ! empty( $concat ) ){
			return josh_minify_css($concat);
		}else{
			return '';
		}
	}




}

functions.php

<?php
//https://gist.githubusercontent.com/tovic/d7b310dea3b33e4732c0/raw/a2aec8653a893c42f4cf22662e775814c2d91f0a/php-html-css-js-minifier.php


// Helper function(s) ...

define('X', "\x1A"); // a placeholder character

$SS = '"(?:[^"\\\]++|\\\.)*+"|\'(?:[^\'\\\\]++|\\\.)*+\'';
$CC = '\/\*[\s\S]*?\*\/';
$CH = '<\!--[\s\S]*?-->';

function josh__minify_x($input) {
	return str_replace(array("\n", "\t", ' '), array(X . '\n', X . '\t', X . '\s'), $input);
}

function josh__minify_v($input) {
	return str_replace(array(X . '\n', X . '\t', X . '\s'), array("\n", "\t", ' '), $input);
}


/**
 * =======================================================
 *  CSS MINIFIER
 * =======================================================
 * -- CODE: ----------------------------------------------
 *
 *    echo josh_minify_css(file_get_contents('test.css'));
 *
 * -------------------------------------------------------
 */

function josh__minifiy_css($input) {
	// Keep important white-space(s) in `calc()`
	if(stripos($input, 'calc(') !== false) {
		$input = preg_replace_callback('#\b(calc\()\s*(.*?)\s*\)#i', function($m) {
			return $m[1] . preg_replace('#\s+#', X . '\s', $m[2]) . ')';
		}, $input);
	}
	// Minify ...
	return preg_replace(
		array(
			// Fix case for `#foo [bar="baz"]` and `#foo :first-child` [^1]
			'#(?<![,\{\}])\s+(\[|:\w)#',
			// Fix case for `[bar="baz"] .foo` and `@media (foo: bar) and (baz: qux)` [^2]
			'#\]\s+#', '#\b\s+\(#', '#\)\s+\b#',
			// Minify HEX color code ... [^3]
			'#\#([\da-f])\1([\da-f])\2([\da-f])\3\b#i',
			// Remove white-space(s) around punctuation(s) [^4]
			'#\s*([~!@*\(\)+=\{\}\[\]:;,>\/])\s*#',
			// Replace zero unit(s) with `0` [^5]
			'#\b(?:0\.)?0([a-z]+\b|%)#i',
			// Replace `0.6` with `.6` [^6]
			'#\b0+\.(\d+)#',
			// Replace `:0 0`, `:0 0 0` and `:0 0 0 0` with `:0` [^7]
			'#:(0\s+){0,3}0(?=[!,;\)\}]|$)#',
			// Replace `background(?:-position)?:(0|none)` with `background$1:0 0` [^8]
			'#\b(background(?:-position)?):(0|none)\b#i',
			// Replace `(border(?:-radius)?|outline):none` with `$1:0` [^9]
			'#\b(border(?:-radius)?|outline):none\b#i',
			// Remove empty selector(s) [^10]
			'#(^|[\{\}])(?:[^\{\}]+)\{\}#',
			// Remove the last semi-colon and replace multiple semi-colon(s) with a semi-colon [^11]
			'#;+([;\}])#',
			// Replace multiple white-space(s) with a space [^12]
			'#\s+#'
		),
		array(
			// [^1]
			X . '\s$1',
			// [^2]
			']' . X . '\s', X . '\s(', ')' . X . '\s',
			// [^3]
			'#$1$2$3',
			// [^4]
			'$1',
			// [^5]
			'0',
			// [^6]
			'.$1',
			// [^7]
			':0',
			// [^8]
			'$1:0 0',
			// [^9]
			'$1:0',
			// [^10]
			'$1',
			// [^11]
			'$1',
			// [^12]
			' '
		),
		$input);
}

function josh_minify_css($input) {
	if( ! $input = trim($input)) return $input;
	global $SS, $CC;
	// Keep important white-space(s) between comment(s)
	$input = preg_replace('#(' . $CC . ')\s+(' . $CC . ')#', '$1' . X . '\s$2', $input);
	// Create chunk(s) of string(s), comment(s) and text
	$input = preg_split('#(' . $SS . '|' . $CC . ')#', $input, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE);
	$output = "";
	foreach($input as $v) {
		if(trim($v) === "") continue;
		if(
			($v[0] === '"' && substr($v, -1) === '"') ||
			($v[0] === "'" && substr($v, -1) === "'") ||
			(strpos($v, '/*') === 0 && substr($v, -2) === '*/')
		) {
			// Remove if not detected as important comment ...
			if($v[0] === '/' && strpos($v, '/*!') !== 0) continue;
			$output .= $v; // String or comment ...
		} else {
			$output .= josh__minifiy_css($v);
		}
	}
	// Remove quote(s) where possible ...
	$output = preg_replace(
		array(
			// '#(' . $CC . ')|(?<!\bcontent\:|[\s\(])([\'"])([a-z_][-\w]*?)\2#i',
			'#(' . $CC . ')|\b(url\()([\'"])([^\s]+?)\3(\))#i'
		),
		array(
			// '$1$3',
			'$1$2$4$5'
		),
		$output);
	return josh__minify_v($output);
}

init.php

<?php

add_action( 'wp_print_styles', function() {
	$styles_to_inline = apply_filters( 'josh_css_minifier_styles', [ ] );
	if ( empty( $styles_to_inline ) ) {
		return;
	}

	include_once __DIR__ . '/functions.php';
	include_once __DIR__  . '/css-inliner.php';
	new Josh_CSS_Inliner( $styles_to_inline );
});