CSS (A CSS parser and minifier written in PHP)

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A CSS parser, beautifier and minifier written in PHP. It supports the following features

Features

• multibyte characters encoding
• sourcemap
• multiprocessing: process large CSS input very fast
• CSS Nesting module
• partially implemented CSS Syntax module level 3
• partial CSS validation
• CSS colors module level 4
• parse and render CSS
• optimize css:
  • merge duplicate rules
  • remove duplicate declarations
  • remove empty rules
  • compute css shorthand (margin, padding, outline, border-radius, font, background)
  • process @import document to reduce the number of HTTP requests
  • remove @charset directive
• query api with xpath like or class name syntax
• traverser api to transform the css and ast
• command line utility

Installation

install using Composer

PHP version >= 8.0

$ composer require tbela99/css

PHP version >= 5.6

$ composer require "tbela99/css:dev-php56-backport"

Requirements

• PHP version >= 8.0 on master branch.
• PHP version >= 5.6 supported in this branch
• mbstring extension

Usage:

h1 {
color: green;
color: blue;
color: black;
}
h1 {
color:#000;
color: aliceblue;
}

PHP Code

use \TBela\CSS\Parser;
$parser = newParser();
$parser->setContent('h1 { color: green; color: blue; color: black;}h1 { color: #000; color: aliceblue;}');
echo$parser->parse();

Result

h1 {
color:#f0f8ff;
}

Parse the css file and generate the AST

use \TBela\CSS\Parser;
use \TBela\CSS\Renderer;
$parser = newParser($css);
$element = $parser->parse();
// append an existing css file$parser->append('https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css');
// append css string$parser->appendContent($css_string);
// pretty print css$css = (string) $element;
// minified output$renderer = newRenderer([
'compress' => true,
'convert_color' => 'hex',
'css_level' => 4,
'sourcemap' => true,
'allow_duplicate_declarations' => false
]);
// fast$css = $renderer->renderAst($parser);
// or$css = $renderer->renderAst($parser->getAst());
// slow$css = $renderer->render($element);
// generate sourcemap -> css/all.css.map$renderer->save($element, 'css/all.css');
// save as jsonfile_put_contents('style.json', json_encode($element));

Load the AST and generate css code

use \TBela\CSS\Renderer;
// fastest way to render css$beautify = (newRenderer())->renderAst($parser->setContent($css)->getAst());
// or$beautify = (newRenderer())->renderAst($parser->setContent($css));
// or$css = (newRenderer())->renderAst(json_decode(file_get_contents('style.json')));

use \TBela\CSS\Renderer;
$ast = json_decode(file_get_contents('style.json'));
$renderer = newRenderer([
'convert_color' => true,
'compress' => true, // minify the output'remove_empty_nodes' => true// remove empty css classes
]);
$css = $renderer->renderAst($ast);

Sourcemap generation

$renderer = newRenderer([
'sourcemap' => true
]);
// call save and specify the file name// generate sourcemap -> css/all.css.map$renderer->save($element, 'css/all.css');

The CSS Query API

Example: get all background and background-image declarations that contain an image url

$element = Element::fromUrl('https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/css/bootstrap.min.css');
foreach ($element->query('[@name=background][@value*="url("]|[@name=background-image][@value*="url("]') as$p) {
echo"$p\n";
}

result

.form-select {
background-image:url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3e%3cpath fill='none' stroke='%23343a40' stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='M2 5l6 6 6-6'/%3e%3c/svg%3e")
}
.form-check-input:checked[type=checkbox] {
background-image:url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20'%3e%3cpath fill='none' stroke='%23fff' stroke-linecap='round' stroke-linejoin='round' stroke-width='3' d='M6 10l3 3l6-6'/%3e%3c/svg%3e")
}
...

Example: Extract Font-src declaration

CSS source

@font-face {
font-family:"Bitstream Vera Serif Bold";
src:url("/static/styles/libs/font-awesome/fonts/fontawesome-webfont.fdf491ce5ff5.woff");
}
body {
background-color: green;
color:#fff;
font-family: Arial, Helvetica, sans-serif;
}
h1 {
color:#fff;
font-size:50px;
font-family: Arial, Helvetica, sans-serif;
font-weight: bold;
}
@media print {
@font-face {
font-family: MaHelvetica;
src:local("Helvetica Neue Bold"),local("HelveticaNeue-Bold"),url(MgOpenModernaBold.ttf);
font-weight: bold;
}
body {
font-family:"Bitstream Vera Serif Bold", serif;
}
p {
font-size:12px;
color:#000;
text-align: left;
}
@font-face {
font-family: Arial, MaHelvetica;
src:local("Helvetica Neue Bold"),local("HelveticaNeue-Bold"),url(MgOpenModernaBold.ttf);
font-weight: bold;
}
}

PHP source

use \TBela\CSS\Parser;
$parser = newParser();
$parser->setContent($css);
$stylesheet = $parser->parse();
// get @font-face nodes by class names$nodes = $stylesheet->queryByClassNames('@font-face, .foo .bar');
// or// get all src properties in a @font-face rule$nodes = $stylesheet->query('@font-face/src');
echoimplode("\n", array_map('trim', $nodes));

result

@font-face {
src:url("/static/styles/libs/font-awesome/fonts/fontawesome-webfont.fdf491ce5ff5.woff");
}
@media print {
@font-face {
src:local("Helvetica Neue Bold"),local("HelveticaNeue-Bold"),url(MgOpenModernaBold.ttf);
}
}
@media print {
@font-face {
src:local("Helvetica Neue Bold"),local("HelveticaNeue-Bold"),url(MgOpenModernaBold.ttf);
}
}

render optimized css

$stylesheet->setChildren(array_map(function ($node) { return$node->copy()->getRoot(); }, $nodes));
$stylesheet->deduplicate();
echo$stylesheet;

result

@font-face {
src:url(/static/styles/libs/font-awesome/fonts/fontawesome-webfont.fdf491ce5ff5.woff)
}
@media print {
@font-face {
src:local("Helvetica Neue Bold"),local(HelveticaNeue-Bold),url(MgOpenModernaBold.ttf)
}
}

CSS Nesting

table.colortable {
&td {
text-align:center;
&.c { text-transform:uppercase }
&:first-child,&:first-child+td { border:1px solid black }
}
&th {
text-align:center;
background:black;
color:white;
}
}

render CSS nesting

useTBela\CSS\Parser;
echonewParser($css);

result

table.colortable {
&td {
text-align: center;
&.c {
text-transform: uppercase
}
&:first-child,&:first-child+td {
border:1px solid #000
}
}
&th {
text-align: center;
background:#000;
color:#fff
}
}

convert nesting CSS to older representation

useTBela\CSS\Parser;
use \TBela\CSS\Renderer;
$renderer = newRenderer( ['legacy_rendering' => true]);
echo$renderer->renderAst(newParser($css));

result

table.colortabletd {
text-align: center
}
table.colortabletd.c {
text-transform: uppercase
}
table.colortabletd:first-child,table.colortabletd:first-child+td {
border:1px solid #000
}
table.colortableth {
text-align: center;
background:#000;
color:#fff
}

The Traverser Api

The traverser will iterate over all the nodes and process them with the callbacks provided. It will return a new tree Example using ast

useTBela\CSS\Ast\Traverser;
useTBela\CSS\Parser;
useTBela\CSS\Renderer;
$parser = (newParser())->load('ast/media.css');
$traverser = newTraverser();
$renderer = newRenderer(['remove_empty_nodes' => true]);
$ast = $parser->getAst();
// remove @media print$traverser->on('enter', function ($node) {
if ($node->type == 'AtRule' && $node->name == 'media' && $node->value == 'print') {
return Traverser::IGNORE_NODE;
}
});
$newAst = $traverser->traverse($ast);
echo$renderer->renderAst($newAst);

Example using an Element instance

useTBela\CSS\Ast\Traverser;
useTBela\CSS\Parser;
useTBela\CSS\Renderer;
$parser = (newParser())->load('ast/media.css');
$traverser = newTraverser();
$renderer = newRenderer(['remove_empty_nodes' => true]);
$element = $parser->parse();
// remove @media print$traverser->on('enter', function ($node) {
if ($node->type == 'AtRule' && $node->name == 'media' && $node->value == 'print') {
return Traverser::IGNORE_NODE;
}
});
$newElement = $traverser->traverse($element);
echo$renderer->renderAst($newElement);

Build a CSS Document

use \TBela\CSS\Element\Stylesheet;
$stylesheet = newStylesheet();
$rule = $stylesheet->addRule('div');
$rule->addDeclaration('background-color', 'white');
$rule->addDeclaration('color', 'black');
echo$stylesheet;

output

div {
background-color:#fff;
color:#000;
}

$media = $stylesheet->addAtRule('media', 'print');
$media->append($rule);

output

@media print {
div {
background-color:#fff;
color:#000;
}
}

$div = $stylesheet->addRule('div');
$div->addDeclaration('max-width', '100%');
$div->addDeclaration('border-width', '0px');

output

@media print {
div {
background-color:#fff;
color:#000;
}
}
div {
max-width:100%;
border-width:0;
}

$media->append($div);

output

@media print {
div {
background-color:#fff;
color:#000;
}
div {
max-width:100%;
border-width:0;
}
}

$stylesheet->insert($div, 0);

output

div {
max-width:100%;
border-width:0;
}
@media print {
div {
background-color:#fff;
color:#000;
}
}

Adding existing css

// append css string$stylesheet->appendCss($css_string);
// append css file$stylesheet->append('style/main.css');
// append url$stylesheet->append('https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.15.3/css/brands.min.css');

Performance

Utility methods

The renderer class provides utility methods to format css data

$css = \TBela\CSS\Renderer::fromFile($url_or_file, $renderOptions = [], $parseOptions = []);
#$css = \TBela\CSS\Renderer::fromString($css, $renderOptions = [], $parseOptions = []);

Manual parsing and rendering

parsing and rendering ast is 3x faster than parsing an element.

use \TBela\CSS\Element\Parser;
use \TBela\CSS\Element\Renderer;
$parser = newParser($css);
// parse and renderecho (string) $parser;
// or render minified css$renderer = newRenderer(['compress' => true]);
echo$renderer->renderAst($parser);
# or echo$renderer->renderAst($parser->getAst());
# or// slower - will build a stylesheet objectecho$renderer->render($parser->parse());

Parser Options

• flatten_import: process @import directive and import the content into the css document. default to false.
• allow_duplicate_rules: allow duplicated rules. By default, duplicate rules except @font-face are merged
• allow_duplicate_declarations: allow duplicated declarations in the same rule.
• capture_errors: silently capture parse error if true, otherwise throw a parse exception. Default to true

Renderer Options

• remove_comments: remove comments.
• preserve_license: preserve comments starting with '/*!'
• compress: minify output, will also remove comments
• remove_empty_nodes: do not render empty css nodes
• compute_shorthand: compute shorthand declaration
• charset: preserve @charset. default to false
• glue: the line separator character. default to '\n'
• indent: character used to pad lines in css, default to a space character
• convert_color: convert colors to a format between hex, hsl, rgb, hwb and device-cmyk
• css_level: produce CSS color level 3 or 4. default to 4
• allow_duplicate_declarations: allow duplicate declarations.
• legacy_rendering: convert nesting css. default false

Command line utility

the command line utility is located at './cli/css-parser'

$ ./cli/css-parser -h
Usage: $ css-parser [OPTIONS] [PARAMETERS]
-v, --version	print version number
-h	print help
--help	print extended help
Parse options:
-e, --capture-errors ignore parse error
-f, --file input css file or url
-m, --flatten-import process @import
-I, --input-format input format: json (ast), serialize (PHP serialized ast)
-d, --parse-allow-duplicate-declarations	allow duplicate declaration
-p, --parse-allow-duplicate-rules allow duplicate rule
-P, --parse-children-process maximum children process
-M, --parse-multi-processing enable multi-processing parser
Render options:
-a, --ast dump ast as JSON
-S, --charset remove @charset
-c, --compress minify output
-u, --compute-shorthand compute shorthand properties
-t, --convert-color convert colors
-l, --css-level css color module
-G, --legacy-rendering convert nested css syntax
-o, --output output file name
-F, --output-format output export format. string (css), json (ast), serialize (PHP serialized ast), json-array, serialize-array, requires --input-format
-L, --preserve-license preserve license comments
-C, --remove-comments remove comments
-E, --remove-empty-nodes remove empty nodes
-r, --render-allow-duplicate-declarations	render duplicate declarations
-R, --render-multi-processing enable multi-processing renderer
-s, --sourcemap generate sourcemap, requires --file

Minify inline css

$ ./cli/css-parser 'a, div {display:none} b {}' -c
#
$ echo'a, div {display:none} b {}'| ./cli/css-parser -c

Minify css file

$ ./cli/css-parser -f nested.css -c
#
$ ./cli/css-parser -f 'https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.15.3/css/brands.min.css' -c

Dump ast

$ ./cli/css-parser -f nested.css -f 'https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.5.0/css/bootstrap.min.css' -c -a
#
$ ./cli/css-parser 'a, div {display:none} b {}' -c -a
#
$ echo'a, div {display:none} b {}'| ./cli/css-parser -c -a

The full documentation can be found here

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Thanks to Jetbrains for providing a free PhpStorm license

This was originally a PHP port of https://github.com/reworkcss/css