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PHP Function to Minify HTML, CSS and JavaScript
<?php
// Based on <https://github.com/mecha-cms/extend.minify>
define('MINIFY_STRING', '"(?:[^"\\\]|\\\.)*"|\'(?:[^\'\\\]|\\\.)*\'');
define('MINIFY_COMMENT_CSS', '/\*[\s\S]*?\*/');
define('MINIFY_COMMENT_HTML', '<!\-{2}[\s\S]*?\-{2}>');
define('MINIFY_COMMENT_JS', '//[^\n]*');
define('MINIFY_PATTERN_JS', '/[^\n]+?/[gimuy]*');
define('MINIFY_HTML', '<[!/]?[a-zA-Z\d:.-]+[\s\S]*?>');
define('MINIFY_HTML_ENT', '&(?:[a-zA-Z\d]+|\#\d+|\#x[a-fA-F\d]+);');
define('MINIFY_HTML_KEEP', '<pre(?:\s[^<>]*?)?>[\s\S]*?</pre>|<code(?:\s[^<>]*?)?>[\s\S]*?</code>|<script(?:\s[^<>]*?)?>[\s\S]*?</script>|<style(?:\s[^<>]*?)?>[\s\S]*?</style>|<textarea(?:\s[^<>]*?)?>[\s\S]*?</textarea>');
// get URL
$protocol = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off' || $_SERVER['SERVER_PORT'] === 443 ? 'https' : 'http') . '://';
$host = isset($_SERVER['HTTP_HOST']) ? $_SERVER['HTTP_HOST'] : (isset($_SERVER['SERVER_NAME']) ? $_SERVER['SERVER_NAME'] : "");
$url = $protocol . $host;
// escape character
define('X', "\x1A");
// normalize line–break(s)
function n($s) {
return str_replace(["\r\n", "\r"], "\n", $s);
}
// trim once
function t($a, $b) {
if ($a && strpos($a, $b) === 0 && substr($a, -strlen($b)) === $b) {
return substr(substr($a, strlen($b)), 0, -strlen($b));
}
return $a;
}
function fn_minify($pattern, $input) {
return preg_split('#(' . implode('|', $pattern) . ')#', $input, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE);
}
function fn_minify_css($input, $comment = 2, $quote = 2) {
if (!is_string($input) || !$input = n(trim($input))) return $input;
$output = $prev = "";
foreach (fn_minify([MINIFY_COMMENT_CSS, MINIFY_STRING], $input) as $part) {
if (trim($part) === "") continue;
if ($comment !== 1 && strpos($part, '/*') === 0 && substr($part, -2) === '*/') {
if (
$comment === 2 && (
// Detect special comment(s) from the third character. It should be a `!` or `*` → `/*! keep */` or `/** keep */`
strpos('*!', $part[2]) !== false ||
// Detect license comment(s) from the content. It should contains character(s) like `@license`
stripos($part, '@licence') !== false || // noun
stripos($part, '@license') !== false || // verb
stripos($part, '@preserve') !== false
)
) {
$output .= $part;
}
continue;
}
if ($part[0] === '"' && substr($part, -1) === '"' || $part[0] === "'" && substr($part, -1) === "'") {
// Remove quote(s) where possible …
$q = $part[0];
if (
$quote !== 1 && (
// <https://www.w3.org/TR/CSS2/syndata.html#uri>
substr($prev, -4) === 'url(' && preg_match('#\burl\($#', $prev) ||
// <https://www.w3.org/TR/CSS2/syndata.html#characters>
substr($prev, -1) === '=' && preg_match('#^' . $q . '[a-zA-Z_][\w-]*?' . $q . '$#', $part)
)
) {
$part = t($part, $q); // trim quote(s)
}
$output .= $part;
} else {
$output .= fn_minify_css_union($part);
}
$prev = $part;
}
return trim($output);
}
function fn_minify_css_union($input) {
if (stripos($input, 'calc(') !== false) {
// Keep important white–space(s) in `calc()`
$input = preg_replace_callback('#\b(calc\()\s*(.*?)\s*\)#i', function($m) {
return $m[1] . preg_replace('#\s+#', X, $m[2]) . ')';
}, $input);
}
$input = preg_replace([
// Fix case for `#foo<space>[bar="baz"]`, `#foo<space>*` and `#foo<space>:first-child` [^1]
'#(?<=[\w])\s+(\*|\[|:[\w-]+)#',
// Fix case for `[bar="baz"]<space>.foo`, `*<space>.foo`, `:nth-child(2)<space>.foo` and `@media<space>(foo: bar)<space>and<space>(baz: qux)` [^2]
'#([*\]\)])\s+(?=[\w\#.])#', '#\b\s+\(#', '#\)\s+\b#',
// Minify HEX color code … [^3]
'#\#([a-f\d])\1([a-f\d])\2([a-f\d])\3\b#i',
// Remove white–space(s) around punctuation(s) [^4]
'#\s*([~!@*\(\)+=\{\}\[\]:;,>\/])\s*#',
// Replace zero unit(s) with `0` [^5]
'#\b(?<!\d\.)(?: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)([;,\}])#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+#'
], [
// [^1]
X . '$1',
// [^2]
'$1' . X, X . '(', ')' . X,
// [^3]
'#$1$2$3',
// [^4]
'$1',
// [^5]
'0',
// [^6]
'.$1',
// [^7]
':0',
// [^8]
'$1:0 0$2',
// [^9]
'$1:0',
// [^10]
'$1',
// [^11]
'$1',
// [^12]
' '
], $input);
return trim(str_replace(X, ' ', $input));
}
function fn_minify_html($input, $comment = 2, $quote = 1) {
if (!is_string($input) || !$input = n(trim($input))) return $input;
$output = $prev = "";
foreach (fn_minify([MINIFY_COMMENT_HTML, MINIFY_HTML_KEEP, MINIFY_HTML, MINIFY_HTML_ENT], $input) as $part) {
if ($part === "\n") continue;
if ($part !== ' ' && trim($part) === "" || $comment !== 1 && strpos($part, '<!--') === 0) {
// Detect IE conditional comment(s) by its closing tag …
if ($comment === 2 && substr($part, -12) === '<![endif]-->') {
$output .= $part;
}
continue;
}
if ($part[0] === '<' && substr($part, -1) === '>') {
$output .= fn_minify_html_union($part, $quote);
} else if ($part[0] === '&' && substr($part, -1) === ';' && $part !== '&lt;' && $part !== '&gt;' && $part !== '&amp;') {
$output .= html_entity_decode($part); // Evaluate HTML entit(y|ies)
} else {
$output .= preg_replace('#\s+#', ' ', $part);
}
$prev = $part;
}
$output = str_replace(' </', '</', $output);
// Force space with `&#x0020;` and line–break with `&#x000A;`
return str_ireplace(['&#x0020;', '&#x20;', '&#x000A;', '&#xA;'], [' ', ' ', "\n", "\n"], trim($output));
}
function fn_minify_html_union($input, $quote) {
if (
strpos($input, ' ') === false &&
strpos($input, "\n") === false &&
strpos($input, "\t") === false
) return $input;
global $url;
return preg_replace_callback('#<\s*([^\/\s]+)\s*(?:>|(\s[^<>]+?)\s*>)#', function($m) use($quote, $url) {
if (isset($m[2])) {
// Minify inline CSS(s)
if (stripos($m[2], ' style=') !== false) {
$m[2] = preg_replace_callback('#( style=)([\'"]?)(.*?)\2#i', function($m) {
return $m[1] . $m[2] . fn_minify_css($m[3]) . $m[2];
}, $m[2]);
}
// Minify URL(s)
if (strpos($m[2], '://') !== false) {
$m[2] = str_replace([
$url . '/',
$url . '?',
$url . '&',
$url . '#',
$url . '"',
$url . "'"
], [
'/',
'?',
'&',
'#',
'/"',
"/'"
], $m[2]);
}
$a = 'a(sync|uto(focus|play))|c(hecked|ontrols)|d(efer|isabled)|hidden|ismap|loop|multiple|open|re(adonly|quired)|s((cop|elect)ed|pellcheck)';
$a = '<' . $m[1] . preg_replace([
// From `a="a"`, `a='a'`, `a="true"`, `a='true'`, `a=""` and `a=''` to `a` [^1]
'#\s(' . $a . ')(?:=([\'"]?)(?:true|\1)?\2)#i',
// Remove extra white–space(s) between HTML attribute(s) [^2]
'#\s*([^\s=]+?)(=(?:\S+|([\'"]?).*?\3)|$)#',
// From `<img />` to `<img/>` [^3]
'#\s+\/$#'
], [
// [^1]
' $1',
// [^2]
' $1$2',
// [^3]
'/'
], str_replace("\n", ' ', $m[2])) . '>';
return $quote !== 1 ? fn_minify_html_union_attr($a) : $a;
}
return '<' . $m[1] . '>';
}, $input);
}
function fn_minify_html_union_attr($input) {
if (strpos($input, '=') === false) return $input;
return preg_replace_callback('#=(' . MINIFY_STRING . ')#', function($m) {
$q = $m[1][0];
if (strpos($m[1], ' ') === false && preg_match('#^' . $q . '[a-zA-Z_][\w-]*?' . $q . '$#', $m[1])) {
return '=' . t($m[1], $q);
}
return $m[0];
}, $input);
}
function fn_minify_js($input, $comment = 2, $quote = 2) {
if (!is_string($input) || !$input = n(trim($input))) return $input;
$output = $prev = "";
foreach (fn_minify([MINIFY_COMMENT_CSS, MINIFY_STRING, MINIFY_COMMENT_JS, MINIFY_PATTERN_JS], $input) as $part) {
if (trim($part) === "") continue;
if ($comment !== 1 && (
strpos($part, '//') === 0 || // Remove inline comment(s)
strpos($part, '/*') === 0 && substr($part, -2) === '*/'
)) {
if (
$comment === 2 && (
// Detect special comment(s) from the third character. It should be a `!` or `*` → `/*! keep */` or `/** keep */`
strpos('*!', $part[2]) !== false ||
// Detect license comment(s) from the content. It should contains character(s) like `@license`
stripos($part, '@licence') !== false || // noun
stripos($part, '@license') !== false || // verb
stripos($part, '@preserve') !== false
)
) {
$output .= $part;
}
continue;
}
if ($part[0] === '/' && (substr($part, -1) === '/' || preg_match('#\/[gimuy]*$#', $part))) {
$output .= $part;
} else if ($part[0] === '"' && substr($part, -1) === '"' || $part[0] === "'" && substr($part, -1) === "'") {
// TODO: Remove quote(s) where possible …
$output .= $part;
} else {
$output .= fn_minify_js_union($part);
}
$prev = $part;
}
return $output;
}
function fn_minify_js_union($input) {
return preg_replace([
// Remove white–space(s) around punctuation(s) [^1]
'#\s*([!%&*\(\)\-=+\[\]\{\}|;:,.<>?\/])\s*#',
// Remove the last semi–colon and comma [^2]
'#[;,]([\]\}])#',
// Replace `true` with `!0` and `false` with `!1` [^3]
'#\btrue\b#', '#\bfalse\b#', '#\b(return\s?)\s*\b#',
// Replace `new Array(x)` with `[x]` … [^4]
'#\b(?:new\s+)?Array\((.*?)\)#', '#\b(?:new\s+)?Object\((.*?)\)#'
], [
// [^1]
'$1',
// [^2]
'$1',
// [^3]
'!0', '!1', '$1',
// [^4]
'[$1]', '{$1}'
], $input);
}
/**
* Backward Compatibility
* ----------------------
*/
function minify_css(...$lot) {
return fn_minify_css(...$lot);
}
function minify_html(...$lot) {
return fn_minify_html(...$lot);
}
function minify_js(...$lot) {
return fn_minify_js(...$lot);
}
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