Zend_Filter_Minify_Javascript - Nick Daugherty

Zend_Filter_Minify_Javascript
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[Nick Daugherty|mailto:ndaugherty987@gmail.com]
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TBD
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1.0 - 23 April 2010: Initial Draft.
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{zone-data:overview}
Zend_Filter_Minify_Javascript is a filter to minify Javascript code, reducing it's size while keeping all functionality intact
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* This component *will* minify Javascript.
* This component *will* accept strings as input to the filter() method.
* This component *will* implement Zend_Filter_Interface
* This component *will* generate valid Javascript code
* This component *will* implement an adapter system allowing for different methods of minification
* This component *will* provide options for control of minification (such as opting not to remove comments, for example)
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* Zend_Filter
* Zend_Filter_Interface
* Zend_Filter_Exception
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Minifying Javascript leads to faster load times on the client by reducing the overall size of Javascript code. This component aims to perform the work of removing comments, extra whitespace, etc while retaining the familiar Zend_Filter interface.

This component can be integrated into other framework components, such as HeadScript view helper for automatic Javascript minification.

The component is used like any other Zend_Filter_* component, passing the string to be minified to the filter() method.
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{zone-data:milestones}
* Milestone 1: Working prototype checked into the incubator supporting minification of Javascript strings
* Milestone 2: Working prototype checked into the incubator supporting minification of Javascript files (and optionally writing output to a file)
* Milestone 3: Unit tests exist, work, and are checked into SVN.
* Milestone 4: Initial documentation exists.
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{zone-data:class-list}
* Zend_Filter_Minify_Javascript
* Zend_Filter_Minify_Javascript_JsMin
* Zend_Filter_Minify_Interface
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||UC-01 Minifying a string of javascript||
{code}
$filter = new Zend_Filter_Minify_Javascript();

$minified = $filter->filter('alert("hello world");');
{code}
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{code:php}

/**
* @see Zend_Filter_Interface
*/
require_once 'Zend/Filter/Interface.php';

* @copyright Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
*/
class Zend_Filter_Minify_Javascript implements Zend_Filter_Interface
{
/**
* Minification adapter
*/
protected $_adapter;

/**
* Store options
*/
protected $_options;

/**
* Class constructor
*
* @param string|array $options (Optional) Options to set, if no adapter set, RegEx is used
*/
public function __construct($options = null)
{
$this->setOptions($options);

$this->setAdapter($options);
}

/**
* Returns the adapter instance
*
* @return Zend_Filter_Minify_Interface
*/
public function getAdapter()
{
return $this->_adapter;
}

/**
* Sets minification adapter
*
* @param string|array $options (Optional) Minification options
* @return Zend_Filter_Minify_Css
*/
public function setAdapter($options = null)
{
if (is_string($options)) {
$adapter = $options;
} else if (isset($options['adapter'])) {
$adapter = $options['adapter'];
unset($options['adapter']);
} else {
$adapter = 'JsMin';
}

if (!is_array($options)) {
$options = array();
}

if (Zend_Loader::isReadable('Zend/Filter/Minify/Javascript/' . ucfirst($adapter). '.php')) {
$adapter = 'Zend_Filter_Minify_Javascript_' . ucfirst($adapter);
}

if (!class_exists($adapter)) {
Zend_Loader::loadClass($adapter);
}

$this->_adapter = new $adapter($options);

if (!$this->_adapter instanceof Zend_Filter_Minify_Interface) {
require_once 'Zend/Filter/Minify/Exception.php';
throw new Zend_Filter_Minify_Exception("Minification adapter '" . $adapter . "' does not implement Zend_Filter_Minify_Interface");
}

return $this;
}

public function getOptions()
{
return $this->_options;
}

public function setOptions($options)
{
$this->_options = $options;

return $this;
}

/**
* Defined by Zend_Filter_Interface
*
* Returns a string containing the minified javascript. Accepts a string of javascript to be minified
*
* @param string $value
* @return string
*/
public function filter($value)
{
return $this->_adapter->minify($value);
}
}

{code}



{code:php}

<?php

/**
* Based on JSMin by Ryan Grove and Steve Clay (in turn based on JsMin.c by Douglas Crockford
* Copyright (c) 2002 Douglas Crockford (www.crockford.com)
*
* Copyright (c) 2008 Ryan Grove <ryan@wonko.com>
* Copyright (c) 2008 Steve Clay <steve@mrclay.org>
* All rights reserved.
*
* @category Zend
* @package Zend_Filter_Minify
* @copyright Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
*/
class Zend_Filter_Minify_Javascript_JsMin implements Zend_Filter_Minify_Interface
{
const ORD_LF = 10;
const ORD_SPACE = 32;
const ACTION_KEEP_A = 1;
const ACTION_DELETE_A = 2;
const ACTION_DELETE_A_B = 3;

protected $_a = "\n";
protected $_b = '';
protected $_input = '';
protected $_inputIndex = 0;
protected $_inputLength = 0;
protected $_lookAhead = null;
protected $_output = '';

/**
* Defined by Zend_Filter_Interface
*
* Returns a string containing the minified Javascript.
*
* @param string $value
* @return string
*/
public function filter($value)
{
//Perform minification on $value
$value =& $this->_minify($value);

//Return the minified string
return $value;
}

/**
* Take a string of javascript and minify it
*
* Also takes into account the set options when performing minification
*
* @param string $javascript
* @return string
*/
protected function _minify($javascript){
$this->_input = str_replace("\r\n", "\n", $javascript);
$this->_inputLength = strlen($this->_input);

$this->_action(self::ACTION_DELETE_A_B);

while ($this->_a !== null) {
// determine next command
$command = self::ACTION_KEEP_A; // default
if ($this->_a === ' ') {
if (! $this->_isAlphaNum($this->_b)) {
$command = self::ACTION_DELETE_A;
}
} elseif ($this->_a === "\n") {
if ($this->_b === ' ') {
$command = self::ACTION_DELETE_A_B;
} elseif (false === strpos('{[(+-', $this->_b)
&& ! $this->_isAlphaNum($this->_b)) {
$command = self::ACTION_DELETE_A;
}
} elseif (! $this->_isAlphaNum($this->_a)) {
if ($this->_b === ' '
|| ($this->_b === "\n"
&& (false === strpos('}])+-"\'', $this->_a)))) {
$command = self::ACTION_DELETE_A_B;
}
}
$this->_action($command);
}
$this->_output = trim($this->_output);
return $this->_output;
}

/**
* ACTION_KEEP_A = Output A. Copy B to A. Get the next B.
* ACTION_DELETE_A = Copy B to A. Get the next B.
* ACTION_DELETE_A_B = Get the next B.
*/
protected function _action($command)
{
switch ($command) {
case self::ACTION_KEEP_A:
$this->_output .= $this->_a;
// fallthrough
case self::ACTION_DELETE_A:
$this->_a = $this->_b;
if ($this->_a === "'" || $this->_a === '"') { // string literal
$str = $this->_a; // in case needed for exception
while (true) {
$this->_output .= $this->_a;
$this->_a = $this->_get();
if ($this->_a === $this->_b) { // end quote
break;
}
if (ord($this->_a) <= self::ORD_LF) {
throw new Zend_Filter_Minify_Javascript_Exception(
'Unterminated String: ' . var_export($str, true));
}
$str .= $this->_a;
if ($this->_a === '\\') {
$this->_output .= $this->_a;
$this->_a = $this->_get();
$str .= $this->_a;
}
}
}
// fallthrough
case self::ACTION_DELETE_A_B:
$this->_b = $this->_next();
if ($this->_b === '/' && $this->_isRegexpLiteral()) { // RegExp literal
$this->_output .= $this->_a . $this->_b;
$pattern = '/'; // in case needed for exception
while (true) {
$this->_a = $this->_get();
$pattern .= $this->_a;
if ($this->_a === '/') { // end pattern
break; // while (true)
} elseif ($this->_a === '\\') {
$this->_output .= $this->_a;
$this->_a = $this->_get();
$pattern .= $this->_a;
} elseif (ord($this->_a) <= self::ORD_LF) {
throw new Zend_Filter_Minify_Javascript_Exception(
'Unterminated RegExp: '. var_export($pattern, true));
}
$this->_output .= $this->_a;
}
$this->_b = $this->_next();
}
// end case ACTION_DELETE_A_B
}
}

protected function _isRegexpLiteral()
{
if (false !== strpos("\n{;(,=:[!&|?", $this->_a)) { // we aren't dividing
return true;
}
if (' ' === $this->_a) {
$length = strlen($this->_output);
if ($length < 2) { // weird edge case
return true;
}
// you can't divide a keyword
if (preg_match('/(?:case|else|in|return|typeof)$/', $this->_output, $m)) {
if ($this->_output === $m[0]) { // odd but could happen
return true;
}
// make sure it's a keyword, not end of an identifier
$charBeforeKeyword = substr($this->_output, $length - strlen($m[0]) - 1, 1);
if (! $this->isAlphaNum($charBeforeKeyword)) {
return true;
}
}
}
return false;
}

/**
* Get next char. Convert ctrl char to space.
*/
protected function _get()
{
$c = $this->_lookAhead;
$this->_lookAhead = null;
if ($c === null) {
if ($this->_inputIndex < $this->_inputLength) {
$c = $this->_input{$this->_inputIndex};
$this->_inputIndex += 1;
} else {
return null;
}
}
if ($c === "\r" || $c === "\n") {
return "\n";
}
if (ord($c) < self::ORD_SPACE) { // control char
return ' ';
}
return $c;
}

/**
* Get next char. If is ctrl character, translate to a space or newline.
*/
protected function _peek()
{
$this->_lookAhead = $this->_get();
return $this->_lookAhead;
}

/**
* Is $c a letter, digit, underscore, dollar sign, escape, or non-ASCII?
*/
protected function _isAlphaNum($c)
{
return (preg_match('/^[0-9a-zA-Z_\\$\\\\]$/', $c) || ord($c) > 126);
}

protected function _singleLineComment()
{
$comment = '';
while (true) {
$get = $this->_get();
$comment .= $get;
if (ord($get) <= self::ORD_LF) { // EOL reached
// if IE conditional comment
if (preg_match('/^\\/@(?:cc_on|if|elif|else|end)\\b/', $comment)) {
return "/{$comment}";
}
return $get;
}
}
}

protected function _multipleLineComment()
{
$this->_get();
$comment = '';
while (true) {
$get = $this->_get();
if ($get === '*') {
if ($this->_peek() === '/') { // end of comment reached
$this->_get();
// if comment preserved by YUI Compressor
if (0 === strpos($comment, '!')) {
return "\n/*" . substr($comment, 1) . "*/\n";
}
// if IE conditional comment
if (preg_match('/^@(?:cc_on|if|elif|else|end)\\b/', $comment)) {
return "/*{$comment}*/";
}
return ' ';
}
} elseif ($get === null) {
throw new Zend_Filter_Minify_Javascript_Exception('Unterminated Comment: ' . var_export('/*' . $comment, true));
}
$comment .= $get;
}
}

/**
* Get the next character, skipping over comments.
* Some comments may be preserved.
*/
protected function _next()
{
$get = $this->_get();
if ($get !== '/') {
return $get;
}
switch ($this->_peek()) {
case '/': return $this->_singleLineComment();
case '*': return $this->_multipleLineComment();
default: return $get;
}
}
}

{code}