336 lines
10 KiB
PHP
336 lines
10 KiB
PHP
<?php
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/**
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* Class HTTP_Encoder
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* @package Minify
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* @subpackage HTTP
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*/
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/**
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* Encode and send gzipped/deflated content
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*
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* The "Vary: Accept-Encoding" header is sent. If the client allows encoding,
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* Content-Encoding and Content-Length are added.
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*
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* <code>
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* // Send a CSS file, compressed if possible
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* $he = new HTTP_Encoder(array(
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* 'content' => file_get_contents($cssFile)
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* ,'type' => 'text/css'
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* ));
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* $he->encode();
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* $he->sendAll();
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* </code>
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*
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* <code>
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* // Shortcut to encoding output
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* header('Content-Type: text/css'); // needed if not HTML
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* HTTP_Encoder::output($css);
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* </code>
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*
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* <code>
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* // Just sniff for the accepted encoding
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* $encoding = HTTP_Encoder::getAcceptedEncoding();
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* </code>
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*
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* For more control over headers, use getHeaders() and getData() and send your
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* own output.
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*
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* Note: If you don't need header mgmt, use PHP's native gzencode, gzdeflate,
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* and gzcompress functions for gzip, deflate, and compress-encoding
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* respectively.
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*
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* @package Minify
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* @subpackage HTTP
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* @author Stephen Clay <steve@mrclay.org>
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*/
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class HTTP_Encoder {
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/**
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* Should the encoder allow HTTP encoding to IE6?
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*
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* If you have many IE6 users and the bandwidth savings is worth troubling
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* some of them, set this to true.
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*
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* By default, encoding is only offered to IE7+. When this is true,
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* getAcceptedEncoding() will return an encoding for IE6 if its user agent
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* string contains "SV1". This has been documented in many places as "safe",
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* but there seem to be remaining, intermittent encoding bugs in patched
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* IE6 on the wild web.
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*
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* @var bool
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*/
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public static $encodeToIe6 = true;
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/**
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* Default compression level for zlib operations
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*
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* This level is used if encode() is not given a $compressionLevel
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*
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* @var int
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*/
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public static $compressionLevel = 6;
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/**
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* Get an HTTP Encoder object
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*
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* @param array $spec options
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*
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* 'content': (string required) content to be encoded
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*
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* 'type': (string) if set, the Content-Type header will have this value.
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*
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* 'method: (string) only set this if you are forcing a particular encoding
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* method. If not set, the best method will be chosen by getAcceptedEncoding()
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* The available methods are 'gzip', 'deflate', 'compress', and '' (no
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* encoding)
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*/
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public function __construct($spec)
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{
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$this->_useMbStrlen = (function_exists('mb_strlen')
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&& (ini_get('mbstring.func_overload') !== '')
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&& ((int)ini_get('mbstring.func_overload') & 2));
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$this->_content = $spec['content'];
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$this->_headers['Content-Length'] = $this->_useMbStrlen
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? (string)mb_strlen($this->_content, '8bit')
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: (string)strlen($this->_content);
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if (isset($spec['type'])) {
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$this->_headers['Content-Type'] = $spec['type'];
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}
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if (isset($spec['method'])
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&& in_array($spec['method'], array('gzip', 'deflate', 'compress', '')))
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{
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$this->_encodeMethod = array($spec['method'], $spec['method']);
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} else {
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$this->_encodeMethod = self::getAcceptedEncoding();
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}
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}
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/**
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* Get content in current form
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*
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* Call after encode() for encoded content.
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*
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* @return string
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*/
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public function getContent()
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{
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return $this->_content;
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}
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/**
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* Get array of output headers to be sent
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*
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* E.g.
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* <code>
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* array(
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* 'Content-Length' => '615'
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* ,'Content-Encoding' => 'x-gzip'
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* ,'Vary' => 'Accept-Encoding'
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* )
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* </code>
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*
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* @return array
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*/
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public function getHeaders()
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{
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return $this->_headers;
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}
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/**
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* Send output headers
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*
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* You must call this before headers are sent and it probably cannot be
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* used in conjunction with zlib output buffering / mod_gzip. Errors are
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* not handled purposefully.
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*
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* @see getHeaders()
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*/
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public function sendHeaders()
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{
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foreach ($this->_headers as $name => $val) {
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header($name . ': ' . $val);
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}
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}
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/**
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* Send output headers and content
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*
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* A shortcut for sendHeaders() and echo getContent()
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*
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* You must call this before headers are sent and it probably cannot be
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* used in conjunction with zlib output buffering / mod_gzip. Errors are
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* not handled purposefully.
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*/
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public function sendAll()
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{
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$this->sendHeaders();
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echo $this->_content;
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}
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/**
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* Determine the client's best encoding method from the HTTP Accept-Encoding
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* header.
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*
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* If no Accept-Encoding header is set, or the browser is IE before v6 SP2,
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* this will return ('', ''), the "identity" encoding.
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*
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* A syntax-aware scan is done of the Accept-Encoding, so the method must
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* be non 0. The methods are favored in order of gzip, deflate, then
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* compress. Deflate is always smallest and generally faster, but is
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* rarely sent by servers, so client support could be buggier.
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*
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* @param bool $allowCompress allow the older compress encoding
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*
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* @param bool $allowDeflate allow the more recent deflate encoding
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*
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* @return array two values, 1st is the actual encoding method, 2nd is the
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* alias of that method to use in the Content-Encoding header (some browsers
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* call gzip "x-gzip" etc.)
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*/
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public static function getAcceptedEncoding($allowCompress = true, $allowDeflate = true)
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{
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// @link http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
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if (! isset($_SERVER['HTTP_ACCEPT_ENCODING'])
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|| self::isBuggyIe())
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{
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return array('', '');
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}
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$ae = $_SERVER['HTTP_ACCEPT_ENCODING'];
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// gzip checks (quick)
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if (0 === strpos($ae, 'gzip,') // most browsers
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|| 0 === strpos($ae, 'deflate, gzip,') // opera
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) {
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return array('gzip', 'gzip');
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}
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// gzip checks (slow)
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if (preg_match(
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'@(?:^|,)\\s*((?:x-)?gzip)\\s*(?:$|,|;\\s*q=(?:0\\.|1))@'
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,$ae
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,$m)) {
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return array('gzip', $m[1]);
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}
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if ($allowDeflate) {
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// deflate checks
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$aeRev = strrev($ae);
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if (0 === strpos($aeRev, 'etalfed ,') // ie, webkit
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|| 0 === strpos($aeRev, 'etalfed,') // gecko
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|| 0 === strpos($ae, 'deflate,') // opera
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// slow parsing
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|| preg_match(
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'@(?:^|,)\\s*deflate\\s*(?:$|,|;\\s*q=(?:0\\.|1))@', $ae)) {
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return array('deflate', 'deflate');
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}
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}
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if ($allowCompress && preg_match(
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'@(?:^|,)\\s*((?:x-)?compress)\\s*(?:$|,|;\\s*q=(?:0\\.|1))@'
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,$ae
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,$m)) {
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return array('compress', $m[1]);
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}
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return array('', '');
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}
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/**
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* Encode (compress) the content
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*
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* If the encode method is '' (none) or compression level is 0, or the 'zlib'
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* extension isn't loaded, we return false.
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*
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* Then the appropriate gz_* function is called to compress the content. If
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* this fails, false is returned.
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*
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* The header "Vary: Accept-Encoding" is added. If encoding is successful,
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* the Content-Length header is updated, and Content-Encoding is also added.
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*
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* @param int $compressionLevel given to zlib functions. If not given, the
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* class default will be used.
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*
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* @return bool success true if the content was actually compressed
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*/
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public function encode($compressionLevel = null)
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{
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if (! self::isBuggyIe()) {
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$this->_headers['Vary'] = 'Accept-Encoding';
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}
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if (null === $compressionLevel) {
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$compressionLevel = self::$compressionLevel;
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}
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if ('' === $this->_encodeMethod[0]
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|| ($compressionLevel == 0)
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|| !extension_loaded('zlib'))
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{
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return false;
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}
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if ($this->_encodeMethod[0] === 'deflate') {
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$encoded = gzdeflate($this->_content, $compressionLevel);
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} elseif ($this->_encodeMethod[0] === 'gzip') {
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$encoded = gzencode($this->_content, $compressionLevel);
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} else {
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$encoded = gzcompress($this->_content, $compressionLevel);
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}
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if (false === $encoded) {
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return false;
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}
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$this->_headers['Content-Length'] = $this->_useMbStrlen
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? (string)mb_strlen($encoded, '8bit')
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: (string)strlen($encoded);
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$this->_headers['Content-Encoding'] = $this->_encodeMethod[1];
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$this->_content = $encoded;
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return true;
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}
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/**
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* Encode and send appropriate headers and content
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*
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* This is a convenience method for common use of the class
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*
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* @param string $content
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*
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* @param int $compressionLevel given to zlib functions. If not given, the
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* class default will be used.
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*
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* @return bool success true if the content was actually compressed
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*/
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public static function output($content, $compressionLevel = null)
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{
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if (null === $compressionLevel) {
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$compressionLevel = self::$compressionLevel;
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}
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$he = new HTTP_Encoder(array('content' => $content));
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$ret = $he->encode($compressionLevel);
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$he->sendAll();
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return $ret;
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}
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/**
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* Is the browser an IE version earlier than 6 SP2?
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*
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* @return bool
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*/
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public static function isBuggyIe()
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{
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if (empty($_SERVER['HTTP_USER_AGENT'])) {
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return false;
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}
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$ua = $_SERVER['HTTP_USER_AGENT'];
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// quick escape for non-IEs
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if (0 !== strpos($ua, 'Mozilla/4.0 (compatible; MSIE ')
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|| false !== strpos($ua, 'Opera')) {
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return false;
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}
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// no regex = faaast
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$version = (float)substr($ua, 30);
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return self::$encodeToIe6
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? ($version < 6 || ($version == 6 && false === strpos($ua, 'SV1')))
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: ($version < 7);
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}
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protected $_content = '';
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protected $_headers = array();
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protected $_encodeMethod = array('', '');
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protected $_useMbStrlen = false;
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}
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