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<?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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/** |
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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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|
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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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/** |
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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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/** |
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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($spec['method'], array('gzip', 'deflate', 'compress', ''))) { |
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$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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/** |
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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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/** |
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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 $this->_headers; |
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} |
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|
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/** |
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* Send output headers |
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* |
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* You must call this before headers are sent and it probably cannot be |
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* used in conjunction with zlib output buffering / mod_gzip. Errors are |
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* not handled purposefully. |
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* |
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* @see getHeaders() |
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*/ |
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public function sendHeaders() |
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{ |
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foreach ($this->_headers as $name => $val) { |
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header($name . ': ' . $val); |
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} |
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} |
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|
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/** |
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* Send output headers and content |
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* |
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* A shortcut for sendHeaders() and echo getContent() |
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* |
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* You must call this before headers are sent and it probably cannot be |
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* used in conjunction with zlib output buffering / mod_gzip. Errors are |
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* not handled purposefully. |
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*/ |
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public function sendAll() |
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{ |
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$this->sendHeaders(); |
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echo $this->_content; |
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} |
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|
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/** |
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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, $allowDeflate = true) |
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{ |
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// @link http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html |
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|
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if (! isset($_SERVER['HTTP_ACCEPT_ENCODING']) |
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|| self::isBuggyIe()) { |
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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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)) { |
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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))@', |
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$ae |
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)) { |
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return array('deflate', 'deflate'); |
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} |
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} |
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if ($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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)) { |
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return array('compress', $m[1]); |
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} |
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|
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return array('', ''); |
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} |
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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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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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|
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return true; |
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} |
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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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|
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return $ret; |
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} |
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|
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/** |
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* Is the browser an IE version earlier than 6 SP2? |
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* |
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* @return bool |
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*/ |
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public static function isBuggyIe() |
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{ |
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if (empty($_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($ua, 30); |
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|
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return self::$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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|
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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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|
