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Diffstat (limited to 'vendors/min/lib/HTTP/ConditionalGet.php')
| -rw-r--r-- | vendors/min/lib/HTTP/ConditionalGet.php | 348 |
1 files changed, 348 insertions, 0 deletions
diff --git a/vendors/min/lib/HTTP/ConditionalGet.php b/vendors/min/lib/HTTP/ConditionalGet.php new file mode 100644 index 000000000..823db058f --- /dev/null +++ b/vendors/min/lib/HTTP/ConditionalGet.php @@ -0,0 +1,348 @@ +<?php +/** + * Class HTTP_ConditionalGet + * @package Minify + * @subpackage HTTP + */ + +/** + * Implement conditional GET via a timestamp or hash of content + * + * E.g. Content from DB with update time: + * <code> + * list($updateTime, $content) = getDbUpdateAndContent(); + * $cg = new HTTP_ConditionalGet(array( + * 'lastModifiedTime' => $updateTime + * ,'isPublic' => true + * )); + * $cg->sendHeaders(); + * if ($cg->cacheIsValid) { + * exit(); + * } + * echo $content; + * </code> + * + * E.g. Shortcut for the above + * <code> + * HTTP_ConditionalGet::check($updateTime, true); // exits if client has cache + * echo $content; + * </code> + * + * E.g. Content from DB with no update time: + * <code> + * $content = getContentFromDB(); + * $cg = new HTTP_ConditionalGet(array( + * 'contentHash' => md5($content) + * )); + * $cg->sendHeaders(); + * if ($cg->cacheIsValid) { + * exit(); + * } + * echo $content; + * </code> + * + * E.g. Static content with some static includes: + * <code> + * // before content + * $cg = new HTTP_ConditionalGet(array( + * 'lastUpdateTime' => max( + * filemtime(__FILE__) + * ,filemtime('/path/to/header.inc') + * ,filemtime('/path/to/footer.inc') + * ) + * )); + * $cg->sendHeaders(); + * if ($cg->cacheIsValid) { + * exit(); + * } + * </code> + * @package Minify + * @subpackage HTTP + * @author Stephen Clay <steve@mrclay.org> + */ +class HTTP_ConditionalGet { + + /** + * Does the client have a valid copy of the requested resource? + * + * You'll want to check this after instantiating the object. If true, do + * not send content, just call sendHeaders() if you haven't already. + * + * @var bool + */ + public $cacheIsValid = null; + + /** + * @param array $spec options + * + * 'isPublic': (bool) if true, the Cache-Control header will contain + * "public", allowing proxies to cache the content. Otherwise "private" will + * be sent, allowing only browser caching. (default false) + * + * 'lastModifiedTime': (int) if given, both ETag AND Last-Modified headers + * will be sent with content. This is recommended. + * + * 'encoding': (string) if set, the header "Vary: Accept-Encoding" will + * always be sent and a truncated version of the encoding will be appended + * to the ETag. E.g. "pub123456;gz". This will also trigger a more lenient + * checking of the client's If-None-Match header, as the encoding portion of + * the ETag will be stripped before comparison. + * + * 'contentHash': (string) if given, only the ETag header can be sent with + * content (only HTTP1.1 clients can conditionally GET). The given string + * should be short with no quote characters and always change when the + * resource changes (recommend md5()). This is not needed/used if + * lastModifiedTime is given. + * + * 'eTag': (string) if given, this will be used as the ETag header rather + * than values based on lastModifiedTime or contentHash. Also the encoding + * string will not be appended to the given value as described above. + * + * 'invalidate': (bool) if true, the client cache will be considered invalid + * without testing. Effectively this disables conditional GET. + * (default false) + * + * 'maxAge': (int) if given, this will set the Cache-Control max-age in + * seconds, and also set the Expires header to the equivalent GMT date. + * After the max-age period has passed, the browser will again send a + * conditional GET to revalidate its cache. + * + * @return null + */ + public function __construct($spec) + { + $scope = (isset($spec['isPublic']) && $spec['isPublic']) + ? 'public' + : 'private'; + $maxAge = 0; + // backwards compatibility (can be removed later) + if (isset($spec['setExpires']) + && is_numeric($spec['setExpires']) + && ! isset($spec['maxAge'])) { + $spec['maxAge'] = $spec['setExpires'] - $_SERVER['REQUEST_TIME']; + } + if (isset($spec['maxAge'])) { + $maxAge = $spec['maxAge']; + $this->_headers['Expires'] = self::gmtDate( + $_SERVER['REQUEST_TIME'] + $spec['maxAge'] + ); + } + $etagAppend = ''; + if (isset($spec['encoding'])) { + $this->_stripEtag = true; + $this->_headers['Vary'] = 'Accept-Encoding'; + if ('' !== $spec['encoding']) { + if (0 === strpos($spec['encoding'], 'x-')) { + $spec['encoding'] = substr($spec['encoding'], 2); + } + $etagAppend = ';' . substr($spec['encoding'], 0, 2); + } + } + if (isset($spec['lastModifiedTime'])) { + $this->_setLastModified($spec['lastModifiedTime']); + if (isset($spec['eTag'])) { // Use it + $this->_setEtag($spec['eTag'], $scope); + } else { // base both headers on time + $this->_setEtag($spec['lastModifiedTime'] . $etagAppend, $scope); + } + } elseif (isset($spec['eTag'])) { // Use it + $this->_setEtag($spec['eTag'], $scope); + } elseif (isset($spec['contentHash'])) { // Use the hash as the ETag + $this->_setEtag($spec['contentHash'] . $etagAppend, $scope); + } + $this->_headers['Cache-Control'] = "max-age={$maxAge}, {$scope}"; + // invalidate cache if disabled, otherwise check + $this->cacheIsValid = (isset($spec['invalidate']) && $spec['invalidate']) + ? false + : $this->_isCacheValid(); + } + + /** + * Get array of output headers to be sent + * + * In the case of 304 responses, this array will only contain the response + * code header: array('_responseCode' => 'HTTP/1.0 304 Not Modified') + * + * Otherwise something like: + * <code> + * array( + * 'Cache-Control' => 'max-age=0, public' + * ,'ETag' => '"foobar"' + * ) + * </code> + * + * @return array + */ + public function getHeaders() + { + return $this->_headers; + } + + /** + * Set the Content-Length header in bytes + * + * With most PHP configs, as long as you don't flush() output, this method + * is not needed and PHP will buffer all output and set Content-Length for + * you. Otherwise you'll want to call this to let the client know up front. + * + * @param int $bytes + * + * @return int copy of input $bytes + */ + public function setContentLength($bytes) + { + return $this->_headers['Content-Length'] = $bytes; + } + + /** + * Send headers + * + * @see getHeaders() + * + * Note this doesn't "clear" the headers. Calling sendHeaders() will + * call header() again (but probably have not effect) and getHeaders() will + * still return the headers. + * + * @return null + */ + public function sendHeaders() + { + $headers = $this->_headers; + if (array_key_exists('_responseCode', $headers)) { + header($headers['_responseCode']); + unset($headers['_responseCode']); + } + foreach ($headers as $name => $val) { + header($name . ': ' . $val); + } + } + + /** + * Exit if the client's cache is valid for this resource + * + * This is a convenience method for common use of the class + * + * @param int $lastModifiedTime if given, both ETag AND Last-Modified headers + * will be sent with content. This is recommended. + * + * @param bool $isPublic (default false) if true, the Cache-Control header + * will contain "public", allowing proxies to cache the content. Otherwise + * "private" will be sent, allowing only browser caching. + * + * @param array $options (default empty) additional options for constructor + * + * @return null + */ + public static function check($lastModifiedTime = null, $isPublic = false, $options = array()) + { + if (null !== $lastModifiedTime) { + $options['lastModifiedTime'] = (int)$lastModifiedTime; + } + $options['isPublic'] = (bool)$isPublic; + $cg = new HTTP_ConditionalGet($options); + $cg->sendHeaders(); + if ($cg->cacheIsValid) { + exit(); + } + } + + + /** + * Get a GMT formatted date for use in HTTP headers + * + * <code> + * header('Expires: ' . HTTP_ConditionalGet::gmtdate($time)); + * </code> + * + * @param int $time unix timestamp + * + * @return string + */ + public static function gmtDate($time) + { + return gmdate('D, d M Y H:i:s \G\M\T', $time); + } + + protected $_headers = array(); + protected $_lmTime = null; + protected $_etag = null; + protected $_stripEtag = false; + + protected function _setEtag($hash, $scope) + { + $this->_etag = '"' . substr($scope, 0, 3) . $hash . '"'; + $this->_headers['ETag'] = $this->_etag; + } + + protected function _setLastModified($time) + { + $this->_lmTime = (int)$time; + $this->_headers['Last-Modified'] = self::gmtDate($time); + } + + /** + * Determine validity of client cache and queue 304 header if valid + */ + protected function _isCacheValid() + { + if (null === $this->_etag) { + // lmTime is copied to ETag, so this condition implies that the + // server sent neither ETag nor Last-Modified, so the client can't + // possibly has a valid cache. + return false; + } + $isValid = ($this->resourceMatchedEtag() || $this->resourceNotModified()); + if ($isValid) { + $this->_headers['_responseCode'] = 'HTTP/1.0 304 Not Modified'; + } + return $isValid; + } + + protected function resourceMatchedEtag() + { + if (!isset($_SERVER['HTTP_IF_NONE_MATCH'])) { + return false; + } + $clientEtagList = get_magic_quotes_gpc() + ? stripslashes($_SERVER['HTTP_IF_NONE_MATCH']) + : $_SERVER['HTTP_IF_NONE_MATCH']; + $clientEtags = explode(',', $clientEtagList); + + $compareTo = $this->normalizeEtag($this->_etag); + foreach ($clientEtags as $clientEtag) { + if ($this->normalizeEtag($clientEtag) === $compareTo) { + // respond with the client's matched ETag, even if it's not what + // we would've sent by default + $this->_headers['ETag'] = trim($clientEtag); + return true; + } + } + return false; + } + + protected function normalizeEtag($etag) { + $etag = trim($etag); + return $this->_stripEtag + ? preg_replace('/;\\w\\w"$/', '"', $etag) + : $etag; + } + + protected function resourceNotModified() + { + if (!isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])) { + return false; + } + $ifModifiedSince = $_SERVER['HTTP_IF_MODIFIED_SINCE']; + if (false !== ($semicolon = strrpos($ifModifiedSince, ';'))) { + // IE has tacked on extra data to this header, strip it + $ifModifiedSince = substr($ifModifiedSince, 0, $semicolon); + } + if ($ifModifiedSince == self::gmtDate($this->_lmTime)) { + // Apache 2.2's behavior. If there was no ETag match, send the + // non-encoded version of the ETag value. + $this->_headers['ETag'] = $this->normalizeEtag($this->_etag); + return true; + } + return false; + } +} |