EhcacheBagOStuff.php

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<?php

class EhcacheBagOStuff extends BagOStuff {
        var $servers, $cacheName, $connectTimeout, $timeout, $curlOptions, 
                $requestData, $requestDataPos;
        
        var $curls = array();

        function __construct( $params ) {
                if ( !defined( 'CURLOPT_TIMEOUT_MS' ) ) {
                        throw new MWException( __CLASS__.' requires curl version 7.16.2 or later.' );
                }
                if ( !extension_loaded( 'zlib' ) ) {
                        throw new MWException( __CLASS__.' requires the zlib extension' );
                }
                if ( !isset( $params['servers'] ) ) {
                        throw new MWException( __METHOD__.': servers parameter is required' );
                }
                $this->servers = $params['servers'];
                $this->cacheName = isset( $params['cache'] ) ? $params['cache'] : 'mw';
                $this->connectTimeout = isset( $params['connectTimeout'] ) 
                        ? $params['connectTimeout'] : 1;
                $this->timeout = isset( $params['timeout'] ) ? $params['timeout'] : 1;
                $this->curlOptions = array(
                        CURLOPT_CONNECTTIMEOUT_MS => intval( $this->connectTimeout * 1000 ),
                        CURLOPT_TIMEOUT_MS => intval( $this->timeout * 1000 ),
                        CURLOPT_RETURNTRANSFER => 1,
                        CURLOPT_CUSTOMREQUEST => 'GET',
                        CURLOPT_POST => 0,
                        CURLOPT_POSTFIELDS => '',
                        CURLOPT_HTTPHEADER => array(),
                );
        }

        public function get( $key ) {
                wfProfileIn( __METHOD__ );
                $response = $this->doItemRequest( $key );
                if ( !$response || $response['http_code'] == 404 ) {
                        wfProfileOut( __METHOD__ );
                        return false;
                }
                if ( $response['http_code'] >= 300 ) {
                        wfDebug( __METHOD__.": GET failure, got HTTP {$response['http_code']}\n" );
                        wfProfileOut( __METHOD__ );
                        return false;                   
                }
                $body = $response['body'];
                $type = $response['content_type'];
                if ( $type == 'application/vnd.php.serialized+deflate' ) {
                        $body = gzinflate( $body );
                        if ( !$body ) {
                                wfDebug( __METHOD__.": error inflating $key\n" );
                                wfProfileOut( __METHOD__ );
                                return false;
                        }
                        $data = unserialize( $body );
                } elseif ( $type == 'application/vnd.php.serialized' ) {
                        $data = unserialize( $body );
                } else {
                        wfDebug( __METHOD__.": unknown content type \"$type\"\n" );
                        wfProfileOut( __METHOD__ );
                        return false;
                }

                wfProfileOut( __METHOD__ );
                return $data;
        }

        public function set( $key, $value, $expiry = 0 ) {
                wfProfileIn( __METHOD__ );
                $expiry = $this->convertExpiry( $expiry );
                $ttl = $expiry ? $expiry - time() : 2147483647;
                $blob = serialize( $value );
                if ( strlen( $blob ) > 100 ) {
                        $blob = gzdeflate( $blob );
                        $contentType = 'application/vnd.php.serialized+deflate';
                } else {
                        $contentType = 'application/vnd.php.serialized';
                }

                $code = $this->attemptPut( $key, $blob, $contentType, $ttl );

                if ( $code == 404 ) {
                        // Maybe the cache does not exist yet, let's try creating it
                        if ( !$this->createCache( $key ) ) {
                                wfDebug( __METHOD__.": cache creation failed\n" );
                                wfProfileOut( __METHOD__ );
                                return false;
                        }
                        $code = $this->attemptPut( $key, $blob, $contentType, $ttl );
                }

                $result = false;
                if ( !$code ) {
                        wfDebug( __METHOD__.": PUT failure for key $key\n" );
                } elseif ( $code >= 300 ) {
                        wfDebug( __METHOD__.": PUT failure for key $key: HTTP $code\n" );
                } else {
                        $result = true;
                }

                wfProfileOut( __METHOD__ );
                return $result;
        }

        public function delete( $key, $time = 0 ) {
                wfProfileIn( __METHOD__ );
                $response = $this->doItemRequest( $key,
                        array( CURLOPT_CUSTOMREQUEST => 'DELETE' ) );
                $code = isset( $response['http_code'] ) ? $response['http_code'] : 0;
                if ( !$response || ( $code != 404 && $code >= 300 ) ) {
                        wfDebug( __METHOD__.": DELETE failure for key $key\n" );
                        $result = false;
                } else {
                        $result = true;
                }
                wfProfileOut( __METHOD__ );
                return $result;
        }

        protected function getCacheUrl( $key ) {
                if ( count( $this->servers ) == 1 ) {
                        $server = reset( $this->servers );
                } else {
                        // Use consistent hashing
                        $hashes = array();
                        foreach ( $this->servers as $server ) {
                                $hashes[$server] = md5( $server . '/' . $key );
                        }
                        asort( $hashes );
                        reset( $hashes );
                        $server = key( $hashes );
                }
                return "http://$server/ehcache/rest/{$this->cacheName}";
        }

        protected function getCurl( $cacheUrl ) {
                if ( !isset( $this->curls[$cacheUrl] ) ) {
                        $this->curls[$cacheUrl] = curl_init();
                }
                return $this->curls[$cacheUrl];
        }

        protected function attemptPut( $key, $data, $type, $ttl ) {
                // In initial benchmarking, it was 30 times faster to use CURLOPT_POST 
                // than CURLOPT_UPLOAD with CURLOPT_READFUNCTION. This was because
                // CURLOPT_UPLOAD was pushing the request headers first, then waiting 
                // for an ACK packet, then sending the data, whereas CURLOPT_POST just
                // sends the headers and the data in a single send().
                $response = $this->doItemRequest( $key,
                        array(
                                CURLOPT_POST => 1,
                                CURLOPT_CUSTOMREQUEST => 'PUT',
                                CURLOPT_POSTFIELDS => $data,
                                CURLOPT_HTTPHEADER => array(
                                        'Content-Type: ' . $type,
                                        'ehcacheTimeToLiveSeconds: ' . $ttl
                                )
                        )
                );
                if ( !$response ) {
                        return 0;
                } else {
                        return $response['http_code'];
                }
        }

        protected function createCache( $key ) {
                wfDebug( __METHOD__.": creating cache for $key\n" );
                $response = $this->doCacheRequest( $key, 
                        array(
                                CURLOPT_POST => 1,
                                CURLOPT_CUSTOMREQUEST => 'PUT',
                                CURLOPT_POSTFIELDS => '',
                        ) );
                if ( !$response ) {
                        wfDebug( __CLASS__.": failed to create cache for $key\n" );
                        return false;
                }
                if ( $response['http_code'] == 201 /* created */ 
                        || $response['http_code'] == 409 /* already there */ ) 
                {
                        return true;
                } else {
                        return false;
                }                       
        }

        protected function doCacheRequest( $key, $curlOptions = array() ) {
                $cacheUrl = $this->getCacheUrl( $key );
                $curl = $this->getCurl( $cacheUrl );
                return $this->doRequest( $curl, $cacheUrl, $curlOptions );
        }

        protected function doItemRequest( $key, $curlOptions = array() ) {
                $cacheUrl = $this->getCacheUrl( $key );
                $curl = $this->getCurl( $cacheUrl );
                $url = $cacheUrl . '/' . rawurlencode( $key );
                return $this->doRequest( $curl, $url, $curlOptions );
        }

        protected function doRequest( $curl, $url, $curlOptions = array() ) {
                if ( array_diff_key( $curlOptions, $this->curlOptions ) ) {
                        // var_dump( array_diff_key( $curlOptions, $this->curlOptions ) );
                        throw new MWException( __METHOD__.": to prevent options set in one doRequest() " .
                                "call from affecting subsequent doRequest() calls, only options listed " . 
                                "in \$this->curlOptions may be specified in the \$curlOptions parameter." );
                }
                $curlOptions += $this->curlOptions;
                $curlOptions[CURLOPT_URL] = $url;

                curl_setopt_array( $curl, $curlOptions );
                $result = curl_exec( $curl );
                if ( $result === false ) {
                        wfDebug( __CLASS__.": curl error: " . curl_error( $curl ) . "\n" );
                        return false;
                }
                $info = curl_getinfo( $curl );
                $info['body'] = $result;
                return $info;
        }
}