+<?php
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+namespace MediaWiki\Sparql;
+
+use Http;
+use MediaWiki\Http\HttpRequestFactory;
+
+/**
+ * Simple SPARQL client
+ *
+ * @author Stas Malyshev
+ */
+class SparqlClient {
+
+ /**
+ * Limit on how long can be the query to be sent by GET.
+ */
+ const MAX_GET_SIZE = 2048;
+
+ /**
+ * User agent for HTTP requests.
+ * @var string
+ */
+ private $userAgent;
+
+ /**
+ * Query timeout (seconds)
+ * @var int
+ */
+ private $timeout = 30;
+
+ /**
+ * SPARQL endpoint URL
+ * @var string
+ */
+ private $endpoint;
+
+ /**
+ * Client options
+ * @var array
+ */
+ private $options = [];
+
+ /**
+ * @var HttpRequestFactory
+ */
+ private $requestFactory;
+
+ /**
+ * @param string $url SPARQL Endpoint
+ * @param HttpRequestFactory $requestFactory
+ */
+ public function __construct( $url, HttpRequestFactory $requestFactory ) {
+ $this->endpoint = $url;
+ $this->requestFactory = $requestFactory;
+ $this->userAgent = Http::userAgent() . " SparqlClient";
+ }
+
+ /**
+ * Set query timeout (in seconds)
+ * @param int $timeout
+ * @return $this
+ */
+ public function setTimeout( $timeout ) {
+ if ( $timeout >= 0 ) {
+ $this->timeout = $timeout;
+ }
+ return $this;
+ }
+
+ /**
+ * Set client options
+ * @param array $options
+ * @return $this
+ */
+ public function setClientOptions( $options ) {
+ $this->options = $options;
+ return $this;
+ }
+
+ /**
+ * Get current user agent.
+ * @return string
+ */
+ public function getUserAgent() {
+ return $this->userAgent;
+ }
+
+ /**
+ * Set user agent string.
+ *
+ * Mote it is not recommended to completely override user agent for
+ * most applications.
+ * @see appendUserAgent() for recommended way of specifying user agent.
+ *
+ * @param string $agent
+ */
+ public function setUserAgent( $agent ) {
+ $this->userAgent = $agent;
+ }
+
+ /**
+ * Append specific string to user agent.
+ *
+ * This is the recommended way of specifying the user agent
+ * for specific applications of the SparqlClient inside MediaWiki
+ * and extension code.
+ *
+ * @param string $agent
+ */
+ public function appendUserAgent( $agent ) {
+ $this->userAgent .= ' ' . $agent;
+ }
+
+ /**
+ * Query SPARQL endpoint
+ *
+ * @param string $sparql query
+ * @param bool $rawData Whether to return only values or full data objects
+ *
+ * @return array List of results, one row per array element
+ * Each row will contain fields indexed by variable name.
+ * @throws SparqlException
+ */
+ public function query( $sparql, $rawData = false ) {
+ if ( empty( $this->endpoint ) ) {
+ throw new SparqlException( 'Endpoint URL can not be empty' );
+ }
+ $queryData = [ "query" => $sparql, "format" => "json" ];
+ $options = array_merge( [ 'method' => 'GET' ], $this->options );
+
+ if ( empty( $options['userAgent'] ) ) {
+ $options['userAgent'] = $this->userAgent;
+ }
+
+ if ( $this->timeout >= 0 ) {
+ // Blazegraph setting, see https://wiki.blazegraph.com/wiki/index.php/REST_API
+ $queryData['maxQueryTimeMillis'] = $this->timeout * 1000;
+ $options['timeout'] = $this->timeout;
+ }
+
+ if ( strlen( $sparql ) > self::MAX_GET_SIZE ) {
+ // big requests go to POST
+ $options['method'] = 'POST';
+ $options['postData'] = 'query=' . urlencode( $sparql );
+ unset( $queryData['query'] );
+ }
+
+ $url = wfAppendQuery( $this->endpoint, $queryData );
+ $request = $this->requestFactory->create( $url, $options, __METHOD__ );
+
+ $status = $request->execute();
+
+ if ( !$status->isOK() ) {
+ throw new SparqlException( "HTTP error: {$status->getWikiText()}" );
+ }
+ $result = $request->getContent();
+ \MediaWiki\suppressWarnings();
+ $data = json_decode( $result, true );
+ \MediaWiki\restoreWarnings();
+ if ( $data === null || $data === false ) {
+ throw new SparqlException( "HTTP request failed, response:\n" .
+ substr( $result, 1024 ) );
+ }
+
+ return $this->extractData( $data, $rawData );
+ }
+
+ /**
+ * Extract data from SPARQL response format.
+ * The response must be in format described in:
+ * https://www.w3.org/TR/sparql11-results-json/
+ *
+ * @param array $data SPARQL result
+ * @param bool $rawData Whether to return only values or full data objects
+ *
+ * @return array List of results, one row per element.
+ */
+ private function extractData( $data, $rawData = false ) {
+ $result = [];
+ if ( $data && !empty( $data['results'] ) ) {
+ $vars = $data['head']['vars'];
+ $resrow = [];
+ foreach ( $data['results']['bindings'] as $row ) {
+ foreach ( $vars as $var ) {
+ if ( !isset( $row[$var] ) ) {
+ $resrow[$var] = null;
+ continue;
+ }
+ if ( $rawData ) {
+ $resrow[$var] = $row[$var];
+ } else {
+ $resrow[$var] = $row[$var]['value'];
+ }
+ }
+ $result[] = $resrow;
+ }
+ }
+ return $result;
+ }
+
+}
dépôts / lhc / web / wiklou.git / commitdiff