1 <?php

     2 namespace CorpusParole\Libraries\Sparql;

     3 

     4 use EasyRdf\Sparql\Client;

     5 use EasyRdf\Exception;

     6 use EasyRdf\Format;

     7 use EasyRdf\Http;

     8 

     9 class TimeoutSparqlClient extends Client {

    10 

    11     public function query($query, $timeout=0)

    12     {

    13         return $this->request('query', $query, $timeout);

    14     }

    15 

    16     protected function request($type, $query, $timeout=0)

    17     {

    18         $processed_query = $this->preprocessQuery($query);

    19         $response = $this->executeQuery($processed_query, $type, $timeout);

    20         if (!$response->isSuccessful()) {

    21             throw new Http\Exception("HTTP request for SPARQL query failed", 0, null, $response->getBody());

    22         }

    23         if ($response->getStatus() == 204) {

    24             // No content

    25             return $response;

    26         }

    27         return $this->parseResponseToQuery($response);

    28     }

    29 

    30     /**

    31      * Build http-client object, execute request and return a response

    32      *

    33      * @param string $processed_query

    34      * @param string $type            Should be either "query" or "update"

    35      *

    36      * @return Http\Response|\Zend\Http\Response

    37      * @throws Exception

    38      */

    39     protected function executeQuery($processed_query, $type, $timeout=0)

    40     {

    41         $client = Http::getDefaultHttpClient();

    42         $client->resetParameters();

    43         // Tell the server which response formats we can parse

    44         $sparql_results_types = array(

    45             'application/sparql-results+json' => 1.0,

    46             'application/sparql-results+xml' => 0.8

    47         );

    48         if ($type == 'update') {

    49             // accept anything, as "response body of a […] update request is implementation defined"

    50             // @see http://www.w3.org/TR/sparql11-protocol/#update-success

    51             $accept = Format::getHttpAcceptHeader($sparql_results_types);

    52             $client->setHeaders('Accept', $accept);

    53             $client->setMethod('POST');

    54             $client->setUri($this->updateUri);

    55             $client->setRawData($processed_query);

    56             $client->setHeaders('Content-Type', 'application/sparql-update');

    57         } elseif ($type == 'query') {

    58             $re = '(?:(?:\s*BASE\s*<.*?>\s*)|(?:\s*PREFIX\s+.+:\s*<.*?>\s*))*'.

    59                 '(CONSTRUCT|SELECT|ASK|DESCRIBE)[\W]';

    60             $result = null;

    61             $matched = mb_eregi($re, $processed_query, $result);

    62             if (false === $matched or count($result) !== 2) {

    63                 // non-standard query. is this something non-standard?

    64                 $query_verb = null;

    65             } else {

    66                 $query_verb = strtoupper($result[1]);

    67             }

    68             if ($query_verb === 'SELECT' or $query_verb === 'ASK') {

    69                 // only "results"

    70                 $accept = Format::formatAcceptHeader($sparql_results_types);

    71             } elseif ($query_verb === 'CONSTRUCT' or $query_verb === 'DESCRIBE') {

    72                 // only "graph"

    73                 $accept = Format::getHttpAcceptHeader();

    74             } else {

    75                 // both

    76                 $accept = Format::getHttpAcceptHeader($sparql_results_types);

    77             }

    78             $client->setHeaders('Accept', $accept);

    79             $encodedQuery = 'query=' . urlencode($processed_query).(($timeout>0)?"&timeout=$timeout":"");

    80             // Use GET if the query is less than 2kB

    81             // 2046 = 2kB minus 1 for '?' and 1 for NULL-terminated string on server

    82             if (strlen($encodedQuery) + strlen($this->queryUri) <= 2046) {

    83                 $delimiter = $this->queryUri_has_params ? '&' : '?';

    84                 $client->setMethod('GET');

    85                 $client->setUri($this->queryUri . $delimiter . $encodedQuery);

    86             } else {

    87                 // Fall back to POST instead (which is un-cacheable)

    88                 $client->setMethod('POST');

    89                 $client->setUri($this->queryUri);

    90                 $client->setRawData($encodedQuery);

    91                 $client->setHeaders('Content-Type', 'application/x-www-form-urlencoded');

    92             }

    93         } else {

    94             throw new Exception('unexpected request-type: '.$type);

    95         }

    96         return $client->request();

    97     }

    98 

    99 

   100 }