| 1 | <?php
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| 2 |
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| 3 | // ----------------------------------------------------------------------------------
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| 4 | // Class: SparqlEngine
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| 5 | // ----------------------------------------------------------------------------------
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| 6 |
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| 7 | /**
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| 8 | * Client for querying a sparql server.
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| 9 | *
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| 10 | * @version $Id: SparqlClient.php 573 2008-05-26 09:04:29Z cyganiak $
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| 11 | * @author Tobias Gauà <tobias.gauss@web.de>
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| 12 | * @license http://www.gnu.org/licenses/lgpl.html LGPL
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| 13 | *
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| 14 | * @package sparql
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| 15 | */
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| 16 |
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| 17 | class SparqlClient extends Object {
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| 18 |
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| 19 | var $server;
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| 20 | var $output;
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| 21 |
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| 22 | /**
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| 23 | * Constructor of SparlClient.
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| 24 | *
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| 25 | * @param String $server server address.
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| 26 | */
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| 27 | function SparqlClient($server){
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| 28 | $this->server = $server;
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| 29 | $this->output = "array";
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| 30 | }
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| 31 |
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| 32 |
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| 33 | /**
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| 34 | * Sets the output format for a SELECT or ASK query. Possible formats are "xml" for
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| 35 | * Sparql Query Results XML Format (http://www.w3.org/TR/rdf-sparql-XMLres/) or array
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| 36 | * for the format described in our SparqlEngine.
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| 37 | *
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| 38 | * @param String $format the format.
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| 39 | */
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| 40 | function setOutputFormat($format){
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| 41 | if(strtolower($format)=="xml")
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| 42 | $this->output = "xml";
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| 43 | if(strtolower($format)=="array")
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| 44 | $this->output = "array";
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| 45 |
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| 46 | }
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| 47 |
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| 48 | /**
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| 49 | * Main function of SparqlClient.
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| 50 | *
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| 51 | * @param ClientQuery $query the ClientQuery object.
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| 52 | * @return mixed returns an array that contains the variables an their bindings or a MemModel
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| 53 | *
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| 54 | */
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| 55 | function query($query){
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| 56 | if(!is_a($query,"ClientQuery"))
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| 57 | die;//ErrorHandling
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| 58 |
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| 59 | $url = $this->_buildurl($query);
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| 60 | $result = $this->_http_get($url);
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| 61 | return $this->returnResult($result);
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| 62 |
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| 63 | }
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| 64 |
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| 65 |
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| 66 | /**
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| 67 | * Helper function that builds the url.
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| 68 | *
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| 69 | * @param ClientQuery $query the ClientQuery Object.
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| 70 | */
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| 71 |
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| 72 | function _buildurl($query){
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| 73 | $url = "";
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| 74 | $url = $this->server."?query=".urlencode($query->query);
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| 75 | foreach($query->default as $defaultg){
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| 76 | $url = $url."&default-graph-uri=".$defaultg;
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| 77 | }
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| 78 | foreach($query->named as $namedg){
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| 79 | $url = $url."&named-graph-uri=".$namedg;
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| 80 | }
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| 81 |
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| 82 | return $url;
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| 83 |
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| 84 | }
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| 85 |
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| 86 | /**
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| 87 | * Returns the query result.
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| 88 | *
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| 89 | * @param String $result the result.
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| 90 | * @return mixed
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| 91 | */
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| 92 | function returnResult($result){
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| 93 |
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| 94 | if(strpos($result,"<rdf:RDF")){
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| 95 | include_once(RDFAPI_INCLUDE_DIR.PACKAGE_SYNTAX_RDF);
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| 96 | $parser = new RdfParser();
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| 97 | return $parser->generateModel(substr($result,strpos($result,"<rdf:RDF")));
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| 98 | }
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| 99 |
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| 100 | if($this->output == "xml"){
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| 101 | $pos = strpos($result,"<?xml");
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| 102 | return substr($result,$pos);
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| 103 | }
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| 104 | if($this->output == "array"){
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| 105 | // $pos = strpos($buffer,"<?xml");
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| 106 | return $this->parseResult($result);
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| 107 | }
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| 108 | return $result;
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| 109 | }
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| 110 |
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| 111 |
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| 112 | function parseResult($buffer){
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| 113 | include_once(RDFAPI_INCLUDE_DIR.PACKAGE_SYNTAX_SPARQLRES);
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| 114 | $parser = new SparqlResultParser();
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| 115 | return $parser->parse($buffer);
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| 116 | }
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| 117 |
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| 118 |
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| 119 | /**
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| 120 | * Executes the GET Request.
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| 121 | *
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| 122 | * @param String $url the url.
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| 123 | * @return String result.
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| 124 | */
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| 125 | function _http_get($url)
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| 126 | {
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| 127 | $url = parse_url($url);
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| 128 | $port = isset($url['port']) ? $url['port'] : 80;
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| 129 |
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| 130 | $fp = fsockopen($url['host'], $port);
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| 131 |
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| 132 | $replace = $url['path'];
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| 133 |
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| 134 | fputs($fp, "GET ".$replace."?".$url['query']." HTTP/1.0\r\n");
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| 135 | fputs($fp, "Host: ". $url['host']."\r\n");
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| 136 | fputs($fp, "Accept: application/sparql-results+xml, application/rdf+xml\r\n");
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| 137 | fputs($fp, "Connection: close\r\n\r\n");
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| 138 |
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| 139 | $buffer = "";
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| 140 | while ($tmp = fread($fp, 1024))
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| 141 | {
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| 142 | $buffer .= $tmp;
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| 143 | }
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| 144 |
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| 145 | return preg_replace("/^.*?(\r\n\r\n|\n\n)/s", "", $buffer);
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| 146 | }
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| 147 | }
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| 148 |
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| 149 |
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| 150 |
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| 151 | ?>
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