CrudRead.php

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<?php


class CrudRead extends WebService
{
  private $db;

  private $conneg;

  private $dtdURL;

  private $include_linksback = "";

  private $include_reification = "";

  private $resourceUri = "";

  private $requester_ip = "";

  private $registered_ip = "";

  private $dataset = "";

  private $datasetsDescription = array();

  private $globalDataset = FALSE;

  private $namespaces =
    array ("http://www.w3.org/2002/07/owl#" => "owl", "http://www.w3.org/1999/02/22-rdf-syntax-ns#" => "rdf",
      "http://www.w3.org/2000/01/rdf-schema#" => "rdfs", "http://purl.org/ontology/wsf#" => "wsf");

  public $subjectTriples = array();

  public $objectTriples = array();

  public $reificationTriples = array();

  public static $supportedSerializations =
    array ("application/bib+json", "application/iron+json", "application/json", "application/rdf+xml",
      "application/rdf+n3", "application/*", "text/xml", "text/*", "*/*");

  private $errorMessenger =
    '{
                        "ws": "/ws/crud/read/",
                        "_200": {
                          "id": "WS-CRUD-READ-200",
                          "level": "Warning",
                          "name": "No URI specified for any resource",
                          "description": "No record URI defined for this query"
                        },
                        "_201": {
                          "id": "WS-CRUD-READ-201",
                          "level": "Warning",
                          "name": "Missing Dataset URIs",
                          "description": "Not all dataset URIs have been defined for each requested record URI. Remember that each URI of the list of URIs have to have a matching dataset URI in the datasets list."
                        },
                        "_202": {
                          "id": "WS-CRUD-READ-202",
                          "level": "Warning",
                          "name": "Record URI(s) not existing or not accessible",
                          "description": "The requested record URI(s) are not existing in this structWSF instance, or are not accessible to the requester. This error is only sent when no data URI are defined."
                        },
                        "_300": {
                          "id": "WS-CRUD-READ-300",
                          "level": "Warning",
                          "name": "This resource is not existing",
                          "description": "The target resource to be read is not existing in the system"
                        },
                        "_301": {
                          "id": "WS-CRUD-READ-301",
                          "level": "Warning",
                          "name": "You can\'t read more than 64 resources at once",
                          "description": "You are limited to read maximum 64 resources for each query to the CrudRead web service endpoint"
                        },
                        "_302": {
                          "id": "WS-CRUD-READ-302",
                          "level": "Fatal",
                          "name": "Can\'t get the description of the resource(s)",
                          "description": "An error occured when we tried to get the description of the resource(s)"
                        },  
                        "_303": {
                          "id": "WS-CRUD-READ-303",
                          "level": "Fatal",
                          "name": "Can\'t get the links-to the resource(s)",
                          "description": "An error occured when we tried to get the links-to the resource(s)"
                        },  
                        "_304": {
                          "id": "WS-CRUD-READ-304",
                          "level": "Fatal",
                          "name": "Can\'t get the reification statements for that resource(s)",
                          "description": "An error occured when we tried to get the reification statements of the resource(s)"
                        }  

                      }';


  function __construct($uri, $dataset, $include_linksback, $include_reification, $registered_ip, $requester_ip)
  {
    parent::__construct();

    $this->db = new DB_Virtuoso($this->db_username, $this->db_password, $this->db_dsn, $this->db_host);

    $this->dataset = $dataset;

    // If no dataset URI is defined for this query, we simply query all datasets accessible by the requester.
    if($this->dataset == "")
    {
      $this->globalDataset = TRUE;
    }

    $this->resourceUri = $uri;

    $this->include_linksback = $include_linksback;
    $this->include_reification = $include_reification;
    $this->requester_ip = $requester_ip;

    if($registered_ip == "")
    {
      $this->registered_ip = $requester_ip;
    }
    else
    {
      $this->registered_ip = $registered_ip;
    }

    if(strtolower(substr($this->registered_ip, 0, 4)) == "self")
    {
      $pos = strpos($this->registered_ip, "::");

      if($pos !== FALSE)
      {
        $account = substr($this->registered_ip, $pos + 2, strlen($this->registered_ip) - ($pos + 2));

        $this->registered_ip = $requester_ip . "::" . $account;
      }
      else
      {
        $this->registered_ip = $requester_ip;
      }
    }

    $this->uri = $this->wsf_base_url . "/wsf/ws/crud/read/";
    $this->title = "Crud Read Web Service";
    $this->crud_usage = new CrudUsage(FALSE, TRUE, FALSE, FALSE);
    $this->endpoint = $this->wsf_base_url . "/ws/crud/read/";

    $this->dtdURL = "crud/crudRead.dtd";

    $this->errorMessenger = json_decode($this->errorMessenger);
  }

  function __destruct()
  {
    parent::__destruct();

    if(isset($this->db))
    {
      @$this->db->close();
    }
  }

  protected function validateQuery()
  {
    /*
      Check if dataset(s) URI(s) have been defined for this request. If not, then we query the
      AuthLister web service endpoint to get the list of datasets accessible by this user to see
      if the URI he wants to read is defined in one of these accessible dataset. 
     */
    if($this->globalDataset === TRUE)
    {
      include_once("../../auth/lister/AuthLister.php");

      $ws_al = new AuthLister("access_user", "", $this->registered_ip, $this->wsf_local_ip);

      $ws_al->pipeline_conneg($this->conneg->getAccept(), $this->conneg->getAcceptCharset(),
        $this->conneg->getAcceptEncoding(), $this->conneg->getAcceptLanguage());

      $ws_al->process();

      $xml = new ProcessorXML();
      $xml->loadXML($ws_al->pipeline_getResultset());

      $accesses = $xml->getSubjectsByType("wsf:Access");

      $accessibleDatasets = array();

      foreach($accesses as $access)
      {
        $predicates = $xml->getPredicatesByType($access, "wsf:datasetAccess");
        $objects = $xml->getObjects($predicates->item(0));
        $datasetUri = $xml->getURI($objects->item(0));

        $predicates = $xml->getPredicatesByType($access, "wsf:read");
        $objects = $xml->getObjects($predicates->item(0));
        $read = $xml->getContent($objects->item(0));

        if(strtolower($read) == "true")
        {
          $this->dataset .= "$datasetUri;";
          array_push($accessibleDatasets, $datasetUri);
        }
      }

      if(count($accessibleDatasets) <= 0)
      {
        $this->conneg->setStatus(400);
        $this->conneg->setStatusMsg("Bad Request");
        $this->conneg->setStatusMsgExt($this->errorMessenger->_202->name);
        $this->conneg->setError($this->errorMessenger->_202->id, $this->errorMessenger->ws,
          $this->errorMessenger->_202->name, $this->errorMessenger->_202->description, "",
          $this->errorMessenger->_202->level);

        return;
      }

      unset($ws_al);

      $this->dataset = rtrim($this->dataset, ";");
    }
    else
    {
      $datasets = explode(";", $this->dataset);

      $datasets = array_unique($datasets);

      // Validate for each requested records of each dataset
      foreach($datasets as $dataset)
      {
        // Validation of the "requester_ip" to make sure the system that is sending the query as the rights.
        $ws_av = new AuthValidator($this->requester_ip, $dataset, $this->uri);

        $ws_av->pipeline_conneg("text/xml", $this->conneg->getAcceptCharset(), $this->conneg->getAcceptEncoding(),
          $this->conneg->getAcceptLanguage());

        $ws_av->process();

        if($ws_av->pipeline_getResponseHeaderStatus() != 200)
        {
          $this->conneg->setStatus($ws_av->pipeline_getResponseHeaderStatus());
          $this->conneg->setStatusMsg($ws_av->pipeline_getResponseHeaderStatusMsg());
          $this->conneg->setStatusMsgExt($ws_av->pipeline_getResponseHeaderStatusMsgExt());
          $this->conneg->setError($ws_av->pipeline_getError()->id, $ws_av->pipeline_getError()->webservice,
            $ws_av->pipeline_getError()->name, $ws_av->pipeline_getError()->description,
            $ws_av->pipeline_getError()->debugInfo, $ws_av->pipeline_getError()->level);

          return;
        }

        unset($ws_av);

        // Validation of the "registered_ip" to make sure the user of this system has the rights
        $ws_av = new AuthValidator($this->registered_ip, $dataset, $this->uri);

        $ws_av->pipeline_conneg("text/xml", $this->conneg->getAcceptCharset(), $this->conneg->getAcceptEncoding(),
          $this->conneg->getAcceptLanguage());

        $ws_av->process();

        if($ws_av->pipeline_getResponseHeaderStatus() != 200)
        {
          $this->conneg->setStatus($ws_av->pipeline_getResponseHeaderStatus());
          $this->conneg->setStatusMsg($ws_av->pipeline_getResponseHeaderStatusMsg());
          $this->conneg->setStatusMsgExt($ws_av->pipeline_getResponseHeaderStatusMsgExt());
          $this->conneg->setError($ws_av->pipeline_getError()->id, $ws_av->pipeline_getError()->webservice,
            $ws_av->pipeline_getError()->name, $ws_av->pipeline_getError()->description,
            $ws_av->pipeline_getError()->debugInfo, $ws_av->pipeline_getError()->level);
          return;
        }
      }
    }
  }

  public function pipeline_getError() { return ($this->conneg->error); }


  public function pipeline_getResultset()
  {
    $xml = new ProcessorXML();

    // Creation of the RESULTSET
    $resultset = $xml->createResultset();

    // Creation of the prefixes elements.
    $void = $xml->createPrefix("owl", "http://www.w3.org/2002/07/owl#");
    $resultset->appendChild($void);
    $rdf = $xml->createPrefix("rdf", "http://www.w3.org/1999/02/22-rdf-syntax-ns#");
    $resultset->appendChild($rdf);
    $dcterms = $xml->createPrefix("rdfs", "http://www.w3.org/2000/01/rdf-schema#");
    $resultset->appendChild($dcterms);
    $dcterms = $xml->createPrefix("wsf", "http://purl.org/ontology/wsf#");
    $resultset->appendChild($dcterms);

    $subject;

    foreach($this->subjectTriples as $u => $sts)
    {
      if(isset($sts["http://www.w3.org/1999/02/22-rdf-syntax-ns#type"]))
      {
        foreach($sts["http://www.w3.org/1999/02/22-rdf-syntax-ns#type"] as $key => $type)
        {
          if($key > 0)
          {
            $pred = $xml->createPredicate("http://www.w3.org/1999/02/22-rdf-syntax-ns#type");
            $object = $xml->createObject("", $type[0]);
            $pred->appendChild($object);
            $subject->appendChild($pred);
          }
          else
          {
            $subject = $xml->createSubject($type[0], $u);
          }
        }
      }
      else
      {
        $subject = $xml->createSubject("http://www.w3.org/2002/07/owl#Thing", $u);
      }

      foreach($sts as $property => $values)
      {
        if($property != "http://www.w3.org/1999/02/22-rdf-syntax-ns#type")
        {
          foreach($values as $value)
          {
            if($value[1] != NULL)
            {
              /*
                @TODO The internal XML structure of structWSF should be enhanced with datatypes such as xsd:double, int, 
                      literal, etc.
              */
              $pred = $xml->createPredicate($property);
              $object = $xml->createObjectContent($value[0]);
              $pred->appendChild($object);

              if(isset($this->reificationTriples[$u][$property][$value[0]]))
              {
                foreach($this->reificationTriples[$u][$property][$value[0]] as $rStatement => $rValue)
                {
                  foreach($rValue as $rv)
                  {
                    $reify = $xml->createReificationStatement($rStatement, $rv);
                    $object->appendChild($reify);
                  }
                }
              }

              $subject->appendChild($pred);
            }
            else
            {
              $pred = $xml->createPredicate($property);
              $object = $xml->createObject("", $value[0]);
              $pred->appendChild($object);

              if(isset($this->reificationTriples[$u][$property][$value[0]]))
              {
                foreach($this->reificationTriples[$u][$property][$value[0]] as $rStatement => $rValue)
                {
                  foreach($rValue as $rv)
                  {
                    $reify = $xml->createReificationStatement($rStatement, $rv);
                    $object->appendChild($reify);
                  }
                }
              }

              $subject->appendChild($pred);
            }
          }
        }
      }

      $resultset->appendChild($subject);

      // Now let add object references
      if(count($this->objectTriples[$u]) > 0)
      {
        foreach($this->objectTriples[$u] as $property => $propertyValue)
        {
          foreach($propertyValue as $resource)
          {
            $subject = $xml->createSubject("http://www.w3.org/2002/07/owl#Thing", $resource);

            $pred = $xml->createPredicate($property);
            $object = $xml->createObject("", $u);
            $pred->appendChild($object);
            $subject->appendChild($pred);

            $resultset->appendChild($subject);
          }
        }
      }
    }

    return ($this->injectDoctype($xml->saveXML($resultset)));
  }

  public function injectDoctype($xmlDoc)
  {
    $posHeader = strpos($xmlDoc, '"?>') + 3;
    $xmlDoc = substr($xmlDoc, 0, $posHeader)
      . "\n<!DOCTYPE resultset PUBLIC \"-//Structured Dynamics LLC//Crud Read DTD 0.1//EN\" \"" . $this->dtdBaseURL
        . $this->dtdURL . "\">" . substr($xmlDoc, $posHeader, strlen($xmlDoc) - $posHeader);

    return ($xmlDoc);
  }

  public function ws_conneg($accept, $accept_charset, $accept_encoding, $accept_language)
  {
    $this->conneg =
      new Conneg($accept, $accept_charset, $accept_encoding, $accept_language, CrudRead::$supportedSerializations);

    // Validate query
    $this->validateQuery();

    // If the query is still valid
    if($this->conneg->getStatus() == 200)
    {
      // Check for errors
      if($this->resourceUri == "")
      {
        $this->conneg->setStatus(400);
        $this->conneg->setStatusMsg("Bad Request");
        $this->conneg->setStatusMsgExt($this->errorMessenger->_200->name);
        $this->conneg->setError($this->errorMessenger->_200->id, $this->errorMessenger->ws,
          $this->errorMessenger->_200->name, $this->errorMessenger->_200->description, "",
          $this->errorMessenger->_200->level);

        return;
      }
    }

    // Check if we have the same number of URIs than Dataset URIs (only if at least one dataset URI is defined).
    if($this->globalDataset === FALSE)
    {
      $uris = explode(";", $this->resourceUri);
      $datasets = explode(";", $this->dataset);

      if(count($uris) != count($datasets))
      {
        $this->conneg->setStatus(400);
        $this->conneg->setStatusMsg("Bad Request");
        $this->conneg->setStatusMsgExt($this->errorMessenger->_201->name);
        $this->conneg->setError($this->errorMessenger->_201->id, $this->errorMessenger->ws,
          $this->errorMessenger->_201->name, $this->errorMessenger->_201->description, "",
          $this->errorMessenger->_201->level);

        return;
      }
    }
  }

  public function pipeline_conneg($accept, $accept_charset, $accept_encoding, $accept_language)
    { $this->ws_conneg($accept, $accept_charset, $accept_encoding, $accept_language); }

  public function pipeline_getResponseHeaderStatus() { return $this->conneg->getStatus(); }

  public function pipeline_getResponseHeaderStatusMsg() { return $this->conneg->getStatusMsg(); }

  public function pipeline_getResponseHeaderStatusMsgExt() { return $this->conneg->getStatusMsgExt(); }

  public function pipeline_serialize()
  {
    $rdf_part = "";

    switch($this->conneg->getMime())
    {
      case "application/bib+json":
      case "application/iron+json":
        include_once("../../converter/irjson/ConverterIrJSON.php");
        include_once("../../converter/irjson/Dataset.php");
        include_once("../../converter/irjson/InstanceRecord.php");
        include_once("../../converter/irjson/LinkageSchema.php");
        include_once("../../converter/irjson/StructureSchema.php");
        include_once("../../converter/irjson/irJSONParser.php");

        // Include more information about the dataset (at least the ID)
        $documentToConvert = $this->pipeline_getResultset();

        $datasets = explode(";", $this->dataset);

        $datasets = array_unique($datasets);

        // Note: this is temporary. A more consistent dataset-URI/resource-URIs has to be implemented in conStruct
        $d = $datasets[0];

        $d = str_replace("/wsf/datasets/", "/conStruct/datasets/", $d) . "resource/";


        /*
          @TODO In the future, we will have to include the dataset's meta-data information in the data to convert.
                This meta-data include: its name, description, creator, maintainer, owner, schema and linkage.
                
                This will be done by querying the DatasetRead web service endpoint for the "$d" dataset
        */

        $ws_irv =
          new ConverterIrJSON($documentToConvert, "text/xml", "true", $this->registered_ip, $this->requester_ip);

        $ws_irv->pipeline_conneg("application/iron+json", $this->conneg->getAcceptCharset(),
          $this->conneg->getAcceptEncoding(), $this->conneg->getAcceptLanguage());

        $ws_irv->process();

        if($ws_irv->pipeline_getResponseHeaderStatus() != 200)
        {
          $this->conneg->setStatus($ws_irv->pipeline_getResponseHeaderStatus());
          $this->conneg->setStatusMsg($ws_irv->pipeline_getResponseHeaderStatusMsg());
          $this->conneg->setStatusMsgExt($ws_irv->pipeline_getResponseHeaderStatusMsgExt());
          $this->conneg->setError($ws_irv->pipeline_getError()->id, $ws_irv->pipeline_getError()->webservice,
            $ws_irv->pipeline_getError()->name, $ws_irv->pipeline_getError()->description,
            $ws_irv->pipeline_getError()->debugInfo, $ws_irv->pipeline_getError()->level);
          return;
        }

        return ($ws_irv->pipeline_serialize());

      break;

      case "application/json":
        $json_part = "";
        $xml = new ProcessorXML();
        $xml->loadXML($this->pipeline_getResultset());

        $subjects = $xml->getSubjects();

        $nsId = 0;

        foreach($subjects as $subject)
        {
          $subjectURI = $xml->getURI($subject);
          $subjectType = $xml->getType($subject);

          $ns = $this->getNamespace($subjectType);

          if(!isset($this->namespaces[$ns[0]]))
          {
            $this->namespaces[$ns[0]] = "ns" . $nsId;
            $nsId++;
          }

          $json_part .= "      { \n";
          $json_part .= "        \"uri\": \"" . parent::jsonEncode($subjectURI) . "\", \n";
          $json_part .= "        \"type\": \"" . parent::jsonEncode($this->namespaces[$ns[0]] . ":" . $ns[1])
            . "\", \n";

          $predicates = $xml->getPredicates($subject);

          $nbPredicates = 0;

          foreach($predicates as $predicate)
          {
            $objects = $xml->getObjects($predicate);

            foreach($objects as $object)
            {
              $nbPredicates++;

              if($nbPredicates == 1)
              {
                $json_part .= "        \"predicate\": [ \n";
              }

              $objectType = $xml->getType($object);
              $predicateType = $xml->getType($predicate);

              if($objectType == "rdfs:Literal")
              {
                $objectValue = $xml->getContent($object);

                $ns = $this->getNamespace($predicateType);

                if(!isset($this->namespaces[$ns[0]]))
                {
                  $this->namespaces[$ns[0]] = "ns" . $nsId;
                  $nsId++;
                }

                $json_part .= "          { \n";
                $json_part .= "            \"" . parent::jsonEncode($this->namespaces[$ns[0]] . ":" . $ns[1]) . "\": \""
                  . parent::jsonEncode($objectValue) . "\" \n";
                $json_part .= "          },\n";
              }
              else
              {
                $objectURI = $xml->getURI($object);

                $ns = $this->getNamespace($predicateType);

                if(!isset($this->namespaces[$ns[0]]))
                {
                  $this->namespaces[$ns[0]] = "ns" . $nsId;
                  $nsId++;
                }

                $json_part .= "          { \n";
                $json_part .= "            \"" . parent::jsonEncode($this->namespaces[$ns[0]] . ":" . $ns[1])
                  . "\": { \n";
                $json_part .= "                \"uri\": \"" . parent::jsonEncode($objectURI) . "\",\n";

                // Check if there is a reification statement for this object.
                $reifies = $xml->getReificationStatements($object, "wsf:objectLabel");

                $nbReification = 0;

                foreach($reifies as $reify)
                {
                  $nbReification++;

                  if($nbReification > 0)
                  {
                    $json_part .= "               \"reify\": [\n";
                  }

                  $json_part .= "                 { \n";
                  $json_part .= "                     \"type\": \"wsf:objectLabel\", \n";
                  $json_part .= "                     \"value\": \"" . parent::jsonEncode($xml->getValue($reify))
                    . "\" \n";
                  $json_part .= "                 },\n";
                }

                if($nbReification > 0)
                {
                  $json_part = substr($json_part, 0, strlen($json_part) - 2) . "\n";

                  $json_part .= "               ]\n";
                }
                else
                {
                  $json_part = substr($json_part, 0, strlen($json_part) - 2) . "\n";
                }

                $json_part .= "                } \n";
                $json_part .= "          },\n";
              }
            }
          }

          if(strlen($json_part) > 0)
          {
            $json_part = substr($json_part, 0, strlen($json_part) - 2) . "\n";
          }

          if($nbPredicates > 0)
          {
            $json_part .= "        ]\n";
          }

          $json_part .= "      },\n";
        }

        if(strlen($json_part) > 0)
        {
          $json_part = substr($json_part, 0, strlen($json_part) - 2) . "\n";
        }

        $json_header .= "  \"prefixes\": [ \n";
        $json_header .= "    {\n";
        $json_header .= "      \"rdf\": \"http://www.w3.org/1999/02/22-rdf-syntax-ns#\",\n";
        $json_header .= "      \"wsf\": \"http://purl.org/ontology/wsf#\",\n";

        foreach($this->namespaces as $ns => $prefix)
        {
          $json_header .= "      \"$prefix\": \"$ns\",\n";
        }

        if(strlen($json_header) > 0)
        {
          $json_header = substr($json_header, 0, strlen($json_header) - 2) . "\n";
        }

        $json_header .= "    } \n";
        $json_header .= "  ],\n";
        $json_header .= "  \"resultset\": {\n";
        $json_header .= "    \"subject\": [\n";
        $json_header .= $json_part;
        $json_header .= "    ]\n";
        $json_header .= "  }\n";

        return ($json_header);
/*
        $json_part = "";
        $xml = new ProcessorXML();
        $xml->loadXML($this->pipeline_getResultset());
        
        $subjects = $xml->getSubjects();
      
        foreach($subjects as $subject)
        {
          $subjectURI = $xml->getURI($subject);
          $subjectType = $xml->getType($subject);
        
          $json_part .= "      { \n";
          $json_part .= "        \"uri\": \"".parent::jsonEncode($subjectURI)."\", \n";
          $json_part .= "        \"type\": \"".parent::jsonEncode($subjectType)."\", \n";

          $predicates = $xml->getPredicates($subject);
          
          $nbPredicates = 0;
          
          foreach($predicates as $predicate)
          {
            $objects = $xml->getObjects($predicate);
            
            foreach($objects as $object)
            {
              $nbPredicates++;
              
              if($nbPredicates == 1)
              {
                $json_part .= "        \"predicates\": [ \n";
              }
              
              $objectType = $xml->getType($object);            
              $predicateType = $xml->getType($predicate);
              
              if($objectType == "rdfs:Literal")
              {
                $objectValue = $xml->getContent($object);
                            
                $json_part .= "          { \n";
                $json_part .= "            \"".parent::jsonEncode($predicateType)."\": \"".parent::jsonEncode($objectValue)."\" \n";
                $json_part .= "          },\n";
              }
              else
              {
                $objectURI = $xml->getURI($object);            
                $rdf_part .= "          <$predicateType> <$objectURI> ;\n";
                
                $json_part .= "          { \n";
                $json_part .= "            \"".parent::jsonEncode($predicateType)."\": { \n";
                $json_part .= "                \"uri\": \"".parent::jsonEncode($objectURI)."\", \n";
                
                                // Check if there is a reification statement for this object.
                                  $reifies = $xml->getReificationStatements($object);
                                
                                  $nbReification = 0;
                                
                                  foreach($reifies as $reify)
                                  {
                                    $nbReification++;
                                    
                                    if($nbReification > 0)
                                    {
                                      $json_part .= "               \"reifies\": [\n";
                                    }
                                    
                                    $json_part .= "                 { \n";
                                    $json_part .= "                     \"type\": \"wsf:objectLabel\", \n";
                                    $json_part .= "                     \"value\": \"".parent::jsonEncode($xml->getValue($reify))."\" \n";
                                    $json_part .= "                 },\n";
                                  }
                                  
                                  if($nbReification > 0)
                                  {
                                    $json_part = substr($json_part, 0, strlen($json_part) - 2)."\n";
                                    
                                    $json_part .= "               ]\n";
                                  }
                                  else
                                  {
                                    $json_part = substr($json_part, 0, strlen($json_part) - 2)."\n";
                                  }                
                                                  
                                  
                                  $json_part .= "                } \n";
                                  $json_part .= "          },\n";
                                }
                              }
                            }
                            
                            if(strlen($json_part) > 0)
                            {
                              $json_part = substr($json_part, 0, strlen($json_part) - 2)."\n";
                            }            
                            
                            if($nbPredicates > 0)
                            {
                              $json_part .= "        ]\n";
                            }
                            
                            $json_part .= "      },\n";          
                          }
                          
                          if(strlen($json_part) > 0)
                          {
                            $json_part = substr($json_part, 0, strlen($json_part) - 2)."\n";
                          }
                          
                  
                          return($json_part);    
                          */
      break;

      case "application/rdf+n3":

        $xml = new ProcessorXML();
        $xml->loadXML($this->pipeline_getResultset());

        $subjects = $xml->getSubjects();

        foreach($subjects as $subject)
        {
          $subjectURI = $xml->getURI($subject);
          $subjectType = $xml->getType($subject, FALSE);

          $rdf_part .= "\n    <$subjectURI> a <$subjectType> ;\n";

          $predicates = $xml->getPredicates($subject);

          foreach($predicates as $predicate)
          {
            $objects = $xml->getObjects($predicate);

            foreach($objects as $object)
            {
              $objectType = $xml->getType($object);
              $predicateType = $xml->getType($predicate, FALSE);

              if($objectType == "rdfs:Literal")
              {
                $objectValue = $xml->getContent($object);
                $rdf_part .= "        <$predicateType> \"\"\"" . str_replace(array( "\\" ), "\\\\", $objectValue)
                  . "\"\"\" ;\n";
              }
              else
              {
                $objectURI = $xml->getURI($object);
                $rdf_part .= "        <$predicateType> <$objectURI> ;\n";
              }
            }
          }

          if(strlen($rdf_part) > 0)
          {
            $rdf_part = substr($rdf_part, 0, strlen($rdf_part) - 2) . ". \n";
          }
        }

        return ($rdf_part);
      break;

      case "application/rdf+xml":
        $xml = new ProcessorXML();
        $xml->loadXML($this->pipeline_getResultset());

        $subjects = $xml->getSubjects();

        $nsId = 0;

        foreach($subjects as $subject)
        {
          $subjectURI = $xml->getURI($subject);
          $subjectType = $xml->getType($subject);

          $ns1 = $this->getNamespace($subjectType);

          if(!isset($this->namespaces[$ns1[0]]))
          {
            $this->namespaces[$ns1[0]] = "ns" . $nsId;
            $nsId++;
          }

          $rdf_part .= "\n    <" . $this->namespaces[$ns1[0]] . ":" . $ns1[1] . " rdf:about=\"".
                                                                            $this->xmlEncode($subjectURI)."\">\n";

          $predicates = $xml->getPredicates($subject);

          foreach($predicates as $predicate)
          {
            $objects = $xml->getObjects($predicate);

            foreach($objects as $object)
            {
              $objectType = $xml->getType($object);
              $predicateType = $xml->getType($predicate);

              if($objectType == "rdfs:Literal")
              {
                $objectValue = $xml->getContent($object);

                $ns = $this->getNamespace($predicateType);

                if(!isset($this->namespaces[$ns[0]]))
                {
                  $this->namespaces[$ns[0]] = "ns" . $nsId;
                  $nsId++;
                }

                $rdf_part .= "        <" . $this->namespaces[$ns[0]] . ":" . $ns[1] . ">"
                  . $this->xmlEncode($objectValue) . "</" . $this->namespaces[$ns[0]] . ":" . $ns[1] . ">\n";
              }
              else
              {
                $objectURI = $xml->getURI($object);

                $ns = $this->getNamespace($predicateType);

                if(!isset($this->namespaces[$ns[0]]))
                {
                  $this->namespaces[$ns[0]] = "ns" . $nsId;
                  $nsId++;
                }

                $rdf_part .= "        <" . $this->namespaces[$ns[0]] . ":" . $ns[1]
                  . " rdf:resource=\"".$this->xmlEncode($objectURI)."\" />\n";
              }
            }
          }

          $rdf_part .= "    </" . $this->namespaces[$ns1[0]] . ":" . $ns1[1] . ">\n";
        }

        $rdf_header = "<rdf:RDF ";

        foreach($this->namespaces as $ns => $prefix)
        {
          $rdf_header .= " xmlns:$prefix=\"$ns\"";
        }

        $rdf_header .= ">\n\n";

        $rdf_part = $rdf_header . $rdf_part;

        return ($rdf_part);
      break;
    }
  }

  private function getNamespace($uri)
  {
    $pos = strrpos($uri, "#");

    if($pos !== FALSE)
    {
      return array (substr($uri, 0, $pos) . "#", substr($uri, $pos + 1, strlen($uri) - ($pos + 1)));
    }
    else
    {
      $pos = strrpos($uri, "/");

      if($pos !== FALSE)
      {
        return array (substr($uri, 0, $pos) . "/", substr($uri, $pos + 1, strlen($uri) - ($pos + 1)));
      }
      else
      {
        $pos = strpos($uri, ":");

        if($pos !== FALSE)
        {
          $nsUri = explode(":", $uri, 2);

          foreach($this->namespaces as $uri2 => $prefix2)
          {
            $uri2 = urldecode($uri2);

            if($prefix2 == $nsUri[0])
            {
              return (array ($uri2, $nsUri[1]));
            }
          }

          return explode(":", $uri, 2);
        }
      }
    }

    return (FALSE);
  }

  public function pipeline_serialize_reification()
  {
    $rdf_reification = "";

    switch($this->conneg->getMime())
    {
      case "application/rdf+n3":
        $xml = new ProcessorXML();
        $xml->loadXML($this->pipeline_getResultset());

        $subjects = $xml->getSubjects();

        $bnodeCounter = 0;

        foreach($subjects as $subject)
        {
          $predicates = $xml->getPredicates($subject);

          foreach($predicates as $predicate)
          {
            $predicateType = $xml->getType($predicate, FALSE);

            $objects = $xml->getObjects($predicate);

            foreach($objects as $object)
            {
              $reifies = $xml->getReificationStatements($object);

              foreach($reifies as $reify)
              {
                $reifyPredicate = $xml->getType($reify, FALSE);

                $ns = $this->getNamespace($reifyPredicate);

                if(!isset($this->namespaces[$ns[0]]))
                {
                  $this->namespaces[$ns[0]] = "ns" . $nsId;
                  $nsId++;
                }

                $rdf_reification .= "_:" . md5($xml->getURI($subject) . $predicateType . $xml->getURI($object))
                  . " a rdf:Statement ;\n";
                $bnodeCounter++;
                $rdf_reification .= "    rdf:subject <" . $xml->getURI($subject) . "> ;\n";
                $rdf_reification .= "    rdf:predicate <" . $predicateType . "> ;\n";
                $rdf_reification .= "    rdf:object <" . $xml->getURI($object) . "> ;\n";
                $rdf_reification .= "    " . $this->namespaces[$ns[0]] . ":" . $ns[1] . " \"" . $xml->getValue($reify)
                  . "\" .\n\n";
                $bnodeCounter++;
              }
            }
          }
        }

        return ($rdf_reification);

      break;

      case "application/rdf+xml":
        $xml = new ProcessorXML();
        $xml->loadXML($this->pipeline_getResultset());

        $subjects = $xml->getSubjects();

        foreach($subjects as $subject)
        {
          $predicates = $xml->getPredicates($subject);

          foreach($predicates as $predicate)
          {
            $predicateType = $xml->getType($predicate, FALSE);

            $objects = $xml->getObjects($predicate);

            foreach($objects as $object)
            {
              $reifies = $xml->getReificationStatements($object);

              foreach($reifies as $reify)
              {
                $reifyPredicate = $xml->getType($reify, FALSE);

                $ns = $this->getNamespace($reifyPredicate);

                if(!isset($this->namespaces[$ns[0]]))
                {
                  $this->namespaces[$ns[0]] = "ns" . $nsId;
                  $nsId++;
                }

                $rdf_reification .= "<rdf:Statement rdf:about=\""
                  . $this->xmlEncode(md5($xml->getURI($subject) . $predicateType . $xml->getURI($object))) . "\">\n";
                $rdf_reification .= "    <rdf:subject rdf:resource=\"" . $xml->getURI($this->xmlEncode($subject)) . "\" />\n";
                $rdf_reification .= "    <rdf:predicate rdf:resource=\"" . $this->xmlEncode($predicateType) . "\" />\n";
                $rdf_reification .= "    <rdf:object rdf:resource=\"" . $this->xmlEncode($xml->getURI($object)) . "\" />\n";
                $rdf_reification .= "    <" . $this->namespaces[$ns[0]] . ":" . $ns[1] . ">"
                  . $this->xmlEncode($xml->getValue($reify)) . "</$reifyPredicate>\n";
                $rdf_reification .= "</rdf:Statement>  \n\n";
              }
            }
          }
        }

        return ($rdf_reification);

      break;
    }
  }

  public function ws_serialize()
  {
    switch($this->conneg->getMime())
    {
      case "application/rdf+n3":
        $rdf_document = "";
        $rdf_document .= "@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .\n";

        $rdf_document .= $this->pipeline_serialize();

        $rdf_document .= $this->pipeline_serialize_reification();

        return $rdf_document;
      break;

      case "application/rdf+xml":
        $rdf_document = "";
        $rdf_document .= "<?xml version=\"1.0\"?>\n";

        $rdf_document .= $this->pipeline_serialize();

        $rdf_document .= $this->pipeline_serialize_reification();

        $rdf_document .= "</rdf:RDF>";

        return $rdf_document;
      break;

      case "text/xml":
        return $this->pipeline_getResultset();
      break;

      case "application/json":
        /*
                $json_document = "";
                $json_document .= "{\n";
                $json_document .= "  \"resultset\": {\n";
                $json_document .= "    \"subject\": [\n";
                $json_document .= $this->pipeline_serialize();
                $json_document .= "    ]\n";
                $json_document .= "  }\n";
                $json_document .= "}";
                
                return($json_document);
        */
        $json_document = "";
        $json_document .= "{\n";
        $json_document .= $this->pipeline_serialize();
        $json_document .= "}";

        return ($json_document);
      break;

      case "application/bib+json":
      case "application/iron+json":
        return ($this->pipeline_serialize());
      break;
    }
  }

  public function ws_respond($content)
  {
    // First send the header of the request
    $this->conneg->respond();

    // second, send the content of the request

    // Make sure there is no error.
    if($this->conneg->getStatus() == 200)
    {
      echo $content;
    }

    $this->__destruct();
  }


  public function process()
  {
    // Make sure there was no conneg error prior to this process call
    if($this->conneg->getStatus() == 200)
    {
      $uris = explode(";", $this->resourceUri);
      $datasets = explode(";", $this->dataset);

      if(count($uris) > 64)
      {
        $this->conneg->setStatus(400);
        $this->conneg->setStatusMsg("Bad Request");
        $this->conneg->setStatusMsgExt($this->errorMessenger->_301->name);
        $this->conneg->setError($this->errorMessenger->_301->id, $this->errorMessenger->ws,
          $this->errorMessenger->_301->name, $this->errorMessenger->_301->description, "",
          $this->errorMessenger->_301->level);

        return;
      }

      foreach($uris as $key => $u)
      {

        // Decode potentially encoded ";" character.
        $u = str_ireplace("%3B", ";", $u);
        $d = str_ireplace("%3B", ";", $datasets[$key]);

        $query = "";

        if($this->globalDataset === FALSE)
        {
          $d = str_ireplace("%3B", ";", $datasets[$key]);

          // Archiving suject triples
          $query = $this->db->build_sparql_query("select ?p ?o (DATATYPE(?o)) as ?otype (LANG(?o)) as ?olang "
            . "from <" . $d . "> where {<" . $u
            . "> ?p ?o.}", array ('p', 'o', 'otype', 'olang'), FALSE);
        }
        else
        {
          $d = "";

          foreach($datasets as $dataset)
          {
            if($dataset != "")
            {
              $d .= " from named <$dataset> ";
            }
          }

          // Archiving suject triples
          $query = $this->db->build_sparql_query("select ?p ?o (DATATYPE(?o)) as ?otype (LANG(?o)) as ?olang "
            . " $d where {graph ?g{<" . $u
            . "> ?p ?o.}}", array ('p', 'o', 'otype', 'olang'), FALSE);
        }

        $resultset = $this->db->query($query);

        if(odbc_error())
        {
          $this->conneg->setStatus(500);
          $this->conneg->setStatusMsg("Internal Error");
          $this->conneg->setStatusMsgExt($this->errorMessenger->_302->name);
          $this->conneg->setError($this->errorMessenger->_302->id, $this->errorMessenger->ws,
            $this->errorMessenger->_302->name, $this->errorMessenger->_302->description, odbc_errormsg(),
            $this->errorMessenger->_302->level);
        }

        while(odbc_fetch_row($resultset))
        {
          $p = odbc_result($resultset, 1);
          $o = odbc_result($resultset, 2);

          $otype = odbc_result($resultset, 3);
          $olang = odbc_result($resultset, 4);

          if(!isset($this->subjectTriples[$u][$p]))
          {
            $this->subjectTriples[$u][$p] = array();
          }

          $objectType = "";
          if($olang && $olang != "")
          {
            /* If a language is defined for an object, we force its type to be xsd:string */
            $objectType = "http://www.w3.org/2001/XMLSchema#string";
          }
          else
          {
            $objectType = $otype;
          }
  
          if($this->globalDataset === TRUE) 
          {
            $found = FALSE;
            foreach($this->subjectTriples[$u][$p] as $value)
            {
              if($o == $value[0])
              {
                $found = TRUE;
              }
            }
            
            if($found === FALSE)
            {
              array_push($this->subjectTriples[$u][$p], array ($o, $objectType));  
            }
          }
          else
          {
            array_push($this->subjectTriples[$u][$p], array ($o, $objectType));  
          }
        }

        if(count($this->subjectTriples) <= 0)
        {
          $this->conneg->setStatus(400);
          $this->conneg->setStatusMsg("Bad Request");
          $this->conneg->setStatusMsgExt($this->errorMessenger->_300->name);
          $this->conneg->setError($this->errorMessenger->_300->id, $this->errorMessenger->ws,
            $this->errorMessenger->_300->name, $this->errorMessenger->_300->description, "",
            $this->errorMessenger->_300->level);

          return;
        }

        // Archiving object triples
        if(strtolower($this->include_linksback) == "true")
        {
          $query = "";

          if($this->globalDataset === FALSE)
          {
            $query = $this->db->build_sparql_query("select ?s ?p from <" . $d . "> where {?s ?p <" . $u . ">.}",
              array ('s', 'p'), FALSE);
          }
          else
          {
            $d = "";

            foreach($datasets as $dataset)
            {
              if($dataset != "")
              {
                $d .= " from named <$dataset> ";
              }
            }

            $query =
              $this->db->build_sparql_query("select ?s ?p $d where {graph ?g{?s ?p <" . $u . ">.}}", array ('s', 'p'),
                FALSE);
          }

          $resultset = $this->db->query($query);

          if(odbc_error())
          {
            $this->conneg->setStatus(500);
            $this->conneg->setStatusMsg("Internal Error");
            $this->conneg->setStatusMsgExt($this->errorMessenger->_303 > name);
            $this->conneg->setError($this->errorMessenger->_303->id, $this->errorMessenger->ws,
              $this->errorMessenger->_303->name, $this->errorMessenger->_303->description, odbc_errormsg(),
              $this->errorMessenger->_303->level);
          }

          while(odbc_fetch_row($resultset))
          {
            $s = odbc_result($resultset, 1);
            $p = odbc_result($resultset, 2);

            if(!isset($this->objectTriples[$u][$p]))
            {
              $this->objectTriples[$u][$p] = array();
            }

            array_push($this->objectTriples[$u][$p], $s);
          }

          unset($resultset);
        }

        // Get reification triples
        if(strtolower($this->include_reification) == "true")
        {

          $query = "";

          if($this->globalDataset === FALSE)
          {
            $query = "  select ?rei_p ?rei_o ?p ?o from <" . $d . "reification/> 
                    where 
                    {
                      ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <"
              . $u
              . ">.
                      ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> ?rei_p.
                      ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?rei_o.
                      ?statement ?p ?o.
                    }";
          }
          else
          {
            $d = "";

            foreach($datasets as $dataset)
            {
              if($dataset != "")
              {
                $d .= " from named <" . $dataset . "reification/> ";
              }
            }

            $query = "  select ?rei_p ?rei_o ?p ?o $d 
                    where 
                    {
                      graph ?g
                      {
                        ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <"
              . $u
                . ">.
                        ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> ?rei_p.
                        ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?rei_o.
                        ?statement ?p ?o.
                      }
                    }";
          }

          $query = $this->db->build_sparql_query(str_replace(array ("\n", "\r", "\t"), " ", $query),
            array ('rei_p', 'rei_o', 'p', 'o'), FALSE);

          $resultset = $this->db->query($query);

          if(odbc_error())
          {
            $this->conneg->setStatus(500);
            $this->conneg->setStatusMsg("Internal Error");
            $this->conneg->setStatusMsgExt($this->errorMessenger->_304->name);
            $this->conneg->setError($this->errorMessenger->_304->id, $this->errorMessenger->ws,
              $this->errorMessenger->_304->name, $this->errorMessenger->_304->description, odbc_errormsg(),
              $this->errorMessenger->_304->level);
          }

          while(odbc_fetch_row($resultset))
          {
            $rei_p = odbc_result($resultset, 1);
            $rei_o = odbc_result($resultset, 2);
            $p = odbc_result($resultset, 3);
            $o = odbc_result($resultset, 4);

            if($p != "http://www.w3.org/1999/02/22-rdf-syntax-ns#subject"
              && $p != "http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate"
              && $p != "http://www.w3.org/1999/02/22-rdf-syntax-ns#object"
              && $p != "http://www.w3.org/1999/02/22-rdf-syntax-ns#type")
            {
              if(!isset($this->reificationTriples[$u][$rei_p][$rei_o][$p]))
              {
                $this->reificationTriples[$u][$rei_p][$rei_o][$p] = array();
              }

              array_push($this->reificationTriples[$u][$rei_p][$rei_o][$p], $o);
            }
          }

          unset($resultset);
        }
      }
    }
  }
}



?>