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   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  
  18  /**
  19   * REST web service implementation classes and methods.
  20   *
  21   * @package    webservice_rest
  22   * @copyright  2009 Jerome Mouneyrac
  23   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24   */
  25  
  26  require_once("$CFG->dirroot/webservice/lib.php");
  27  
  28  /**
  29   * REST service server implementation.
  30   *
  31   * @package    webservice_rest
  32   * @copyright  2009 Petr Skoda (skodak)
  33   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  34   */
  35  class webservice_rest_server extends webservice_base_server {
  36  
  37      /** @var string return method ('xml' or 'json') */
  38      protected $restformat;
  39  
  40      /**
  41       * Contructor
  42       *
  43       * @param string $authmethod authentication method of the web service (WEBSERVICE_AUTHMETHOD_PERMANENT_TOKEN, ...)
  44       * @param string $restformat Format of the return values: 'xml' or 'json'
  45       */
  46      public function __construct($authmethod) {
  47          parent::__construct($authmethod);
  48          $this->wsname = 'rest';
  49      }
  50  
  51      /**
  52       * This method parses the $_POST and $_GET superglobals and looks for
  53       * the following information:
  54       *  1/ user authentication - username+password or token (wsusername, wspassword and wstoken parameters)
  55       *  2/ function name (wsfunction parameter)
  56       *  3/ function parameters (all other parameters except those above)
  57       *  4/ text format parameters
  58       *  5/ return rest format xml/json
  59       */
  60      protected function parse_request() {
  61  
  62          // Retrieve and clean the POST/GET parameters from the parameters specific to the server.
  63          parent::set_web_service_call_settings();
  64  
  65          // Get GET and POST parameters.
  66          $methodvariables = array_merge($_GET, $_POST);
  67  
  68          // Retrieve REST format parameter - 'xml' (default) or 'json'.
  69          $restformatisset = isset($methodvariables['moodlewsrestformat'])
  70                  && (($methodvariables['moodlewsrestformat'] == 'xml' || $methodvariables['moodlewsrestformat'] == 'json'));
  71          $this->restformat = $restformatisset ? $methodvariables['moodlewsrestformat'] : 'xml';
  72          unset($methodvariables['moodlewsrestformat']);
  73  
  74          if ($this->authmethod == WEBSERVICE_AUTHMETHOD_USERNAME) {
  75              $this->username = isset($methodvariables['wsusername']) ? $methodvariables['wsusername'] : null;
  76              unset($methodvariables['wsusername']);
  77  
  78              $this->password = isset($methodvariables['wspassword']) ? $methodvariables['wspassword'] : null;
  79              unset($methodvariables['wspassword']);
  80  
  81              $this->functionname = isset($methodvariables['wsfunction']) ? $methodvariables['wsfunction'] : null;
  82              unset($methodvariables['wsfunction']);
  83  
  84              $this->parameters = $methodvariables;
  85  
  86          } else {
  87              $this->token = isset($methodvariables['wstoken']) ? $methodvariables['wstoken'] : null;
  88              unset($methodvariables['wstoken']);
  89  
  90              $this->functionname = isset($methodvariables['wsfunction']) ? $methodvariables['wsfunction'] : null;
  91              unset($methodvariables['wsfunction']);
  92  
  93              $this->parameters = $methodvariables;
  94          }
  95      }
  96  
  97      /**
  98       * Send the result of function call to the WS client
  99       * formatted as XML document.
 100       */
 101      protected function send_response() {
 102  
 103          //Check that the returned values are valid
 104          try {
 105              if ($this->function->returns_desc != null) {
 106                  $validatedvalues = external_api::clean_returnvalue($this->function->returns_desc, $this->returns);
 107              } else {
 108                  $validatedvalues = null;
 109              }
 110          } catch (Exception $ex) {
 111              $exception = $ex;
 112          }
 113  
 114          if (!empty($exception)) {
 115              $response =  $this->generate_error($exception);
 116          } else {
 117              //We can now convert the response to the requested REST format
 118              if ($this->restformat == 'json') {
 119                  $response = json_encode($validatedvalues);
 120              } else {
 121                  $response = '<?xml version="1.0" encoding="UTF-8" ?>'."\n";
 122                  $response .= '<RESPONSE>'."\n";
 123                  $response .= self::xmlize_result($validatedvalues, $this->function->returns_desc);
 124                  $response .= '</RESPONSE>'."\n";
 125              }
 126          }
 127  
 128          $this->send_headers();
 129          echo $response;
 130      }
 131  
 132      /**
 133       * Send the error information to the WS client
 134       * formatted as XML document.
 135       * Note: the exception is never passed as null,
 136       *       it only matches the abstract function declaration.
 137       * @param exception $ex the exception that we are sending
 138       */
 139      protected function send_error($ex=null) {
 140          $this->send_headers();
 141          echo $this->generate_error($ex);
 142      }
 143  
 144      /**
 145       * Build the error information matching the REST returned value format (JSON or XML)
 146       * @param exception $ex the exception we are converting in the server rest format
 147       * @return string the error in the requested REST format
 148       */
 149      protected function generate_error($ex) {
 150          if ($this->restformat == 'json') {
 151              $errorobject = new stdClass;
 152              $errorobject->exception = get_class($ex);
 153              $errorobject->errorcode = $ex->errorcode;
 154              $errorobject->message = $ex->getMessage();
 155              if (debugging() and isset($ex->debuginfo)) {
 156                  $errorobject->debuginfo = $ex->debuginfo;
 157              }
 158              $error = json_encode($errorobject);
 159          } else {
 160              $error = '<?xml version="1.0" encoding="UTF-8" ?>'."\n";
 161              $error .= '<EXCEPTION class="'.get_class($ex).'">'."\n";
 162              $error .= '<ERRORCODE>' . htmlspecialchars($ex->errorcode, ENT_COMPAT, 'UTF-8')
 163                      . '</ERRORCODE>' . "\n";
 164              $error .= '<MESSAGE>'.htmlspecialchars($ex->getMessage(), ENT_COMPAT, 'UTF-8').'</MESSAGE>'."\n";
 165              if (debugging() and isset($ex->debuginfo)) {
 166                  $error .= '<DEBUGINFO>'.htmlspecialchars($ex->debuginfo, ENT_COMPAT, 'UTF-8').'</DEBUGINFO>'."\n";
 167              }
 168              $error .= '</EXCEPTION>'."\n";
 169          }
 170          return $error;
 171      }
 172  
 173      /**
 174       * Internal implementation - sending of page headers.
 175       */
 176      protected function send_headers() {
 177          if ($this->restformat == 'json') {
 178              header('Content-type: application/json');
 179          } else {
 180              header('Content-Type: application/xml; charset=utf-8');
 181              header('Content-Disposition: inline; filename="response.xml"');
 182          }
 183          header('Cache-Control: private, must-revalidate, pre-check=0, post-check=0, max-age=0');
 184          header('Expires: '. gmdate('D, d M Y H:i:s', 0) .' GMT');
 185          header('Pragma: no-cache');
 186          header('Accept-Ranges: none');
 187          // Allow cross-origin requests only for Web Services.
 188          // This allow to receive requests done by Web Workers or webapps in different domains.
 189          header('Access-Control-Allow-Origin: *');
 190      }
 191  
 192      /**
 193       * Internal implementation - recursive function producing XML markup.
 194       *
 195       * @param mixed $returns the returned values
 196       * @param external_description $desc
 197       * @return string
 198       */
 199      protected static function xmlize_result($returns, $desc) {
 200          if ($desc === null) {
 201              return '';
 202  
 203          } else if ($desc instanceof external_value) {
 204              if (is_bool($returns)) {
 205                  // we want 1/0 instead of true/false here
 206                  $returns = (int)$returns;
 207              }
 208              if (is_null($returns)) {
 209                  return '<VALUE null="null"/>'."\n";
 210              } else {
 211                  return '<VALUE>'.htmlspecialchars($returns, ENT_COMPAT, 'UTF-8').'</VALUE>'."\n";
 212              }
 213  
 214          } else if ($desc instanceof external_multiple_structure) {
 215              $mult = '<MULTIPLE>'."\n";
 216              if (!empty($returns)) {
 217                  foreach ($returns as $val) {
 218                      $mult .= self::xmlize_result($val, $desc->content);
 219                  }
 220              }
 221              $mult .= '</MULTIPLE>'."\n";
 222              return $mult;
 223  
 224          } else if ($desc instanceof external_single_structure) {
 225              $single = '<SINGLE>'."\n";
 226              foreach ($desc->keys as $key=>$subdesc) {
 227                  $value = isset($returns[$key]) ? $returns[$key] : null;
 228                  $single .= '<KEY name="'.$key.'">'.self::xmlize_result($value, $subdesc).'</KEY>'."\n";
 229              }
 230              $single .= '</SINGLE>'."\n";
 231              return $single;
 232          }
 233      }
 234  }
 235  
 236  
 237  /**
 238   * REST test client class
 239   *
 240   * @package    webservice_rest
 241   * @copyright  2009 Petr Skoda (skodak)
 242   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 243   */
 244  class webservice_rest_test_client implements webservice_test_client_interface {
 245      /**
 246       * Execute test client WS request
 247       * @param string $serverurl server url (including token parameter or username/password parameters)
 248       * @param string $function function name
 249       * @param array $params parameters of the called function
 250       * @return mixed
 251       */
 252      public function simpletest($serverurl, $function, $params) {
 253          return download_file_content($serverurl.'&wsfunction='.$function, null, $params);
 254      }
 255  }