chamilo-lms/plugin/bbb/lib/bbb_api.php

<?php

/*
  Copyright 2010-2011 Blindside Networks

  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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

  Versions:
  1.0  --  Initial version written by DJP
  (email: djp [a t ]  architectes DOT .org)
  1.1  --  Updated by Omar Shammas and Sebastian Schneider
  (email : omar [at] b l i n ds i de n  e t w o r ks [dt] com)
  (email : seb DOT sschneider [ a t ] g m ail DOT com)
  1.2  --  Updated by Omar Shammas
  (email : omar [at] b l i n ds i de n  e t w o r ks [dt] com)
  1.3  --  Reviewed and extended by Jesus Federico
  (email : jesus [at] b l i n ds i de n  e t w o r ks [dt] com)
  0.8_1.4.10  --  Extended by Jesus Federico to support BigBlueButton 0.8 version
  (email : jesus [at] b l i n ds i de n  e t w o r ks [dt] com)
 */


/*
  @param
  $userName = userName AND meetingID (string)
  $welcomeString = welcome message (string)

  $modPW = moderator password (string)
  $vPW = viewer password (string)
  $voiceBridge = voice bridge (integer)
  $logout = logout url (url)
 */

// create a meeting and return the url to join as moderator
// TODO::
// create some set methods
class BigBlueButtonBN
{

    var $userName = array();
    var $meetingID; // the meeting id
    var $welcomeString;
    // the next 2 fields are maybe not needed?!?
    var $modPW; // the moderator password
    var $attPW; // the attendee pw
    var $securitySalt; // the security salt; gets encrypted with sha1
    var $URL; // the url the bigbluebuttonbn server is installed
    var $sessionURL; // the url for the administrator to join the sessoin
    var $userURL;
    var $conferenceIsRunning = false;

    // this constructor is used to create a BigBlueButton Object
    // use this object to create servers
    // Use is either 0 arguments or all 7 arguments
    public function __construct() {
        $numargs = func_num_args();

        if ($numargs == 0) {
            #	echo "Constructor created";
        }
        // pass the information to the class variables
        else if ($numargs >= 6) {
            $this->userName = func_get_arg(0);
            $this->meetingID = func_get_arg(1);
            $this->welcomeString = func_get_arg(2);
            $this->modPW = func_get_arg(3);
            $this->attPW = func_get_arg(4);
            $this->securitySalt = func_get_arg(5);
            $this->URL = func_get_arg(6);


            $arg_list = func_get_args();
        }// end else if
    }

    //------------------------------------------------GET URLs-------------------------------------------------
    /**
     * This method returns the url to join the specified meeting.
     *
     * @param meetingID -- the unique meeting identifier used to store the meeting in the bigbluebuttonbn server
     * @param username -- the display name to be used when the user joins the meeting
     * @param PW -- the attendee or moderator password of the meeting
     * @param SALT -- the security salt of the bigbluebuttonbn server
     * @param URL -- the url of the bigbluebuttonbn server
     *
     * @return The url to join the meeting
     */
    public static function joinURL($meetingID, $userName, $PW, $SALT, $URL) {
        $url_join = $URL."api/join?";
        $params = 'meetingID='.urlencode($meetingID).'&fullName='.urlencode($userName).'&password='.urlencode($PW);
        return ($url_join.$params.'&checksum='.sha1("join".$params.$SALT) );
    }

    /**
     * This method returns the url to join the specified meeting.
     *
     * @param name -- a name fot the meeting
     * @param meetingID -- the unique meeting identifier used to store the meeting in the bigbluebuttonbn server
     * @param attendeePW -- the attendee of the meeting
     * @param moderatorPW -- the moderator of the meeting
     * @param welcome -- the welcome message that gets displayed on the chat window
     * @param logoutURL -- the URL that the bbb client will go to after users logouut
     * @param SALT -- the security salt of the bigbluebuttonbn server
     * @param URL -- the url of the bigbluebuttonbn server
     * @param record -- the flag which indicate if the meetings will be recorded or not record=true|false, default false
     * @param duration -- this value indicate the duration of a meeting to be recorded. Duration is represented in munutes
     *
     * @return The url to join the meeting
     */
    public static function createMeetingURL($name, $meetingID, $attendeePW, $moderatorPW, $welcome, $logoutURL, $SALT, $URL, $record = 'false', $duration = 0, $voiceBridge = 0, $metadata = array()) {
        $url_create = $URL."api/create?";
        if ($voiceBridge == 0)
            $voiceBridge = 70000 + rand(0, 9999);

        $meta = '';
        while ($data = current($metadata)) {
            $meta = $meta.'&'.key($metadata).'='.urlencode($data);
            next($metadata);
        }


        $params = 'name='.urlencode($name).'&meetingID='.urlencode($meetingID).'&attendeePW='.urlencode($attendeePW).'&moderatorPW='.urlencode($moderatorPW).'&voiceBridge='.$voiceBridge.'&logoutURL='.urlencode($logoutURL).'&record='.$record.$meta;

        $duration = intval($duration);
        if ($duration > 0)
            $params .= '&duration='.$duration;

        if (trim($welcome))
            $params .= '&welcome='.urlencode($welcome);

        return ( $url_create.$params.'&checksum='.sha1("create".$params.$SALT) );
    }

    /**
     * This method returns the url to check if the specified meeting is running.
     *
     * @param meetingID -- the unique meeting identifier used to store the meeting in the bigbluebuttonbn server
     * @param SALT -- the security salt of the bigbluebuttonbn server
     * @param URL -- the url of the bigbluebuttonbn server
     *
     * @return The url to check if the specified meeting is running.
     */
    public static function isMeetingRunningURL($meetingID, $URL, $SALT) {
        $base_url = $URL."api/isMeetingRunning?";
        $params = 'meetingID='.urlencode($meetingID);
        return ($base_url.$params.'&checksum='.sha1("isMeetingRunning".$params.$SALT) );
    }

    /**
     * This method returns the url to getMeetingInfo of the specified meeting.
     *
     * @param meetingID -- the unique meeting identifier used to store the meeting in the bigbluebuttonbn server
     * @param modPW -- the moderator password of the meeting
     * @param SALT -- the security salt of the bigbluebuttonbn server
     * @param URL -- the url of the bigbluebuttonbn server
     *
     * @return The url to check if the specified meeting is running.
     */
    public static function getMeetingInfoURL($meetingID, $modPW, $URL, $SALT) {
        $base_url = $URL."api/getMeetingInfo?";
        $params = 'meetingID='.urlencode($meetingID).'&password='.urlencode($modPW);
        return ( $base_url.$params.'&checksum='.sha1("getMeetingInfo".$params.$SALT));
    }

    /**
     * This method returns the url for listing all meetings in the bigbluebuttonbn server.
     *
     * @param SALT -- the security salt of the bigbluebuttonbn server
     * @param URL -- the url of the bigbluebuttonbn server
     *
     * @return The url of getMeetings.
     */
    public static function getMeetingsURL($URL, $SALT) {
        $base_url = $URL."api/getMeetings?";
        $params = '';
        return ( $base_url.$params.'&checksum='.sha1("getMeetings".$params.$SALT));
    }

    /**
     * This method returns the url to end the specified meeting.
     *
     * @param meetingID -- the unique meeting identifier used to store the meeting in the bigbluebuttonbn server
     * @param modPW -- the moderator password of the meeting
     * @param SALT -- the security salt of the bigbluebuttonbn server
     * @param URL -- the url of the bigbluebuttonbn server
     *
     * @return The url to end the specified meeting.
     */
    public static function endMeetingURL($meetingID, $modPW, $URL, $SALT) {
        $base_url = $URL."api/end?";
        $params = 'meetingID='.urlencode($meetingID).'&password='.urlencode($modPW);
        return ( $base_url.$params.'&checksum='.sha1("end".$params.$SALT) );
    }

    //-----------------------------------------------CREATE----------------------------------------------------
    /**
     * This method creates a meeting and returnS the join url for moderators.
     *
     * @param username
     * @param meetingID -- the unique meeting identifier used to store the meeting in the bigbluebuttonbn server
     * @param welcomeString -- the welcome message to be displayed when a user logs in to the meeting
     * @param mPW -- the moderator password of the meeting
     * @param aPW -- the attendee password of the meeting
     * @param SALT -- the security salt of the bigbluebuttonbn server
     * @param URL -- the url of the bigbluebuttonbn server
     * @param logoutURL -- the url the user should be redirected to when they logout of bigbluebuttonbn
     * @param record -- the flag which indicate if the meetings will be recorded or not record=true|false, default false
     *
     * @return The joinURL if successful or an error message if unsuccessful
     */
    public static function createMeetingAndGetJoinURL($username, $meeting_name, $meetingID, $welcomeString, $mPW, $aPW, $SALT, $URL, $logoutURL, $record = 'false', $duration = 0, $voiceBridge = 0, $metadata = array()) {

        $xml = BigBlueButtonBN::_wrap_simplexml_load_file(BigBlueButtonBN::createMeetingURL($meeting_name, $meetingID, $aPW, $mPW, $welcomeString, $logoutURL, $SALT, $URL, $record, $duration, $voiceBridge, $metadata));

        if ($xml && $xml->returncode == 'SUCCESS') {
            return ( BigBlueButtonBN::joinURL($meetingID, $username, $mPW, $SALT, $URL) );
        } else if ($xml) {
            return ( $xml->messageKey.' : '.$xml->message );
        } else {
            return ('Unable to fetch URL '.$url_create.$params.'&checksum='.sha1("create".$params.$SALT) );
        }
    }

    /**
     * This method creates a meeting and return an array of the xml packet
     *
     * @param username
     * @param meetingID -- the unique meeting identifier used to store the meeting in the bigbluebuttonbn server
     * @param welcomeString -- the welcome message to be displayed when a user logs in to the meeting
     * @param mPW -- the moderator password of the meeting
     * @param aPW -- the attendee password of the meeting
     * @param SALT -- the security salt of the bigbluebuttonbn server
     * @param URL -- the url of the bigbluebuttonbn server
     * @param logoutURL -- the url the user should be redirected to when they logout of bigbluebuttonbn
     * @param record -- the flag which indicate if the meetings will be recorded or not record=true|false, default false
     *
     * @return
     * 	- Null if unable to reach the bigbluebuttonbn server
     * 	- If failed it returns an array containing a returncode, messageKey, message.
     * 	- If success it returns an array containing a returncode, messageKey, message, meetingID, attendeePW, moderatorPW, hasBeenForciblyEnded.
     */
    public static function createMeetingArray($username, $meetingID, $welcomeString, $mPW, $aPW, $SALT, $URL, $logoutURL, $record = 'false', $duration = 0, $voiceBridge = 0, $metadata = array()) {

        $xml = BigBlueButtonBN::_wrap_simplexml_load_file(BigBlueButtonBN::createMeetingURL($username, $meetingID, $aPW, $mPW, $welcomeString, $logoutURL, $SALT, $URL, $record, $duration, $voiceBridge, $metadata));

        if ($xml) {
            if ($xml->meetingID)
                return array('returncode' => $xml->returncode, 'message' => $xml->message, 'messageKey' => $xml->messageKey, 'meetingID' => $xml->meetingID, 'attendeePW' => $xml->attendeePW, 'moderatorPW' => $xml->moderatorPW, 'hasBeenForciblyEnded' => $xml->hasBeenForciblyEnded);
            else
                return array('returncode' => $xml->returncode, 'message' => $xml->message, 'messageKey' => $xml->messageKey);
        }
        else {
            return null;
        }
    }

    //-------------------------------------------getMeetingInfo---------------------------------------------------
    /**
     * This method calls the getMeetingInfo on the bigbluebuttonbn server and returns an xml packet.
     *
     * @param meetingID -- the unique meeting identifier used to store the meeting in the bigbluebuttonbn server
     * @param modPW -- the moderator password of the meeting
     * @param SALT -- the security salt of the bigbluebuttonbn server
     * @param URL -- the url of the bigbluebuttonbn server
     *
     * @return An xml packet.
     * 	If failed it returns an xml packet containing a returncode, messagekey, and message.
     * 	If success it returnsan xml packet containing a returncode,
     */
    public static function getMeetingInfo($meetingID, $modPW, $URL, $SALT) {
        $xml = BigBlueButtonBN::_wrap_simplexml_load_file(BigBlueButtonBN::getMeetingInfoURL($meetingID, $modPW, $URL, $SALT));
        if ($xml) {
            return ( str_replace('</response>', '', str_replace("<?xml version=\"1.0\"?>\n<response>", '', $xml->asXML())));
        }
        return false;
    }

    /**
     * This method calls the getMeetingInfo on the bigbluebuttonbn server and returns an array.
     *
     * @param meetingID -- the unique meeting identifier used to store the meeting in the bigbluebuttonbn server
     * @param modPW -- the moderator password of the meeting
     * @param SALT -- the security salt of the bigbluebuttonbn server
     * @param URL -- the url of the bigbluebuttonbn server
     *
     * @return An Array.
     * 	- Null if unable to reach the bigbluebuttonbn server
     * 	- If failed it returns an array containing a returncode, messagekey, message.
     * 	- If success it returns an array containing a meetingID, moderatorPW, attendeePW, hasBeenForciblyEnded, running, startTime, endTime,
      participantCount, moderatorCount, attendees.
     */
    public static function getMeetingInfoArray($meetingID, $modPW, $URL, $SALT) {
        $xml = BigBlueButtonBN::_wrap_simplexml_load_file(BigBlueButtonBN::getMeetingInfoURL($meetingID, $modPW, $URL, $SALT));

        if ($xml && $xml->returncode == 'SUCCESS' && $xml->messageKey == null) {//The meetings were returned
            return array('returncode' => $xml->returncode, 'message' => $xml->message, 'messageKey' => $xml->messageKey);
        } else if ($xml && $xml->returncode == 'SUCCESS') { //If there were meetings already created
            return array('meetingID' => $xml->meetingID, 'moderatorPW' => $xml->moderatorPW, 'attendeePW' => $xml->attendeePW, 'hasBeenForciblyEnded' => $xml->hasBeenForciblyEnded, 'running' => $xml->running, 'recording' => $xml->recording, 'startTime' => $xml->startTime, 'endTime' => $xml->endTime, 'participantCount' => $xml->participantCount, 'moderatorCount' => $xml->moderatorCount, 'attendees' => $xml->attendees, 'metadata' => $xml->metadata);
        } else if (($xml && $xml->returncode == 'FAILED') || $xml) { //If the xml packet returned failure it displays the message to the user
            return array('returncode' => $xml->returncode, 'message' => $xml->message, 'messageKey' => $xml->messageKey);
            //return array('returncode' => $xml->returncode, 'message' => $xml->errors->error['message'], 'messageKey' => $xml->errors->error['key']);  //For API version 0.8
        } else { //If the server is unreachable, then prompts the user of the necessary action
            return null;
        }
    }

    //-----------------------------------------------getMeetings------------------------------------------------------
    /**
     * This method calls getMeetings on the bigbluebuttonbn server, then calls getMeetingInfo for each meeting and concatenates the result.
     *
     * @param URL -- the url of the bigbluebuttonbn server
     * @param SALT -- the security salt of the bigbluebuttonbn server
     *
     * @return
     * 	- If failed then returns a boolean of false.
     * 	- If succeeded then returns an xml of all the meetings.
     */
    public static function getMeetings($URL, $SALT) {
        $xml = BigBlueButtonBN::_wrap_simplexml_load_file(BigBlueButtonBN::getMeetingsURL($URL, $SALT));
        if ($xml && $xml->returncode == 'SUCCESS') {
            if ($xml->messageKey)
                return ( $xml->message->asXML() );
            ob_start();
            echo '<meetings>';
            if (count($xml->meetings) && count($xml->meetings->meeting)) {
                foreach ($xml->meetings->meeting as $meeting) {
                    echo '<meeting>';
                    echo BigBlueButtonBN::getMeetingInfo($meeting->meetingID, $meeting->moderatorPW, $URL, $SALT);
                    echo '</meeting>';
                }
            }
            echo '</meetings>';
            return (ob_get_clean());
        } else {
            return (false);
        }
    }

    /**
     * This method calls getMeetings on the bigbluebuttonbn server, then calls getMeetingInfo for each meeting and concatenates the result.
     *
     * @param URL -- the url of the bigbluebuttonbn server
     * @param SALT -- the security salt of the bigbluebuttonbn server
     *
     * @return
     * 	- Null if the server is unreachable
     * 	- If FAILED then returns an array containing a returncode, messageKey, message.
     * 	- If SUCCESS then returns an array of all the meetings. Each element in the array is an array containing a meetingID,
      moderatorPW, attendeePW, hasBeenForciblyEnded, running.
     */
    public static function getMeetingsArray($URL, $SALT) {
        $xml = BigBlueButtonBN::_wrap_simplexml_load_file(BigBlueButtonBN::getMeetingsURL($URL, $SALT));

        if ($xml && $xml->returncode == 'SUCCESS' && $xml->messageKey) {//The meetings were returned
            return array('returncode' => $xml->returncode, 'message' => $xml->message, 'messageKey' => $xml->messageKey);
        } else if ($xml && $xml->returncode == 'SUCCESS') { //If there were meetings already created
            foreach ($xml->meetings->meeting as $meeting) {
                $meetings[] = array('meetingID' => $meeting->meetingID, 'moderatorPW' => $meeting->moderatorPW, 'attendeePW' => $meeting->attendeePW, 'hasBeenForciblyEnded' => $meeting->hasBeenForciblyEnded, 'running' => $meeting->running);
            }

            return $meetings;
        } else if ($xml) { //If the xml packet returned failure it displays the message to the user
            return array('returncode' => $xml->returncode, 'message' => $xml->message, 'messageKey' => $xml->messageKey);
        } else { //If the server is unreachable, then prompts the user of the necessary action
            return null;
        }
    }

    //----------------------------------------------getUsers---------------------------------------
    /**
     * This method prints the usernames of the attendees in the specified conference.
     *
     * @param meetingID -- the unique meeting identifier used to store the meeting in the bigbluebuttonbn server
     * @param modPW -- the moderator password of the meeting
     * @param URL -- the url of the bigbluebuttonbn server
     * @param SALT -- the security salt of the bigbluebuttonbn server
     * @param UNAME -- is a boolean to determine how the username is formatted when printed. Default if false.
     *
     * @return A boolean of true if the attendees were printed successfully and false otherwise.
     */
    public static function getUsers($meetingID, $modPW, $URL, $SALT, $UNAME = false) {
        $xml = BigBlueButtonBN::_wrap_simplexml_load_file(BigBlueButtonBN::getMeetingInfoURL($meetingID, $modPW, $URL, $SALT));
        if ($xml && $xml->returncode == 'SUCCESS') {
            ob_start();
            if (count($xml->attendees) && count($xml->attendees->attendee)) {
                foreach ($xml->attendees->attendee as $attendee) {
                    if ($UNAME == true) {
                        echo "User name: ".$attendee->fullName.'<br />';
                    } else {
                        echo $attendee->fullName.'<br />';
                    }
                }
            }
            return (ob_end_flush());
        } else {
            return (false);
        }
    }

    /**
     * This method returns an array of the attendees in the specified meeting.
     *
     * @param meetingID -- the unique meeting identifier used to store the meeting in the bigbluebuttonbn server
     * @param modPW -- the moderator password of the meeting
     * @param URL -- the url of the bigbluebuttonbn server
     * @param SALT -- the security salt of the bigbluebuttonbn server
     *
     * @return
     * 	- Null if the server is unreachable.
     * 	- If FAILED, returns an array containing a returncode, messageKey, message.
     * 	- If SUCCESS, returns an array of array containing the userID, fullName, role of each attendee
     */
    public static function getUsersArray($meetingID, $modPW, $URL, $SALT) {
        $xml = BigBlueButtonBN::_wrap_simplexml_load_file(BigBlueButtonBN::getMeetingInfoURL($meetingID, $modPW, $URL, $SALT));

        if ($xml && $xml->returncode == 'SUCCESS' && $xml->messageKey == null) {//The meetings were returned
            return array('returncode' => $xml->returncode, 'message' => $xml->message, 'messageKey' => $xml->messageKey);
        } else if ($xml && $xml->returncode == 'SUCCESS') { //If there were meetings already created
            foreach ($xml->attendees->attendee as $attendee) {
                $users[] = array('userID' => $attendee->userID, 'fullName' => $attendee->fullName, 'role' => $attendee->role);
            }
            return $users;
        } else if ($xml) { //If the xml packet returned failure it displays the message to the user
            return array('returncode' => $xml->returncode, 'message' => $xml->message, 'messageKey' => $xml->messageKey);
        } else { //If the server is unreachable, then prompts the user of the necessary action
            return null;
        }
    }

    //------------------------------------------------Other Methods------------------------------------
    /**
     * This method calls end meeting on the specified meeting in the bigbluebuttonbn server.
     *
     * @param meetingID -- the unique meeting identifier used to store the meeting in the bigbluebuttonbn server
     * @param modPW -- the moderator password of the meeting
     * @param SALT -- the security salt of the bigbluebuttonbn server
     * @param URL -- the url of the bigbluebuttonbn server
     *
     * @return
     * 	- Null if the server is unreachable
     * 	- An array containing a returncode, messageKey, message.
     */
    public static function endMeeting($meetingID, $modPW, $URL, $SALT) {
        $xml = BigBlueButtonBN::_wrap_simplexml_load_file(BigBlueButtonBN::endMeetingURL($meetingID, $modPW, $URL, $SALT));

        if ($xml) { //If the xml packet returned failure it displays the message to the user
            return array('returncode' => $xml->returncode, 'message' => $xml->message, 'messageKey' => $xml->messageKey);
        } else { //If the server is unreachable, then prompts the user of the necessary action
            return null;
        }
    }

    /**
     * This method check the BigBlueButton server to see if the meeting is running (i.e. there is someone in the meeting)
     *
     * @param meetingID -- the unique meeting identifier used to store the meeting in the bigbluebuttonbn server
     * @param SALT -- the security salt of the bigbluebuttonbn server
     * @param URL -- the url of the bigbluebuttonbn server
     *
     * @return A boolean of true if the meeting is running and false if it is not running
     */
    public static function isMeetingRunning($meetingID, $URL, $SALT) {
        $xml = BigBlueButtonBN::_wrap_simplexml_load_file(BigBlueButtonBN::isMeetingRunningURL($meetingID, $URL, $SALT));
        if ($xml && $xml->returncode == 'SUCCESS')
            return ( ( $xml->running == 'true' ) ? true : false);
        else
            return ( false );
    }

    /**
     * This method calls isMeetingRunning on the BigBlueButton server.
     *
     * @param meetingID -- the unique meeting identifier used to store the meeting in the bigbluebuttonbn server
     * @param SALT -- the security salt of the bigbluebuttonbn server
     * @param URL -- the url of the bigbluebuttonbn server
     *
     * @return
     * 	- If SUCCESS it returns an xml packet
     * 	- If the FAILED or the server is unreachable returns a string of 'false'
     */
    public static function getMeetingXML($meetingID, $URL, $SALT) {
        $xml = BigBlueButtonBN::_wrap_simplexml_load_file(BigBlueButtonBN::isMeetingRunningURL($meetingID, $URL, $SALT));
        if ($xml && $xml->returncode == 'SUCCESS')
            return ( str_replace('</response>', '', str_replace("<?xml version=\"1.0\"?>\n<response>", '', $xml->asXML())));
        else
            return 'false';
    }

    // TODO: WRITE AN ITERATOR WHICH GOES OVER WHATEVER IT IS BEING TOLD IN THE API AND LIST INFORMATION
    /* we have to define at least 2 variable fields for getInformation to read out information at any position
      The first is: An identifier to chose if we look for attendees or the meetings or something else
      The second is: An identifier to chose what integrated functions are supposed to be used

      @param IDENTIFIER -- needs to be put in for the function to identify the information to print out
      current values which can be used are 'attendee' and 'meetings'
      @param meetingID -- needs to be put in to identify the meeting
      @param modPW -- needs to be put in if the users are supposed to be shown or to retrieve information about the meetings
      @param URL -- needs to be put in the URL to the bigbluebuttonbn server
      @param SALT -- needs to be put in for the security salt calculation

      Note: If 'meetings' is used, then only the parameters URL and SALT needs to be used
      If 'attendee' is used, then all the parameters needs to be used
     */
    public static function getInformation($IDENTIFIER, $meetingID, $modPW, $URL, $SALT) {
        // if the identifier is null or '', then return false
        if ($IDENTIFIER == "" || $IDENTIFIER == null) {
            echo "You need to type in a valid value into the identifier.";
            return false;
        }
        // if the identifier is attendee, call getUsers
        else if ($IDENTIFIER == 'attendee') {
            return BigBlueButtonBN::getUsers($meetingID, $modPW, $URL, $SALT);
        }
        // if the identifier is meetings, call getMeetings
        else if ($IDENTIFIER == 'meetings') {
            return BigBlueButtonBN::getMeetings($URL, $SALT);
        }
        // return nothing
        else {
            return true;
        }
    }

    function getServerIP() {
        // get the server url
        $sIP = $_SERVER['SERVER_ADDR'];
        return $serverIP = 'http://'.$sIP.'/bigbluebuttonbn/';
    }

    /**
     * This method check the BigBlueButton server to see if the meeting has been created
     *
     * @param meetingID -- the unique meeting identifier used to store the meeting in the bigbluebuttonbn server
     * @param SALT -- the security salt of the bigbluebuttonbn server
     * @param URL -- the url of the bigbluebuttonbn server
     *
     * @return A boolean of true if the meeting has been created, doesn't matter if is running or not and false if it does not exist
     */
    public static function isMeetingCreated($meetingID, $URL, $SALT) {

        $xml = BigBlueButtonBN::_wrap_simplexml_load_file(BigBlueButtonBN::getMeetingsURL($URL, $SALT));
        if ($xml && $xml->returncode == 'SUCCESS')
            foreach ($xml->meetings->meeting as $meeting)
                if ($meeting->meetingID == $meetingID && $meeting->hasBeenForciblyEnded == 'false')
                    return true;
        return false;
    }

    /**
     * This method creates a new meeting room in the BigBlueButton server
     *
     * @param name -- a name fot the meeting
     * @param meetingID -- the unique meeting identifier used to store the meeting in the bigbluebuttonbn server
     * @param attendeePW -- the attendee of the meeting
     * @param moderatorPW -- the moderator of the meeting
     * @param welcome -- the welcome message that gets displayed on the chat window
     * @param logoutURL -- the URL that the bbb client will go to after users logouut
     * @param SALT -- the security salt of the bigbluebuttonbn server
     * @param URL -- the url of the bigbluebuttonbn server
     * @param record -- the flag which indicate if the meetings will be recorded or not record=true|false, default false
     *
     * @return A boolean of true if the meeting has been created, doesn't matter if is running or not and false if it was an error
     */
    public static function createMeeting($name, $meetingID, $attendeePW, $moderatorPW, $welcome, $logoutURL, $SALT, $URL, $record = 'false', $duration = 0, $voiceBridge = 0, $metadata = array()) {

        $xml = BigBlueButtonBN::_wrap_simplexml_load_file(BigBlueButtonBN::createMeetingURL($name, $meetingID, $attendeePW, $moderatorPW, $welcome, $logoutURL, $SALT, $URL, $record, $duration, $voiceBridge, $metadata));
        if ($xml && $xml->returncode == 'SUCCESS')
            return true;
        else
            return false;
    }

////////////////////////TO DO: CHANGE THE DESCRIPTION OF THE NEW METHODS

    public static function getRecordingsURL($meetingID, $URL, $SALT) {
        $base_url_record = $URL."api/getRecordings?";
        $params = "meetingID=".urlencode($meetingID);

        return ($base_url_record.$params."&checksum=".sha1("getRecordings".$params.$SALT) );
    }

    /**
     * This method calls getMeetings on the bigbluebuttonbn server, then calls getMeetingInfo for each meeting and concatenates the result.
     *
     * @param URL -- the url of the bigbluebuttonbn server
     * @param SALT -- the security salt of the bigbluebuttonbn server
     *
     * @return
     * 	- Null if the server is unreachable
     * 	- If FAILED then returns an array containing a returncode, messageKey, message.
     * 	- If SUCCESS then returns an array of all the meetings. Each element in the array is an array containing a meetingID,
      moderatorPW, attendeePW, hasBeenForciblyEnded, running.
     */
    public static function getRecordingsArray($meetingID, $URL, $SALT) {
        $xml = BigBlueButtonBN::_wrap_simplexml_load_file(BigBlueButtonBN::getRecordingsURL($meetingID, $URL, $SALT));
        if ($xml && $xml->returncode == 'SUCCESS' && $xml->messageKey) {//The meetings were returned
            return array('returncode' => (string) $xml->returncode, 'message' => (string) $xml->message, 'messageKey' => (string) $xml->messageKey);
        } else if ($xml && $xml->returncode == 'SUCCESS') { //If there were meetings already created
            $recordings = array();

            foreach ($xml->recordings->recording as $recording) {
                $recordings[(string) $recording->recordID] = array('recordID' => (string) $recording->recordID, 'meetingID' => (string) $recording->meetingID, 'meetingName' => (string) $recording->name, 'published' => (string) $recording->published, 'startTime' => (string) $recording->startTime, 'endTime' => (string) $recording->endTime);
                $recordings[(string) $recording->recordID]['playbacks'] = array();
                foreach ($recording->playback->format as $format) {
                    $recordings[(string) $recording->recordID]['playbacks'][(string) $format->type] = array('type' => (string) $format->type, 'url' => (string) $format->url);
                }
                // THIS IS FOR TESTING MULTIPLE FORMATS, DO REMOVE IT FOR FINAL RELEASE
                //$recordings[(string) $recording->recordID]['playbacks']['desktop'] = array( 'type' => 'desktop', 'url' => (string) $recording->playback->format->url );
                //Add the metadata to the recordings array
                $metadata = get_object_vars($recording->metadata);
                while ($data = current($metadata)) {
                    $recordings[(string) $recording->recordID]['meta_'.key($metadata)] = $data;
                    next($metadata);
                }
            }

            ksort($recordings);

            return $recordings;
        } else if ($xml) { //If the xml packet returned failure it displays the message to the user
            return array('returncode' => (string) $xml->returncode, 'message' => (string) $xml->message, 'messageKey' => (string) $xml->messageKey);
        } else { //If the server is unreachable, then prompts the user of the necessary action
            return NULL;
        }
    }

    public static function deleteRecordingsURL($recordID, $URL, $SALT) {
        $url_delete = $URL."api/deleteRecordings?";
        $params = 'recordID='.urlencode($recordID);
        return ($url_delete.$params.'&checksum='.sha1("deleteRecordings".$params.$SALT) );
    }

    public static function deleteRecordings($recordIDs, $URL, $SALT) {

        $ids = explode(",", $recordIDs);
        foreach ($ids as $id) {
            $xml = BigBlueButtonBN::_wrap_simplexml_load_file(BigBlueButtonBN::deleteRecordingsURL($id, $URL, $SALT));
            if ($xml && $xml->returncode != 'SUCCESS')
                return false;
        }
        return true;
    }

    public static function setPublishRecordingsURL($recordID, $set, $URL, $SALT) {
        $url_delete = $URL."api/publishRecordings?";
        $params = 'recordID='.$recordID."&publish=".$set;
        return ($url_delete.$params.'&checksum='.sha1("publishRecordings".$params.$SALT) );
    }

    public static function setPublishRecordings($recordIDs, $set, $URL, $SALT) {

        $ids = explode(",", $recordIDs);
        foreach ($ids as $id) {
            $xml = BigBlueButtonBN::_wrap_simplexml_load_file(BigBlueButtonBN::setPublishRecordingsURL($id, $set, $URL, $SALT));
            if ($xml && $xml->returncode != 'SUCCESS')
                return false;
        }
        return true;
    }

    public static function getServerVersion($URL) {
        $base_url_record = $URL."api";

        $xml = BigBlueButtonBN::_wrap_simplexml_load_file($base_url_record);
        if ($xml && $xml->returncode == 'SUCCESS')
            return $xml->version;
        else
            return NULL;
    }

    public static function isServerRunning($URL) {
        $base_url_record = $URL."api";

        $xml = BigBlueButtonBN::_wrap_simplexml_load_file($base_url_record);
        if ($xml && $xml->returncode == 'SUCCESS')
            return true;
        else
            return false;
    }

    public function _wrap_simplexml_load_file($url) {

        if (extension_loaded('curl')) {
            $ch = curl_init() or die(curl_error());
            $timeout = 10;
            curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
            curl_setopt($ch, CURLOPT_URL, $url);
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
            curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
            $data = curl_exec($ch);
            curl_close($ch);

            if ($data) {
                try {
                    $res = new SimpleXMLElement($data, LIBXML_NOCDATA);
                } catch (Exception $e) {
                    return false;
                }
                return $res;
            } else {
                return false;
            }
        }

        return (simplexml_load_file($url, 'SimpleXMLElement', LIBXML_NOCDATA));
    }

}