initial sabre upgrade (needs lots of work - to wit: authentication, redo the browser interface, and rework event export/import)

8 files changed, 1837 insertions, 0 deletions

diff --git a/vendor/sabre/dav/lib/CalDAV/Schedule/IInbox.php b/vendor/sabre/dav/lib/CalDAV/Schedule/IInbox.php
new file mode 100644
index 000000000..c9fd77d93
--- /dev/null
+++ b/vendor/sabre/dav/lib/CalDAV/Schedule/IInbox.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace Sabre\CalDAV\Schedule;
+
+/**
+ * Implement this interface to have a node be recognized as a CalDAV scheduling
+ * inbox.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+interface IInbox extends \Sabre\CalDAV\ICalendarObjectContainer, \Sabre\DAVACL\IACL {
+
+}
diff --git a/vendor/sabre/dav/lib/CalDAV/Schedule/IMipPlugin.php b/vendor/sabre/dav/lib/CalDAV/Schedule/IMipPlugin.php
new file mode 100644
index 000000000..ffb1fe45b
--- /dev/null
+++ b/vendor/sabre/dav/lib/CalDAV/Schedule/IMipPlugin.php
@@ -0,0 +1,190 @@
+<?php
+
+namespace Sabre\CalDAV\Schedule;
+
+use Sabre\DAV;
+use Sabre\VObject\ITip;
+
+/**
+ * iMIP handler.
+ *
+ * This class is responsible for sending out iMIP messages. iMIP is the
+ * email-based transport for iTIP. iTIP deals with scheduling operations for
+ * iCalendar objects.
+ *
+ * If you want to customize the email that gets sent out, you can do so by
+ * extending this class and overriding the sendMessage method.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class IMipPlugin extends DAV\ServerPlugin {
+
+    /**
+     * Email address used in From: header.
+     *
+     * @var string
+     */
+    protected $senderEmail;
+
+    /**
+     * ITipMessage
+     *
+     * @var ITip\Message
+     */
+    protected $itipMessage;
+
+    /**
+     * Creates the email handler.
+     *
+     * @param string $senderEmail. The 'senderEmail' is the email that shows up
+     *                             in the 'From:' address. This should
+     *                             generally be some kind of no-reply email
+     *                             address you own.
+     */
+    function __construct($senderEmail) {
+
+        $this->senderEmail = $senderEmail;
+
+    }
+
+    /*
+     * This initializes the plugin.
+     *
+     * This function is called by Sabre\DAV\Server, after
+     * addPlugin is called.
+     *
+     * This method should set up the required event subscriptions.
+     *
+     * @param DAV\Server $server
+     * @return void
+     */
+    function initialize(DAV\Server $server) {
+
+        $server->on('schedule', [$this, 'schedule'], 120);
+
+    }
+
+    /**
+     * Returns a plugin name.
+     *
+     * Using this name other plugins will be able to access other plugins
+     * using \Sabre\DAV\Server::getPlugin
+     *
+     * @return string
+     */
+    function getPluginName() {
+
+        return 'imip';
+
+    }
+
+    /**
+     * Event handler for the 'schedule' event.
+     *
+     * @param ITip\Message $iTipMessage
+     * @return void
+     */
+    function schedule(ITip\Message $iTipMessage) {
+
+        // Not sending any emails if the system considers the update
+        // insignificant.
+        if (!$iTipMessage->significantChange) {
+            if (!$iTipMessage->scheduleStatus) {
+                $iTipMessage->scheduleStatus = '1.0;We got the message, but it\'s not significant enough to warrant an email';
+            }
+            return;
+        }
+
+        $summary = $iTipMessage->message->VEVENT->SUMMARY;
+
+        if (parse_url($iTipMessage->sender, PHP_URL_SCHEME) !== 'mailto')
+            return;
+
+        if (parse_url($iTipMessage->recipient, PHP_URL_SCHEME) !== 'mailto')
+            return;
+
+        $sender = substr($iTipMessage->sender, 7);
+        $recipient = substr($iTipMessage->recipient, 7);
+
+        if ($iTipMessage->senderName) {
+            $sender = $iTipMessage->senderName . ' <' . $sender . '>';
+        }
+        if ($iTipMessage->recipientName) {
+            $recipient = $iTipMessage->recipientName . ' <' . $recipient . '>';
+        }
+
+        $subject = 'SabreDAV iTIP message';
+        switch (strtoupper($iTipMessage->method)) {
+            case 'REPLY' :
+                $subject = 'Re: ' . $summary;
+                break;
+            case 'REQUEST' :
+                $subject = $summary;
+                break;
+            case 'CANCEL' :
+                $subject = 'Cancelled: ' . $summary;
+                break;
+        }
+
+        $headers = [
+            'Reply-To: ' . $sender,
+            'From: ' . $this->senderEmail,
+            'Content-Type: text/calendar; charset=UTF-8; method=' . $iTipMessage->method,
+        ];
+        if (DAV\Server::$exposeVersion) {
+            $headers[] = 'X-Sabre-Version: ' . DAV\Version::VERSION;
+        }
+        $this->mail(
+            $recipient,
+            $subject,
+            $iTipMessage->message->serialize(),
+            $headers
+        );
+        $iTipMessage->scheduleStatus = '1.1; Scheduling message is sent via iMip';
+
+    }
+
+    // @codeCoverageIgnoreStart
+    // This is deemed untestable in a reasonable manner
+
+    /**
+     * This function is responsible for sending the actual email.
+     *
+     * @param string $to Recipient email address
+     * @param string $subject Subject of the email
+     * @param string $body iCalendar body
+     * @param array $headers List of headers
+     * @return void
+     */
+    protected function mail($to, $subject, $body, array $headers) {
+
+        mail($to, $subject, $body, implode("\r\n", $headers));
+
+    }
+
+    // @codeCoverageIgnoreEnd
+
+    /**
+     * Returns a bunch of meta-data about the plugin.
+     *
+     * Providing this information is optional, and is mainly displayed by the
+     * Browser plugin.
+     *
+     * The description key in the returned array may contain html and will not
+     * be sanitized.
+     *
+     * @return array
+     */
+    function getPluginInfo() {
+
+        return [
+            'name'        => $this->getPluginName(),
+            'description' => 'Email delivery (rfc6037) for CalDAV scheduling',
+            'link'        => 'http://sabre.io/dav/scheduling/',
+        ];
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/CalDAV/Schedule/IOutbox.php b/vendor/sabre/dav/lib/CalDAV/Schedule/IOutbox.php
new file mode 100644
index 000000000..88fbdc411
--- /dev/null
+++ b/vendor/sabre/dav/lib/CalDAV/Schedule/IOutbox.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace Sabre\CalDAV\Schedule;
+
+/**
+ * Implement this interface to have a node be recognized as a CalDAV scheduling
+ * outbox.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+interface IOutbox extends \Sabre\DAV\ICollection, \Sabre\DAVACL\IACL {
+
+}
diff --git a/vendor/sabre/dav/lib/CalDAV/Schedule/ISchedulingObject.php b/vendor/sabre/dav/lib/CalDAV/Schedule/ISchedulingObject.php
new file mode 100644
index 000000000..b37cb40a1
--- /dev/null
+++ b/vendor/sabre/dav/lib/CalDAV/Schedule/ISchedulingObject.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace Sabre\CalDAV\Schedule;
+
+/**
+ * The SchedulingObject represents a scheduling object in the Inbox collection
+ *
+ * @license http://sabre.io/license/ Modified BSD License
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ */
+interface ISchedulingObject extends \Sabre\CalDAV\ICalendarObject {
+
+}
diff --git a/vendor/sabre/dav/lib/CalDAV/Schedule/Inbox.php b/vendor/sabre/dav/lib/CalDAV/Schedule/Inbox.php
new file mode 100644
index 000000000..13212565e
--- /dev/null
+++ b/vendor/sabre/dav/lib/CalDAV/Schedule/Inbox.php
@@ -0,0 +1,261 @@
+<?php
+
+namespace Sabre\CalDAV\Schedule;
+
+use Sabre\DAV;
+use Sabre\CalDAV;
+use Sabre\DAVACL;
+use Sabre\CalDAV\Backend;
+use Sabre\VObject;
+
+/**
+ * The CalDAV scheduling inbox
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class Inbox extends DAV\Collection implements IInbox {
+
+    /**
+     * CalDAV backend
+     *
+     * @var Backend\BackendInterface
+     */
+    protected $caldavBackend;
+
+    /**
+     * The principal Uri
+     *
+     * @var string
+     */
+    protected $principalUri;
+
+    /**
+     * Constructor
+     *
+     * @param Backend\SchedulingSupport $caldavBackend
+     * @param string $principalUri
+     */
+    function __construct(Backend\SchedulingSupport $caldavBackend, $principalUri) {
+
+        $this->caldavBackend = $caldavBackend;
+        $this->principalUri = $principalUri;
+
+    }
+
+    /**
+     * Returns the name of the node.
+     *
+     * This is used to generate the url.
+     *
+     * @return string
+     */
+    function getName() {
+
+        return 'inbox';
+
+    }
+
+    /**
+     * Returns an array with all the child nodes
+     *
+     * @return \Sabre\DAV\INode[]
+     */
+    function getChildren() {
+
+        $objs = $this->caldavBackend->getSchedulingObjects($this->principalUri);
+        $children = [];
+        foreach ($objs as $obj) {
+            //$obj['acl'] = $this->getACL();
+            $obj['principaluri'] = $this->principalUri;
+            $children[] = new SchedulingObject($this->caldavBackend, $obj);
+        }
+        return $children;
+
+    }
+
+    /**
+     * Creates a new file in the directory
+     *
+     * Data will either be supplied as a stream resource, or in certain cases
+     * as a string. Keep in mind that you may have to support either.
+     *
+     * After succesful creation of the file, you may choose to return the ETag
+     * of the new file here.
+     *
+     * The returned ETag must be surrounded by double-quotes (The quotes should
+     * be part of the actual string).
+     *
+     * If you cannot accurately determine the ETag, you should not return it.
+     * If you don't store the file exactly as-is (you're transforming it
+     * somehow) you should also not return an ETag.
+     *
+     * This means that if a subsequent GET to this new file does not exactly
+     * return the same contents of what was submitted here, you are strongly
+     * recommended to omit the ETag.
+     *
+     * @param string $name Name of the file
+     * @param resource|string $data Initial payload
+     * @return null|string
+     */
+    function createFile($name, $data = null) {
+
+        $this->caldavBackend->createSchedulingObject($this->principalUri, $name, $data);
+
+    }
+
+    /**
+     * Returns the owner principal
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    function getOwner() {
+
+        return $this->principalUri;
+
+    }
+
+    /**
+     * Returns a group principal
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    function getGroup() {
+
+        return null;
+
+    }
+
+    /**
+     * Returns a list of ACE's for this node.
+     *
+     * Each ACE has the following properties:
+     *   * 'privilege', a string such as {DAV:}read or {DAV:}write. These are
+     *     currently the only supported privileges
+     *   * 'principal', a url to the principal who owns the node
+     *   * 'protected' (optional), indicating that this ACE is not allowed to
+     *      be updated.
+     *
+     * @return array
+     */
+    function getACL() {
+
+        return [
+            [
+                'privilege' => '{DAV:}read',
+                'principal' => '{DAV:}authenticated',
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{DAV:}write-properties',
+                'principal' => $this->getOwner(),
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{DAV:}unbind',
+                'principal' => $this->getOwner(),
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{DAV:}unbind',
+                'principal' => $this->getOwner() . '/calendar-proxy-write',
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{' . CalDAV\Plugin::NS_CALDAV . '}schedule-deliver-invite',
+                'principal' => '{DAV:}authenticated',
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{' . CalDAV\Plugin::NS_CALDAV . '}schedule-deliver-reply',
+                'principal' => '{DAV:}authenticated',
+                'protected' => true,
+            ],
+        ];
+
+    }
+
+    /**
+     * Updates the ACL
+     *
+     * This method will receive a list of new ACE's.
+     *
+     * @param array $acl
+     * @return void
+     */
+    function setACL(array $acl) {
+
+        throw new DAV\Exception\MethodNotAllowed('You\'re not allowed to update the ACL');
+
+    }
+
+    /**
+     * Returns the list of supported privileges for this node.
+     *
+     * The returned data structure is a list of nested privileges.
+     * See Sabre\DAVACL\Plugin::getDefaultSupportedPrivilegeSet for a simple
+     * standard structure.
+     *
+     * If null is returned from this method, the default privilege set is used,
+     * which is fine for most common usecases.
+     *
+     * @return array|null
+     */
+    function getSupportedPrivilegeSet() {
+
+        $ns = '{' . CalDAV\Plugin::NS_CALDAV . '}';
+
+        $default = DAVACL\Plugin::getDefaultSupportedPrivilegeSet();
+        $default['aggregates'][] = [
+            'privilege'  => $ns . 'schedule-deliver',
+            'aggregates' => [
+               ['privilege' => $ns . 'schedule-deliver-invite'],
+               ['privilege' => $ns . 'schedule-deliver-reply'],
+            ],
+        ];
+        return $default;
+
+    }
+
+    /**
+     * Performs a calendar-query on the contents of this calendar.
+     *
+     * The calendar-query is defined in RFC4791 : CalDAV. Using the
+     * calendar-query it is possible for a client to request a specific set of
+     * object, based on contents of iCalendar properties, date-ranges and
+     * iCalendar component types (VTODO, VEVENT).
+     *
+     * This method should just return a list of (relative) urls that match this
+     * query.
+     *
+     * The list of filters are specified as an array. The exact array is
+     * documented by \Sabre\CalDAV\CalendarQueryParser.
+     *
+     * @param array $filters
+     * @return array
+     */
+    function calendarQuery(array $filters) {
+
+        $result = [];
+        $validator = new CalDAV\CalendarQueryValidator();
+
+        $objects = $this->caldavBackend->getSchedulingObjects($this->principalUri);
+        foreach ($objects as $object) {
+            $vObject = VObject\Reader::read($object['calendardata']);
+            if ($validator->validate($vObject, $filters)) {
+                $result[] = $object['uri'];
+            }
+
+            // Destroy circular references to PHP will GC the object.
+            $vObject->destroy();
+        }
+        return $result;
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/CalDAV/Schedule/Outbox.php b/vendor/sabre/dav/lib/CalDAV/Schedule/Outbox.php
new file mode 100644
index 000000000..dabaee2ca
--- /dev/null
+++ b/vendor/sabre/dav/lib/CalDAV/Schedule/Outbox.php
@@ -0,0 +1,184 @@
+<?php
+
+namespace Sabre\CalDAV\Schedule;
+
+use Sabre\DAV;
+use Sabre\CalDAV;
+use Sabre\DAVACL;
+
+/**
+ * The CalDAV scheduling outbox
+ *
+ * The outbox is mainly used as an endpoint in the tree for a client to do
+ * free-busy requests. This functionality is completely handled by the
+ * Scheduling plugin, so this object is actually mostly static.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class Outbox extends DAV\Collection implements IOutbox {
+
+    /**
+     * The principal Uri
+     *
+     * @var string
+     */
+    protected $principalUri;
+
+    /**
+     * Constructor
+     *
+     * @param string $principalUri
+     */
+    function __construct($principalUri) {
+
+        $this->principalUri = $principalUri;
+
+    }
+
+    /**
+     * Returns the name of the node.
+     *
+     * This is used to generate the url.
+     *
+     * @return string
+     */
+    function getName() {
+
+        return 'outbox';
+
+    }
+
+    /**
+     * Returns an array with all the child nodes
+     *
+     * @return \Sabre\DAV\INode[]
+     */
+    function getChildren() {
+
+        return [];
+
+    }
+
+    /**
+     * Returns the owner principal
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    function getOwner() {
+
+        return $this->principalUri;
+
+    }
+
+    /**
+     * Returns a group principal
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    function getGroup() {
+
+        return null;
+
+    }
+
+    /**
+     * Returns a list of ACE's for this node.
+     *
+     * Each ACE has the following properties:
+     *   * 'privilege', a string such as {DAV:}read or {DAV:}write. These are
+     *     currently the only supported privileges
+     *   * 'principal', a url to the principal who owns the node
+     *   * 'protected' (optional), indicating that this ACE is not allowed to
+     *      be updated.
+     *
+     * @return array
+     */
+    function getACL() {
+
+        return [
+            [
+                'privilege' => '{' . CalDAV\Plugin::NS_CALDAV . '}schedule-query-freebusy',
+                'principal' => $this->getOwner(),
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{' . CalDAV\Plugin::NS_CALDAV . '}schedule-post-vevent',
+                'principal' => $this->getOwner(),
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{DAV:}read',
+                'principal' => $this->getOwner(),
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{' . CalDAV\Plugin::NS_CALDAV . '}schedule-query-freebusy',
+                'principal' => $this->getOwner() . '/calendar-proxy-write',
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{' . CalDAV\Plugin::NS_CALDAV . '}schedule-post-vevent',
+                'principal' => $this->getOwner() . '/calendar-proxy-write',
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{DAV:}read',
+                'principal' => $this->getOwner() . '/calendar-proxy-read',
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{DAV:}read',
+                'principal' => $this->getOwner() . '/calendar-proxy-write',
+                'protected' => true,
+            ],
+        ];
+
+    }
+
+    /**
+     * Updates the ACL
+     *
+     * This method will receive a list of new ACE's.
+     *
+     * @param array $acl
+     * @return void
+     */
+    function setACL(array $acl) {
+
+        throw new DAV\Exception\MethodNotAllowed('You\'re not allowed to update the ACL');
+
+    }
+
+    /**
+     * Returns the list of supported privileges for this node.
+     *
+     * The returned data structure is a list of nested privileges.
+     * See Sabre\DAVACL\Plugin::getDefaultSupportedPrivilegeSet for a simple
+     * standard structure.
+     *
+     * If null is returned from this method, the default privilege set is used,
+     * which is fine for most common usecases.
+     *
+     * @return array|null
+     */
+    function getSupportedPrivilegeSet() {
+
+        $default = DAVACL\Plugin::getDefaultSupportedPrivilegeSet();
+        $default['aggregates'][] = [
+            'privilege' => '{' . CalDAV\Plugin::NS_CALDAV . '}schedule-query-freebusy',
+        ];
+        $default['aggregates'][] = [
+            'privilege' => '{' . CalDAV\Plugin::NS_CALDAV . '}schedule-post-vevent',
+        ];
+
+        return $default;
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/CalDAV/Schedule/Plugin.php b/vendor/sabre/dav/lib/CalDAV/Schedule/Plugin.php
new file mode 100644
index 000000000..827d6209b
--- /dev/null
+++ b/vendor/sabre/dav/lib/CalDAV/Schedule/Plugin.php
@@ -0,0 +1,994 @@
+<?php
+
+namespace Sabre\CalDAV\Schedule;
+
+use DateTimeZone;
+use Sabre\DAV\Server;
+use Sabre\DAV\ServerPlugin;
+use Sabre\DAV\PropFind;
+use Sabre\DAV\PropPatch;
+use Sabre\DAV\INode;
+use Sabre\DAV\Xml\Property\Href;
+use Sabre\HTTP\RequestInterface;
+use Sabre\HTTP\ResponseInterface;
+use Sabre\VObject;
+use Sabre\VObject\Reader;
+use Sabre\VObject\Component\VCalendar;
+use Sabre\VObject\ITip;
+use Sabre\VObject\ITip\Message;
+use Sabre\DAVACL;
+use Sabre\CalDAV\ICalendar;
+use Sabre\CalDAV\ICalendarObject;
+use Sabre\CalDAV\Xml\Property\ScheduleCalendarTransp;
+use Sabre\DAV\Exception\NotFound;
+use Sabre\DAV\Exception\Forbidden;
+use Sabre\DAV\Exception\BadRequest;
+use Sabre\DAV\Exception\NotImplemented;
+
+/**
+ * CalDAV scheduling plugin.
+ * =========================
+ *
+ * This plugin provides the functionality added by the "Scheduling Extensions
+ * to CalDAV" standard, as defined in RFC6638.
+ *
+ * calendar-auto-schedule largely works by intercepting a users request to
+ * update their local calendar. If a user creates a new event with attendees,
+ * this plugin is supposed to grab the information from that event, and notify
+ * the attendees of this.
+ *
+ * There's 3 possible transports for this:
+ * * local delivery
+ * * delivery through email (iMip)
+ * * server-to-server delivery (iSchedule)
+ *
+ * iMip is simply, because we just need to add the iTip message as an email
+ * attachment. Local delivery is harder, because we both need to add this same
+ * message to a local DAV inbox, as well as live-update the relevant events.
+ *
+ * iSchedule is something for later.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class Plugin extends ServerPlugin {
+
+    /**
+     * This is the official CalDAV namespace
+     */
+    const NS_CALDAV = 'urn:ietf:params:xml:ns:caldav';
+
+    /**
+     * Reference to main Server object.
+     *
+     * @var Server
+     */
+    protected $server;
+
+    /**
+     * Returns a list of features for the DAV: HTTP header.
+     *
+     * @return array
+     */
+    function getFeatures() {
+
+        return ['calendar-auto-schedule', 'calendar-availability'];
+
+    }
+
+    /**
+     * Returns the name of the plugin.
+     *
+     * Using this name other plugins will be able to access other plugins
+     * using Server::getPlugin
+     *
+     * @return string
+     */
+    function getPluginName() {
+
+        return 'caldav-schedule';
+
+    }
+
+    /**
+     * Initializes the plugin
+     *
+     * @param Server $server
+     * @return void
+     */
+    function initialize(Server $server) {
+
+        $this->server = $server;
+        $server->on('method:POST',          [$this, 'httpPost']);
+        $server->on('propFind',             [$this, 'propFind']);
+        $server->on('propPatch',            [$this, 'propPatch']);
+        $server->on('calendarObjectChange', [$this, 'calendarObjectChange']);
+        $server->on('beforeUnbind',         [$this, 'beforeUnbind']);
+        $server->on('schedule',             [$this, 'scheduleLocalDelivery']);
+
+        $ns = '{' . self::NS_CALDAV . '}';
+
+        /**
+         * This information ensures that the {DAV:}resourcetype property has
+         * the correct values.
+         */
+        $server->resourceTypeMapping['\\Sabre\\CalDAV\\Schedule\\IOutbox'] = $ns . 'schedule-outbox';
+        $server->resourceTypeMapping['\\Sabre\\CalDAV\\Schedule\\IInbox'] = $ns . 'schedule-inbox';
+
+        /**
+         * Properties we protect are made read-only by the server.
+         */
+        array_push($server->protectedProperties,
+            $ns . 'schedule-inbox-URL',
+            $ns . 'schedule-outbox-URL',
+            $ns . 'calendar-user-address-set',
+            $ns . 'calendar-user-type',
+            $ns . 'schedule-default-calendar-URL'
+        );
+
+    }
+
+    /**
+     * Use this method to tell the server this plugin defines additional
+     * HTTP methods.
+     *
+     * This method is passed a uri. It should only return HTTP methods that are
+     * available for the specified uri.
+     *
+     * @param string $uri
+     * @return array
+     */
+    function getHTTPMethods($uri) {
+
+        try {
+            $node = $this->server->tree->getNodeForPath($uri);
+        } catch (NotFound $e) {
+            return [];
+        }
+
+        if ($node instanceof IOutbox) {
+            return ['POST'];
+        }
+
+        return [];
+
+    }
+
+    /**
+     * This method handles POST request for the outbox.
+     *
+     * @param RequestInterface $request
+     * @param ResponseInterface $response
+     * @return bool
+     */
+    function httpPost(RequestInterface $request, ResponseInterface $response) {
+
+        // Checking if this is a text/calendar content type
+        $contentType = $request->getHeader('Content-Type');
+        if (strpos($contentType, 'text/calendar') !== 0) {
+            return;
+        }
+
+        $path = $request->getPath();
+
+        // Checking if we're talking to an outbox
+        try {
+            $node = $this->server->tree->getNodeForPath($path);
+        } catch (NotFound $e) {
+            return;
+        }
+        if (!$node instanceof IOutbox)
+            return;
+
+        $this->server->transactionType = 'post-caldav-outbox';
+        $this->outboxRequest($node, $request, $response);
+
+        // Returning false breaks the event chain and tells the server we've
+        // handled the request.
+        return false;
+
+    }
+
+    /**
+     * This method handler is invoked during fetching of properties.
+     *
+     * We use this event to add calendar-auto-schedule-specific properties.
+     *
+     * @param PropFind $propFind
+     * @param INode $node
+     * @return void
+     */
+    function propFind(PropFind $propFind, INode $node) {
+
+        if ($node instanceof DAVACL\IPrincipal) {
+
+            $caldavPlugin = $this->server->getPlugin('caldav');
+            $principalUrl = $node->getPrincipalUrl();
+
+            // schedule-outbox-URL property
+            $propFind->handle('{' . self::NS_CALDAV . '}schedule-outbox-URL', function() use ($principalUrl, $caldavPlugin) {
+
+                $calendarHomePath = $caldavPlugin->getCalendarHomeForPrincipal($principalUrl);
+                if (!$calendarHomePath) {
+                    return null;
+                }
+                $outboxPath = $calendarHomePath . '/outbox/';
+
+                return new Href($outboxPath);
+
+            });
+            // schedule-inbox-URL property
+            $propFind->handle('{' . self::NS_CALDAV . '}schedule-inbox-URL', function() use ($principalUrl, $caldavPlugin) {
+
+                $calendarHomePath = $caldavPlugin->getCalendarHomeForPrincipal($principalUrl);
+                if (!$calendarHomePath) {
+                    return null;
+                }
+                $inboxPath = $calendarHomePath . '/inbox/';
+
+                return new Href($inboxPath);
+
+            });
+
+            $propFind->handle('{' . self::NS_CALDAV . '}schedule-default-calendar-URL', function() use ($principalUrl, $caldavPlugin) {
+
+                // We don't support customizing this property yet, so in the
+                // meantime we just grab the first calendar in the home-set.
+                $calendarHomePath = $caldavPlugin->getCalendarHomeForPrincipal($principalUrl);
+
+                if (!$calendarHomePath) {
+                    return null;
+                }
+
+                $sccs = '{' . self::NS_CALDAV . '}supported-calendar-component-set';
+
+                $result = $this->server->getPropertiesForPath($calendarHomePath, [
+                    '{DAV:}resourcetype',
+                    $sccs,
+                ], 1);
+
+                foreach ($result as $child) {
+                    if (!isset($child[200]['{DAV:}resourcetype']) || !$child[200]['{DAV:}resourcetype']->is('{' . self::NS_CALDAV . '}calendar') || $child[200]['{DAV:}resourcetype']->is('{http://calendarserver.org/ns/}shared')) {
+                        // Node is either not a calendar or a shared instance.
+                        continue;
+                    }
+                    if (!isset($child[200][$sccs]) || in_array('VEVENT', $child[200][$sccs]->getValue())) {
+                        // Either there is no supported-calendar-component-set
+                        // (which is fine) or we found one that supports VEVENT.
+                        return new Href($child['href']);
+                    }
+                }
+
+            });
+
+            // The server currently reports every principal to be of type
+            // 'INDIVIDUAL'
+            $propFind->handle('{' . self::NS_CALDAV . '}calendar-user-type', function() {
+
+                return 'INDIVIDUAL';
+
+            });
+
+        }
+
+        // Mapping the old property to the new property.
+        $propFind->handle('{http://calendarserver.org/ns/}calendar-availability', function() use ($propFind, $node) {
+
+             // In case it wasn't clear, the only difference is that we map the
+            // old property to a different namespace.
+             $availProp = '{' . self::NS_CALDAV . '}calendar-availability';
+             $subPropFind = new PropFind(
+                 $propFind->getPath(),
+                 [$availProp]
+             );
+
+             $this->server->getPropertiesByNode(
+                 $subPropFind,
+                 $node
+             );
+
+             $propFind->set(
+                 '{http://calendarserver.org/ns/}calendar-availability',
+                 $subPropFind->get($availProp),
+                 $subPropFind->getStatus($availProp)
+             );
+
+        });
+
+    }
+
+    /**
+     * This method is called during property updates.
+     *
+     * @param string $path
+     * @param PropPatch $propPatch
+     * @return void
+     */
+    function propPatch($path, PropPatch $propPatch) {
+
+        // Mapping the old property to the new property.
+        $propPatch->handle('{http://calendarserver.org/ns/}calendar-availability', function($value) use ($path) {
+
+            $availProp = '{' . self::NS_CALDAV . '}calendar-availability';
+            $subPropPatch = new PropPatch([$availProp => $value]);
+            $this->server->emit('propPatch', [$path, $subPropPatch]);
+            $subPropPatch->commit();
+
+            return $subPropPatch->getResult()[$availProp];
+
+        });
+
+    }
+
+    /**
+     * This method is triggered whenever there was a calendar object gets
+     * created or updated.
+     *
+     * @param RequestInterface $request HTTP request
+     * @param ResponseInterface $response HTTP Response
+     * @param VCalendar $vCal Parsed iCalendar object
+     * @param mixed $calendarPath Path to calendar collection
+     * @param mixed $modified The iCalendar object has been touched.
+     * @param mixed $isNew Whether this was a new item or we're updating one
+     * @return void
+     */
+    function calendarObjectChange(RequestInterface $request, ResponseInterface $response, VCalendar $vCal, $calendarPath, &$modified, $isNew) {
+
+        if (!$this->scheduleReply($this->server->httpRequest)) {
+            return;
+        }
+
+        $calendarNode = $this->server->tree->getNodeForPath($calendarPath);
+
+        $addresses = $this->getAddressesForPrincipal(
+            $calendarNode->getOwner()
+        );
+
+        if (!$isNew) {
+            $node = $this->server->tree->getNodeForPath($request->getPath());
+            $oldObj = Reader::read($node->get());
+        } else {
+            $oldObj = null;
+        }
+
+        $this->processICalendarChange($oldObj, $vCal, $addresses, [], $modified);
+
+        if ($oldObj) {
+            // Destroy circular references so PHP will GC the object.
+            $oldObj->destroy();
+        }
+
+    }
+
+    /**
+     * This method is responsible for delivering the ITip message.
+     *
+     * @param ITip\Message $itipMessage
+     * @return void
+     */
+    function deliver(ITip\Message $iTipMessage) {
+
+        $this->server->emit('schedule', [$iTipMessage]);
+        if (!$iTipMessage->scheduleStatus) {
+            $iTipMessage->scheduleStatus = '5.2;There was no system capable of delivering the scheduling message';
+        }
+        // In case the change was considered 'insignificant', we are going to
+        // remove any error statuses, if any. See ticket #525.
+        list($baseCode) = explode('.', $iTipMessage->scheduleStatus);
+        if (!$iTipMessage->significantChange && in_array($baseCode, ['3', '5'])) {
+            $iTipMessage->scheduleStatus = null;
+        }
+
+    }
+
+    /**
+     * This method is triggered before a file gets deleted.
+     *
+     * We use this event to make sure that when this happens, attendees get
+     * cancellations, and organizers get 'DECLINED' statuses.
+     *
+     * @param string $path
+     * @return void
+     */
+    function beforeUnbind($path) {
+
+        // FIXME: We shouldn't trigger this functionality when we're issuing a
+        // MOVE. This is a hack.
+        if ($this->server->httpRequest->getMethod() === 'MOVE') return;
+
+        $node = $this->server->tree->getNodeForPath($path);
+
+        if (!$node instanceof ICalendarObject || $node instanceof ISchedulingObject) {
+            return;
+        }
+
+        if (!$this->scheduleReply($this->server->httpRequest)) {
+            return;
+        }
+
+        $addresses = $this->getAddressesForPrincipal(
+            $node->getOwner()
+        );
+
+        $broker = new ITip\Broker();
+        $messages = $broker->parseEvent(null, $addresses, $node->get());
+
+        foreach ($messages as $message) {
+            $this->deliver($message);
+        }
+
+    }
+
+    /**
+     * Event handler for the 'schedule' event.
+     *
+     * This handler attempts to look at local accounts to deliver the
+     * scheduling object.
+     *
+     * @param ITip\Message $iTipMessage
+     * @return void
+     */
+    function scheduleLocalDelivery(ITip\Message $iTipMessage) {
+
+        $aclPlugin = $this->server->getPlugin('acl');
+
+        // Local delivery is not available if the ACL plugin is not loaded.
+        if (!$aclPlugin) {
+            return;
+        }
+
+        $caldavNS = '{' . self::NS_CALDAV . '}';
+
+        $principalUri = $aclPlugin->getPrincipalByUri($iTipMessage->recipient);
+        if (!$principalUri) {
+            $iTipMessage->scheduleStatus = '3.7;Could not find principal.';
+            return;
+        }
+
+        // We found a principal URL, now we need to find its inbox.
+        // Unfortunately we may not have sufficient privileges to find this, so
+        // we are temporarily turning off ACL to let this come through.
+        //
+        // Once we support PHP 5.5, this should be wrapped in a try..finally
+        // block so we can ensure that this privilege gets added again after.
+        $this->server->removeListener('propFind', [$aclPlugin, 'propFind']);
+
+        $result = $this->server->getProperties(
+            $principalUri,
+            [
+                '{DAV:}principal-URL',
+                 $caldavNS . 'calendar-home-set',
+                 $caldavNS . 'schedule-inbox-URL',
+                 $caldavNS . 'schedule-default-calendar-URL',
+                '{http://sabredav.org/ns}email-address',
+            ]
+        );
+
+        // Re-registering the ACL event
+        $this->server->on('propFind', [$aclPlugin, 'propFind'], 20);
+
+        if (!isset($result[$caldavNS . 'schedule-inbox-URL'])) {
+            $iTipMessage->scheduleStatus = '5.2;Could not find local inbox';
+            return;
+        }
+        if (!isset($result[$caldavNS . 'calendar-home-set'])) {
+            $iTipMessage->scheduleStatus = '5.2;Could not locate a calendar-home-set';
+            return;
+        }
+        if (!isset($result[$caldavNS . 'schedule-default-calendar-URL'])) {
+            $iTipMessage->scheduleStatus = '5.2;Could not find a schedule-default-calendar-URL property';
+            return;
+        }
+
+        $calendarPath = $result[$caldavNS . 'schedule-default-calendar-URL']->getHref();
+        $homePath = $result[$caldavNS . 'calendar-home-set']->getHref();
+        $inboxPath = $result[$caldavNS . 'schedule-inbox-URL']->getHref();
+
+        if ($iTipMessage->method === 'REPLY') {
+            $privilege = 'schedule-deliver-reply';
+        } else {
+            $privilege = 'schedule-deliver-invite';
+        }
+
+        if (!$aclPlugin->checkPrivileges($inboxPath, $caldavNS . $privilege, DAVACL\Plugin::R_PARENT, false)) {
+            $iTipMessage->scheduleStatus = '3.8;organizer did not have the ' . $privilege . ' privilege on the attendees inbox';
+            return;
+        }
+
+        // Next, we're going to find out if the item already exits in one of
+        // the users' calendars.
+        $uid = $iTipMessage->uid;
+
+        $newFileName = 'sabredav-' . \Sabre\DAV\UUIDUtil::getUUID() . '.ics';
+
+        $home = $this->server->tree->getNodeForPath($homePath);
+        $inbox = $this->server->tree->getNodeForPath($inboxPath);
+
+        $currentObject = null;
+        $objectNode = null;
+        $isNewNode = false;
+
+        $result = $home->getCalendarObjectByUID($uid);
+        if ($result) {
+            // There was an existing object, we need to update probably.
+            $objectPath = $homePath . '/' . $result;
+            $objectNode = $this->server->tree->getNodeForPath($objectPath);
+            $oldICalendarData = $objectNode->get();
+            $currentObject = Reader::read($oldICalendarData);
+        } else {
+            $isNewNode = true;
+        }
+
+        $broker = new ITip\Broker();
+        $newObject = $broker->processMessage($iTipMessage, $currentObject);
+
+        $inbox->createFile($newFileName, $iTipMessage->message->serialize());
+
+        if (!$newObject) {
+            // We received an iTip message referring to a UID that we don't
+            // have in any calendars yet, and processMessage did not give us a
+            // calendarobject back.
+            //
+            // The implication is that processMessage did not understand the
+            // iTip message.
+            $iTipMessage->scheduleStatus = '5.0;iTip message was not processed by the server, likely because we didn\'t understand it.';
+            return;
+        }
+
+        // Note that we are bypassing ACL on purpose by calling this directly.
+        // We may need to look a bit deeper into this later. Supporting ACL
+        // here would be nice.
+        if ($isNewNode) {
+            $calendar = $this->server->tree->getNodeForPath($calendarPath);
+            $calendar->createFile($newFileName, $newObject->serialize());
+        } else {
+            // If the message was a reply, we may have to inform other
+            // attendees of this attendees status. Therefore we're shooting off
+            // another itipMessage.
+            if ($iTipMessage->method === 'REPLY') {
+                $this->processICalendarChange(
+                    $oldICalendarData,
+                    $newObject,
+                    [$iTipMessage->recipient],
+                    [$iTipMessage->sender]
+                );
+            }
+            $objectNode->put($newObject->serialize());
+        }
+        $iTipMessage->scheduleStatus = '1.2;Message delivered locally';
+
+    }
+
+    /**
+     * This method looks at an old iCalendar object, a new iCalendar object and
+     * starts sending scheduling messages based on the changes.
+     *
+     * A list of addresses needs to be specified, so the system knows who made
+     * the update, because the behavior may be different based on if it's an
+     * attendee or an organizer.
+     *
+     * This method may update $newObject to add any status changes.
+     *
+     * @param VCalendar|string $oldObject
+     * @param VCalendar $newObject
+     * @param array $addresses
+     * @param array $ignore Any addresses to not send messages to.
+     * @param bool $modified A marker to indicate that the original object
+     *   modified by this process.
+     * @return void
+     */
+    protected function processICalendarChange($oldObject = null, VCalendar $newObject, array $addresses, array $ignore = [], &$modified = false) {
+
+        $broker = new ITip\Broker();
+        $messages = $broker->parseEvent($newObject, $addresses, $oldObject);
+
+        if ($messages) $modified = true;
+
+        foreach ($messages as $message) {
+
+            if (in_array($message->recipient, $ignore)) {
+                continue;
+            }
+
+            $this->deliver($message);
+
+            if (isset($newObject->VEVENT->ORGANIZER) && ($newObject->VEVENT->ORGANIZER->getNormalizedValue() === $message->recipient)) {
+                if ($message->scheduleStatus) {
+                    $newObject->VEVENT->ORGANIZER['SCHEDULE-STATUS'] = $message->getScheduleStatus();
+                }
+                unset($newObject->VEVENT->ORGANIZER['SCHEDULE-FORCE-SEND']);
+
+            } else {
+
+                if (isset($newObject->VEVENT->ATTENDEE)) foreach ($newObject->VEVENT->ATTENDEE as $attendee) {
+
+                    if ($attendee->getNormalizedValue() === $message->recipient) {
+                        if ($message->scheduleStatus) {
+                            $attendee['SCHEDULE-STATUS'] = $message->getScheduleStatus();
+                        }
+                        unset($attendee['SCHEDULE-FORCE-SEND']);
+                        break;
+                    }
+
+                }
+
+            }
+
+        }
+
+    }
+
+    /**
+     * Returns a list of addresses that are associated with a principal.
+     *
+     * @param string $principal
+     * @return array
+     */
+    protected function getAddressesForPrincipal($principal) {
+
+        $CUAS = '{' . self::NS_CALDAV . '}calendar-user-address-set';
+
+        $properties = $this->server->getProperties(
+            $principal,
+            [$CUAS]
+        );
+
+        // If we can't find this information, we'll stop processing
+        if (!isset($properties[$CUAS])) {
+            return;
+        }
+
+        $addresses = $properties[$CUAS]->getHrefs();
+        return $addresses;
+
+    }
+
+    /**
+     * This method handles POST requests to the schedule-outbox.
+     *
+     * Currently, two types of requests are support:
+     *   * FREEBUSY requests from RFC 6638
+     *   * Simple iTIP messages from draft-desruisseaux-caldav-sched-04
+     *
+     * The latter is from an expired early draft of the CalDAV scheduling
+     * extensions, but iCal depends on a feature from that spec, so we
+     * implement it.
+     *
+     * @param IOutbox $outboxNode
+     * @param RequestInterface $request
+     * @param ResponseInterface $response
+     * @return void
+     */
+    function outboxRequest(IOutbox $outboxNode, RequestInterface $request, ResponseInterface $response) {
+
+        $outboxPath = $request->getPath();
+
+        // Parsing the request body
+        try {
+            $vObject = VObject\Reader::read($request->getBody());
+        } catch (VObject\ParseException $e) {
+            throw new BadRequest('The request body must be a valid iCalendar object. Parse error: ' . $e->getMessage());
+        }
+
+        // The incoming iCalendar object must have a METHOD property, and a
+        // component. The combination of both determines what type of request
+        // this is.
+        $componentType = null;
+        foreach ($vObject->getComponents() as $component) {
+            if ($component->name !== 'VTIMEZONE') {
+                $componentType = $component->name;
+                break;
+            }
+        }
+        if (is_null($componentType)) {
+            throw new BadRequest('We expected at least one VTODO, VJOURNAL, VFREEBUSY or VEVENT component');
+        }
+
+        // Validating the METHOD
+        $method = strtoupper((string)$vObject->METHOD);
+        if (!$method) {
+            throw new BadRequest('A METHOD property must be specified in iTIP messages');
+        }
+
+        // So we support one type of request:
+        //
+        // REQUEST with a VFREEBUSY component
+
+        $acl = $this->server->getPlugin('acl');
+
+        if ($componentType === 'VFREEBUSY' && $method === 'REQUEST') {
+
+            $acl && $acl->checkPrivileges($outboxPath, '{' . self::NS_CALDAV . '}schedule-query-freebusy');
+            $this->handleFreeBusyRequest($outboxNode, $vObject, $request, $response);
+
+            // Destroy circular references so PHP can GC the object.
+            $vObject->destroy();
+            unset($vObject);
+
+        } else {
+
+            throw new NotImplemented('We only support VFREEBUSY (REQUEST) on this endpoint');
+
+        }
+
+    }
+
+    /**
+     * This method is responsible for parsing a free-busy query request and
+     * returning it's result.
+     *
+     * @param IOutbox $outbox
+     * @param VObject\Component $vObject
+     * @param RequestInterface $request
+     * @param ResponseInterface $response
+     * @return string
+     */
+    protected function handleFreeBusyRequest(IOutbox $outbox, VObject\Component $vObject, RequestInterface $request, ResponseInterface $response) {
+
+        $vFreeBusy = $vObject->VFREEBUSY;
+        $organizer = $vFreeBusy->organizer;
+
+        $organizer = (string)$organizer;
+
+        // Validating if the organizer matches the owner of the inbox.
+        $owner = $outbox->getOwner();
+
+        $caldavNS = '{' . self::NS_CALDAV . '}';
+
+        $uas = $caldavNS . 'calendar-user-address-set';
+        $props = $this->server->getProperties($owner, [$uas]);
+
+        if (empty($props[$uas]) || !in_array($organizer, $props[$uas]->getHrefs())) {
+            throw new Forbidden('The organizer in the request did not match any of the addresses for the owner of this inbox');
+        }
+
+        if (!isset($vFreeBusy->ATTENDEE)) {
+            throw new BadRequest('You must at least specify 1 attendee');
+        }
+
+        $attendees = [];
+        foreach ($vFreeBusy->ATTENDEE as $attendee) {
+            $attendees[] = (string)$attendee;
+        }
+
+
+        if (!isset($vFreeBusy->DTSTART) || !isset($vFreeBusy->DTEND)) {
+            throw new BadRequest('DTSTART and DTEND must both be specified');
+        }
+
+        $startRange = $vFreeBusy->DTSTART->getDateTime();
+        $endRange = $vFreeBusy->DTEND->getDateTime();
+
+        $results = [];
+        foreach ($attendees as $attendee) {
+            $results[] = $this->getFreeBusyForEmail($attendee, $startRange, $endRange, $vObject);
+        }
+
+        $dom = new \DOMDocument('1.0', 'utf-8');
+        $dom->formatOutput = true;
+        $scheduleResponse = $dom->createElement('cal:schedule-response');
+        foreach ($this->server->xml->namespaceMap as $namespace => $prefix) {
+
+            $scheduleResponse->setAttribute('xmlns:' . $prefix, $namespace);
+
+        }
+        $dom->appendChild($scheduleResponse);
+
+        foreach ($results as $result) {
+            $xresponse = $dom->createElement('cal:response');
+
+            $recipient = $dom->createElement('cal:recipient');
+            $recipientHref = $dom->createElement('d:href');
+
+            $recipientHref->appendChild($dom->createTextNode($result['href']));
+            $recipient->appendChild($recipientHref);
+            $xresponse->appendChild($recipient);
+
+            $reqStatus = $dom->createElement('cal:request-status');
+            $reqStatus->appendChild($dom->createTextNode($result['request-status']));
+            $xresponse->appendChild($reqStatus);
+
+            if (isset($result['calendar-data'])) {
+
+                $calendardata = $dom->createElement('cal:calendar-data');
+                $calendardata->appendChild($dom->createTextNode(str_replace("\r\n", "\n", $result['calendar-data']->serialize())));
+                $xresponse->appendChild($calendardata);
+
+            }
+            $scheduleResponse->appendChild($xresponse);
+        }
+
+        $response->setStatus(200);
+        $response->setHeader('Content-Type', 'application/xml');
+        $response->setBody($dom->saveXML());
+
+    }
+
+    /**
+     * Returns free-busy information for a specific address. The returned
+     * data is an array containing the following properties:
+     *
+     * calendar-data : A VFREEBUSY VObject
+     * request-status : an iTip status code.
+     * href: The principal's email address, as requested
+     *
+     * The following request status codes may be returned:
+     *   * 2.0;description
+     *   * 3.7;description
+     *
+     * @param string $email address
+     * @param DateTimeInterface $start
+     * @param DateTimeInterface $end
+     * @param VObject\Component $request
+     * @return array
+     */
+    protected function getFreeBusyForEmail($email, \DateTimeInterface $start, \DateTimeInterface $end, VObject\Component $request) {
+
+        $caldavNS = '{' . self::NS_CALDAV . '}';
+
+        $aclPlugin = $this->server->getPlugin('acl');
+        if (substr($email, 0, 7) === 'mailto:') $email = substr($email, 7);
+
+        $result = $aclPlugin->principalSearch(
+            ['{http://sabredav.org/ns}email-address' => $email],
+            [
+                '{DAV:}principal-URL',
+                $caldavNS . 'calendar-home-set',
+                $caldavNS . 'schedule-inbox-URL',
+                '{http://sabredav.org/ns}email-address',
+
+            ]
+        );
+
+        if (!count($result)) {
+            return [
+                'request-status' => '3.7;Could not find principal',
+                'href'           => 'mailto:' . $email,
+            ];
+        }
+
+        if (!isset($result[0][200][$caldavNS . 'calendar-home-set'])) {
+            return [
+                'request-status' => '3.7;No calendar-home-set property found',
+                'href'           => 'mailto:' . $email,
+            ];
+        }
+        if (!isset($result[0][200][$caldavNS . 'schedule-inbox-URL'])) {
+            return [
+                'request-status' => '3.7;No schedule-inbox-URL property found',
+                'href'           => 'mailto:' . $email,
+            ];
+        }
+        $homeSet = $result[0][200][$caldavNS . 'calendar-home-set']->getHref();
+        $inboxUrl = $result[0][200][$caldavNS . 'schedule-inbox-URL']->getHref();
+
+        // Grabbing the calendar list
+        $objects = [];
+        $calendarTimeZone = new DateTimeZone('UTC');
+
+        foreach ($this->server->tree->getNodeForPath($homeSet)->getChildren() as $node) {
+            if (!$node instanceof ICalendar) {
+                continue;
+            }
+
+            $sct = $caldavNS . 'schedule-calendar-transp';
+            $ctz = $caldavNS . 'calendar-timezone';
+            $props = $node->getProperties([$sct, $ctz]);
+
+            if (isset($props[$sct]) && $props[$sct]->getValue() == ScheduleCalendarTransp::TRANSPARENT) {
+                // If a calendar is marked as 'transparent', it means we must
+                // ignore it for free-busy purposes.
+                continue;
+            }
+
+            $aclPlugin->checkPrivileges($homeSet . $node->getName(), $caldavNS . 'read-free-busy');
+
+            if (isset($props[$ctz])) {
+                $vtimezoneObj = VObject\Reader::read($props[$ctz]);
+                $calendarTimeZone = $vtimezoneObj->VTIMEZONE->getTimeZone();
+
+                // Destroy circular references so PHP can garbage collect the object.
+                $vtimezoneObj->destroy();
+
+            }
+
+            // Getting the list of object uris within the time-range
+            $urls = $node->calendarQuery([
+                'name'         => 'VCALENDAR',
+                'comp-filters' => [
+                    [
+                        'name'           => 'VEVENT',
+                        'comp-filters'   => [],
+                        'prop-filters'   => [],
+                        'is-not-defined' => false,
+                        'time-range'     => [
+                            'start' => $start,
+                            'end'   => $end,
+                        ],
+                    ],
+                ],
+                'prop-filters'   => [],
+                'is-not-defined' => false,
+                'time-range'     => null,
+            ]);
+
+            $calObjects = array_map(function($url) use ($node) {
+                $obj = $node->getChild($url)->get();
+                return $obj;
+            }, $urls);
+
+            $objects = array_merge($objects, $calObjects);
+
+        }
+
+        $inboxProps = $this->server->getProperties(
+            $inboxUrl,
+            $caldavNS . 'calendar-availability'
+        );
+
+        $vcalendar = new VObject\Component\VCalendar();
+        $vcalendar->METHOD = 'REPLY';
+
+        $generator = new VObject\FreeBusyGenerator();
+        $generator->setObjects($objects);
+        $generator->setTimeRange($start, $end);
+        $generator->setBaseObject($vcalendar);
+        $generator->setTimeZone($calendarTimeZone);
+
+        if ($inboxProps) {
+            $generator->setVAvailability(
+                VObject\Reader::read(
+                    $inboxProps[$caldavNS . 'calendar-availability']
+                )
+            );
+        }
+
+        $result = $generator->getResult();
+
+        $vcalendar->VFREEBUSY->ATTENDEE = 'mailto:' . $email;
+        $vcalendar->VFREEBUSY->UID = (string)$request->VFREEBUSY->UID;
+        $vcalendar->VFREEBUSY->ORGANIZER = clone $request->VFREEBUSY->ORGANIZER;
+
+        return [
+            'calendar-data'  => $result,
+            'request-status' => '2.0;Success',
+            'href'           => 'mailto:' . $email,
+        ];
+    }
+
+    /**
+     * This method checks the 'Schedule-Reply' header
+     * and returns false if it's 'F', otherwise true.
+     *
+     * @param RequestInterface $request
+     * @return bool
+     */
+    private function scheduleReply(RequestInterface $request) {
+
+        $scheduleReply = $request->getHeader('Schedule-Reply');
+        return $scheduleReply !== 'F';
+
+    }
+
+    /**
+     * Returns a bunch of meta-data about the plugin.
+     *
+     * Providing this information is optional, and is mainly displayed by the
+     * Browser plugin.
+     *
+     * The description key in the returned array may contain html and will not
+     * be sanitized.
+     *
+     * @return array
+     */
+    function getPluginInfo() {
+
+        return [
+            'name'        => $this->getPluginName(),
+            'description' => 'Adds calendar-auto-schedule, as defined in rf6868',
+            'link'        => 'http://sabre.io/dav/scheduling/',
+        ];
+
+    }
+}
diff --git a/vendor/sabre/dav/lib/CalDAV/Schedule/SchedulingObject.php b/vendor/sabre/dav/lib/CalDAV/Schedule/SchedulingObject.php
new file mode 100644
index 000000000..a36646e6c
--- /dev/null
+++ b/vendor/sabre/dav/lib/CalDAV/Schedule/SchedulingObject.php
@@ -0,0 +1,165 @@
+<?php
+
+namespace Sabre\CalDAV\Schedule;
+
+use Sabre\CalDAV\Backend;
+use Sabre\DAV\Exception\MethodNotAllowed;
+
+/**
+ * The SchedulingObject represents a scheduling object in the Inbox collection
+ *
+ * @author Brett (https://github.com/bretten)
+ * @license http://sabre.io/license/ Modified BSD License
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ */
+class SchedulingObject extends \Sabre\CalDAV\CalendarObject implements ISchedulingObject {
+
+    /**
+     /* The CalDAV backend
+     *
+     * @var Backend\SchedulingSupport
+     */
+    protected $caldavBackend;
+
+    /**
+     * Array with information about this SchedulingObject
+     *
+     * @var array
+     */
+    protected $objectData;
+
+    /**
+     * Constructor
+     *
+     * The following properties may be passed within $objectData:
+     *
+     *   * uri - A unique uri. Only the 'basename' must be passed.
+     *   * principaluri - the principal that owns the object.
+     *   * calendardata (optional) - The iCalendar data
+     *   * etag - (optional) The etag for this object, MUST be encloded with
+     *            double-quotes.
+     *   * size - (optional) The size of the data in bytes.
+     *   * lastmodified - (optional) format as a unix timestamp.
+     *   * acl - (optional) Use this to override the default ACL for the node.
+     *
+     * @param Backend\BackendInterface $caldavBackend
+     * @param array $objectData
+     */
+    function __construct(Backend\SchedulingSupport $caldavBackend, array $objectData) {
+
+        $this->caldavBackend = $caldavBackend;
+
+        if (!isset($objectData['uri'])) {
+            throw new \InvalidArgumentException('The objectData argument must contain an \'uri\' property');
+        }
+
+        $this->objectData = $objectData;
+
+    }
+
+    /**
+     * Returns the ICalendar-formatted object
+     *
+     * @return string
+     */
+    function get() {
+
+        // Pre-populating the 'calendardata' is optional, if we don't have it
+        // already we fetch it from the backend.
+        if (!isset($this->objectData['calendardata'])) {
+            $this->objectData = $this->caldavBackend->getSchedulingObject($this->objectData['principaluri'], $this->objectData['uri']);
+        }
+        return $this->objectData['calendardata'];
+
+    }
+
+    /**
+     * Updates the ICalendar-formatted object
+     *
+     * @param string|resource $calendarData
+     * @return string
+     */
+    function put($calendarData) {
+
+        throw new MethodNotAllowed('Updating scheduling objects is not supported');
+
+    }
+
+    /**
+     * Deletes the scheduling message
+     *
+     * @return void
+     */
+    function delete() {
+
+        $this->caldavBackend->deleteSchedulingObject($this->objectData['principaluri'], $this->objectData['uri']);
+
+    }
+
+    /**
+     * Returns the owner principal
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    function getOwner() {
+
+        return $this->objectData['principaluri'];
+
+    }
+
+
+    /**
+     * Returns a list of ACE's for this node.
+     *
+     * Each ACE has the following properties:
+     *   * 'privilege', a string such as {DAV:}read or {DAV:}write. These are
+     *     currently the only supported privileges
+     *   * 'principal', a url to the principal who owns the node
+     *   * 'protected' (optional), indicating that this ACE is not allowed to
+     *      be updated.
+     *
+     * @return array
+     */
+    function getACL() {
+
+        // An alternative acl may be specified in the object data.
+        //
+
+        if (isset($this->objectData['acl'])) {
+            return $this->objectData['acl'];
+        }
+
+        // The default ACL
+        return [
+            [
+                'privilege' => '{DAV:}read',
+                'principal' => $this->objectData['principaluri'],
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{DAV:}write',
+                'principal' => $this->objectData['principaluri'],
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{DAV:}read',
+                'principal' => $this->objectData['principaluri'] . '/calendar-proxy-write',
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{DAV:}write',
+                'principal' => $this->objectData['principaluri'] . '/calendar-proxy-write',
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{DAV:}read',
+                'principal' => $this->objectData['principaluri'] . '/calendar-proxy-read',
+                'protected' => true,
+            ],
+        ];
+
+    }
+
+}