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

1 files changed, 871 insertions, 0 deletions

diff --git a/vendor/sabre/dav/lib/CardDAV/Plugin.php b/vendor/sabre/dav/lib/CardDAV/Plugin.php
new file mode 100644
index 000000000..b8bded098
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/Plugin.php
@@ -0,0 +1,871 @@
+<?php
+
+namespace Sabre\CardDAV;
+
+use Sabre\DAV;
+use Sabre\DAV\Exception\ReportNotSupported;
+use Sabre\DAV\Xml\Property\Href;
+use Sabre\DAVACL;
+use Sabre\HTTP;
+use Sabre\HTTP\RequestInterface;
+use Sabre\HTTP\ResponseInterface;
+use Sabre\VObject;
+
+/**
+ * CardDAV plugin
+ *
+ * The CardDAV plugin adds CardDAV functionality to the WebDAV server
+ *
+ * @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 DAV\ServerPlugin {
+
+    /**
+     * Url to the addressbooks
+     */
+    const ADDRESSBOOK_ROOT = 'addressbooks';
+
+    /**
+     * xml namespace for CardDAV elements
+     */
+    const NS_CARDDAV = 'urn:ietf:params:xml:ns:carddav';
+
+    /**
+     * Add urls to this property to have them automatically exposed as
+     * 'directories' to the user.
+     *
+     * @var array
+     */
+    public $directories = [];
+
+    /**
+     * Server class
+     *
+     * @var Sabre\DAV\Server
+     */
+    protected $server;
+
+    /**
+     * The default PDO storage uses a MySQL MEDIUMBLOB for iCalendar data,
+     * which can hold up to 2^24 = 16777216 bytes. This is plenty. We're
+     * capping it to 10M here.
+     */
+    protected $maxResourceSize = 10000000;
+
+    /**
+     * Initializes the plugin
+     *
+     * @param DAV\Server $server
+     * @return void
+     */
+    function initialize(DAV\Server $server) {
+
+        /* Events */
+        $server->on('propFind',            [$this, 'propFindEarly']);
+        $server->on('propFind',            [$this, 'propFindLate'], 150);
+        $server->on('report',              [$this, 'report']);
+        $server->on('onHTMLActionsPanel',  [$this, 'htmlActionsPanel']);
+        $server->on('beforeWriteContent',  [$this, 'beforeWriteContent']);
+        $server->on('beforeCreateFile',    [$this, 'beforeCreateFile']);
+        $server->on('afterMethod:GET',     [$this, 'httpAfterGet']);
+
+        $server->xml->namespaceMap[self::NS_CARDDAV] = 'card';
+
+        $server->xml->elementMap['{' . self::NS_CARDDAV . '}addressbook-query'] = 'Sabre\\CardDAV\\Xml\\Request\\AddressBookQueryReport';
+        $server->xml->elementMap['{' . self::NS_CARDDAV . '}addressbook-multiget'] = 'Sabre\\CardDAV\\Xml\\Request\\AddressBookMultiGetReport';
+
+        /* Mapping Interfaces to {DAV:}resourcetype values */
+        $server->resourceTypeMapping['Sabre\\CardDAV\\IAddressBook'] = '{' . self::NS_CARDDAV . '}addressbook';
+        $server->resourceTypeMapping['Sabre\\CardDAV\\IDirectory'] = '{' . self::NS_CARDDAV . '}directory';
+
+        /* Adding properties that may never be changed */
+        $server->protectedProperties[] = '{' . self::NS_CARDDAV . '}supported-address-data';
+        $server->protectedProperties[] = '{' . self::NS_CARDDAV . '}max-resource-size';
+        $server->protectedProperties[] = '{' . self::NS_CARDDAV . '}addressbook-home-set';
+        $server->protectedProperties[] = '{' . self::NS_CARDDAV . '}supported-collation-set';
+
+        $server->xml->elementMap['{http://calendarserver.org/ns/}me-card'] = 'Sabre\\DAV\\Xml\\Property\\Href';
+
+        $this->server = $server;
+
+    }
+
+    /**
+     * Returns a list of supported features.
+     *
+     * This is used in the DAV: header in the OPTIONS and PROPFIND requests.
+     *
+     * @return array
+     */
+    function getFeatures() {
+
+        return ['addressbook'];
+
+    }
+
+    /**
+     * Returns a list of reports this plugin supports.
+     *
+     * This will be used in the {DAV:}supported-report-set property.
+     * Note that you still need to subscribe to the 'report' event to actually
+     * implement them
+     *
+     * @param string $uri
+     * @return array
+     */
+    function getSupportedReportSet($uri) {
+
+        $node = $this->server->tree->getNodeForPath($uri);
+        if ($node instanceof IAddressBook || $node instanceof ICard) {
+            return [
+                 '{' . self::NS_CARDDAV . '}addressbook-multiget',
+                 '{' . self::NS_CARDDAV . '}addressbook-query',
+            ];
+        }
+        return [];
+
+    }
+
+
+    /**
+     * Adds all CardDAV-specific properties
+     *
+     * @param DAV\PropFind $propFind
+     * @param DAV\INode $node
+     * @return void
+     */
+    function propFindEarly(DAV\PropFind $propFind, DAV\INode $node) {
+
+        $ns = '{' . self::NS_CARDDAV . '}';
+
+        if ($node instanceof IAddressBook) {
+
+            $propFind->handle($ns . 'max-resource-size', $this->maxResourceSize);
+            $propFind->handle($ns . 'supported-address-data', function() {
+                return new Xml\Property\SupportedAddressData();
+            });
+            $propFind->handle($ns . 'supported-collation-set', function() {
+                return new Xml\Property\SupportedCollationSet();
+            });
+
+        }
+        if ($node instanceof DAVACL\IPrincipal) {
+
+            $path = $propFind->getPath();
+
+            $propFind->handle('{' . self::NS_CARDDAV . '}addressbook-home-set', function() use ($path) {
+                return new Href($this->getAddressBookHomeForPrincipal($path) . '/');
+            });
+
+            if ($this->directories) $propFind->handle('{' . self::NS_CARDDAV . '}directory-gateway', function() {
+                return new Href($this->directories);
+            });
+
+        }
+
+        if ($node instanceof ICard) {
+
+            // The address-data property is not supposed to be a 'real'
+            // property, but in large chunks of the spec it does act as such.
+            // Therefore we simply expose it as a property.
+            $propFind->handle('{' . self::NS_CARDDAV . '}address-data', function() use ($node) {
+                $val = $node->get();
+                if (is_resource($val))
+                    $val = stream_get_contents($val);
+
+                return $val;
+
+            });
+
+        }
+
+    }
+
+    /**
+     * This functions handles REPORT requests specific to CardDAV
+     *
+     * @param string $reportName
+     * @param \DOMNode $dom
+     * @param mixed $path
+     * @return bool
+     */
+    function report($reportName, $dom, $path) {
+
+        switch ($reportName) {
+            case '{' . self::NS_CARDDAV . '}addressbook-multiget' :
+                $this->server->transactionType = 'report-addressbook-multiget';
+                $this->addressbookMultiGetReport($dom);
+                return false;
+            case '{' . self::NS_CARDDAV . '}addressbook-query' :
+                $this->server->transactionType = 'report-addressbook-query';
+                $this->addressBookQueryReport($dom);
+                return false;
+            default :
+                return;
+
+        }
+
+
+    }
+
+    /**
+     * Returns the addressbook home for a given principal
+     *
+     * @param string $principal
+     * @return string
+     */
+    protected function getAddressbookHomeForPrincipal($principal) {
+
+        list(, $principalId) = \Sabre\HTTP\URLUtil::splitPath($principal);
+        return self::ADDRESSBOOK_ROOT . '/' . $principalId;
+
+    }
+
+
+    /**
+     * This function handles the addressbook-multiget REPORT.
+     *
+     * This report is used by the client to fetch the content of a series
+     * of urls. Effectively avoiding a lot of redundant requests.
+     *
+     * @param Xml\Request\AddressBookMultiGetReport $report
+     * @return void
+     */
+    function addressbookMultiGetReport($report) {
+
+        $contentType = $report->contentType;
+        $version = $report->version;
+        if ($version) {
+            $contentType .= '; version=' . $version;
+        }
+
+        $vcardType = $this->negotiateVCard(
+            $contentType
+        );
+
+        $propertyList = [];
+        $paths = array_map(
+            [$this->server, 'calculateUri'],
+            $report->hrefs
+        );
+        foreach ($this->server->getPropertiesForMultiplePaths($paths, $report->properties) as $props) {
+
+            if (isset($props['200']['{' . self::NS_CARDDAV . '}address-data'])) {
+
+                $props['200']['{' . self::NS_CARDDAV . '}address-data'] = $this->convertVCard(
+                    $props[200]['{' . self::NS_CARDDAV . '}address-data'],
+                    $vcardType
+                );
+
+            }
+            $propertyList[] = $props;
+
+        }
+
+        $prefer = $this->server->getHTTPPrefer();
+
+        $this->server->httpResponse->setStatus(207);
+        $this->server->httpResponse->setHeader('Content-Type', 'application/xml; charset=utf-8');
+        $this->server->httpResponse->setHeader('Vary', 'Brief,Prefer');
+        $this->server->httpResponse->setBody($this->server->generateMultiStatus($propertyList, $prefer['return'] === 'minimal'));
+
+    }
+
+    /**
+     * This method is triggered before a file gets updated with new content.
+     *
+     * This plugin uses this method to ensure that Card nodes receive valid
+     * vcard data.
+     *
+     * @param string $path
+     * @param DAV\IFile $node
+     * @param resource $data
+     * @param bool $modified Should be set to true, if this event handler
+     *                       changed &$data.
+     * @return void
+     */
+    function beforeWriteContent($path, DAV\IFile $node, &$data, &$modified) {
+
+        if (!$node instanceof ICard)
+            return;
+
+        $this->validateVCard($data, $modified);
+
+    }
+
+    /**
+     * This method is triggered before a new file is created.
+     *
+     * This plugin uses this method to ensure that Card nodes receive valid
+     * vcard data.
+     *
+     * @param string $path
+     * @param resource $data
+     * @param DAV\ICollection $parentNode
+     * @param bool $modified Should be set to true, if this event handler
+     *                       changed &$data.
+     * @return void
+     */
+    function beforeCreateFile($path, &$data, DAV\ICollection $parentNode, &$modified) {
+
+        if (!$parentNode instanceof IAddressBook)
+            return;
+
+        $this->validateVCard($data, $modified);
+
+    }
+
+    /**
+     * Checks if the submitted iCalendar data is in fact, valid.
+     *
+     * An exception is thrown if it's not.
+     *
+     * @param resource|string $data
+     * @param bool $modified Should be set to true, if this event handler
+     *                       changed &$data.
+     * @return void
+     */
+    protected function validateVCard(&$data, &$modified) {
+
+        // If it's a stream, we convert it to a string first.
+        if (is_resource($data)) {
+            $data = stream_get_contents($data);
+        }
+
+        $before = md5($data);
+
+        // Converting the data to unicode, if needed.
+        $data = DAV\StringUtil::ensureUTF8($data);
+
+        if (md5($data) !== $before) $modified = true;
+
+        try {
+
+            // If the data starts with a [, we can reasonably assume we're dealing
+            // with a jCal object.
+            if (substr($data, 0, 1) === '[') {
+                $vobj = VObject\Reader::readJson($data);
+
+                // Converting $data back to iCalendar, as that's what we
+                // technically support everywhere.
+                $data = $vobj->serialize();
+                $modified = true;
+            } else {
+                $vobj = VObject\Reader::read($data);
+            }
+
+        } catch (VObject\ParseException $e) {
+
+            throw new DAV\Exception\UnsupportedMediaType('This resource only supports valid vCard or jCard data. Parse error: ' . $e->getMessage());
+
+        }
+
+        if ($vobj->name !== 'VCARD') {
+            throw new DAV\Exception\UnsupportedMediaType('This collection can only support vcard objects.');
+        }
+
+        if (!isset($vobj->UID)) {
+            // No UID in vcards is invalid, but we'll just add it in anyway.
+            $vobj->add('UID', DAV\UUIDUtil::getUUID());
+            $data = $vobj->serialize();
+            $modified = true;
+        }
+
+        // Destroy circular references to PHP will GC the object.
+        $vobj->destroy();
+    }
+
+
+    /**
+     * This function handles the addressbook-query REPORT
+     *
+     * This report is used by the client to filter an addressbook based on a
+     * complex query.
+     *
+     * @param Xml\Request\AddressBookQueryReport $report
+     * @return void
+     */
+    protected function addressbookQueryReport($report) {
+
+        $depth = $this->server->getHTTPDepth(0);
+
+        if ($depth == 0) {
+            $candidateNodes = [
+                $this->server->tree->getNodeForPath($this->server->getRequestUri())
+            ];
+            if (!$candidateNodes[0] instanceof ICard) {
+                throw new ReportNotSupported('The addressbook-query report is not supported on this url with Depth: 0');
+            }
+        } else {
+            $candidateNodes = $this->server->tree->getChildren($this->server->getRequestUri());
+        }
+
+        $contentType = $report->contentType;
+        if ($report->version) {
+            $contentType .= '; version=' . $report->version;
+        }
+
+        $vcardType = $this->negotiateVCard(
+            $contentType
+        );
+
+        $validNodes = [];
+        foreach ($candidateNodes as $node) {
+
+            if (!$node instanceof ICard)
+                continue;
+
+            $blob = $node->get();
+            if (is_resource($blob)) {
+                $blob = stream_get_contents($blob);
+            }
+
+            if (!$this->validateFilters($blob, $report->filters, $report->test)) {
+                continue;
+            }
+
+            $validNodes[] = $node;
+
+            if ($report->limit && $report->limit <= count($validNodes)) {
+                // We hit the maximum number of items, we can stop now.
+                break;
+            }
+
+        }
+
+        $result = [];
+        foreach ($validNodes as $validNode) {
+
+            if ($depth == 0) {
+                $href = $this->server->getRequestUri();
+            } else {
+                $href = $this->server->getRequestUri() . '/' . $validNode->getName();
+            }
+
+            list($props) = $this->server->getPropertiesForPath($href, $report->properties, 0);
+
+            if (isset($props[200]['{' . self::NS_CARDDAV . '}address-data'])) {
+
+                $props[200]['{' . self::NS_CARDDAV . '}address-data'] = $this->convertVCard(
+                    $props[200]['{' . self::NS_CARDDAV . '}address-data'],
+                    $vcardType
+                );
+
+            }
+            $result[] = $props;
+
+        }
+
+        $prefer = $this->server->getHTTPPrefer();
+
+        $this->server->httpResponse->setStatus(207);
+        $this->server->httpResponse->setHeader('Content-Type', 'application/xml; charset=utf-8');
+        $this->server->httpResponse->setHeader('Vary', 'Brief,Prefer');
+        $this->server->httpResponse->setBody($this->server->generateMultiStatus($result, $prefer['return'] === 'minimal'));
+
+    }
+
+    /**
+     * Validates if a vcard makes it throught a list of filters.
+     *
+     * @param string $vcardData
+     * @param array $filters
+     * @param string $test anyof or allof (which means OR or AND)
+     * @return bool
+     */
+    function validateFilters($vcardData, array $filters, $test) {
+
+
+        if (!$filters) return true;
+        $vcard = VObject\Reader::read($vcardData);
+
+        foreach ($filters as $filter) {
+
+            $isDefined = isset($vcard->{$filter['name']});
+            if ($filter['is-not-defined']) {
+                if ($isDefined) {
+                    $success = false;
+                } else {
+                    $success = true;
+                }
+            } elseif ((!$filter['param-filters'] && !$filter['text-matches']) || !$isDefined) {
+
+                // We only need to check for existence
+                $success = $isDefined;
+
+            } else {
+
+                $vProperties = $vcard->select($filter['name']);
+
+                $results = [];
+                if ($filter['param-filters']) {
+                    $results[] = $this->validateParamFilters($vProperties, $filter['param-filters'], $filter['test']);
+                }
+                if ($filter['text-matches']) {
+                    $texts = [];
+                    foreach ($vProperties as $vProperty)
+                        $texts[] = $vProperty->getValue();
+
+                    $results[] = $this->validateTextMatches($texts, $filter['text-matches'], $filter['test']);
+                }
+
+                if (count($results) === 1) {
+                    $success = $results[0];
+                } else {
+                    if ($filter['test'] === 'anyof') {
+                        $success = $results[0] || $results[1];
+                    } else {
+                        $success = $results[0] && $results[1];
+                    }
+                }
+
+            } // else
+
+            // There are two conditions where we can already determine whether
+            // or not this filter succeeds.
+            if ($test === 'anyof' && $success) {
+
+                // Destroy circular references to PHP will GC the object.
+                $vcard->destroy();
+
+                return true;
+            }
+            if ($test === 'allof' && !$success) {
+
+                // Destroy circular references to PHP will GC the object.
+                $vcard->destroy();
+
+                return false;
+            }
+
+        } // foreach
+
+
+        // Destroy circular references to PHP will GC the object.
+        $vcard->destroy();
+
+        // If we got all the way here, it means we haven't been able to
+        // determine early if the test failed or not.
+        //
+        // This implies for 'anyof' that the test failed, and for 'allof' that
+        // we succeeded. Sounds weird, but makes sense.
+        return $test === 'allof';
+
+    }
+
+    /**
+     * Validates if a param-filter can be applied to a specific property.
+     *
+     * @todo currently we're only validating the first parameter of the passed
+     *       property. Any subsequence parameters with the same name are
+     *       ignored.
+     * @param array $vProperties
+     * @param array $filters
+     * @param string $test
+     * @return bool
+     */
+    protected function validateParamFilters(array $vProperties, array $filters, $test) {
+
+        foreach ($filters as $filter) {
+
+            $isDefined = false;
+            foreach ($vProperties as $vProperty) {
+                $isDefined = isset($vProperty[$filter['name']]);
+                if ($isDefined) break;
+            }
+
+            if ($filter['is-not-defined']) {
+                if ($isDefined) {
+                    $success = false;
+                } else {
+                    $success = true;
+                }
+
+            // If there's no text-match, we can just check for existence
+            } elseif (!$filter['text-match'] || !$isDefined) {
+
+                $success = $isDefined;
+
+            } else {
+
+                $success = false;
+                foreach ($vProperties as $vProperty) {
+                    // If we got all the way here, we'll need to validate the
+                    // text-match filter.
+                    $success = DAV\StringUtil::textMatch($vProperty[$filter['name']]->getValue(), $filter['text-match']['value'], $filter['text-match']['collation'], $filter['text-match']['match-type']);
+                    if ($success) break;
+                }
+                if ($filter['text-match']['negate-condition']) {
+                    $success = !$success;
+                }
+
+            } // else
+
+            // There are two conditions where we can already determine whether
+            // or not this filter succeeds.
+            if ($test === 'anyof' && $success) {
+                return true;
+            }
+            if ($test === 'allof' && !$success) {
+                return false;
+            }
+
+        }
+
+        // If we got all the way here, it means we haven't been able to
+        // determine early if the test failed or not.
+        //
+        // This implies for 'anyof' that the test failed, and for 'allof' that
+        // we succeeded. Sounds weird, but makes sense.
+        return $test === 'allof';
+
+    }
+
+    /**
+     * Validates if a text-filter can be applied to a specific property.
+     *
+     * @param array $texts
+     * @param array $filters
+     * @param string $test
+     * @return bool
+     */
+    protected function validateTextMatches(array $texts, array $filters, $test) {
+
+        foreach ($filters as $filter) {
+
+            $success = false;
+            foreach ($texts as $haystack) {
+                $success = DAV\StringUtil::textMatch($haystack, $filter['value'], $filter['collation'], $filter['match-type']);
+
+                // Breaking on the first match
+                if ($success) break;
+            }
+            if ($filter['negate-condition']) {
+                $success = !$success;
+            }
+
+            if ($success && $test === 'anyof')
+                return true;
+
+            if (!$success && $test == 'allof')
+                return false;
+
+
+        }
+
+        // If we got all the way here, it means we haven't been able to
+        // determine early if the test failed or not.
+        //
+        // This implies for 'anyof' that the test failed, and for 'allof' that
+        // we succeeded. Sounds weird, but makes sense.
+        return $test === 'allof';
+
+    }
+
+    /**
+     * This event is triggered when fetching properties.
+     *
+     * This event is scheduled late in the process, after most work for
+     * propfind has been done.
+     *
+     * @param DAV\PropFind $propFind
+     * @param DAV\INode $node
+     * @return void
+     */
+    function propFindLate(DAV\PropFind $propFind, DAV\INode $node) {
+
+        // If the request was made using the SOGO connector, we must rewrite
+        // the content-type property. By default SabreDAV will send back
+        // text/x-vcard; charset=utf-8, but for SOGO we must strip that last
+        // part.
+        if (strpos($this->server->httpRequest->getHeader('User-Agent'), 'Thunderbird') === false) {
+            return;
+        }
+        $contentType = $propFind->get('{DAV:}getcontenttype');
+        list($part) = explode(';', $contentType);
+        if ($part === 'text/x-vcard' || $part === 'text/vcard') {
+            $propFind->set('{DAV:}getcontenttype', 'text/x-vcard');
+        }
+
+    }
+
+    /**
+     * This method is used to generate HTML output for the
+     * Sabre\DAV\Browser\Plugin. This allows us to generate an interface users
+     * can use to create new addressbooks.
+     *
+     * @param DAV\INode $node
+     * @param string $output
+     * @return bool
+     */
+    function htmlActionsPanel(DAV\INode $node, &$output) {
+
+        if (!$node instanceof AddressBookHome)
+            return;
+
+        $output .= '<tr><td colspan="2"><form method="post" action="">
+            <h3>Create new address book</h3>
+            <input type="hidden" name="sabreAction" value="mkcol" />
+            <input type="hidden" name="resourceType" value="{DAV:}collection,{' . self::NS_CARDDAV . '}addressbook" />
+            <label>Name (uri):</label> <input type="text" name="name" /><br />
+            <label>Display name:</label> <input type="text" name="{DAV:}displayname" /><br />
+            <input type="submit" value="create" />
+            </form>
+            </td></tr>';
+
+        return false;
+
+    }
+
+    /**
+     * This event is triggered after GET requests.
+     *
+     * This is used to transform data into jCal, if this was requested.
+     *
+     * @param RequestInterface $request
+     * @param ResponseInterface $response
+     * @return void
+     */
+    function httpAfterGet(RequestInterface $request, ResponseInterface $response) {
+
+        if (strpos($response->getHeader('Content-Type'), 'text/vcard') === false) {
+            return;
+        }
+
+        $target = $this->negotiateVCard($request->getHeader('Accept'), $mimeType);
+
+        $newBody = $this->convertVCard(
+            $response->getBody(),
+            $target
+        );
+
+        $response->setBody($newBody);
+        $response->setHeader('Content-Type', $mimeType . '; charset=utf-8');
+        $response->setHeader('Content-Length', strlen($newBody));
+
+    }
+
+    /**
+     * This helper function performs the content-type negotiation for vcards.
+     *
+     * It will return one of the following strings:
+     * 1. vcard3
+     * 2. vcard4
+     * 3. jcard
+     *
+     * It defaults to vcard3.
+     *
+     * @param string $input
+     * @param string $mimeType
+     * @return string
+     */
+    protected function negotiateVCard($input, &$mimeType = null) {
+
+        $result = HTTP\Util::negotiate(
+            $input,
+            [
+                // Most often used mime-type. Version 3
+                'text/x-vcard',
+                // The correct standard mime-type. Defaults to version 3 as
+                // well.
+                'text/vcard',
+                // vCard 4
+                'text/vcard; version=4.0',
+                // vCard 3
+                'text/vcard; version=3.0',
+                // jCard
+                'application/vcard+json',
+            ]
+        );
+
+        $mimeType = $result;
+        switch ($result) {
+
+            default :
+            case 'text/x-vcard' :
+            case 'text/vcard' :
+            case 'text/vcard; version=3.0' :
+                $mimeType = 'text/vcard';
+                return 'vcard3';
+            case 'text/vcard; version=4.0' :
+                return 'vcard4';
+            case 'application/vcard+json' :
+                return 'jcard';
+
+        // @codeCoverageIgnoreStart
+        }
+        // @codeCoverageIgnoreEnd
+
+    }
+
+    /**
+     * Converts a vcard blob to a different version, or jcard.
+     *
+     * @param string $data
+     * @param string $target
+     * @return string
+     */
+    protected function convertVCard($data, $target) {
+
+        $data = VObject\Reader::read($data);
+        switch ($target) {
+            default :
+            case 'vcard3' :
+                $data = $data->convert(VObject\Document::VCARD30);
+                $newResult = $data->serialize();
+                break;
+            case 'vcard4' :
+                $data = $data->convert(VObject\Document::VCARD40);
+                $newResult = $data->serialize();
+                break;
+            case 'jcard' :
+                $data = $data->convert(VObject\Document::VCARD40);
+                $newResult = json_encode($data->jsonSerialize());
+                break;
+
+        }
+        // Destroy circular references to PHP will GC the object.
+        $data->destroy();
+
+        return $newResult;
+
+    }
+
+    /**
+     * Returns a plugin name.
+     *
+     * Using this name other plugins will be able to access other plugins
+     * using DAV\Server::getPlugin
+     *
+     * @return string
+     */
+    function getPluginName() {
+
+        return 'carddav';
+
+    }
+
+    /**
+     * 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 support for CardDAV (rfc6352)',
+            'link'        => 'http://sabre.io/dav/carddav/',
+        ];
+
+    }
+
+}