repo_zf1/documentation/manual/en/module_specs/Zend_Gdata_YouTube.xml

<?xml version="1.0" encoding="UTF-8"?>
<!-- Reviewed: no -->
<sect1 id="zend.gdata.youtube">
    <title>Using the YouTube Data API</title>

    <para>
        The YouTube Data <acronym>API</acronym> offers read and write access to YouTube's content.
        Users can perform unauthenticated requests to Google Data feeds to
        retrieve feeds of popular videos, comments, public information about
        YouTube user profiles, user playlists, favorites, subscriptions and so on.
    </para>

    <para>
        For more information on the YouTube Data <acronym>API</acronym>, please refer
        to the official <ulink
            url="http://code.google.com/apis/youtube/developers_guide_php.html"><acronym>PHP</acronym>
            Developer's Guide</ulink> on code.google.com.
    </para>

    <sect2 id="zend.gdata.youtube.authentication">
        <title>Authentication</title>

        <para>
            The YouTube Data <acronym>API</acronym> allows read-only access to public data, which
            does not require authentication. For any write requests, a user
            needs to authenticate either using ClientLogin or AuthSub authentication. Please refer
            to the <ulink
                url="http://code.google.com/apis/youtube/developers_guide_php.html#Authentication">Authentication
                section in the <acronym>PHP</acronym> Developer's Guide</ulink> for more detail.
        </para>
    </sect2>

    <sect2 id="zend.gdata.youtube.developer_key">
        <title>Developer Keys and Client ID</title>

        <para>
            A developer key identifies the YouTube developer that is submitting
            an <acronym>API</acronym> request. A client ID identifies your application for logging
            and debugging purposes. Please visit <ulink
                url="http://code.google.com/apis/youtube/dashboard/">http://code.google.com/apis/youtube/dashboard/</ulink>
            to obtain a developer key and client ID. The example below demonstrates how to pass the
            developer key and client ID to the <ulink
                url="http://framework.zend.com/apidoc/core/Zend_Gdata/Zend_Gdata_YouTube.html">Zend_Gdata_YouTube</ulink>
            service object.
        </para>

        <example id="zend.gdata.youtube.developer_key.example">
            <title>Passing a Developer Key and ClientID to Zend_Gdata_YouTube</title>

            <programlisting language="php"><![CDATA[
$yt = new Zend_Gdata_YouTube($httpClient,
                             $applicationId,
                             $clientId,
                             $developerKey);
]]></programlisting>
        </example>
    </sect2>

    <sect2 id="zend.gdata.youtube.videos">
        <title>Retrieving public video feeds</title>

        <para>
            The YouTube Data <acronym>API</acronym> provides numerous feeds that return a list of
            videos, such as standard feeds, related videos, video responses,
            user's uploads, and user's favorites. For example, the
            user's uploads feed returns all videos uploaded by a specific user. See the <ulink
                url="http://code.google.com/apis/youtube/reference.html#Video_Feeds">YouTube
                <acronym>API</acronym> reference guide</ulink> for a detailed list of available
            feeds.
        </para>

        <sect3 id="zend.gdata.youtube.videos.searching">
            <title>Searching for videos by metadata</title>

            <para>
                You can retrieve a list of videos that match specified
                search criteria, using the YouTubeQuery class. The following query
                looks for videos which contain the word "cat" in their
                metadata, starting with the 10th video and displaying 20
                videos per page, ordered by the view count.
            </para>

            <example id="zend.gdata.youtube.videos.searching.example">
                <title>Searching for videos</title>

                <programlisting language="php"><![CDATA[
$yt = new Zend_Gdata_YouTube();
$query = $yt->newVideoQuery();
$query->videoQuery = 'cat';
$query->startIndex = 10;
$query->maxResults = 20;
$query->orderBy = 'viewCount';

echo $query->queryUrl . "\n";
$videoFeed = $yt->getVideoFeed($query);

foreach ($videoFeed as $videoEntry) {
    echo "---------VIDEO----------\n";
    echo "Title: " . $videoEntry->getVideoTitle() . "\n";
    echo "\nDescription:\n";
    echo $videoEntry->getVideoDescription();
    echo "\n\n\n";
}
]]></programlisting>
            </example>

            <para>
                For more details on the different query parameters, please refer to the <ulink
                    url="http://code.google.com/apis/youtube/reference.html#Searching_for_videos">
                    Reference Guide</ulink>. The available helper functions in <ulink
                    url="http://framework.zend.com/apidoc/core/Zend_Gdata/Zend_Gdata_YouTube_VideoQuery.html"><classname>Zend_Gdata_YouTube_VideoQuery</classname></ulink>
                for each of these parameters are described in more detail in the <ulink
                    url="http://code.google.com/apis/youtube/developers_guide_php.html#SearchingVideos">PHP
                    Developer's Guide</ulink>.
            </para>
        </sect3>

        <sect3 id="zend.gdata.youtube.videos.searchingcategories">
            <title>Searching for videos by categories and tags/keywords</title>

            <para>
                Searching for videos in specific categories is done by generating a <ulink
                    url="http://code.google.com/apis/youtube/reference.html#Category_search">specially
                    formatted <acronym>URL</acronym></ulink>. For example, to search for
                comedy videos which contain the keyword dog:
            </para>

            <example id="zend.gdata.youtube.videos.searchingcategories.example">
                <title>Searching for videos in specific categories</title>

                <programlisting language="php"><![CDATA[
$yt = new Zend_Gdata_YouTube();
$query = $yt->newVideoQuery();
$query->category = 'Comedy/dog';

echo $query->queryUrl . "\n";
$videoFeed = $yt->getVideoFeed($query);
]]></programlisting>
            </example>
        </sect3>

        <sect3 id="zend.gdata.youtube.videos.standard">
            <title>Retrieving standard feeds</title>

            <para>
                The YouTube Data <acronym>API</acronym> has a number of <ulink
                    url="http://code.google.com/apis/youtube/reference.html#Standard_feeds">standard
                    feeds</ulink>. These standard feeds can be retrieved as <ulink
                    url="http://framework.zend.com/apidoc/core/Zend_Gdata/Zend_Gdata_YouTube_VideoFeed.html">Zend_Gdata_YouTube_VideoFeed</ulink>
                objects using the specified <acronym>URL</acronym>s, using the predefined constants
                within the <ulink
                    url="http://framework.zend.com/apidoc/core/Zend_Gdata/Zend_Gdata_YouTube.html">Zend_Gdata_YouTube</ulink>
                class (Zend_Gdata_YouTube::STANDARD_TOP_RATED_URI for example) or
                using the predefined helper methods (see code listing below).
            </para>

            <para>
                To retrieve the top rated videos using the helper method:
            </para>

            <example id="zend.gdata.youtube.videos.standard.example-1">
                <title>Retrieving a standard video feed</title>

                <programlisting language="php"><![CDATA[
$yt = new Zend_Gdata_YouTube();
$videoFeed = $yt->getTopRatedVideoFeed();
]]></programlisting>
            </example>

            <para>
                There are also query parameters to specify the time period
                over which the standard feed is computed.
            </para>

            <para>
                For example, to retrieve the top rated videos for today:
            </para>

            <example id="zend.gdata.youtube.videos.standard.example-2">
                <title>Using a Zend_Gdata_YouTube_VideoQuery to Retrieve Videos</title>

                <programlisting language="php"><![CDATA[
$yt = new Zend_Gdata_YouTube();
$query = $yt->newVideoQuery();
$query->setTime('today');
$videoFeed = $yt->getTopRatedVideoFeed($query);
]]></programlisting>
            </example>

            <para>
                Alternatively, you could just retrieve the feed using the
                <acronym>URL</acronym>:
            </para>

            <example id="zend.gdata.youtube.videos.standard.example-3">
                <title>Retrieving a video feed by URL</title>

                <programlisting language="php"><![CDATA[
$yt = new Zend_Gdata_YouTube();
$url = 'http://gdata.youtube.com/feeds/standardfeeds/top_rated?time=today'
$videoFeed = $yt->getVideoFeed($url);
]]></programlisting>
            </example>
        </sect3>

        <sect3 id="zend.gdata.youtube.videos.user">
            <title>Retrieving videos uploaded by a user</title>

            <para>
                You can retrieve a list of videos uploaded by a particular user
                using a simple helper method. This example retrieves videos
                uploaded by the user 'liz'.
            </para>

            <example id="zend.gdata.youtube.videos.user.example">
                <title>Retrieving videos uploaded by a specific user</title>

                <programlisting language="php"><![CDATA[
$yt = new Zend_Gdata_YouTube();
$videoFeed = $yt->getUserUploads('liz');
]]></programlisting>
            </example>
        </sect3>

        <sect3 id="zend.gdata.youtube.videos.favorites">
            <title>Retrieving videos favorited by a user</title>

            <para>
                You can retrieve a list of a user's favorite videos
                using a simple helper method. This example retrieves videos
                favorited by the user 'liz'.
            </para>

            <example id="zend.gdata.youtube.videos.favorites.example">
                <title>Retrieving a user's favorite videos</title>

                <programlisting language="php"><![CDATA[
$yt = new Zend_Gdata_YouTube();
$videoFeed = $yt->getUserFavorites('liz');
]]></programlisting>
            </example>
        </sect3>

        <sect3 id="zend.gdata.youtube.videos.responses">
            <title>Retrieving video responses for a video</title>

            <para>
                You can retrieve a list of a video's video responses
                using a simple helper method. This example retrieves video
                response for a video with the ID 'abc123813abc'.
            </para>

            <example id="zend.gdata.youtube.videos.responses.example">
                <title>Retrieving a feed of video responses</title>

                <programlisting language="php"><![CDATA[
$yt = new Zend_Gdata_YouTube();
$videoFeed = $yt->getVideoResponseFeed('abc123813abc');
]]></programlisting>
            </example>
        </sect3>
    </sect2>

    <sect2 id="zend.gdata.youtube.comments">
        <title>Retrieving video comments</title>

        <para>
            The comments for each YouTube video can be retrieved in
            several ways. To retrieve the comments for the video with
            the ID 'abc123813abc', use the following code:
        </para>

        <example id="zend.gdata.youtube.videos.comments.example-1">
            <title>Retrieving a feed of video comments from a video ID</title>

            <programlisting language="php"><![CDATA[
$yt = new Zend_Gdata_YouTube();
$commentFeed = $yt->getVideoCommentFeed('abc123813abc');

foreach ($commentFeed as $commentEntry) {
    echo $commentEntry->title->text . "\n";
    echo $commentEntry->content->text . "\n\n\n";
}
]]></programlisting>
        </example>

        <para>
            Comments can also be retrieved for a video if you have a copy of the <ulink
                url="http://framework.zend.com/apidoc/core/Zend_Gdata/Zend_Gdata_YouTube_VideoEntry.html">Zend_Gdata_YouTube_VideoEntry</ulink>
            object:
        </para>

        <example id="zend.gdata.youtube.videos.comments.example-2">
            <title>Retrieving a Feed of Video Comments from a Zend_Gdata_YouTube_VideoEntry</title>

            <programlisting language="php"><![CDATA[
$yt = new Zend_Gdata_YouTube();
$videoEntry = $yt->getVideoEntry('abc123813abc');
// we don't know the video ID in this example, but we do have the URL
$commentFeed = $yt->getVideoCommentFeed(null,
                                        $videoEntry->comments->href);
]]></programlisting>
        </example>
    </sect2>

    <sect2 id="zend.gdata.youtube.playlists">
        <title>Retrieving playlist feeds</title>

        <para>
          The YouTube Data <acronym>API</acronym> provides information about users, including
            profiles, playlists, subscriptions, and more.
        </para>

        <sect3 id="zend.gdata.youtube.playlists.user">
            <title>Retrieving the playlists of a user</title>

            <para>
                The library provides a helper method to retrieve
                the playlists associated with a given user. To retrieve the
                playlists for the user 'liz':
            </para>

            <example id="zend.gdata.youtube.playlists.user.example">
                <title>Retrieving the playlists of a user</title>

                <programlisting language="php"><![CDATA[
$yt = new Zend_Gdata_YouTube();
$playlistListFeed = $yt->getPlaylistListFeed('liz');

foreach ($playlistListFeed as $playlistEntry) {
    echo $playlistEntry->title->text . "\n";
    echo $playlistEntry->description->text . "\n";
    echo $playlistEntry->getPlaylistVideoFeedUrl() . "\n\n\n";
}
]]></programlisting>
            </example>
        </sect3>

        <sect3 id="zend.gdata.youtube.playlists.special">
            <title>Retrieving a specific playlist</title>

            <para>
                The library provides a helper method to retrieve
                the videos associated with a given playlist. To retrieve the
                playlists for a specific playlist entry:
            </para>

            <example id="zend.gdata.youtube.playlists.special.example">
                <title>Retrieving a specific playlist</title>

                <programlisting language="php"><![CDATA[
$feedUrl = $playlistEntry->getPlaylistVideoFeedUrl();
$playlistVideoFeed = $yt->getPlaylistVideoFeed($feedUrl);
]]></programlisting>
            </example>
        </sect3>
    </sect2>

    <sect2 id="zend.gdata.youtube.subscriptions">
        <title>Retrieving a list of a user's subscriptions</title>

        <para>
            A user can have several types of subscriptions: channel
            subscription, tag subscription, or favorites subscription. A <ulink
                url="http://framework.zend.com/apidoc/core/Zend_Gdata/Zend_Gdata_YouTube_SubscriptionEntry.html">Zend_Gdata_YouTube_SubscriptionEntry</ulink>
            is used to represent individual subscriptions.
        </para>

        <para>
            To retrieve all subscriptions for the user 'liz':
        </para>

        <example id="zend.gdata.youtube.subscriptions.example">
            <title>Retrieving all subscriptions for a user</title>

            <programlisting language="php"><![CDATA[
$yt = new Zend_Gdata_YouTube();
$subscriptionFeed = $yt->getSubscriptionFeed('liz');

foreach ($subscriptionFeed as $subscriptionEntry) {
    echo $subscriptionEntry->title->text . "\n";
}
]]></programlisting>
        </example>
    </sect2>

    <sect2 id="zend.gdata.youtube.profile">
        <title>Retrieving a user's profile</title>

        <para>
            You can retrieve the public profile information
            for any YouTube user. To retrieve the profile
            for the user 'liz':
        </para>

        <example id="zend.gdata.youtube.profile.example">
            <title>Retrieving a user's profile</title>

            <programlisting language="php"><![CDATA[
$yt = new Zend_Gdata_YouTube();
$userProfile = $yt->getUserProfile('liz');
echo "username: " . $userProfile->username->text . "\n";
echo "age: " . $userProfile->age->text . "\n";
echo "hometown: " . $userProfile->hometown->text . "\n";
]]></programlisting>
        </example>
    </sect2>

    <sect2 id="zend.gdata.youtube.uploads">
        <title>Uploading Videos to YouTube</title>

        <para>
            Please make sure to review the diagrams in the <ulink
                url="http://code.google.com/apis/youtube/developers_guide_protocol.html#Process_Flows_for_Uploading_Videos">protocol
                guide</ulink> on code.google.com for a high-level
            overview of the upload process. Uploading videos can be done in one of
            two ways: either by uploading the video directly or by sending just the video
            meta-data and having a user upload the video through an <acronym>HTML</acronym> form.
        </para>

        <para>
            In order to upload a video directly, you must first construct a new <ulink
                url="http://framework.zend.com/apidoc/core/Zend_Gdata/Zend_Gdata_YouTube_VideoEntry.html">Zend_Gdata_YouTube_VideoEntry</ulink>
            object and specify some required meta-data. The following example shows uploading the
            Quicktime video "mytestmovie.mov" to YouTube with the following properties:
        </para>

        <table id="zend.gdata.youtube.uploads.metadata">
            <title>Metadata used in the code-sample below</title>

            <tgroup cols="2" align="left" colsep="1" rowsep="1">
                <thead>
                    <row>
                        <entry>Property</entry>
                        <entry>Value</entry>
                    </row>
                </thead>

                <tbody>
                    <row>
                        <entry>Title</entry>
                        <entry>My Test Movie</entry>
                    </row>

                    <row>
                        <entry>Category</entry>
                        <entry>Autos</entry>
                    </row>

                    <row>
                        <entry>Keywords</entry>
                        <entry>cars, funny</entry>
                    </row>

                    <row>
                        <entry>Description</entry>
                        <entry>My description</entry>
                    </row>

                    <row>
                        <entry>Filename</entry>
                        <entry>mytestmovie.mov</entry>
                    </row>

                    <row>
                        <entry>File <acronym>MIME</acronym> type</entry>
                        <entry>video/quicktime</entry>
                    </row>

                    <row>
                        <entry>Video private?</entry>
                        <entry><constant>FALSE</constant></entry>
                    </row>

                    <row>
                        <entry>Video location</entry>
                        <entry>37, -122 (lat, long)</entry>
                    </row>

                    <row>
                        <entry>Developer Tags</entry>
                        <entry>mydevelopertag, anotherdevelopertag</entry>
                    </row>
                </tbody>
            </tgroup>
        </table>

        <para>
            The code below creates a blank <ulink
                url="http://framework.zend.com/apidoc/core/Zend_Gdata/Zend_Gdata_YouTube_VideoEntry.html">Zend_Gdata_YouTube_VideoEntry</ulink>
            to be uploaded. A <ulink
                url="http://framework.zend.com/apidoc/core/Zend_Gdata/Zend_Gdata_App_MediaFileSource.html">Zend_Gdata_App_MediaFileSource</ulink>
            object is then used to hold the actual video file. Under the hood, the <ulink
                url="http://framework.zend.com/apidoc/core/Zend_Gdata/Zend_Gdata_YouTube_Extension_MediaGroup.html">Zend_Gdata_YouTube_Extension_MediaGroup</ulink>
            object is used to hold all of the video's meta-data. Our helper methods detailed below
            allow you to just set the video meta-data without having to worry about the media group
            object. The $uploadUrl is the location where the new entry gets posted to.
            This can be specified either with the $userName of the
            currently authenticated user, or, alternatively, you can simply use the
            string 'default' to refer to the currently authenticated user.
        </para>

        <example id="zend.gdata.youtube.uploads.example">
            <title>Uploading a video</title>

            <programlisting language="php"><![CDATA[
$yt = new Zend_Gdata_YouTube($httpClient);
$myVideoEntry = new Zend_Gdata_YouTube_VideoEntry();

$filesource = $yt->newMediaFileSource('mytestmovie.mov');
$filesource->setContentType('video/quicktime');
$filesource->setSlug('mytestmovie.mov');

$myVideoEntry->setMediaSource($filesource);

$myVideoEntry->setVideoTitle('My Test Movie');
$myVideoEntry->setVideoDescription('My Test Movie');
// Note that category must be a valid YouTube category !
$myVideoEntry->setVideoCategory('Comedy');

// Set keywords, note that this must be a comma separated string
// and that each keyword cannot contain whitespace
$myVideoEntry->SetVideoTags('cars, funny');

// Optionally set some developer tags
$myVideoEntry->setVideoDeveloperTags(array('mydevelopertag',
                                           'anotherdevelopertag'));

// Optionally set the video's location
$yt->registerPackage('Zend_Gdata_Geo');
$yt->registerPackage('Zend_Gdata_Geo_Extension');
$where = $yt->newGeoRssWhere();
$position = $yt->newGmlPos('37.0 -122.0');
$where->point = $yt->newGmlPoint($position);
$myVideoEntry->setWhere($where);

// Upload URI for the currently authenticated user
$uploadUrl =
    'http://uploads.gdata.youtube.com/feeds/users/default/uploads';

// Try to upload the video, catching a Zend_Gdata_App_HttpException
// if availableor just a regular Zend_Gdata_App_Exception

try {
    $newEntry = $yt->insertEntry($myVideoEntry,
                                 $uploadUrl,
                                 'Zend_Gdata_YouTube_VideoEntry');
} catch (Zend_Gdata_App_HttpException $httpException) {
    echo $httpException->getRawResponseBody();
} catch (Zend_Gdata_App_Exception $e) {
    echo $e->getMessage();
}
]]></programlisting>
        </example>

        <para>
            To upload a video as private, simply use: $myVideoEntry->setVideoPrivate(); prior to
            performing the upload. $videoEntry->isVideoPrivate() can be used to check whether a
            video entry is private or not.
        </para>
    </sect2>

    <sect2 id="zend.gdata.youtube.uploads.browser">
        <title>Browser-based upload</title>

        <para>
            Browser-based uploading is performed almost identically to direct uploading,
            except that you do not attach a <ulink
                url="http://framework.zend.com/apidoc/core/Zend_Gdata/Zend_Gdata_App_MediaFileSource.html">Zend_Gdata_App_MediaFileSource</ulink>
            object to the <ulink
                url="http://framework.zend.com/apidoc/core/Zend_Gdata/Zend_Gdata_YouTube_VideoEntry.html">Zend_Gdata_YouTube_VideoEntry</ulink>
            you are constructing. Instead you simply submit all of your video's meta-data to receive
            back a token element which can be used to construct an <acronym>HTML</acronym> upload
            form.
        </para>

        <example id="zend.gdata.youtube.uploads.browser.example-1">
            <title>Browser-based upload</title>

            <programlisting language="php"><![CDATA[
$yt = new Zend_Gdata_YouTube($httpClient);

$myVideoEntry= new Zend_Gdata_YouTube_VideoEntry();
$myVideoEntry->setVideoTitle('My Test Movie');
$myVideoEntry->setVideoDescription('My Test Movie');

// Note that category must be a valid YouTube category
$myVideoEntry->setVideoCategory('Comedy');
$myVideoEntry->SetVideoTags('cars, funny');

$tokenHandlerUrl = 'http://gdata.youtube.com/action/GetUploadToken';
$tokenArray = $yt->getFormUploadToken($myVideoEntry, $tokenHandlerUrl);
$tokenValue = $tokenArray['token'];
$postUrl = $tokenArray['url'];
]]></programlisting>
        </example>

        <para>
            The above code prints out a link and a token that is used to construct an
            <acronym>HTML</acronym> form to display in the user's browser. A simple example form is
            shown below with $tokenValue representing the content of the returned token element,
            as shown being retrieved from $myVideoEntry above. In order for the user
            to be redirected to your website after submitting the form, make sure to
            append a $nextUrl parameter to the $postUrl above, which functions in the
            same way as the $next parameter of an AuthSub link. The only difference is
            that here, instead of a single-use token, a status and an id variable are
            returned in the <acronym>URL</acronym>.
        </para>

        <example id="zend.gdata.youtube.uploads.browser.example-2">
            <title>Browser-based upload: Creating the HTML form</title>

            <programlisting language="php"><![CDATA[
// place to redirect user after upload
$nextUrl = 'http://mysite.com/youtube_uploads';

$form = '<form action="'. $postUrl .'?nexturl='. $nextUrl .
        '" method="post" enctype="multipart/form-data">'.
        '<input name="file" type="file"/>'.
        '<input name="token" type="hidden" value="'. $tokenValue .'"/>'.
        '<input value="Upload Video File" type="submit" />'.
        '</form>';
]]></programlisting>
        </example>
    </sect2>

    <sect2 id="zend.gdata.youtube.uploads.status">
        <title>Checking upload status</title>

        <para>
            After uploading a video, it will immediately be visible in an
            authenticated user's uploads feed. However, it will not be public on
            the site until it has been processed. Videos that have been rejected or
            failed to upload successfully will also only be in the authenticated
            user's uploads feed. The following code checks the status of a <ulink
                url="http://framework.zend.com/apidoc/core/Zend_Gdata/Zend_Gdata_YouTube_VideoEntry.html">Zend_Gdata_YouTube_VideoEntry</ulink>
            to see if it is not live yet or if it has been rejected.
        </para>

        <example id="zend.gdata.youtube.uploads.status.example">
            <title>Checking video upload status</title>

            <programlisting language="php"><![CDATA[
try {
    $control = $videoEntry->getControl();
} catch (Zend_Gdata_App_Exception $e) {
    echo $e->getMessage();
}

if ($control instanceof Zend_Gdata_App_Extension_Control) {
    if ($control->getDraft() != null &&
        $control->getDraft()->getText() == 'yes') {
        $state = $videoEntry->getVideoState();

        if ($state instanceof Zend_Gdata_YouTube_Extension_State) {
            print 'Upload status: '
                  . $state->getName()
                  .' '. $state->getText();
        } else {
            print 'Not able to retrieve the video status information'
                  .' yet. ' . "Please try again shortly.\n";
        }
    }
}
]]></programlisting>
        </example>
    </sect2>

    <sect2 id="zend.gdata.youtube.other">
        <title>Other Functions</title>

        <para>
            In addition to the functionality described above, the YouTube <acronym>API</acronym>
            contains many other functions that allow you to modify video meta-data,
            delete video entries and use the full range of community features on the site. Some of
            the community features that can be modified through the <acronym>API</acronym> include:
            ratings, comments, playlists, subscriptions, user profiles, contacts and messages.
        </para>
        <para>
            Please refer to the full documentation available in the <ulink
                url="http://code.google.com/apis/youtube/developers_guide_php.html">PHP Developer's
                Guide</ulink> on code.google.com.
        </para>
    </sect2>
</sect1>