The YouTube Data API 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 Authentication section in the PHP Developer's Guide for more detail.

A developer key identifies the YouTube developer that is submitting an API request. A client ID identifies your application for logging and debugging purposes. Please visit http://code.google.com/apis/youtube/dashboard/ to obtain a developer key and client ID. The example below demonstrates how to pass the developer key and client ID to the Zend_Gdata_YouTube service object.

$yt = new Zend_Gdata_YouTube($httpClient,
                             $applicationId,
                             $clientId,
                             $developerKey);

            

The YouTube Data API 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 YouTube API reference guide for a detailed list of available feeds.

$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";
}

            

$yt = new Zend_Gdata_YouTube();
$query = $yt->newVideoQuery();
$query->category = 'Comedy/dog';

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

            

$yt = new Zend_Gdata_YouTube();
$videoFeed = $yt->getTopRatedVideoFeed();

            

$yt = new Zend_Gdata_YouTube();
$query = $yt->newVideoQuery();
$query->setTime('today');
$videoFeed = $yt->getTopRatedVideoFeed($query);

            

$yt = new Zend_Gdata_YouTube();
$url = 'http://gdata.youtube.com/feeds/standardfeeds/top_rated?time=today'
$videoFeed = $yt->getVideoFeed($url);

            

$yt = new Zend_Gdata_YouTube();
$videoFeed = $yt->getUserUploads('liz');

            

$yt = new Zend_Gdata_YouTube();
$videoFeed = $yt->getUserFavorites('liz');

            

$yt = new Zend_Gdata_YouTube();
$videoFeed = $yt->getVideoResponseFeed('abc123813abc');

            

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:

$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";
}

        

Comments can also be retrieved for a video if you have a copy of the Zend_Gdata_YouTube_VideoEntry object:

$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);

            

The YouTube Data API provides information about users, including profiles, playlists, subscriptions, and more.

$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";
}

            

$feedUrl = $playlistEntry->getPlaylistVideoFeedUrl();
$playlistVideoFeed = $yt->getPlaylistVideoFeed($feedUrl);

            

A user can have several types of subscriptions: channel subscription, tag subscription, or favorites subscription. A Zend_Gdata_YouTube_SubscriptionEntry is used to represent individual subscriptions.

To retrieve all subscriptions for the user 'liz':

$yt = new Zend_Gdata_YouTube();
$subscriptionFeed = $yt->getSubscriptionFeed('liz');

foreach ($subscriptionFeed as $subscriptionEntry) {
    echo $subscriptionEntry->title->text . "\n";
}

        

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

$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";

        

Please make sure to review the diagrams in the protocol guide 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 HTML form.

In order to upload a video directly, you must first construct a new Zend_Gdata_YouTube_VideoEntry object and specify some required meta-data The following example shows uploading the Quicktime video "mytestmovie.mov" to YouTube with the following properties:

The code below creates a blank Zend_Gdata_YouTube_VideoEntry to be uploaded. A Zend_Gdata_App_MediaFileSource object is then used to hold the actual video file. Under the hood, the Zend_Gdata_YouTube_Extension_MediaGroup 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.

$yt = new Zend_Gdata_YouTube($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();
}

    

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.

Browser-based uploading is performed almost identically to direct uploading, except that you do not attach a Zend_Gdata_App_MediaFileSource object to the Zend_Gdata_YouTube_VideoEntry 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 HTML upload form.

$yt = new Zend_Gdata_YouTube($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'];

      

The above code prints out a link and a token that is used to construct an HTML 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 URL.

// 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>';

      

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 Zend_Gdata_YouTube_VideoEntry to see if it is not live yet or if it has been rejected.

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";
        }
    }
}

      

In addition to the functionality described above, the YouTube API 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 API include: ratings, comments, playlists, subscriptions, user profiles, contacts and messages.

Please refer to the full documentation available in the PHP Developer's Guide on code.google.com.