Глава 16. Zend_Gdata

Содержание

16.1. Introduction to Gdata
16.1.1. Structure of Zend_Gdata
16.1.2. Interacting with Google Services
16.1.3. Obtaining instances of Zend_Gdata classes
16.1.4. Google Data Client Authentication
16.1.5. Dependencies
16.1.6. Creating a new Gdata client
16.1.7. Common query parameters
16.1.8. Fetching a feed
16.1.9. Working with multi-page feeds
16.1.10. Working with data in feeds and entries
16.1.11. Updating entries
16.1.12. Posting entries to Google servers
16.1.13. Deleting entries on Google servers
16.2. Authenticating with AuthSub
16.2.1. Creating an AuthSub authenticated Http Client
16.2.2. Revoking AuthSub authentication
16.3. Authenticating with ClientLogin
16.3.1. Creating a ClientLogin authenticated Http Client
16.3.2. Terminating a ClientLogin authenticated Http Client
16.4. Using Google Calendar
16.4.1. Connecting To The Calendar Service
16.4.1.1. Authentication
16.4.1.2. Creating A Service Instance
16.4.2. Retrieving A Calendar List
16.4.3. Retrieving Events
16.4.3.1. Queries
16.4.3.2. Retrieving Events In Order Of Start Time
16.4.3.3. Retrieving Events In A Specified Date Range
16.4.3.4. Retrieving Events By Fulltext Query
16.4.3.5. Retrieving Individual Events
16.4.4. Creating Events
16.4.4.1. Creating Single-Occurrence Events
16.4.4.2. Event Schedules and Reminders
16.4.4.3. Creating Recurring Events
16.4.4.4. Using QuickAdd
16.4.5. Modifying Events
16.4.6. Deleting Events
16.4.7. Accessing Event Comments
16.5. Using Google Documents List Data API
16.5.1. Get a List of Documents
16.5.2. Upload a Document
16.5.3. Searching the documents feed
16.5.3.1. Get a List of Word Processing Documents
16.5.3.2. Get a List of Spreadsheets
16.5.3.3. Performing a text query
16.6. Using Google Spreadsheets
16.6.1. Create a Spreadsheet
16.6.2. Get a List of Spreadsheets
16.6.3. Get a List of Worksheets
16.6.4. Interacting With List-based Feeds
16.6.4.1. Get a List-based Feed
16.6.4.2. Reverse-sort Rows
16.6.4.3. Send a Structured Query
16.6.4.4. Add a Row
16.6.4.5. Edit a Row
16.6.4.6. Delete a Row
16.6.5. Interacting With Cell-based Feeds
16.6.5.1. Get a Cell-based Feed
16.6.5.2. Send a Cell Range Query
16.6.5.3. Change Contents of a Cell
16.7. Using Google Apps Provisioning
16.7.1. Setting the current domain
16.7.1.1. Setting the domain for the service class
16.7.1.2. Setting the domain for query classes
16.7.2. Interacting with users
16.7.2.1. Creating a user account
16.7.2.2. Retrieving a user account
16.7.2.3. Retrieving all users in a domain
16.7.2.4. Updating a user account
16.7.2.4.1. Resetting a user's password
16.7.2.4.2. Forcing a user to change their password
16.7.2.4.3. Suspending a user account
16.7.2.4.4. Granting administrative rights
16.7.2.5. Deleting user accounts
16.7.3. Interacting with nicknames
16.7.3.1. Creating a nickname
16.7.3.2. Retrieving a nickname
16.7.3.3. Retrieving all nicknames for a user
16.7.3.4. Retrieving all nicknames in a domain
16.7.3.5. Deleting a nickname
16.7.4. Interacting with email lists
16.7.4.1. Creating an email list
16.7.4.2. Retrieving all email lists to which a recipient is subscribed
16.7.4.3. Retrieving all email lists in a domain
16.7.4.4. Deleting an email list
16.7.5. Interacting with email list recipients
16.7.5.1. Adding a recipient to an email list
16.7.5.2. Retrieving the list of subscribers to an email list
16.7.5.3. Removing a recipient from an email list
16.7.6. Handling errors
16.8. Using Google Base
16.8.1. Connect To The Base Service
16.8.1.1. Authentication
16.8.1.2. Create A Service Instance
16.8.2. Retrieve Items
16.8.2.1. Send a Structured Query
16.8.2.1.1. Query Customer Items Feed
16.8.2.1.2. Query Snippets Feed
16.8.2.2. Iterate through the Items
16.8.3. Insert, Update, and Delete Customer Items
16.8.3.1. Insert an Item
16.8.3.2. Modify an Item
16.8.3.3. Delete an Item
16.9. Using the YouTube data API
16.9.1. Retrieving video feeds
16.9.1.1. Searching for videos by metadata
16.9.1.2. Searching for videos by categories and tags/keywords
16.9.1.3. Retrieving standard feeds
16.9.1.4. Retrieving videos uploaded by a user
16.9.1.5. Retrieving videos favorited by a user
16.9.1.6. Retrieving video responses for a video
16.9.2. Retrieving video comments
16.9.3. Retrieving playlist feeds
16.9.3.1. Retrieving the playlists of a user
16.9.3.2. Retrieving a specific playlist
16.9.4. Retrieving a list of a user's subscriptions
16.9.5. Retrieving a user's profile
16.10. Using Picasa Web Albums
16.10.1. Connecting To The Service
16.10.1.1. Authentication
16.10.1.2. Creating A Service Instance
16.10.2. Understanding and Constructing Queries
16.10.3. Retrieving Feeds And Entries
16.10.3.1. Retrieving A User
16.10.3.2. Retrieving An Album
16.10.3.3. Retrieving A Photo
16.10.3.4. Retrieving A Comment
16.10.3.5. Retrieving A Tag
16.10.4. Creating Entries
16.10.4.1. Creating An Album
16.10.4.2. Creating A Photo
16.10.4.3. Creating A Comment
16.10.4.4. Creating A Tag
16.10.5. Deleting Entries
16.10.5.1. Deleting An Album
16.10.5.2. Deleting A Photo
16.10.5.3. Deleting A Comment
16.10.5.4. Deleting A Tag
16.10.5.5. Optimistic Concurrency (Notes On Deletion)
16.11. Catching Gdata Exceptions

16.1. Introduction to Gdata

Google Data APIs provide programmatic interface to some of Google's online services. The Google data Protocol is based upon the Atom Publishing Protocol and allows client applications to retrieve data matching queries, post data, update data and delete data using standard HTTP and the Atom syndication formation. The Zend_Gdata component is a PHP 5 interface for accessing Google Data from PHP. The Zend_Gdata component also supports accessing other services implementing the Atom Publishing Protocol.

See http://code.google.com/apis/gdata/ for more information about Google Data API.

The services that are accessible by Zend_Gdata include the following:

  • Google Calendar is a popular online calendar application.

  • Google Spreadsheets provides an online collaborative spreadsheets tool which can be used as a simple data store for your applications.

  • Google Documents List provides an online list of all spreadsheets, word processing documents, and presentations stored in a Google account.

  • Google Provisioning provides the ability to create, retrieve, update, and delete user accounts, nicknames, and email lists on a Google Apps hosted domain.

  • Google Base provides the ability to retrieve, post, update, and delete items in Google Base.

  • YouTube provides the ability to search and retrieve videos, comments, favorites, subscriptions, user profiles and more.

  • Picasa Web Albums provides an online photo sharing application.

  • Google Blogger is a popular Internet provider of "push-button publishing" and syndication.

  • Google CodeSearch allows you to search public source code from many projects.

  • Google Notebook allows you to view public Notebook content.

[Замечание] Unsupported services

Zend_Gdata does not provide an interface to any other Google service, such as Search, Gmail, Translation, or Maps. Only services that support the Google Data API are supported.

16.1.1. Structure of Zend_Gdata

Zend_Gata is composed of several types of classes:

  • Service classes - inheriting from Zend_Gdata_App. These also include other classes such as Zend_Gdata, Zend_Gdata_Spreadsheets, etc. These classes enable interacting with APP or GData services and provide the ability to retrieve feeds, retrieve entries, post entries, update entries and delete entries.

  • Query classes - inheriting from Zend_Gdata_Query. These also include other classes for specific services, such as Zend_Gdata_Spreadsheets_ListQuery and Zend_Gdata_Spreadsheets_CellQuery. Query classes provide methods used to construct a query for data to be retrieved from GData services. Methods include getters and setters like setUpdatedMin(), setStartIndex(), and getPublishedMin(). The query classes also have a method to generate a URL representing the constructed query -- getQueryUrl. Alternatively, the query string component of the URL can be retrieved used the getQueryString() method.

  • Feed classes - inheriting from Zend_Gdata_App_Feed. These also include other classes such as Zend_Gdata_Feed, Zend_Gdata_Spreadsheets_SpreadsheetFeed, and Zend_Gdata_Spreadsheets_ListFeed. These classes represent feeds of entries retrieved from services. They are primarily used to retrieve data returned from services.

  • Entry classes - inheriting from Zend_Gdata_App_Entry. These also include other classes such as Zend_Gdata_Entry, and Zend_Gdata_Spreadsheets_ListEntry. These classes represent entries retrieved from services or used for constructing data to send to services. In addition to being able to set the properties of an entry (such as the spreadsheet cell value), you can use an entry object to send update or delete requests to a service. For example, you can call $entry->save() to save changes made to an entry back to service from which the entry initiated, or $entry->delete() to delete an entry from the server.

  • Other Data model classes - inheriting from Zend_Gdata_App_Extension. These include classes such as Zend_Gdata_App_Extension_Title (representing the atom:title XML element), Zend_Gdata_Extension_When (representing the gd:when XML element used by the GData Event "Kind"), and Zend_Gdata_Extension_Cell (representing the gs:cell XML element used by Google Spreadsheets). These classes are used purely to store the data retrieved back from services and for constructing data to be sent to services. These include getters and setters such as setText() to set the child text node of an element, getText() to retrieve the text node of an element, getStartTime() to retrieve the start time attribute of a When element, and other similiar methods. The data model classes also include methods such as getDOM() to retrieve a DOM representation of the element and all children and transferFromDOM() to construct a data model representation of a DOM tree.

16.1.2. Interacting with Google Services

Google data services are based upon the Atom Publishing Protocol (APP) and the Atom syndication format. To interact with APP or Google services using the Zend_Gdata component, you need to use the service classes such as Zend_Gdata_App, Zend_Gdata, Zend_Gdata_Spreadsheets, etc. These service classes provide methods to retrieve data from services as feeds, insert new entries into feeds, update entries, and delete entries.

Note: A full example of working with Zend_Gdata is available in the demos/Zend/Gdata directory. This example is runnable from the command-line, but the methods contained within are easily portable to a web application.

16.1.3. Obtaining instances of Zend_Gdata classes

The Zend Framework naming standards require that all classes be named based upon the directory structure in which they are located. For instance, extensions related to Spreadsheets are stored in: Zend/Gdata/Spreadsheets/Extension/... and, as a result of this, are named Zend_Gdata_Spreadsheets_Extension_.... This causes a lot of typing if you're trying to construct a new instance of a spreadsheet cell element!

We've implemented a magic factory method in all service classes (such as Zend_Gdata_App, Zend_Gdata, Zend_Gdata_Spreadsheets) that should make constructing new instances of data model, query and other classes much easier. This magic factory is implemented by using the magic __call method to intercept all attempts to call $service->newXXX(arg1, arg2, ...). Based off the value of XXX, a search is performed in all registered 'packages' for the desired class. Here's some examples:

<?php
require_once 'Zend/Loader.php';
Zend_Loader::loadClass('Zend_Gdata_Spreadsheets');

$ss = new Zend_Gdata_Spreadsheets();

// creates a Zend_Gdata_App_Spreadsheets_CellEntry
$entry = $ss->newCellEntry();

// creates a Zend_Gdata_App_Spreadsheets_Extension_Cell
$cell = $ss->newCell();
$cell->setText('My cell value');
$cell->setRow('1');
$cell->setColumn('3');
$entry->cell = $cell;

// ... $entry can then be used to send an update to a Google Spreadsheet
        

Each service class in the inheritance tree is responsible for registering the appropriate 'packages' (directories) which are to be searched when calling the magic factory method.

16.1.4. Google Data Client Authentication

Most Google Data services require client applications to authenticate against the Google server before accessing private data, or saving or deleting data. There are two implementations of authentication for Google Data: AuthSub and ClientLogin. Zend_Gdata offers class interfaces for both of these methods.

Most other types of queries against Google Data services do not require authentication.

16.1.5. Dependencies

Zend_Gdata makes use of Zend_Http_Client to send requests to google.com and fetch results. The response to most Google Data requests is returned as a subclass of the Zend_Gdata_App_Feed or Zend_Gdata_App_Entry classes.

Zend_Gdata assumes your PHP application is running on a host that has a direct connection to the Internet. The Zend_Gdata client operates by contacting Google Data servers.

16.1.6. Creating a new Gdata client

Create a new object of class Zend_Gdata_App, Zend_Gdata, or one of the subclasses available that offer helper methods for service-specific behavior.

The single optional parameter to the Zend_Gdata_App constructor is an instance of Zend_Http_Client. If you don't pass this parameter, Zend_Gdata creates a default Zend_Http_Client object, which will not have associated credentials to access private feeds. Specifying the Zend_Http_Client object also allows you to pass configuration options to that client object.

<?php
require_once 'Zend/Loader.php';
Zend_Loader::loadClass('Zend_Http_Client');
Zend_Loader::loadClass('Zend_Gdata');

$client = new Zend_Http_Client();
$client->setConfig( ...options... );

$gdata = new Zend_Gdata($client);
        

Also see the sections on authentication for methods to create an authenticated Zend_Http_Client object.

16.1.7. Common query parameters

You can specify parameters to customize queries with Zend_Gdata. Query parameters are specified using subclasses of Zend_Gdata_Query. The Zend_Gdata_Query class includes methods to set all query parameters used throughout GData services. Individual services, such as Spreadsheets, also provide query classes to defined parameters which are custom to the particular service and feeds. Spreadsheets includes a CellQuery class to query the Cell Feed and a ListQuery class to query the List Feed, as different query parameters are applicable to each of those feed types. The GData-wide parameters are described below.

  • The q parameter specifies a full-text query. The value of the parameter is a string.

    Set this parameter with the setQuery() function.

  • The alt parameter specifies the feed type. The value of the parameter can be atom, rss, json, or json-in-script. If you don't specify this parameter, the default feed type is atom. NOTE: Only the output of the atom feed format can be processed using Zend_Gdata. The Zend_Http_Client could be used to retrieve feeds in other formats, using query URLs generated by the Zend_Gdata_Query class and its subclasses.

    Set this parameter with the setAlt() function.

  • The maxResults parameter limits the number of entries in the feed. The value of the parameter is an integer. The number of entries returned in the feed will not exceed this value.

    Set this parameter with the setMaxResults() function.

  • The startIndex parameter specifies the ordinal number of the first entry returned in the feed. Entries before this number are skipped.

    Set this parameter with the setStartIndex() function.

  • The updatedMin and updatedMax parameters specify bounds on the entry date. If you specify a value for updatedMin, no entries that were updated earlier than the date you specify are included in the feed. Likewise no entries updated after the date specified by updatedMax are included.

    You can use numeric timestamps, or a variety of date/time string representations as the value for these parameters.

    Set this parameter with the setUpdatedMin() and setUpdatedMax() functions.

There is a get function for each set function.

<?php
$query = new Zend_Gdata_Query();
$query->setMaxResults(10);
echo $query->getMaxResults();   // returns 10
        

The Zend_Gdata class also implements "magic" getter and setter methods, so you can use the name of the parameter as a virtual member of the class.

<?php
$query = new Zend_Gdata_Query();
$query->maxResults = 10;
echo $query->maxResults;        // returns 10
        

You can clear all parameters with the resetParameters() function. This is useful to do if you reuse a Zend_Gdata object for multiple queries.

<?php
$query = new Zend_Gdata_Query();
$query->maxResults = 10;
// ...get feed...

$query->resetParameters();      // clears all parameters
// ...get a different feed...
        

16.1.8. Fetching a feed

Use the getFeed() function to retrieve a feed from a specified URI. This function returns an instance of class specified as the second argument to getFeed, which defaults to Zend_Gdata_Feed.

<?php
$gdata = new Zend_Gdata();
$query = new Zend_Gdata_Query(
        'http://www.blogger.com/feeds/blogID/posts/default');
$query->setMaxResults(10);
$feed = $gdata->getFeed($query);
        

See later sections for special functions in each helper class for Google Data services. These functions help you to get feeds from the URI that is appropriate for the respective service.

16.1.9. Working with multi-page feeds

When retrieving a feed that contains a large number of entries, the feed may be broken up into many smaller "pages" of feeds. When this occurs, each page will contain a link to the next page in the series. This link can be accessed by calling getLink('next'). The following example shows how to retrieve the next page of a feed:

<?php
function getNextPage($feed) {
    $nextURL = $feed->getLink('next');
    if ($nextURL !== null) {
        return $gdata->getFeed($nextURL);
    } else {
        return null;
    }
}
        

If you would prefer not to work with pages in your application, pass the first page of the feed into Zend_Gdata_App::retrieveAllEntriesForFeed(), which will consolidate all entries from each page into a single feed. This example shows how to use this function:

<?php
$gdata = new Zend_Gdata();
$query = new Zend_Gdata_Query(
        'http://www.blogger.com/feeds/blogID/posts/default');
$feed = $gdata->retrieveAllEntriesForFeed($gdata->getFeed($query));
        

Keep in mind when calling this function that it may take a long time to complete on large feeds. You may need to increase PHP's execution time limit by calling set_time_limit().

16.1.10. Working with data in feeds and entries

After retrieving a feed, you can read the data from the feed or the entries contained in the feed using either the accessors defined in each of the data model classes or the magic accessors. Here's an example:

<?php
$client = Zend_Gdata_ClientLogin::getHttpClient($user, $pass, $service);
$gdata = new Zend_Gdata($client);
$query = new Zend_Gdata_Query(
        'http://www.blogger.com/feeds/blogID/posts/default');
$query->setMaxResults(10);
$feed = $gdata->getFeed($query);
foreach ($feed as $entry) {
    // using the magic accessor
    echo 'Title: ' . $entry->title->text;
    // using the defined accessors
    echo 'Content: ' . $entry->getContent()->getText();
}
        

16.1.11. Updating entries

After retrieving an entry, you can update that entry and save changes back to the server. Here's an example:

<?php
$client = Zend_Gdata_ClientLogin::getHttpClient($user, $pass, $service);
$gdata = new Zend_Gdata($client);
$query = new Zend_Gdata_Query(
        'http://www.blogger.com/feeds/blogID/posts/default');
$query->setMaxResults(10);
$feed = $gdata->getFeed($query);
foreach ($feed as $entry) {
    // update the title to append 'NEW'
    echo 'Old Title: ' . $entry->title->text;
    $entry->title->text = $entry->title->text . ' NEW';

    // update the entry on the server
    $newEntry = $entry->save();
    echo 'New Title: ' . $newEntry->title->text;
}
        

16.1.12. Posting entries to Google servers

The Zend_Gdata object has a function post() with which you can upload data to save new entries to Google Data services.

You can use the data model classes for each service to construct the appropriate entry to post to Google's services. The post() function will accept a child of Zend_Gdata_App_Entry as data to post to the service. The method returns a child of Zend_Gdata_App_Entry which represents the state of the entry as it was returned from the server.

Alternatively, you could construct the XML structure for an entry as a string and pass the string to the post() function.

<?php
$gdata = new Zend_Gdata($authenticatedHttpClient);

$entry = $gdata->newEntry();
$entry->title = $gdata->newTitle('Playing football at the park');
$content = $gdata->newContent('We will visit the park and play a few football matches');
$content->setType('text');
$entry->content = $content;

$entryResult = $gdata->insertEntry($entry,
        'http://www.blogger.com/feeds/blogID/posts/default');

echo 'The <id> of the resulting entry is: ' . $entryResult->id->text;
        

To post entries, you must be using an authenticated Zend_Http_Client that you created using the Zend_Gdata_AuthSub or Zend_Gdata_ClientLogin classes.

16.1.13. Deleting entries on Google servers

Option 1: The Zend_Gdata object has a function delete() with which you can delete entries from Google Data services. Pass the edit URL value from a feed entry to the delete() method.

Option 2: Alternatively, you can call $entry->delete() on an entry retrieved from a Google service.

<?php
$gdata = new Zend_Gdata($authenticatedHttpClient);
// a Google Data feed
$feedUri = ...;
$feed = $gdata->getFeed($feedUri);
foreach ($feed as $feedEntry) {
    // Option 1 - delete the entry directly
    $feedEntry->delete();
    // Option 2 - delete the entry by passing the edit URL to $gdata->delete()
    // $gdata->delete($feedEntry->getEditLink()->href);
}
        

To delete entries, you must be using an authenticated Zend_Http_Client that you created using the Zend_Gdata_AuthSub or Zend_Gdata_ClientLogin classes.

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