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.

Zend_Gdata makes use of Zend_Feed and Zend_Http_Client to send requests to google.com and fetch results. The response to most Google Data requests is returned as a Zend_Feed object in the format of an Atom or RSS feed.

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.

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

The single optional parameter to the Zend_Gdata constructor is an instance of Zend_Http_Client. If you don't pass this parameter, Zend_Gdata creates a default Zend_Http_Client object. Specifying the Zend_Http_Client object allows you to pass configuration options to that client object.

<?php
require_once 'Zend/Gdata.php';
require_once 'Zend/Http/Client.php';

$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.

You can specify parameters to customize queries with Zend_Gdata. Some parameters apply only to individual Google Data services. These parameters are documented in later sections for each service. Some parameters apply in a common way to multiple Google Data services. These parameters are described below.

There is a get function for each set function.

<?php
$gdata = new Zend_Gdata();
$gdata->setMaxResults(10);
echo $gdata->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. You can use isset() and unset() on these virtual members.

<?php
$gdata = new Zend_Gdata();
$gdata->maxResults = 10;
echo $gdata->maxResults;        // returns 10
echo isset($gdata->maxResults); // returns true
unset($gdata->maxResults);      // clears parameter
?>

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
$gdata = new Zend_Gdata();
$gdata->maxResults = 10;
// ...get feed...

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

Use the getFeed() function to retrieve a feed from a specified URI. This function returns an object of class Zend_Feed.

<?php
$gdata = new Zend_Gdata();
$gdata->setQuery('digital camera');
$gdata->setMaxResults(10);
$uri = 'http://www.google.com/base/feeds/snippets'
    . $gdata->getQueryString();
$feed = $gdata->getFeed($uri);
?>

See the documentation for Zend_Feed for more information on how to use this object.

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.

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

You are responsible for constructing a string containing the correct XML structure for an entry of the respective Google Data service you are using. You may use PHP class libraries such as DOM XML or SimpleXML.

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

$xmlString = <<<XML
<entry xmlns='http://www.w3.org/2005/Atom'
    xmlns:gd='http://schemas.google.com/g/2005'>
  <category scheme='http://schemas.google.com/g/2005#kind'
    term='http://schemas.google.com/g/2005#event'></category>
  <title type='text'>Tennis with Beth</title>
  <content type='text'>Meet for a quick lesson.</content>
  <author>
    <name>Jo March</name>
    <email>jo@gmail.com</email>
  </author>
  <gd:transparency
    value='http://schemas.google.com/g/2005#event.opaque'>
  </gd:transparency>
  <gd:eventStatus
    value='http://schemas.google.com/g/2005#event.confirmed'>
  </gd:eventStatus>
  <gd:where valueString='Rolling Lawn Courts'></gd:where>
  <gd:when startTime='2006-04-17T15:00:00.000Z'
    endTime='2006-04-17T17:00:00.000Z'></gd:when>
</entry>
XML;

$xml = new SimpleXMLElement($xmlString);

$myCalendar = 'http://www.google.com/calendar/feeds/default/private/full';
$gdata->post($xml->asXML(), $myCalendar);
?>

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.

The Zend_Gdata object has a function delete() with which you can delete entries from Google Data services. Pass the <id> value from a feed entry to the delete() method.

<?php
$gdata = new Zend_Gdata($authenticatedHttpClient);
// a Google Data feed
$feedUri = ...;
$feed = $gdata->getFeed($feedUri);
foreach ($feed as $feedEntry) {
    // extract the <id> element
    $id = $feedEntry->id();
    $gdata->delete($id);
}
?>

You can also use the delete() method without a feed object, if you pass a correct URI identifying an entry.

<?php
$gdata = new Zend_Gdata($authenticatedHttpClient);
$uri = 'http://www.google.com/calendar/feeds/default/private/entryID';
$gdata->delete($uri);
?>

In the above example, replace "entryID" with the ID value for the specific entry you want to delete.

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.