To use Greqo, load the appropriate library and create a new object.  For Blogger, you would use the following code:

Sample Code
%%
require_once($_PATH['greqo'] . 'blogger.class.php');
$GreqoBlogger = new GreqoBlogger($debug=1);
$GreqoBlogger->email = 'user@gmail.com';
$GreqoBlogger->password = '**********';
$GreqoBlogger->blog_id = '0000000000000000000';
%%

Since the Google Data API requires supplying your Google account password, make sure it is located in a secure location on your server (outside the document root, if possible).

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CategoryGreqo