Question

This query is related to Google Apps. Is there a way we can get a trigger or a callback or force the user to visit a page from my app when user deletes my app from his domain?
I want to perform some operations when a user deletes the app from his domain.
Please help.

Answer 1

The license notifications API allows you to retrieve a list of license-related events that have occurred for customers of your application. These events may be of four types:

provisions — A new license of the application has been provisioned.
expiries — A license of the application has expired.
deletions — An application has been deleted from a domain.
reassignments — An administrator has assigned or revoked a seat license for the application on the provided domain.
The license notification API allows several optional parameters:

timestamp — The time, measured in milliseconds since the UNIX epoch, to begin querying for notifications. The API will return results that occurred approximately after this time, but occasionally may return results that occurred prior to the timestamp. If you must have a list of notifications that only contains results after the timestamp, it is recommended that you apply a second filter in your code. The timestamp may not be used simultaneously with a start-token.
start-token — A continuation token, returned from a previous query, that may be used to continue retrieving notifications after the previous result set stopped. The start-token may not be used simultaneously with a timestamp.
max-results — The maximum number of notifications to return.
For a complete description of all response fields and possible values for those fields, see the reference.

For more : http://code.google.com/googleapps/marketplace/v2/developers_guide.html#license_notifications