Using the Atom Publishing Protocol, also known as AtomPub, you can create and update activity nodes, which are entries that you can add to an activity to add content such as bookmarks, chats, email messages, files, and to-do items. A single activity can contain up to 2000 nodes. You can create and update activity entries that you own or to which you have edit access.
Creating activity nodes
To create an entry in an activity, such as a to-do item or to add a reply to another entry, send an Atom entry document containing the new activity node of the appropriate type to the parent activity's node list.
Creating an activity node from a template
You can create activity nodes of type entry from an entry template. To do so, retrieve the Atom document of the entry template that you want to use, edit the document to contain your new entry content, and then post the edited Atom document to the activity's node list.
Retrieving activity nodes
To retrieve an activity entry, use the edit link found in the corresponding activity node in the user's My Activities feed.
Updating activity nodes
To update an activity entry, send a replacement Atom entry document containing the modified activity node to the existing activity's edit web address.
Deleting activity nodes
To delete an activity entry, send an HTTP DELETE method to the edit web address specified for the node.
Restoring activity nodes
To restore a deleted entry to an activity, send a HTTP PUT request to the edit web address for the node defined in the trash feed. This moves the entry from the trash feed to the user's activity node list.
Changing entry types
You can change certain activity entries from one type to another.
Moving an entry to a section programmatically
To move a standard entry or a to-do entry to a section in an activity, send an updated Atom entry document to the parent activity's node list.