I am using Gmail push notifications for email processing. When I receive a message notification from Google, I use the history list API with the previously stored
historyId and can see new messages using messagesAdded. Once I have retrieved the messages, I store the last historyId for the next request.
When testing, if I send two mail messages (about 30 seconds apart) to the watched mailbox, I see two messages notifications from Google and when I call the history API for each of the notifications I see the message ids. This is all good.
If I repeat the same test but send the two mail messages immediately after each other, I get the two notifications from Google but when I call the history API for the first message, I get the two message ids in that history API call. When I call the history API call for the second notification, I get a duplicate of the last message id.
How can I prevent seeing duplicate message ids in this scenario? Any help or pointers would be much appreciated.
Updated: Added request and response example for second test.