Google Calendar API watch channels not stopping - google-calendar-api

Question

Stopping a watch channel is not working, though it's not responding with an error, even after allowing for propagation overnight.  I'm still receiving 5 notifications for one calendarlist change.  Sometimes 6.  Sometimes 3.  It's sporadic. We're also receiving a second round of notifications for the same action after 8 seconds.  Sometimes 6 seconds.  Sometimes a third set with a random count.  Also sporadic. Received a total of 10 unique messages for a single calendar created via web browser.

Answer 1

You can perform infinite amount of watch requests on specific calendar resource, Google will always return the same calendar resource Id for the same calendar, but the uuid you generate in the request will be different, and because of that, you will receive multiple notifications for each watch request that you've made. One way to stop all notifications from specific calendar resource, is to listen for notifications, pull out "x-goog-channel-id" and "x-goog-resource-id" from notification headers, and use them in Channels.stop request.
{
"id": string,
"resourceId": string
}
Every time you perform a watch request, you should persist the data from the response, and check if the uuid or resource id already exist, if yes don't perform watch request for that resource id again (if you don't want to receive multiple notifications).
e.g.
app.post("/calendar/listen", async function (req, res) {
var pushNotification = req.headers;
res.writeHead(200, {
'Content-Type': 'text/html'
});
res.end("Post recieved");
var userData = await dynamoDB.getSignInData(pushNotification["x-goog-channel-token"]).catch(function (err) {
console.log("Promise rejected: " + err);
});
if (!userData) {
console.log("User data not found in the database");
} else {
if (!userData.calendar) {
console.log("Calendar token not found in the user data object, can't perform Calendar API calls");
} else {
oauth2client.credentials = userData.calendar;
await calendarManager.stopWatching(oauth2client, pushNotification["x-goog-channel-id"], pushNotification["x-goog-resource-id"])
}
}
};
calendarManager.js
module.exports.stopWatching = function (oauth2client, channelId, resourceId) {
return new Promise(function (resolve, reject) {
calendar.channels.stop({
auth: oauth2client,
resource: {
id: channelId,
resourceId: resourceId
}
}, async function (err, response) {
if (err) {
console.log('The API returned an error: ' + err);
return reject(err);
} else {
console.log("Stopped watching channel " + channelId);
await dynamoDB.deleteWatchData(channelId)
resolve(response);
}
})
})
}

Answer 2

Not a google expert but I recently implement it in my application,
I am trying to answer some of your questions for future readers:
It's sporadic
Tha's because you have create more than 1 channels for watching events.
We're also receiving a second round of notifications for the same action after 8 seconds
Google doesn't say anything about the maximum delay for sending a push notification.
Suggestions:
CREATE:
When you create a new channel, always save the channel_id and channel_resource in your database.
DELETE:
When you want to delete a channel just use stop API endpoint with the channel data saved in your database
RENEW:
As you have noticed the channels do expire, so you need to update them once in a while. To do that create a crone in your server that is going to STOP all previous channels and it will create new one.
Comment: Whenever something is going wrong please read the error message sent from the Google API calendar. Most of the time, it tells you what is wrong.

Answer 3

Use Channels.stop which is mentioned in the docs. Supply the following data in your request body:
{
"id": string,
"resourceId": string
}
id is the channel ID when you created your watch request. Same goes with resource ID.
Read this SO thread and this github forum for additional reference.