Push notifications can be rather hard to get right, and there are plenty of places to trip up and have nothing but silence to show for your efforts.
This document offers some suggestions of what to check and lists some common pitfalls you may encounter, based on experience.
There are also appendices with information which may be useful for manual debugging.
Your first steps are to ensure that you have logging so you can see what is going
on; a level of INFO
or even DEBUG
will be useful.
Typically, applications will register a pusher on startup.
If you have access to your homeserver, you can check that it is making it there.
Start your application and then run a query against the database.
Use sqlite3 /path/to/homeserver.db
or psql synapse
as required for your
deployment.
SELECT app_id, data FROM pushers
WHERE user_name = '@my.user:example.org' AND kind='http';
You should see something like:
app_id | data
-------------------+--------------------------------------------------------
org.example.chat | {"format":"event_id_only",
| "url":"https://example.org/_matrix/push/v1/notify"}
No details available, but contributions welcome.
Following on from the example above, the homeserver's database contains the
push gateway URL of https://example.org/_matrix/push/v1/notify
.
It may be worth manually checking that the push gateway is reachable from the homeserver; e.g. with curl:
$ curl https://example.org/_matrix/push/v1/notify
<html>
<head><title>405 - Method Not Allowed</title></head>
<body>
<h1>Method Not Allowed</h1>
<p>Your browser approached me (at /_matrix/push/v1/notify) with the method "GET". I only allow the methods HEAD, POST here.</p>
</body>
</html>
If you get a response, such as an error like 405 Method Not Allowed, as above, this would suggest that the push gateway is at least reachable.
If you get a 404 No Such Resource error on the /_matrix/push/v1/notify
endpoint,
then chances are that your reverse proxy is not configured to pass through the
full URL.
If you don't get an HTTP response, then it is probably worth investigation. Check that:
- Sygnal is running
- Sygnal's configuration makes it listen on the desired port
- Any reverse proxies are correctly set up and running
- The firewall permits inbound traffic on the port in question
Sygnal currently only sends 'data messages' (also called 'silent notifications', but this name could be misleading).
Whereas data messages will wake up apps on Android with no additional changes,
iOS needs to be told that a notification is meant to wake up an inactive app.
This is done with FCM's content_available
flag, which you can set in your
fcm_options
dictionary for the Firebase pushkin.
(See sygnal.yaml.sample
.)
Sygnal's APNs support expects your pushkeys to be base64 encoded rather than hexadecimally encoded.
(Why? The previous APNs API which Sygnal supported was binary and didn't define a text-safe encoding, so it was chosen to use base64 in Sygnal. Now the new API exists and specifies hexadecimal encoding, but Sygnal retains backwards compatibility and will do the base64-to-hex conversion.)
If you are using Firebase for your iOS app, you will get Firebase tokens
(looking a bit like blahblahblah:APA91blahblahblah
… note the presence of a
colon which is not valid base64).
In this case, you need to configure Sygnal to use a FCM (gcm) pushkin rather than an APNs one, as Firebase talks to APNs on your behalf. Instead of configuring Sygnal with your APNs secrets, you need to configure Firebase with your APNs secrets, and Sygnal with your Firebase secrets.
If you want your application to be woken up to be able to process APNs messages
received when your application is in the background, you need to set the
content-available
flag in your pusher's default payload — see
the notes for iOS applications.
If you get a bad device token error and you have doubled-checked the token is correct, it is possible that you have used a token from the wrong 'environment', such as a development token when Sygnal is configured to use the production environment.
Sygnal connects to the production APNs instance by default. This will return
400 BadDeviceToken
if you send it a token intended for the sandbox APNs
server.
Either use production tokens, or switch to the sandbox APNs server by setting:
com.example.myapp.ios:
type: apns
...
platform: sandbox
in your Sygnal config file.
Note: this depends on the heredoc syntax of the bash
shell.
curl -i -H "Content-Type: application/json" --request POST -d '@-' http://syg1:8008/_matrix/push/v1/notify <<EOF
{
"notification": {
"event_id": "\$3957tyerfgewrf384",
"room_id": "!slw48wfj34rtnrf:example.org",
"type": "m.room.message",
"sender": "@exampleuser:example.org",
"sender_display_name": "Major Tom",
"room_name": "Mission Control",
"room_alias": "#exampleroom:example.org",
"prio": "high",
"content": {
"msgtype": "m.text",
"body": "I'm floating in a most peculiar way."
},
"counts": {
"unread": 2,
"missed_calls": 1
},
"devices": [
{
"app_id": "<APP ID HERE>",
"pushkey": "<PUSHKEY HERE>",
"pushkey_ts": 12345678,
"data": {},
"tweaks": {
"sound": "bing"
}
}
]
}
}
EOF
HTTP data sent to https://fcm.googleapis.com/fcm/send
:
POST /fcm/send HTTP/1.1
User-Agent: sygnal
Content-Type: application/json
Authorization: key=<FCM TOKEN HERE>
Host: fcm.googleapis.com
{"data": {"event_id": "$3957tyerfgewrf384", "type": "m.room.message", "sender": "@exampleuser:example.org", "room_name": "Mission Control", "room_alias": "#exampleroom:example.org", "membership": null, "sender_display_name": "Major Tom", "content": {"msgtype": "m.text", "body": "I'm floating in a most peculiar way."}, "room_id": "!slw48wfj34rtnrf:example.org", "prio": "high", "unread": 2, "missed_calls": 1}, "priority": "high", "to": "<PUSHKEY HERE>"}
You can send using curl using:
curl -i -H "Content-Type: application/json" -H "Authorization: key=<FCM TOKEN HERE>" --request POST -d '@-' https://fcm.googleapis.com/fcm/send <<EOF
{"data": {"event_id": "$3957tyerfgewrf384", "type": "m.room.message", "sender": "@exampleuser:example.org", "room_name": "Mission Control", "room_alias": "#exampleroom:example.org", "membership": null, "sender_display_name": "Major Tom", "content": {"msgtype": "m.text", "body": "I'm floating in a most peculiar way."}, "room_id": "!slw48wfj34rtnrf:example.org", "prio": "high", "unread": 2, "missed_calls": 1}, "priority": "high", "to": "<PUSHKEY HERE>"}
EOF