Matrix Hedwig

This is a dead simple Push Gateway for a Matrix.org application. It implements the Matrix Push Notification API r0.1.1 and supports Firebase Cloud Messaging only with iOS and Android being supported. If you need to push to iOS be sure to add the appropriate push key or certificate to your FCM project.

Features:

Implements the POST /_matrix/push/v1/notify endpoint
Forwards notifications from the format event_id_only
Returns invalid push keys in the rejected response field
Health status endpoint at GET /health
Version endpoint at GET /version
Prometheus metrics at GET /metrics

This project name aged badly, trans rights are human rights!

Getting Started

Hedwig configuration:

Please reference config.sample.yaml for which settings can be set. The configuration file needs to be named config.yaml The fcm_service_account_token_path setting needs to point to an FCM service account token json file.
The fcm_push_max_retries setting specifies how many attempts at pushing a notification to a device should be made before giving up and reporting the push key as dead.

To output to stdout instead of files, remove the file_output section from the config.yaml file.

There is partial support for the proposed delayed push MSC which is defined here, a maximum jitter delay can be specified with the max_jitter_delay setting. Set to 0.0 to disable the jitter completely.

In low traffic situations it might be advisable to disable jitter as it can lead to messages being sent out of order.

On app side:

Example valid pusher set request (to homeserver, the homeserver will then talk to hedwig whenever there is a notification):

/_matrix/client/v3/pushers/set:

{
  "app_display_name": "Aweseome matrix client!",

  // Deprecated: {APP_ID}.data_message is equivalent to setting data-message: "android" in data (keep app_id in hedwig config without the .data_message); This is due to removal, do not rely on it staying around!
  "app_id": "app.id.from.cfg", 
  "append": false,
  "data": {
    "format": "event_id_only",
    "url": "https://your-awesome-pusher.example/_matrix/push/v1/notify",
    "data_message": null | "android" | "ios" // Optional!
  },
  "device_display_name": "🦊phone",
  "kind": "http",
  "lang": "en",
  "profile_tag": "magic-profile-tag",
  "pushkey": "🏰🦊🔒"
}

This will result in an FCM notification being sent to the device with the notification request in a key from json -> content from json as string format.

Example request sent from hedwig to FCM for an android notification:

{
   "token":"Android",
   "data":{
      "content":"null",
      "counts":"{\"unread\":1337,\"missed_calls\":null}",
      "devices":"[{\"app_id\":\"com.famedly.🦊\",\"pushkey\":\"Android\",\"pushkey_ts\":1655896032,\"data\":{\"data_message\":\"android\",\"format\":\"event_id_only\"},\"tweaks\":null}]", 
      "prio":"\"high\"",
      "room_id":"owo"
   },
   "android":{
      "priority":"high",
      "direct_boot_ok":false
   }
}

Example request to FCM for an iOS notification:

{
   "token":"IoS",
   "data":{
      "content":"null",
      "counts":"{\"unread\":1337,\"missed_calls\":null}",
      "devices":"[{\"app_id\":\"com.famedly.🦊\",\"pushkey\":\"IoS\",\"pushkey_ts\":1655896032,\"data\":{\"data_message\":\"ios\",\"format\":\"event_id_only\"},\"tweaks\":null}]",
      "prio":"\"high\"",
      "room_id":"owo"
   },
   "notification":{
      "title":"🦊 1337 🦊",
      "body":"read the notification pls :c"
   },
   "apns":{
      "headers":{
         "apns-priority":"5",
         "apns-push-type":"background"
      },
      "payload":{
         "aps":{
            "badge":1337,
            "mutable-content":1,
            "sound":"default"
         }
      }
   }
}

Example request to FCM for a notification without having specified the device type (no message content can be displayed):

{
   "token":"Generic",
   "notification":{
      "title":"🦊 1337 🦊",
      "body":"read the notification pls :c"
   },
   "android":{
      "priority":"high",
      "notification":{
         "icon":"notifications_icon",
         "sound":"default",
         "tag":"org.matrix.default_notification",
         "click_action":"FLUTTER_NOTIFICATION_CLICK",
         "channel_id":"org.matrix.app.message"
      },
      "direct_boot_ok":false
   },
   "apns":{
      "headers":{
         "apns-priority":"10"
      },
      "payload":{
         "aps":{
            "badge":1337,
            "sound":"default"
         }
      }
   }
}

Lints

We have plenty of lints in lints.toml that we use. Cargo currently does not natively support an extra file for lints, so we use cargo-lints. To check everything with our lints, run this locally:

cargo lints clippy --workspace --all-targets

and this in your IDE:

cargo lints clippy --workspace --all-targets --message-format=json

A few lints are commented out in lints.toml. This is because they should not be enabled by default, because e.g. they have false positives. However, they can be very useful sometimes.

Pre-commit usage

If not installed, install with your package manager, or pip install --user pre-commit
Run pre-commit autoupdate to update the pre-commit config to use the newest template
Run pre-commit install to install the pre-commit hooks to your local environment

Healthcheck for Docker container

The service API implements the /health check for the Docker containers.

IMPORTANT: In order the Docker container to be able to perform the check, the image MUST provide the curl tool. If changing or updating the base image's version, please ensure the curl availability!

curl -s http://localhost:7022/health || exit 1

S. Dockerfile for details.

Famedly

This project is part of the source code of Famedly.

We think that software for healthcare should be open source, so we publish most parts of our source code at github.com/famedly.

Please read CONTRIBUTING.md for details on our code of conduct, and the process for submitting pull requests to us.

For licensing information of this project, have a look at the LICENSE file within the repository.

If you compile the open source software that we make available to develop your own mobile, desktop or embeddable application, and cause that application to connect to our servers for any purposes, you have to agree to our Terms of Service. In short, if you choose to connect to our servers, certain restrictions apply as follows:

You agree not to change the way the open source software connects and interacts with our servers
You agree not to weaken any of the security features of the open source software
You agree not to use the open source software to gather data
You agree not to use our servers to store data for purposes other than the intended and original functionality of the Software
You acknowledge that you are solely responsible for any and all updates to your software

No license is granted to the Famedly trademark and its associated logos, all of which will continue to be owned exclusively by Famedly GmbH. Any use of the Famedly trademark and/or its associated logos is expressly prohibited without the express prior written consent of Famedly GmbH.

For more information take a look at Famedly.com or contact us by info@famedly.com

famedly / hedwig