gotify-to-signal

This Gotify plugin forwards received messages to the Signal messenger.

Prerequisites

To make the plugin work, you need a running Signal Messenger REST Api instance. Refer to the getting started section on how to run the container.

The Signal Messenger REST Api needs to be reachable from the Gotify server.

If you have a working Signal Messenger REST Api, you can register a spare phone number which will be used to send the messages received by Gotify. (It is also possible to link your primary phone number to the Signal Messenger REST Api, but this setup is currently untested.)

To register your phone number, you need to generate a Signal captcha at their website. Confirm you're a humand and then grab the captcha string from the Open Signal link. The string looks like signal-hcaptcha.<random stuff>.registration.<random stuff>.

Now you can call the REST Api with the following command:

curl -X POST -H "Content-Type: application/json" 'https://<your host>/v1/register/<your phone number in international number format>' \                                                                                  (production/ngrstack)
     -d '{"captcha": "<your generated captcha>", "use_voice": false}'

Afterward you receive a text response with a confirmation code. Grab the code and call the REST Api again with the following command:

curl -X POST -H "Content-Type: application/json" 'https://<your host>/v1/register/<your phone number>/verify/<your confirmation code>' 

Now you're ready to use the registered phone number with the Signal Messenger REST Api. Send a test message to verify that everything works as expected.

curl -X POST -H "Content-Type: application/json" 'https://<your host>/v2/send' \                                                                                                    (production/ngrstack)
     -d '{"message": "Test via Signal API!", "number": "<your registered number>", "recipients": [ "<number to send to>" ]}'

You can now proceed with the installation of the plugin.

Installation :rocket:

If you already have a running Gotify server, generate a new client token for the plugin. After that make sure all necessary environment variables are set in your deployment (you can also skip this step and configure the plugin later in the Gotify web interface, but it's recommended to set them beforehand).

SIGNAL_FROM_NUMBER=<your registered number in international number format>
SIGNAL_TO_NUMBER=<the number to forward messages to (in international format)>
SIGNAL_API_HOST=<your signal api host like https://signal-api.mydomain.tld>
GOTIFY_HOST=<Gotify web api host like ws://localhost:8080>
SIGNAL_CLIENT_TOKEN=<Gotify client token generated above>

Now you can deploy the plugin by building it yourself or grab a binary release from the release section of this repository.

Building :hammer_and_wrench:

For building the plugin, gotify/build docker images are used to ensure compatibility with gotify/server.

Export GOTIFY_VERSION and set it to a tag, commit or branch from the gotify/server repository.

export GOTIFY_VERSION=v2.8.0

This command builds the plugin for amd64, arm-7 and arm64. The resulting shared object will be compatible with gotify/server version 2.8.0.

make build