Relay

Relay transmits POST messages from server throught websockets (socket.io actually) to clients and websockets messages throught POST back to server.

On the client side, it is a common problem of keeping data up-to-date. Sometimes, implementing websokets might be inconvenient due to technological stack or the lack of experience. With Relay you can send data from server to client with a familiar HTTP POST request.

Quickstart

Install Relay

git clone https://github.com/ivanrussu/relay
cd ./relay
npm install
cp config.example.js config.js
npm run serve

Prepare a webhook. Webhook is used to control subscriptions and getting information from Relay. Webhooks are called as form-data POST requests and contain api_key, event and data fields. event field determines the type of a webhook. It might be connected which contains no data and triggers every time a client connects to your link (you will get your link in the next step). When a client is trying to subscribe to a channel subscribe event triggers, in this case data contains array of strings in channels field and any object in payload. For example, you can use payload to authenticate clients. The last type of webhooks is request with any object as data. It is called when a client makes a request to your server.
Create an API Key. API Key is used to authenticate requests between your server and Relay. To create one, use command npm run make api-key. Answer questions and you will obtain API key as well as the link. Keep the key safe. Share the link with frontend.

Send a message. Once the clients are ready to receive messages, simply make POST request like

curl --location --request POST 'https://relay.example.com/api/v1/broadcast' \
--header 'Content-Type: application/json' \
--data-raw '{
    "api_key": "YOUR_API_KEY",
    "channel": "notifications",
    "data": {
        "event": "new_message",
        "user_id": 700695,
        "message": "Hello, how are you?"
    }
}'