CAPTAIN HOOK

⚠️ This project is intended for personal use and might not be suited to production usecases yet. It should mostly do what is expected, but be aware that it was not intended for production usecases.

CaptainHook is a small utility to replicate webhook functionality on APIs that don't provide one. It will basically poll API endpoints on a regular basis (you can set the timing), and forward the API response to any other endpoint if the response changed.

Prerequisites

You will need NodeJS 12+ and PostgreSQL to run this project.

Configuration

There are a few required ENV variables (see .env.sample):

For the database connection:

DATABASE_HOST
DATABASE_PORT
DATABASE_NAME
DATABASE_USER
DATABASE_PASSWORD

And for authenticating the requests:

SECRET_TOKEN

Pick a reasonably long random string.

Run

First install the dependencies:

yarn install

then build and run the project:

yarn build
yarn start:prod

You can also start in development mode, with code reloading:

yarn start:dev

Docker

There is a Dockerfile available as well for running in production.

Usage

This tool is based around objects called Trackers. A tracker monitors an endpoint and forwards the response as is to another endpoint whenever it changes. You can create any number of trackers.

The usage is pretty simple. There are a few API enpoints you can use:

Authentication

All the request must include an authorization header:

Authorization: Bearer <secret token>

The secret token being the one you defined in the env variables.

GET /trackers

Lists all the trackers currently created.

Example response:

[
	{
		"id": 42,
		"name": "Time",
		"interval": 10000,
		"trackedUrl": "http://worldtimeapi.org/api/timezone/Europe/Paris",
		"trackedUrlHeaders": {},
		"latestResponseHash": "7693a0e83121a80eb0497a0ffaae70b5",
		"targetUrl": "https://eoxyy9r8winxf3i.m.pipedream.net"
	},
  ...
]

POST /trackers

Creates a new tracker.

Payload:

{
	"name": "My tracker",
  "interval": 10000,
  "trackedUrl": "http://example.com/endpoint",
	"trackedUrlHeaders": {
	},
  "targetUrl": "http://example.com/webhook"
}

• name: A name for your tracker
• interval: The polling interval in ms
• trackedUrl: The API endpoint you want to track
• trackedUrlHeaders: The headers you want to add to your request. Like authorization headers
• targetUrl: Your target URL where you want the responses to be forwarded

Example response:

{
	"name": "My tracker",
  "interval": 10000,
  "trackedUrl": "http://example.com/endpoint",
	"trackedUrlHeaders": {
	},
  "targetUrl": "http://example.com/webhook"
	"id": 42
}

DELETE /trackers/:id

Delete the tracker with the ID :id. It will stop the polling of the target endpoint.