Traffic Light Server

This is a small node.js server with the purpose to configure and serve a light configuration to a real traffic light, like this one:

It is meant to be used with a corresponding client to read the light and do something awesome with it.

An example is a real traffic light controlled with a Raspberry PI that fetches the light configuration of this app and displays it on a real traffic light.

Modes

At the moment two modes for setting the lights are supported:

• public changes the traffic light using the web UI or the JSON API.

• ci uses webhooks from Codeship to set the lights.

Setup

This app ist meant to run on heroku using the RedisToGo add-on for persistence.

Besides, there are two environment variables that need to be set:

• heroku config:set CI_SECRET=YOURSECRET Sets the secret URL for CI webhook.
• heroku config:set LIGHT_MODE=public Sets the mode of the traffic light server. Possible values: public or ci.

Controlling the traffic light configuration

Web UI

When in public mode, the light configuration can be changed by clicking on the corresponding lights on the UI.

In ci mode the web UI is read-only and only shows the current status.

JSON API

GET /lights

{
  "mode": "public", // read only (set via heroku config:set LIGHT_MODE=public|ci)
  "red": true,      // boolean
  "yellow": true,   // boolean
  "green": true     // boolean
}

curl example:

curl https://yourapp.herokuapp.com/lights

POST /lights

{
  "red": true,      // boolean
  "yellow": true,   // boolean
  "green": true     // boolean
}

curl example:

curl -i -H "Content-Type: application/json" -X POST -d '{ "yellow" : true, "green" : true, "red" : true }' https://yourapp.herokuapp.com/lights

CI webhooks

Pick and set a random secret for the webhook URL:

heroku config:set CI_SECRET=YOURSECRET

Then add the webhook to the notification settings of your codeship project.

Change mode

Just change the heroku env variable like this heroku config:set LIGHT_MODE=public, heroku will automatically restart your app.

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