- Node.js v8.4.0
To install the dependencies, run the following command:
npm install
To start the server, a firebase admin SKD account is required. Follow this guide, put the JSON file with your service account credentials under project directory, and update firebase.js accordingly.
Then run the following command:
npm start
To request a new trip, send a GET request to http://localhost:3000/passengers/:passengerId/trips/new
where :passengerId is the trip Passenger's ID, which is also his/her Firebase ID.
If you deployed it on Heroku, GET from http://:your-app-name.herokuapp.com/passengers/:passengerId/trips/new
where :your-app-name is your heroku app's name.
The response is a JSON object, which contains:
{
"shuttleId": "",
"status": ""
}
Both of the two attributes are string. shuttleId is the shuttle ID the requesting trip is assigned to. status is either existed, meaning the trip already exists and is ongoing, or new, meaning the trip is new. If the trip already exists, shuttleId will be the shuttle ID of the existing trip.
The server itself does not modify data in firebase. It simply keeps track of the environment and assign passengers to shuttles without passenger clients assigning themselves, thus avoids race condition.
To deploy the server on heroku, follow this guide.
Also, in order to not leak your Firebase admin SDK credentials, add your JSON file into .gitignore, set environmental variable FIREBASE_DATABASEURL to your firebase database url, and FIREBASE_SERVICE_ACCOUNT to your JSON file as a string.
Race condition can still happen. If a passeneger asks for a trip, but hasn't gotten the result (due to poor network connection) or hasn't updated firebase yet, another passeneger might get assigned to the same shuttle even though it is full. A placeholder should be implemented to reserve the spot and expire after a short period of time.
Haofan Zhang - Initial works
This project is licensed under the MIT License