Marta.js

This library is a wrapper for the MARTA Realtime RESTful APIs.

It's designed to work both in node.js and the browser.

Because the documentation of the upstream APIs is limited, this library alters some naming conventions from what the API returns in an effort to make the data easier to understand.

It uses moment for times and durations, and it's written in TypeScript to aid in defining data structures.

You can request an API key from MARTA to use for the Realtime Rail data. The Realtime Bus data does not require an API key.

Usage

npm install --save marta-js

Promises vs Callbacks

All methods support both promises and callbacks.

Promise mode:

railApi.getRealtimeTrainArrivals().then(function (arrival) {
  // ...
}).catch(function (error) {
  console.error(error)
})

Callback mode:

railApi.getRealtimeTrainArrivals(function (error, arrival) {
  if (error) {
    console.error(error)
  } else {
    // ...
  }
})

In the browser

This library depends on a native ES6 Promise implementation to be supported. If your environment doesn't support ES6 Promises, for example older browsers, you can polyfill.

This library also depends on moment-timezone, which is a fairly large library, so it is not bundled in the browser output blob.

NOTE: currently the Realtime APIs don't work from the browser, as the API does not support CORS. Hopefully this will be resolved soon.

<!-- polyfil for Promises -->
<script src="https://cdn.jsdelivr.net/npm/es6-promise@4/dist/es6-promise.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/es6-promise@4/dist/es6-promise.auto.min.js"></script>
<!-- moment-timezone -->
<!-- marta-js -->
<script src="node_modules/marta-js/dist/marta.js"></script>
<script>
  // library is exposed as a global "Marta":
  const busApi = new window.Marta.RealtimeBusApi()
</script> 

Methods

Realtime Rail

Definition

type RailArrival = {
  destination: string
  direction: 'North' | 'South' | 'East' | 'West'
  eventTime: Moment
  line: 'RED' | 'GOLD' | 'GREEN' | 'BLUE'
  nextArrival: Moment
  station: Station
  trainId: string
  waitingTimeSeconds: number
  waitingTime: Moment.Duration
  waitingState: 'Boarding' | 'Arriving' | string
}

Example

{
  line: 'GOLD', // which train line
  destination: 'Airport', // Name of the train line
  direction: 'South', // Direction of the train line
  eventTime: moment("2017-07-25T21:45:42.000"), // Time at which this update was received
  station: 'AIRPORT STATION', // Name of the station the times are relative to
  nextArrival: moment("2017-07-25T19:45:42.000"), // Time the train will arrive at the station
  trainId: '303506', // A unique identifier for the train
  waitingTimeSeconds: 1608, // how long in seconds until the train arrives at the station
  waitingTime: moment.duration(1608, 'seconds'), // the waiting time, but as a duration object
  waitingState: '26 min' // a string representing the waiting time. Could be also be "Boarding" or "Arriving"
}

RealtimeRailApi#getArrivals

This is the same data that powers the realtime train time monitors in the station. For all stations, it will tell you how long until the next several trains arrive.

const RealtimeRailApi = require('marta-js').RealtimeRailApi
const railApi = new RealtimeRailApi('xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx') // your api key
railApi.getArrivals(function (error, arrivals) {
  // ...
})

RealtimeRailApi#getArrivalsForStation

This is the same as getArrivals, but filtered to only the specified station.

const RealtimeRailApi = require('marta-js').RealtimeRailApi
const railApi = new RealtimeRailApi('xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx') // your api key
railApi.getArrivalsForStation('FIVE POINTS STATION', function (error, arrivals) {
  // ...
})

Realtime Bus

Definition

type BusArrival = {
  adherence: Moment.Duration
  blockId: string
  blockAbbriviation: string
  direction: 'North' | 'South' | 'East' | 'West'
  latitude: number
  longitude: number
  eventTime: Moment
  route: BusRoute
  stopId: string
  timepoint: string
  tripId: string
  busId: string
}

Example

{
  route: '12', // the route the bus is on
  direction: 'North', // the direction the bus is headed
  tripId: '5572278',
  busId: '1453', // a unique id for the bus
  stopId: '901718', // a unique id of the next stop
  // the current location of the bus
  latitude: 33.8206244,
  longitude: -84.4163082,
  eventTime: moment("2017-07-25T21:46:12.000"), // Time at which this update was received
  // Identifies the current time of arrival compared to scheduled arrival time.
  // Negative number indicates bus is running late. Note: this is opposite of what
  // comes back from the API, because I think it makes more sense.
  adherence: moment.duration(-2, 'minutes'),
  blockId: '82', // TODO: ???
  blockAbbriviation: '12-10',  // TODO: ???
  timepoint: 'Howell Mill Rd at Trabert Ave NW',  // TODO: ???
}

RealtimeBusApi#getArrivals

This API returns the lastest location update from each bus, it's route, and if it is on-time.

const RealtimeBusApi = require('marta-js').RealtimeBusApi
const busApi = new RealtimeBusApi()
busApi.getArrivals(function (error, arrivals) {
  // ...
})

RealtimeBusApi#getArrivalsForRoute

This is the same as getArrivals, but filtered to only the specified route.

const RealtimeBusApi = require('marta-js').RealtimeBusApi
const busApi = new RealtimeBusApi()
busApi.getArrivalsForRoute('12', function (error, arrivals) {
  // ...
})

License

MIT