Node.js Backend Challenge

Links

• Indego is Philadelphia's bike-sharing program, with many bike stations in the city.
• The Indego GeoJSON station status API provides a realtime snapshot of the number of bikes available, number of open docks available (not currently containing a bike), and total number of docks at every station. This API is free and requires no API key.
• The Open Weather Map API provides a realtime snapshot of the current weather in a given city. Since Philadelphia is a small geographical area it is sufficient to obtain the weather for a geographical location central to Philadelphia. This API has a free plan, you will need to sign up for an API key.

Goal

Using MongoDB, Node.js, Express, Bluebird, Lodash and the Linux, Node.js and MongoDB hosting of your choice (see below for hosting details including free options), create a new API server which accumulates data over time and provides access to historical data for both weather and Indego bike availability, supporting the following queries at minimum. Note that it is sufficient to store data at hourly intervals.

Running in production

To run in production, schedule the command npm run updater to run hourly on the hour with cron or otherwise to collect data.

Requirements

• App stores Indego and weather data
• App downloads fresh Indego and weather data once per hour
• App provides an API to access Indego and weather data
• App API supports the following queries at a minimum:
  • Snapshot of all stations at a specified time (/api/v1/stations?at=2017-11-01T11:00:00)
  • Snapshot of one station at a specific time (/api/v1/stations/KIOSKIDGOESHERE?at=2017-11-01T11:00:00)
  • Snapshots of one station over a range of times (/api/v1/stations/KIOSKIDGOESHERE?from=2017-11-01T11:00:00&to=2017-12-01T11:00:00&frequency=daily)
• App should have mocha tests built for all requirements
  • Storing indego and weather data
  • Downloading once per hour ???
  • Providing API for data
    • All station at time query
    • One station at time query
    • One station over time span query
• App is hosted and accessible publicly
• Extra credit: Implement Vue front end with data visualization

Snapshot of all stations at a specified time

Data for all stations as of 11am Universal Coordinated Time on November 1st, 2017:

/api/v1/stations?at=2017-11-01T11:00:00

This API should respond as follows, with the actual time of the first snapshot of data on or after the requested time and the data:

{
  at: '2017-11-01:T11:00:01',
  weather: { /* as per the Open Weather Map API response for Philadelphia */ },
  stations: { /* As per the Indego API */ }
}

If no suitable data is available a 404 status code should be given.

Snapshot of one station at a specific time

Data for a specific station (by its kioskId) at a specific time:

/api/v1/stations/KIOSKIDGOESHERE?at=2017-11-01T11:00:00

The response should be the first available on or after the given time, and should look like:

{
  at: '2017-11-01:T11:00:01',
  weather: { /* as per the Open Weather Map API response for Philadelphia */ },
  station: { /* Data just for this one station as per the Indego API */ }
}

Include an at property in the same format indicating the actual time of the snapshot.

If no suitable data is available a 404 status code should be given.

Snapshots of one station over a range of times

All historical data for a specific station between two timestamps:

/api/v1/stations/KIOSKIDGOESHERE?from=2017-11-01T11:00:00&to=2017-12-01T11:00:00&frequency=daily

For this last response, the returned JSON value should be an array of values in ascending chronological order. Each element in the array should look like:

{
  at: '2017-11-02T10:00:00',
  station: { /* snapshot in the same format as the other APIs */ },
  weather: { /* as per the Open Weather Map API response for Philadelphia */ }
}

The frequency query parameter, if present, may be hourly or daily. The API should respond with only one entry from each hour or day. For hourly this should be the first entry on or after the top of the hour. For daily it should be the first entry on or after noon, Philadelphia time. If frequency is absent, hourly is the default.

Unit tests

All of the APIs should have unit test coverage; invoking npm test should test your package. We suggest mocha but other frameworks are fine.