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Fitbit Device Integration

By Matthew Bender


Posted on January 9, 2015


Fitbit and health device data

I currently work as a Lead Software Engineer at Welltok/CaféWell which is a company that specializes in health device data for its users. I have been a major part of the company’s device integrations from the start. So I have an innate passion for health devices and data. This is what drove me to integrate my personal Fitbit Flex into my personal sandbox website http://5280code.com - http://www.5280code.com/fitness

Fitgem!

Thankfully the majority of the Fitbit API and OAuth integration has already been created by the ruby community. whazzmaster has done a great job at keeping fitgem(ruby API client) up to date with Fitbit API changes/deprecations. He also has a good wiki about how to OAuth with Fitbit https://github.com/whazzmaster/fitgem/wiki/The-OAuth-Process

The Fitbit API

The Fitbit API is not perfect but what API is? My biggest gripes are that they don’t [return timestamps in UTC] (https://wiki.fitbit.com/display/API/API+Time+Zones), they return the data in the user’s timezone which requires an extra API call and they don’t give finer grained data without a [partner agreement] (https://wiki.fitbit.com/display/API/API-Get-Intraday-Time-Series). The API is documented pretty well and their support team is responsive, at least when you have a partner agreement. The [pubsub service] (https://wiki.fitbit.com/display/API/Fitbit+Subscriptions+API) they provide is superb, they pass minimal data and can handle high user load.

The Integration

I first created a developer account on the [fitbit dev website] (https://dev.fitbit.com) and register a new application. That creates a client key and secre. I then created user OAuth tokens by hand by following whazzmaster’s tutorial. I then set those tokens/secrets to environment variables . My integration is fairly simple. The fitness angular controller makes 4 separate requests to the rails API controller in order to populate the page.

angular.module('app.controllers.fitness', ['resources.fitbit'])
.controller 'fitnessCtrl', ($scope, Fitbit) ->
Fitbit.user_info().then (fitbit_data) ->
$scope.user = fitbit_data

Fitbit.device_info().then (fitbit_data) ->
$scope.device = fitbit_data

Fitbit.activity_data().then (fitbit_data) ->
$scope.activity = fitbit_data

Fitbit.sleep_data().then (fitbit_data) ->
$scope.sleep = fitbit_data

Each of the 4 actions on the rails side then call fitbit’s API https://github.com/codebender/5280code/tree/master/app/controllers/api/fitbit The rails side weights heavily on the fitgem for API data as I mention https://github.com/codebender/5280code/blob/master/app/models/fitbit/service.rb I just do a little manipulation of the data after it comes in for each API call.

Future

I would love to do some D3 or charting library but I don’t have access to time series data. :-( I also only show today’s data. Perhaps in the future I can integrate a chart of multiple day’s of data into a fancy chart. If I every switch to another device, I would probably replace all of this functionality on the site.

Questions?

If you want more details, hit me up on twitter [@5280code] (https://twitter.com/5280code)!