BodyTrace

BodyTrace is a Ruby gem enabling receiving and storing requests from BodyTrace's digital scale: alt

Installation

run:

    gem install bodytrace

or add to your Gemfile:

    gem 'bodytrace'

Usage

this gem generate a platform to catch/store BodyTrace's digital scale POST requests in this format:

":{"unit":1,"weight":69800,"tare":0}

Where:

  • deviceId: IMEI serial number (without leading zeros and the last digit)

  • ts: timestamp when the measurement was taken represented in milliseconds since UNIX Epoch, UTC

  • batteryVoltage: battery voltage (mV) - functional battery voltage range: 4.7-6.0 V (could go a little over 6.0 V)

  • rssi: signal strength in (- dBm) - can be converted into "percentage" by this formula: min(0, max(1, (115 - rssi) / 52)) * 100

  • values/unit: measurement unit the scale was in at the time of taking the measurement

  • values/weight: weight value (in grams - regardless of unit)

  • values/tare: It shows the difference between the zero point setting before the weigh-in and after. If it is greater than + 0.1 kg, that means that the scale has a calibration error and the value sent as the weight value was offset by the amount indicated in the tare value.

run:

rails g body_trace:install user_name password BodytraceMeasurement Device User

where:

user_name [Required]:

http authentication user_name required to parse BodyTrace requests.

password [Required]:

http authentication password required to parse BodyTrace requests.

BodytraceMeasurement [Optional & default: BodytraceMeasurement]

Name of the model which will hold requests data comes from BodyTrace API.

Device [Optional & default: Device]:

Name of the model which will hold information about "which user uses which scale device"

User [Optional & default: User]:

Name of already existing "user" model that will be used to link with a scale device.

this will generate:

    route  resources :bodytrace_measurements, only: [:create]
    create  app/models/bodytrace_measurement.rb
    create  app/models/device.rb
    create  app/controllers/bodytrace_measurements_controller.rb
    create  db/migrate/20140707135956_create_bodytrace_measurements.rb
    create  db/migrate/20140707135957_create_devices.rb

Then run:

rake db:migrate

And finally:

Provide BodyTrace Team with a URL to [POST] Requests on it. In above example URL will be:

[POST] sitename.com/bodytrace_measurements

and provide them with user_name and password you generated for HTTP basic authentication.

list of supported Requests / Responses :

Request: # heartbeat message

"deviceId":XXXXXXXXXXXXX,"ts":1391436314212,"batteryVoltage":5603,"rssi":80,"values":{}

Response:

204 - No content

Request: # real error-free request

"deviceId":XXXXXXXXXXXXX,"ts":1380562575798,"batteryVoltage":5522,"rssi":91,"values":{"unit":1,"weight":69800}

Response:

200 - OK

Request: # receiving "deviceId" not registered with a user

"deviceId":XXXXXXXXXXXXX,"ts":1380562575798,"batteryVoltage":5522,"rssi":91,"values":{"unit":1,"weight":69800

Response:

404 - Not Found

Request: # missing parameter request, missing "deviceId"

"ts":1380562575798,"batteryVoltage":5522,"rssi":91,"values":{"unit":1,"weight":69800}

Response:

422 - unprocessable entity

Request: # missing parameter request, missing "values" paramter

"deviceId":XXXXXXXXXXXXX,"ts":1380562575798,"batteryVoltage":5522,"rssi":91}

Response:

422 - unprocessable entity

Request: # syntax-error in the request parameters, missing '}'

"deviceId":XXXXXXXXXXXXX,"ts":1380562575798,"batteryVoltage":5522,"rssi":91,"values":{"unit":1,"weight":69800

Response:

400 - Bad Request