Stormglass

Ruby gem for access to the Stormglass Weather forecast API.

Overview

This gem augments the Stormglass API responses to make consuming the API more accessible for ruby developers.

• Provides weather lookup for address and lat/lng
• Provides units and descriptions for all forecast types (from API docs)
• Specify start/end as DateTime
• specify hours to calcuate end offset from start (default 12)
• Creates alternative representations of values (such as Fahrenheit, or knots)
• Specify default units and sources via Stormglass.configure block, or override at method invocation

For more information, visit Stormglass API docs

Note: this gem currently only implements the point API endpoint. Accepting pull requests!

Installation

gem install stormglass

or in your gemfile

gem 'stormglass'

API Key

To use Stormglass you'll need to provide an API key, which can be configured a number of ways:

1. Enviroment variable STORMGLASS_API_KEY
2. within a Stormglass.configure block (more on that below)
3. with Rails secret stormglass_api_key
4. at request invocation by passing key

Configuration

You can configure the gem with the following block

Stormglass.configure do |config|
  config.units = {air_temperature: 'F', gust: 'knot'}
  config.api_key = 'abcd-abcd-abcd'
  config.source = 'sg'
end

Walkthrough

First, let's query the stormglass API for an address. This will look up via Geocoder and then call Stormglass.for_lat_lng for us with the first result.

response = Stormglass.for_address('123 broad street philadelphia pa', hours: 24)
=> #<Stormglass::Response remaining_requests=31,
hours=[#<Stormglass::Hour time='2018-12-12 21:00:00 +0000'> ...]>

The methods we can call are underscored variants of what the camelCaps API returns. Taken from stormglass/hour.rb

 VALUES = [:air_temperature,:cloud_cover,:current_direction,:current_speed,:gust,:humidity,
            :precipitation,:pressure,:sea_level,:swell_direction,:swell_height,:swell_period,
            :visibility,:water_temperature,:wave_direction,:wave_height,:wave_period,
            :wind_direction,:wind_speed,:wind_wave_direction,:wind_wave_height,:wind_wave_period]

Let's see the first hour's air_temperature.

response.hours.first.air_temperature
=> #<Stormglass::Value value=44.91, unit='C', description='Air temperature as degrees Celsius',
unit_type='C', unit_types=["C", "F"], data_source='sg',
data_sources=["sg", "dwd", "noaa", "wrf"]>

we can also call response.first.air_temperature or even response.air_temperature and it will defer to the first hour result.

But what if we don't want the first hour? In addition to calling response.hours.select{...}, you can use #find with your local timezone and it will convert to UTC for lookup

response.find('7AM EST').air_temperature
=> #<Stormglass::Value value=44.91, unit='C', description='Air temperature as degrees Celsius',
unit_type='C', unit_types=["C", "F"], data_source='sg', data_sources=["sg", "dwd", "noaa", "wrf"]>

we can work with the response.find('7AM EST').air_temperature.value directly (a Float), or call to_s for a pretty string

response.air_temperature.to_s
=> "4.91 C"

What if we want air temperature in Fahrenheit instead? No need to whip out the calculator, we've got you covered!

response.air_temperature(unit_type: 'F')
=> #<Stormglass::Value value=44.91, unit='F', description='Air temperature as degrees Fahrenheit',
unit_type='F', unit_types=["C", "F"], data_source='sg', data_sources=["sg", "dwd", "noaa", "wrf"]>

Or we can reference a different data source than the default

response.air_temperature(unit_type: 'F', data_source: 'noaa')
=> #<Stormglass::Value value=45.33, unit='F', description='Air temperature as degrees Fahrenheit',
unit_type='F', unit_types=["C", "F"], data_source='noaa', data_sources=["sg", "dwd", "noaa", "wrf"]>

Structure

There are a few primary classes involved:

1. Stormglass::Response represents the result from stormglass, wrapping hours and meta responses. Calling something like #air_temperature on this delegates to #hours.first
2. Stormglass::Hour represents an hour portion of the API response
3. Stormglass::Value represents a particular forecast value. along with the numeric value it also exposes the description and unit used. It is just a wrapper to the collection of Stormglass::Subvalue's and defers to the preferred/specified one.
4. Stormglass::Subvalue represents a particular variant of forecast value, such as air_temperature in Celsius or in Fahrenheit.

For any of the above instances, you can call #src to access the raw (usually JSON) data that was passed in to populate it.

Because each forecast type has different sources and units, Stormglass::Value instances exposes the progmatic available options data_sources and unit_types you can reference for alternatives to provide.

response.air_temperature(unit_type: 'C')
=> #<Stormglass::Value value=7.17, unit='C', description='Air temperature as degrees Celsius',
unit_type='C', unit_types=["C", "F"], data_source='sg', data_sources=["sg", "dwd", "noaa", "wrf"]>

response.air_temperature(unit_type: 'C', data_source: 'wrf')
=> #<Stormglass::Value value=8.34, unit='C', description='Air temperature as degrees Celsius',
unit_type='C', unit_types=["C", "F"], data_source='noaa', data_sources=["sg", "dwd", "noaa", "wrf"]>