# barometer
[](https://travis-ci.org/attack/barometer)
A multi API consuming weather forecasting superstar.
Barometer provides a common public API to one or more weather services (APIs)
of your choice. Weather services can co-exist to retrieve extensive
information, or they can be used in a hierarchical configuration where lower
preferred weather services are only used if previous services are
unavailable.
Barometer handles all conversions of the supplied query, so that the
same query can be used for all (or most) services, even if they don't
support the query directly. See the "Query" section for more information on
this.
## version
Version 0.7.4 is the current release of this gem. The gem is available from
rubygems (barometer: http://rubygems.org/gems/barometer).
It is fully functional (for five weather service APIs).
## status
Currently this project has completed initial development and will work for a
few weather services (wunderground, yahoo, weather_bug).
Barometer is developed using only Ruby 1.9.3, but will probably on both Ruby 1.8.7, 1.9.1 & 1.9.2.
Features to be added in the future:
* better command line output
* even more weather service drivers (hamweather)
* icon support
# dependencies
## Google API key
As stated on the Google Geocoding API website
(http://code.google.com/apis/maps/documentation/geocoding/), Google no longer
requires an API key. Therefore Barometer no longer requires a Google API key.
### other keys
The '~/.barometer' file can hold all your weather service API keys.
eg. weatherbug.com
weather_bug:
code: YOUR_API_CODE
eg. Yahoo! Placemaker
yahoo:
app_id: YOUR_APP_ID
## HTTParty
Why? HTTParty was created and designed specifically for consuming web services.
I choose to use this over using the Net::HTTP library directly to allow for
faster development of this project.
It is possible that I will use Net::HTTP in the future.
## tzinfo
Why? Barometer deals with time information for locations all over the world.
This information doesn't mean that much if it can't be converted to times
that don't correspond to the applicable timezone.
Tzinfo handles this time zone manipulation.
# queries
The query handling is one of the most beneficial and powerful features of
Barometer. Every weather service accepts a different set of possible
queries, so it usually is the case that the same query can only be used
for a couple weather services.
Barometer will allow the use of all query formats for all services
(mostly). It does this by first determining the original query format,
then converting the query to a compatible format for each specific
weather service.
For example, Yahoo! only accepts US Zip Code or Weather.com ID. With Barometer
you can query Yahoo! with a simple location (ie: Paris) or even an Airport
code (ICAO) and it will return the weather as expected.
## acceptable formats
* zipcode
* icao (international airport code)
* coordinates (latitude and longitude)
* postal code
* weather.com ID
* location name (ie address, city, state, landmark, etc.)
* woeid (where on earth id, by Yahoo!)
*if the query is of the formats zipcode or postal code it may not
support conversion to other formats.*
## conversion caching
Barometer has internal conversion caching. No conversion will be
repeated during a measurement, thus limiting the number of web queries
needed.
Example: If you configure Barometer to use both Yahoo and Weather.com,
then use a query like "denver", this will require a conversion from
"denver" to its weather.com weather_id. This conversion is needed for
both web services but will only happen once and be cached.
# usage
You can use barometer right out of the box, as it is configured to use one
register-less (no API key required) international weather service
(wunderground.com).
```ruby
require 'barometer'
barometer = Barometer.new("Paris")
weather = barometer.measure
puts weather.current.temperature
```
## sources
The available sources are:
Wunderground.com (:wunderground) [default]
Yahoo! Weather (:yahoo)
WeatherBug.com (:weather_bug) [requires key]
## source configuration
Barometer can be configured to use multiple weather service APIs (either in
a primary/failover config or in parallel). Each weather service can also
have its own config.
Weather services in parallel
```ruby
Barometer.config = { 1 => [:yahoo, :wunderground] }
```
Weather services in primary/failover
```ruby
Barometer.config = { 1 => [:yahoo], 2 => :wunderground }
```
Weather services, one with some configuration. In this case we are setting
a weight value, this weight is respected when calculating averages.
```ruby
Barometer.config = { 1 => [{:wunderground => {:weight => 2}}, :yahoo] }
```
Weather services, one with keys.
```ruby
Barometer.config = { 1 => [:yahoo, {:weather_bug => {:keys => {:code => CODE_KEY} }}] }
```
### multiple weather API, with hierarchy
```ruby
require 'barometer'
# use yahoo and weather.com, if they both fail, use wunderground
Barometer.config = { 1 => [:yahoo, {:weather_bug => {:keys => {:code => CODE_KEY} }}], 2 => :wunderground }
barometer = Barometer.new("Paris")
weather = barometer.measure
puts weather.current.temperture
```
## command line
You can use barometer from the command line.
# barometer berlin
This will output the weather information for the given query.
See the help for more command line information.
# barometer -h
### fail
What would cause a weather service to fail? The most obvious is that the
particular weather service in currently unavailable or not reachable.
Other possible reasons would include not having the API (or a valid API
key for the particular weather service, if required), not providing a
valid query, or providing a query for a location not supported by the
weather service.
For example, if you look at the example above, the query of "Paris" refers
to a city in France. Yahoo weather services only supports
weather results for USA (at least at the time of writing). Therefore,
Barometer would not use Yahoo, just WeatherBug and failover to use Wunderground
(if needed).
## searching
After you have measured the data, Barometer provides several methods to help
you get the data you are after. All examples assume you already have measured
the data as shown in the above examples.
### by preference (default service)
```ruby
weather.default # returns measurement for default source
weather.current # returns current_measurement for default
weather.now # returns current_measurement for default
weather.forecast # returns all forecast_measurements for default
weather.today # returns forecast_measurement for default today
weather.tomorrow # returns forecast_measurement for default tomorrow
puts weather.now.temperature.c
puts weather.tomorrow.high.c
```
### by source
```ruby
weather.source(:wunderground) # returns measurement for specified source
weather.sources # lists all successful sources
puts weather.source(:wunderground).current.temperature.c
```
### by date
```ruby
# note, the date is the date of the locations weather, not the date of the
# user measuring the weather
date = Date.parse("01-01-2009")
weather.for(date) # returns forecast_measurement for default on date
weather.source(:wunderground).for(date) # same as above but specific source
puts weather.source(:wunderground).for(date).high.c
```
### by time
```ruby
# note, the time is the time of the locations weather, not the time of the
# user measuring the weather
time = Time.parse("13:00 01-01-2009")
weather.for(time) # returns forecast_measurement for default at time
weather.source(:wunderground).for(time) # same as above but specific source
puts weather.source(:wunderground).for(time).low.f
```
## averages
If you consume more then one weather service, Barometer can provide averages
for the values (currently only for the 'current' values and not the forecasted
values).
```ruby
require 'barometer'
Barometer.google_geocode_key = "THE_GOOGLE_API_KEY"
# use yahoo and wunderground
Barometer.config = { 1 => [:yahoo, :wunderground] }
barometer = Barometer.new("90210")
weather = barometer.measure
puts weather.temperture
```
This will calculate the average temperature as given by :yahoo and :wunderground
### weights
You can weight the values from a weather service so that the values from that
web service have more influence then other values. The weights are set in the
config ... see the config section
## simple answers
After you have measured the data, Barometer provides several "simple answer"
methods to help you get answers to some basic questions. All examples assume
you already have measured the data as shown in the above examples.
All of these questions are ultimately specific to the weather source(s) you
are configured to use. All sources that have successfully measured data
will be asked, but if there is no data that can answer the question then
there will be no answer.
### is it windy?
# 1st parameter is the threshold wind speed for being windy
# 2nd parameter is the utc_time for which you want to know the answer,
# this defaults to the current time
# NOTE: in my example the values are metric, so the threshold is 10 kph
weather.windy?(10)
### is it wet?
# 1st parameter is the threshold pop (%) for being wet
# 2nd parameter is the utc_time for which you want to know the answer,
# this defaults to the current time
# NOTE: in my example the threshold is 50 %
weather.wet?(50)
### is it sunny?
# 1st parameter is the utc_time for which you want to know the answer,
# this defaults to the current time
weather.sunny?
### is it day?
# 1st parameter is the utc_time for which you want to know the answer,
# this defaults to the current time
weather.day?
### is it night?
# 1st parameter is the utc_time for which you want to know the answer,
# this defaults to the current time
weather.night?
# design
* create a Barometer instance
* supply a query, there are very little restrictions on the format:
* city, country, specific address (basically anything Google will geocode)
* US zip code (skips conversion if weather service accepts this directly)
* postal code (skips conversion if weather service accepts this directly)
* latitude and longitude (skips conversion if weather service accepts this
directly)
* weather.com weather id (even if the service you are using doesn't use it)
* international airport code (skips conversion if weather service
accepts this directly)
* determine which weather services will be queried (one or multiple)
* if query conversion required for specific weather service, convert the query
* query the weather services
* save the data
* repeat weather service queries as needed
# extending
Barometer attempts to be a common API to any weather service API. I have included
several weather service 'drivers', but I know there are many more available.
Please use the provided ones as examples to create more.
# development
Barometer now uses 'bundler'. You just need to 'git clone' the repo and 'bundle install'.
## Contributions
Thank you to these developers who have contributed. No contribution is too small.
* nofxx (https://github.com/nofxx)
* floere (https://github.com/floere)
* plukevdh (https://github.com/plukevdh)
* gkop (https://github.com/gkop)
# Links
* repo: http://github.com/attack/barometer
* rdoc: http://rdoc.info/projects/attack/barometer
## copyright
Copyright (c) 2009-2013 Mark G. See LICENSE for details.