Hey it's like a CPI CSV proxy!

Gemfile

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+source 'https://rubygems.org'
+
+ruby '2.2.2' if ENV.key?('DYNO')
+
+gem 'faraday'
+gem 'puma'
+gem 'sinatra'

Gemfile.lock

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+GEM
+  remote: https://rubygems.org/
+  specs:
+    faraday (0.9.1)
+      multipart-post (>= 1.2, < 3)
+    multipart-post (2.0.0)
+    puma (2.13.4)
+    rack (1.6.4)
+    rack-protection (1.5.3)
+      rack
+    sinatra (1.4.6)
+      rack (~> 1.4)
+      rack-protection (~> 1.4)
+      tilt (>= 1.3, < 3)
+    tilt (2.0.1)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  faraday
+  puma
+  sinatra
+
+BUNDLED WITH
+   1.10.6

Procfile

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+web: bundle exec rackup

config.ru

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+require './cpi_feed'
+
+run CPIFeed

cpi_feed.rb

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+require 'sinatra/base'
+require 'faraday'
+require 'json'
+
+class CPIFeed < Sinatra::Base
+  DEFAULT_CPI_SERIES_URL = 'http://api.bls.gov/publicAPI/v2/timeseries/data/CUUSA210SA0'
+
+  get '/' do
+    resp = JSON.parse(Faraday.get(cpi_series_url).body)
+
+    content_type :csv
+    "cpi\n#{resp['Results']['series'].first['data'].first['value']}\n"
+  end
+
+  def cpi_series_url
+    ENV['CPI_SERIES_URL'] || DEFAULT_CPI_SERIES_URL
+  end
+
+  run! if app_file == $PROGRAM_FILE
+end