lib/oxr.rb in oxr-0.1.0.1 vs lib/oxr.rb in oxr-0.2.0

@@ -5,40 +5,77 @@
 require 'open-uri'
 
 class OXR
   BASE_PATH = 'https://openexchangerates.org/api/'.freeze
 
+  class OXRError < StandardError
+    def initialize(message, response)
+      super message
+      @response = response
+    end
+
+    attr_reader :response
+  end
+
   def initialize(app_id)
     @app_id = app_id
   end
 
   attr_reader :app_id
 
-  def latest(only: nil)
-    endpoint        = URI.join BASE_PATH, 'latest.json'
-    endpoint.query  = "app_id=#{app_id}"
-    # Only allowed for paid plans
-    endpoint.query += "&symbols=#{Array(only).join ','}" if only
-    JSON.load open endpoint
+  def [](code)
+    latest['rates'][code]
   end
 
-  def historical(on:, only: nil)
-    date = on.strftime '%Y-%m-%d'
-    endpoint = URI.join BASE_PATH, 'historical/', "#{date}.json"
-    endpoint.query = "app_id=#{app_id}"
-    # Only allowed for paid plans
-    endpoint.query += "&symbols=#{Array(only).join ','}" if only
-    JSON.load open endpoint
+  def latest
+    endpoint = sources[:latest] || build_uri_endpoint('latest.json')
+    call endpoint
   end
 
+  def historical(on:)
+    endpoint = sources[:historical] || \
+      build_uri_endpoint('historical/', "#{on.strftime '%Y-%m-%d'}.json")
+    call endpoint
+  end
+
   def currencies
-    endpoint = URI.join BASE_PATH, 'currencies.json'
-    endpoint.query = "app_id=#{app_id}"
-    JSON.load open endpoint
+    endpoint = sources[:currencies] || build_uri_endpoint('currencies.json')
+    call endpoint
   end
 
   def usage
-    endpoint = URI.join BASE_PATH, 'usage.json'
-    endpoint.query = "app_id=#{app_id}"
+    endpoint= sources[:usage] || build_uri_endpoint('usage.json')
+    call endpoint
+  end
+
+  private
+
+  def build_uri_endpoint(*path, **params)
+    URI.join(BASE_PATH, *path).tap do |uri|
+      uri.query = "app_id=#{app_id}"
+    end
+  end
+
+  def call(endpoint)
     JSON.load open endpoint
+  rescue OpenURI::HTTPError => e
+    case e.message
+    when /\A4[[:digit:]]{2}/
+      response = JSON.load e.io
+      raise OXRError.new response['description'], response
+    else
+      raise
+    end
+  end
+
+  def sources
+    self.class.sources
+  end
+
+  def self.sources
+    @sources ||= {}
+  end
+
+  def self.reset_sources
+    sources.clear
   end
 end