From bdaad2a22ccf95f1a356c4ff048ee9e9b39ebbc6 Mon Sep 17 00:00:00 2001
From: Kir Shatrov <shatrov@me.com>
Date: Mon, 16 Jun 2014 12:41:46 +0300
Subject: [PATCH] Safe fetch with fallback (fixed #5)

---
 README.md                   | 20 ++++++++++++++++++++
 lib/russian_central_bank.rb | 10 ++++++++++
 2 files changed, 30 insertions(+)

diff --git a/README.md b/README.md
index 770de73..260d537 100644
--- a/README.md
+++ b/README.md
@@ -47,6 +47,26 @@ Or install it yourself as:
     # Check expiration date
     bank.rates_expired_at
 
+### Safe rates fetch
+
+There are some cases, when the `cbr.ru` returns HTTP 302.
+To avoid issues in production, you use fallback:
+
+```ruby
+bank = Money::Bank::RussianCentralBank.new
+begin
+  bank.update_rates
+rescue Money::Bank::RussianCentralBank::FetchError => e
+  Rails.logger.info "CBR failed: #{e.response}"
+
+  ## fallback
+  Money.default_bank = Money::Bank::VariableExchange.new
+
+  Money.default_bank.add_rate(:usd, :eur, 1.3)
+  Money.default_bank.add_rate(:eur, :usd, 0.7)
+end
+```
+
 ## Contributing
 
 1. Fork it
diff --git a/lib/russian_central_bank.rb b/lib/russian_central_bank.rb
index ddc3ae0..8175a1a 100644
--- a/lib/russian_central_bank.rb
+++ b/lib/russian_central_bank.rb
@@ -4,6 +4,14 @@
 class Money
   module Bank
     class RussianCentralBank < Money::Bank::VariableExchange
+      class FetchError < StandardError
+        attr_reader :response
+
+        def initialize(message, response=nil)
+          super(message)
+          @response = response
+        end
+      end
 
       CBR_SERVICE_URL = 'http://www.cbr.ru/DailyInfoWebServ/DailyInfo.asmx?WSDL'
 
@@ -65,6 +73,8 @@ def exchange_rates(date)
         client = Savon::Client.new(wsdl: CBR_SERVICE_URL, log: false, log_level: :error)
         response = client.call(:get_curs_on_date, message: { 'On_date' => date.strftime('%Y-%m-%dT%H:%M:%S') })
         response.body[:get_curs_on_date_response][:get_curs_on_date_result][:diffgram][:valute_data][:valute_curs_on_date]
+      rescue Wasabi::Resolver::HTTPError => e
+        raise FetchError.new(e.message, e.response)
       end
 
       def update_parsed_rates rates