1 files changed, 32 insertions, 0 deletions
diff --git a/lib/throttled_api_request.rb b/lib/throttled_api_request.rb
new file mode 100644
index 0000000..c48a66d
--- /dev/null
+++ b/lib/throttled_api_request.rb
@@ -0,0 +1,32 @@
+# limits is in the format:
+#     limits = [
+#       {:unit_time => 10.seconds, :requests_per => 10},
+#       {:unit_time => 10.minutes, :requests_per => 500},
+#     ]
+class ThrottledApiRequest < Struct.new(:api_name, :limits)
+	def before(job)
+		loop do
+			sleep_for = -1
+			ActiveRecord::Base.transaction do
+				ApiRequest.create(:api_name => self.api_name)
+				self.limits.each do |limit|
+					recent_requests = ApiRequest.
+						where(:api_name => self.api_name).
+						where("updated_at > ?", Time.now.utc - limit[:unit_time]).
+						order(:updated_at)
+					if (recent_requests.count > limit[:requests_per])
+						sleep_for = [sleep_for, Time.now.utc - recent_requests[recent_requests.count-limit[:requests_per]].updated_at].max
+					end
+				end
+				if sleep_for != -1
+					raise ActiveRecord::Rollback
+				end
+			end
+			if sleep_for != -1
+				sleep(sleep_for)
+			else
+				break
+			end
+		end
+	end
+end