hash long cache keys

lib/cached_resource/caching.rb

@@ -4,6 +4,8 @@ module CachedResource
   module Caching
     extend ActiveSupport::Concern
 
+    MAX_ARGUMENTS_CACHE_SIZE = 150
+
     included do
       class << self
         alias_method_chain :find, :cache
@@ -112,7 +114,16 @@ def cache_clear
 
       # Generate the request cache key.
       def cache_key(*arguments)
-        "#{name.parameterize.gsub("-", "/")}/#{arguments.join('/')}".downcase.delete(' ')
+        "#{name.parameterize.gsub("-", "/")}/#{arguments_cache_key(*arguments)}".downcase.delete(' ')
+      end
+
+      def arguments_cache_key(*arguments)
+        arguments_string = arguments.join('/')
+        arguments_string.length > MAX_ARGUMENTS_CACHE_SIZE ? hash_string(arguments_string) : arguments_string
+      end
+
+      def hash_string(string)
+        Digest::SHA2.hexdigest(string)
       end
 
       # Make a full duplicate of an ActiveResource record.

spec/cached_resource/caching_spec.rb

@@ -56,6 +56,14 @@ class Thing < ActiveResource::Base
       Thing.cached_resource.cache.read('thing/1/{:from=>"path",:params=>{:foo=>"bar"}}').should == result
     end
 
+    it "should hash long parameters in cache key" do
+      params = [1, {long_params: "l" * Thing::MAX_ARGUMENTS_CACHE_SIZE }]
+      hash_params = Thing.send(:hash_string, params.join("/"))
+
+      result = Thing.find(*params)
+      Thing.cached_resource.cache.read("thing/#{hash_params}").should == result
+    end
+
     it "should empty the cache when clear_cache is called" do
       result = Thing.find(1)
       Thing.clear_cache
@@ -510,4 +518,5 @@ class CustomCollection < ActiveResource::Collection; end
       new_result.name.should_not == old_result.name
     end
   end
+
 end