@@ -100,7 +100,6 @@ class APICache cache.get else begin - raise APICache::CannotFetch unless api.queryable? value = api.get cache.set(value) value lib/api_cache.rb @@ -2,16 +2,18 @@ require 'net/http' class APICache # Wraps up querying the API. - # - # Ensures that the API is not called more frequently than every +period+ seconds, and times out API requests after +timeout+ seconds. + # + # Ensures that the API is not called more frequently than every +period+ + # seconds, and times out API requests after +timeout+ seconds. # class API # Takes the following options # - # period:: Maximum frequency to call the API + # period:: Maximum frequency to call the API. If set to 0 then there is no + # limit on how frequently queries can be made to the API. # timeout:: Timeout when calling api (either to the proviced url or # excecuting the passed block) - # block:: If passed then the block is excecuted instead of HTTP GET + # block:: If passed then the block is excecuted instead of HTTP GET # against the provided key # def initialize(key, options, &block) @@ -20,27 +22,6 @@ class APICache @period = options[:period] end - # Checks whether the API can be queried (i.e. whether :period has passed - # since the last query to the API). - # - # If :period is 0 then there is no limit on how frequently queries can - # be made to the API. - # - def queryable? - if previously_queried? - if Time.now - queried_at > @period - APICache.logger.debug "Queryable: true - retry_time has passed" - true - else - APICache.logger.debug "Queryable: false - queried too recently" - false - end - else - APICache.logger.debug "Queryable: true - never used API before" - true - end - end - # Fetch data from the API. # # If no block is given then the key is assumed to be a URL and which will @@ -51,6 +32,7 @@ class APICache # APICache::Invalid. # def get + check_queryable! APICache.logger.debug "Fetching data from the API" set_queried_at Timeout::timeout(@timeout) do @@ -83,14 +65,31 @@ class APICache r.header['location'] ? redirecting_get(r.header['location']) : r end + # Checks whether the API can be queried (i.e. whether :period has passed + # since the last query to the API). + # + def check_queryable! + if previously_queried? + if Time.now - queried_at > @period + APICache.logger.debug "Queryable: true - retry_time has passed" + else + APICache.logger.debug "Queryable: false - queried too recently" + raise APICache::CannotFetch, + "Cannot fetch #{@key}: queried too recently" + end + else + APICache.logger.debug "Queryable: true - never used API before" + end + end + def previously_queried? APICache.store.exists?("#{@key}_queried_at") end - + def queried_at APICache.store.get("#{@key}_queried_at") end - + def set_queried_at APICache.store.set("#{@key}_queried_at", Time.now) end lib/api_cache/api.rb @@ -41,7 +41,7 @@ describe APICache do describe "get method" do before :each do - @api = mock(APICache::API, :get => @api_data, :queryable? => true) + @api = mock(APICache::API, :get => @api_data) @cache = mock(APICache::Cache, :get => @cache_data, :set => true) APICache::API.stub!(:new).and_return(@api) spec/api_cache_spec.rb @@ -6,15 +6,23 @@ describe APICache::API do :period => 1, :timeout => 5 } + + # Reset the store otherwise get queried too recently erros + APICache.store = nil end - it "should not be queryable? for :period seconds after a request" do + it "should not be queryable for :period seconds after a request" do api = APICache::API.new('http://www.google.com/', @options) - api.should be_queryable + api.get - api.should_not be_queryable + lambda { + api.get + }.should raise_error(APICache::CannotFetch, "Cannot fetch http://www.google.com/: queried too recently") + sleep 1 - api.should be_queryable + lambda { + api.get + }.should_not raise_error end describe "without a block - key is the url" do spec/api_spec.rb e51b438dcf50872d1e0b0b541da1ca0291150741 Martyn Loughran me@mloughran.com http://github.com/mloughran/api_cache/commit/8569dee4cba1f377e8d2777623404f3a0d2f328e 8569dee4cba1f377e8d2777623404f3a0d2f328e 2009-05-05T14:42:40-07:00 2009-05-05T14:42:40-07:00 Refactoring: Check whether API is queryable internally when calling get method * Reduces coupling * Added meaningful message to exception if API queried too recently becc90620801e8a98029c489810fa5ff65418b96 Martyn Loughran me@mloughran.com