rewrite APIs with Grape and RABL

1 files changed, 111 insertions, 0 deletions

diff --git a/app/api/api_tweets.rb b/app/api/api_tweets.rb
new file mode 100644
index 0000000..168fef3
--- /dev/null
+++ b/app/api/api_tweets.rb
@@ -0,0 +1,111 @@
+class ApiTweets < Grape::API
+  resource :tweets do
+    params_user = -> do
+      params do
+        optional :user_id, type: Integer, desc: "The numerical ID of the user for whom to return results for."
+        optional :screen_name, type: String, desc: "The username of the user for whom to return results for."
+      end
+    end
+
+    params_source_user = -> do
+      params do
+        optional :source_user_id, type: Integer, desc: "The numerical ID of the user for whom to return results for."
+        optional :source_screen_name, type: String, desc: "The username of the user for whom to return results for."
+      end
+    end
+
+    params_pagination = -> do
+      params do
+        optional :count, type: Integer, desc: "The number of tweets to retrieve. Must be less than or equal to #{Settings.tweets.count.max}, defaults to #{Settings.tweets.count.default}."
+        optional :page, type: Integer, desc: "The page number of results to retrieve."
+      end
+    end
+
+    params_pagination_with_ids = -> do
+      params_pagination[]
+      params do
+        optional :since_id, type: Integer, desc: "Returns results with an ID greater than the specified ID."
+        optional :max_id, type: Integer, desc: "Returns results with an ID less than or equal to the specified ID."
+      end
+    end
+
+    params_threshold = -> do
+      params do
+        optional :reactions, type: Integer, desc: "Returns Tweets which has received reactions more than (or equal to) the specified number of times."
+      end
+    end
+
+    helpers do
+      def user
+        @_user ||= begin
+          user = User.find(id: params[:user_id], screen_name: params[:screen_name])
+          raise Aclog::Exceptions::Forbidden unless permitted_to_see?(user)
+          user
+        end
+      end
+
+      def source_user
+        user = User.find(id: params[:source_user_id], screen_name: params[:source_screen_name])
+        raise Aclog::Exceptions::Forbidden unless permitted_to_see?(user)
+        user
+      end
+
+      def paginate(tweets)
+        count = [(params[:count] || Settings.tweets.count.default).to_i, Settings.tweets.count.max].min
+        tweets.limit(count).page((params[:page] || 1).to_i)
+      end
+
+      def paginate_with_ids(tweets)
+        paginate(tweets).max_id(params[:max_id]).since_id(params[:since_id])
+      end
+    end
+
+    desc "Returns a single Tweet, specified by ID.", example_params: { id: 43341783446466560 }
+    params do
+      requires :id, type: Integer, desc: "The numerical ID of the desired Tweet."
+    end
+    get "show", rabl: "tweet" do
+      @tweet = Tweet.find(params[:id])
+      raise Aclog::Exceptions::Forbidden unless permitted_to_see?(@tweet)
+    end
+
+    desc "Returns Tweets, specified by comma-separated IDs.", example_params: { ids: "43341783446466560,50220624609685505" }
+    params do
+      requires :ids, type: String, regexp: /^\d+(,\d+)*$/, desc: "A comma-separated list of Tweet IDs, up to #{Settings.tweets.count.max} are allowed in a single request."
+    end
+    get "lookup", rabl: "tweets" do
+      @tweets = Tweet.where(id: params[:ids].split(",").map(&:to_i))
+      @tweets = @tweets.select {|tweet| permitted_to_see?(tweet) }
+    end
+
+    desc "Returns the best Tweets of a user, specified by username or user ID.", example_params: { user_id: 280414022, count: 2, page: 3 }
+    params_user[]
+    params_pagination[]
+    get "user_best", rabl: "tweets" do
+      @tweets = paginate user.tweets.reacted.order_by_reactions
+    end
+
+    desc "Returns the newest Tweets of a user, specified by username or user ID.", example_params: { screen_name: "toshi_a", count: 3, max_id: 432112694871605249 }
+    params_user[]
+    params_pagination_with_ids[]
+    params_threshold[]
+    get "user_timeline", rabl: "tweets" do
+      @tweets = paginate_with_ids user.tweets.reacted(params[:reactions]).order_by_id
+    end
+
+    desc "Returns the Tweets which a user specified by username or user ID discovered.", example_params: { user_id: 120726371, count: 2 }
+    params_user[]
+    params_pagination_with_ids[]
+    get "user_discoveries", rabl: "tweets" do
+      @tweets = paginate_with_ids(Tweet).discovered_by(user).order_by_id
+    end
+
+    desc "Returns the specified user's Tweets which another specified user discovered.", example_params: { user_id: 120726371, count: 2, source_screen_name: "cn" }
+    params_user[]
+    params_source_user[]
+    params_pagination_with_ids[]
+    get "user_discovered_by", rabl: "tweets" do
+      @tweets = paginate_with_ids(user.tweets).discovered_by(source_user).order_by_id
+    end
+  end
+end