Adapt error formatting to documentation

app/controllers/api/v1/base_controller.rb

@@ -10,25 +10,33 @@ module Api
       rescue_from Exception do |e|
         logger.error e.message
         logger.error e.backtrace.join("\n")
-        render json: {error: e.message}, status: 500
+        render json: error_body(500, e.message), status: 500
+      end
+
+      rescue_from Rack::OAuth2::Server::Resource::Forbidden do |e|
+        logger.error e.message
+        render json: error_body(403, e.message), status: 403
       end
 
       rescue_from ActiveRecord::RecordNotFound do |e|
         logger.error e.message
-        render json: {error: I18n.t("api.error.not_found")}, status: 404
+        message = I18n.t("api.error.not_found")
+        render json: error_body(404, message), status: 404
       end
 
       rescue_from ActiveRecord::RecordInvalid do |e|
         logger.error e.message
-        render json: {error: e.to_s}, status: 400
+        render json: error_body(422, e.to_s), status: 422
       end
 
       rescue_from ActionController::ParameterMissing do |e|
         logger.error e.message
-        render json: {
-          error:   I18n.t("api.error.wrong_parameters"),
-          message: e.message
-        }, status: 400
+        message = I18n.t("api.error.wrong_parameters") + ": " + e.message
+        render json: error_body(422, message), status: 422
+      end
+
+      def error_body(code, message)
+        {code: code, message: message}
       end
 
       def current_user

spec/integration/api/conversations_controller_spec.rb

@@ -41,7 +41,7 @@ describe Api::V1::ConversationsController do
     context "without valid data" do
       it "fails at creating the conversation" do
         post api_v1_conversations_path, params: {access_token: access_token}
-        expect(response.status).to eq 400
+        expect(response.status).to eq 422
       end
     end
   end

spec/integration/api/messages_controller_spec.rb

@@ -62,7 +62,7 @@ describe Api::V1::MessagesController do
           api_v1_conversation_messages_path(@conversation_guid),
           params: {access_token: access_token}
         )
-        expect(response.status).to eq 400
+        expect(response.status).to eq 422
       end
     end
 

spec/integration/api/posts_controller_spec.rb

@@ -136,7 +136,7 @@ describe Api::V1::PostsController do
 
       it "doesn't create the post" do
         json_body = JSON.parse(response.body)
-        expect(json_body["error"]).to eq("insufficient_scope")
+        expect(json_body["code"]).to eq(403)
       end
     end
   end
@@ -174,7 +174,7 @@ describe Api::V1::PostsController do
 
       it "doesn't delete the post" do
         json_body = JSON.parse(response.body)
-        expect(json_body["error"]).to eq("insufficient_scope")
+        expect(json_body["code"]).to eq(403)
         expect(response.status).to eq(403)
       end
     end