Trace Web API Execution Time Using Custom Action Filter

Introduction

In this article we will see how to trace the execution time of API methods using a Custom Action Filter.

Step 1

Open Visual Studio 2013. Go to the "File" menu then select "New" and click on "Project...".


Step 2

Select "Web" from the left panel and "ASP.NET Web Application" from the center panel.

Provide an appropriate name for the application, select the location and click on the "OK" button.



Step 3

Select "Empty" in the template list.

Check the "Web API" checkbox and click the "OK" button.



Step 4

As we select the empty template, we need to add one controller. Right-click on Controllers, select "Add" and click on "Controller".



Step 5

Select "Web API 2 Controller with read/write actions" and click the "Add" button.



Step 6

Name it "Home Controller".



Step 7

It will add a controller with 5 API methods.



Step 8

Now it's time to add a class to create the custom action filter. Right-click on the project, select "Add" and click "New Item".



Step 9

Select "Class" and provide the name "ExecutionTimeFilterAttribute".



Step 10

Now inherit the preceding class from "ActionFilterAttribute". The "System.Web.Http.Filters" namespace is required to add the ActionFilterAttribute class. It is a base class for all action-filter attributes. And action-filters are the way to add extra functionality to our Web API service. In this class we are overriding two methods, one is "OnActionExecuting" that occurs before the action method is invoked and another one is "OnActionExecuted" that occurs after the action method is invoked. Our main task is to trace the execution time and we have two methods out of which one is executed before and another is executed after the action method.



Step 11

So here we are using a Stopwatch to calculate the execution time and it requires the "System. Diagnostics" namespace. In the before method, OnActionExecuting, we set the action name property in HTTP request by initializing the stopwatch instance that sets the elapsed time property to zero and starts measuring the elapsed time. And in the after method, OnActionExecuted, we get the stopwatch instance from the same property and get the total elapsed time measured by the instance.



Step 12

Now we need to add this (ExecutionTimeFilterAttribute) attribute to an API method, for which we want to measure the execution time. So let's add this attribute to the "Get" method.



Step 13

Run the application and call the "Get" method. Then check the output in the output window.



Here we can see the execution time for the "Get" method.



Step 14

Now whatever we did, that is for one method. But in a practical scenario there can be many methods in one controller and many controllers in one application, we should not add this attribute for all API methods in order to calculate the execution time. So in this case we can configure it in Global.asax.cs. We can add this custom attribute in GlobalConfiguration inside the Application_Start event.



Step 15

Remove the ExecutionTimeFilter attribute from the Get method as we have configured globally.



Step 16

This attribute works for all API methods now. Let's check by calling two different API methods.



You can check in the output window, the elapsed time for both of the methods.