Wednesday, 9 September 2015

RESTful Day #6: Request logging and Exception handling/logging in Web APIs using Action Filters, Exception Filters and NLog

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We have been learning a lot about WebAPI, its uses, implementations, and security aspects since last five articles of the series. This article of the series will explain how we can handle requests and log them for tracking and for the sake of debugging, how we can handle exceptions and log them. We’ll follow a centralized way of handling exceptions in WebAPI and write our custom classes to be mapped to the type of exception that we encounter and log the accordingly. I’ll use NLog to log requests and exceptions as well. We’ll leverage the capabilities of Exception Filters and Action Filters to centralize request logging and exception handling in WebAPI.


The following is the roadmap I have setup to learn WebAPI step by step,
I’ll purposely use Visual Studio 2010 and .NET Framework 4.0 because there are few implementations that are very hard to find in .NET Framework 4.0, but I’ll make it easy by showing how we can do it.

Request Logging

Since we are writing web services, we are exposing our end points. We must know where the requests are coming from and what requests are coming to our server. Logging could be very beneficial and helps us in a lot of ways like, debugging, tracing, monitoring and analytics.

We already have an existing design. If you open the solution, you’ll get to see the structure as mentioned below or one can also implement this approach in their existing solution as well.