What will you find in this sample of web API ? Here is the answers ;
- IoC Container ; in this project ApiControllers resolve in container.( Castle Windsor )
- Logging Mechanism ; in this project we're using Log4Net for logging mechanism and all requests have Unique track Id ( for c# its Guid )
- Unit Tests ; in this project we're using Microsoft's Unit test framework.
- Global Exception Logging And Handling ; in this project we have 2 services for exception logging and handling.These services are inherited IExceptionLogger and IExceptionHandler interfaces.
- Swagger Configuration ; Documentation for Swagger.
- Global Request Logging ; Global logging Attribute.
This sample project , we will use Castle Windsor for IoC Container.You can use another IoC Container framework (for example : Unity , Ninject etc. )
Web API provides two primary mechanism for controller dependency injection. Implementing a custom IHttpControllerActivator and implementing a custom IDependencyResolver. (ASP. NET Web API 2 Recipes: A Problem-Solution Approach - Filip Wojcieszyn)
In this sample, using the IHttpControllerActivator. It's resolve controller classes.
For Example to IHttpControllerActivator Implentation;
public class WindsorCompositionRoot : IHttpControllerActivator
{
private readonly IWindsorContainer _container;
public WindsorCompositionRoot(IWindsorContainer container)
{
_container = container;
}
public IHttpController Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor, Type controllerType)
{
var controller =
(IHttpController)this._container.Resolve(controllerType);
request.RegisterForDispose(
new Release(
() => this._container.Release(controller)));
return controller;
}
}
public class Release : IDisposable
{
private readonly Action _release;
public Release(Action release)
{
this._release = release;
}
public void Dispose()
{
this._release();
}
}Here is Controller Installer ;
public class ControllerInstaller : IWindsorInstaller
{
public void Install(IWindsorContainer container, IConfigurationStore store)
{
container.Register(Classes.FromThisAssembly()
.BasedOn<ApiController>()
.LifestylePerWebRequest()
);
}
}And Global.asax configuration ;
IWindsorContainer container = new WindsorContainer();
container.Install(FromAssembly.This());
GlobalConfiguration.Configuration.Services.Replace(typeof(IHttpControllerActivator), new WindsorCompositionRoot(container)); After this implentation , all apicontroller release this Activator class and container is carrying all controller.
Log4net is a usefull component for all project because it's easy to configuration and simple to use.
Download the log4net package with nugget and download my other project to use with it :)
I used this guide for Unit testing ;
Here is the TestControllerClass;
[TestClass]
public class TestProductController
{
[TestMethod]
public void getProduct_ReturnEmptyProduct()
{
var service = new ProductService();
var controller = new ProductController(service);
var result = controller.getProduct(9999);
Assert.IsNull(result);
}
[TestMethod]
public void getProduct_ReturnFirstProduct()
{
var service = new ProductService();
var controller = new ProductController(service);
Product sample = new Product()
{
ProductId = 1,
ProductName = "MFA",
Status = 0,
ResponseCode = null,
Message = null
};
var result = controller.getProduct(1);
Assert.AreEqual(sample.ProductName, result.ProductName);
}All unhandled exceptions can now be logged through one central mechanism, and the behavior for unhandled exceptions can be customized.(Global Logging)
When to use ;
- Exception loggers are the solution to seeing all unhandled exception caught by Web API.
- Exception handlers are the solution for customizing all possible responses to unhandled exceptions caught by Web API.
For example IExceptionLogger ;
public class CustomExceptionLogger : ExceptionLogger
{
private readonly ILogger _logger;
public CustomExceptionLogger(ILogger logger)
{
this._logger = logger;
}
public override void Log(ExceptionLoggerContext context)
{
var Guid = context.Request.Headers.GetValues("TrackId").FirstOrDefault();
_logger.Log("Track Id : " + Guid + " - ERROR : {" + context.Exception.Message + "}", LogType.Error);
base.Log(context);
}
}For example IExceptionHandling ;
public class HandlerLogger :ExceptionHandler
{
private readonly ILogger _logger;
public HandlerLogger(ILogger logger)
{
_logger = logger;
}
public override void Handle(ExceptionHandlerContext context)
{
ResponseHeader header;
var ReturnType = context.Request.GetActionDescriptor().ReturnType;
header = Activator.CreateInstance(ReturnType) as ResponseHeader;
header.Message = context.Exception.Message;
header.ResponseCode = "0001";
header.Status = 1;
var response = context.Request.CreateResponse(HttpStatusCode.InternalServerError, header);
context.Result = new ResponseMessageResult(response);
base.Handle(context);
}
}And Global.asax configuration ;
GlobalConfiguration.Configuration.Services.Replace(typeof(IExceptionHandler), new HandlerLogger(container.Resolve<ILogger>()));
GlobalConfiguration.Configuration.Services.Replace(typeof(IExceptionLogger), new CustomExceptionLogger(container.Resolve<ILogger>()));In these code blocks says handle unexpected error globally and return custom response and response model.
When consuming a Web API, understanding its various methods can be challenging for a developer.Swagger, also known as Open API, solves the problem of generating useful documentation and help pages for Web APIs. It provides benefits such as interactive documentation, client SDK generation, and API discoverability.
The goal is ,who is requesting our API and if its success , What is the response?Im managing it with using ActionFilterAttribute.
ActionFilterAttribute has two methods ;
- OnActionExecuting ; Its for using Request logging and create GuID add to Request Header.
- OnActionExecuted ; If request successfully end , log the Response.
Here is the LoggingAttribute ;
public class LoggingAttribute : ActionFilterAttribute
{
private readonly ILogger logger;
private string _Guid;
public LoggingAttribute(ILogger logger)
{
this.logger = logger;
}
public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
{
string jSonData = actionExecutedContext.Response?.Content.ReadAsStringAsync().Result;
this.logger.Log("Track Id : " + _Guid + " - OutGoing Response {" + jSonData + "}", LogType.Debug);
base.OnActionExecuted(actionExecutedContext);
}
public override void OnActionExecuting(HttpActionContext actionContext)
{
string jSonData = actionContext.Request.Content?.ReadAsStringAsync().Result;
_Guid = Guid.NewGuid().ToString();
actionContext.Request.Headers.Add("TrackId", _Guid);
this.logger.Log("Track Id : " + _Guid + " - " + actionContext.Request.RequestUri.LocalPath + " - Incoming Request {" + jSonData + "}", LogType.Debug);
base.OnActionExecuting(actionContext);
}
}Global.asax configuration ;
GlobalConfiguration.Configuration.Filters.Add(new LoggingAttribute(container.Resolve<ILogger>()));Thank you !
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