Configure Web API

Web API supports code based configuration. It cannot be configured in web.config file. We can configure Web API to customize the behaviour of Web API hosting infrastructure and components such as routes, formatters, filters, DependencyResolver, MessageHandlers, ParamterBindingRules, properties, services etc.

We created a simple Web API project in the Create Web API Project section. Web API project includes default WebApiConfig class in the App_Start folder and also includes Global.asax as shown below.

public class WebAPIApplication : System.Web.HttpApplication
{
    protected void Application_Start()
    {
        GlobalConfiguration.Configure(WebApiConfig.Register);
        
        //other configuration
    }
}

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {

        config.MapHttpAttributeRoutes();

        config.Routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "api/{controller}/{id}",
            defaults: new { id = RouteParameter.Optional }
        );

        // configure additional webapi settings here..
    }
}

Web API configuration process starts when the application starts. It calls GlobalConfiguration.Configure(WebApiConfig.Register) in the Application_Start method. The Configure() method requires the callback method where Web API has been configured in code. By default this is the static WebApiConfig.Register() method.

As you can see above, WebApiConfig.Register() method includes a parameter of HttpConfiguration type which is then used to configure the Web API. The HttpConfiguration is the main class which includes following properties using which you can override the default behaviour of Web API.

Visit MSDN to learn about all the members of HttpConfiguration.

Learn how to configure Web API routes in the next section.