OwinGlobalAsax

This page explains how to use the NSwag OWIN middleware in your "Global.asax"-based web project. It is recommended to migrate your project to a completely OWIN-based project and use the OWIN middleware directly.

Sample project

Integration

1. Install NuGet packages

Install the NuGet packages:

• Microsoft.Owin.Host.SystemWeb
• NSwag.AspNet.Owin

2. Edit web.config

Then open your Web.config and add the following app setting:

<configuration>
    <appSettings>
        <add key="owin:AutomaticAppStartup" value="false" />
    </appSettings>
    ...

Now we need setup the routing of the Swagger requests. There are two ways to do this:

2.a) Pipe all request to the .NET pipeline

In the system.webServer tag, set runAllManagedModulesForAllRequests to true so that all requests are piped to ASP.NET:

<system.webServer>
	...
	<modules runAllManagedModulesForAllRequests="true">
		...

2.b) Pipe only the Swagger request to the specific middlewares

Important: The routes defined in the web.config and the UseSwagger/UseSwaggerUi methods must be the same:

<system.webServer>
	...
	<handlers>
		...
		<add name="NSwag" path="swagger" verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />

3. Edit Global.asax.cs

Now, open the Global.asax.cs and add the following call at the beginning of the Application_Start method:

public class WebApiApplication : System.Web.HttpApplication
{
	protected void Application_Start()
	{
		RouteTable.Routes.MapOwinPath("swagger", app =>
		{
			app.UseSwaggerUi(typeof(WebApiApplication).Assembly, settings => 
			{
				settings.MiddlewareBasePath = "/swagger";
			});
		});
	
		...

Now, start the web project and browse to "http:/localhost:port/swagger" and the Swagger UI should be loaded.