Add Custom Middleware in ASP.NET Core Application

Add Custom Middleware in ASP.NET Core Application

Heading: Introduction ASP.NET Core provides a flexible and extensible middleware pipeline to handle incoming HTTP requests and outgoing responses. Middleware components can be added to the pipeline to perform various tasks such as authentication, logging, error handling, and more. In this documentation, we will explore how to add custom middleware to an ASP.NET Core application.

Heading: Prerequisites Before adding custom middleware to an ASP.NET Core application, ensure that you have the following prerequisites:

• Basic knowledge of C# and ASP.NET Core.
• An existing ASP.NET Core application.
• Visual Studio or any other code editor installed on your machine.

Heading: Steps to Add Custom Middleware

Step 1: Create a new class for the custom middleware

1. Open your ASP.NET Core application in Visual Studio or your preferred code editor.
2. Create a new class file for your custom middleware. For example, "CustomMiddleware.cs".

Step 2: Implement the custom middleware

1. Inside the "CustomMiddleware.cs" file, create a new class and inherit from the IMiddleware interface.
2. Implement the InvokeAsync method from the IMiddleware interface. This method will be called for each HTTP request that passes through the middleware pipeline.
3. Write the logic for your custom middleware in the InvokeAsync method. This logic can include handling the request, modifying the response, or performing any other required tasks.

Example code:

csharp
using Microsoft.AspNetCore.Http;
using System.Threading.Tasks;

public class CustomMiddleware : IMiddleware
{
    public async Task InvokeAsync(HttpContext context, RequestDelegate next)
    {
        // Perform tasks before the request reaches the next middleware

        await next(context); // Call the next middleware in the pipeline

        // Perform tasks after the request has been processed by subsequent middleware
    }
}

Step 3: Register the custom middleware in the startup class

1. Open the "Startup.cs" file in your ASP.NET Core application.
2. In the Configure method, use the UseMiddleware extension method to register your custom middleware.

Example code:

csharp
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    // Other middleware configurations

    app.UseMiddleware<CustomMiddleware>();

    // Other middleware configurations
}

Heading: Explanation The custom middleware is implemented as a class that inherits from the IMiddleware interface. The IMiddleware interface requires the implementation of the InvokeAsync method, which receives the HttpContext object and a RequestDelegate representing the next middleware in the pipeline.

Inside the InvokeAsync method, you can perform tasks before and after the request reaches the next middleware by calling await next(context).

Finally, the custom middleware is registered in the Configure method of the startup class using the UseMiddleware extension method, ensuring it is included in the middleware pipeline.

Heading: Conclusion By following the steps outlined in this documentation, you can add custom middleware to your ASP.NET Core application. Custom middleware allows you to add additional functionality to the request pipeline, enabling you to handle specific requirements for your application.