How can I create custom middleware in ASP.NET Core?

How can I create custom middleware in ASP.NET Core?

To create custom middleware in ASP.NET Core, you need to define a class that contains a method called 'Invoke' or 'InvokeAsync'. This method will handle the HTTP context.

Can you show me a simple example of a custom middleware?

Sure! Here's a simple example:

public class CustomMiddleware
{
    private readonly RequestDelegate _next;

    public CustomMiddleware(RequestDelegate next)
    {
        _next = next;
    }

    public async Task InvokeAsync(HttpContext context)
    {
        // Do something before the next middleware
        await context.Response.WriteAsync("Before next middleware\n");

        await _next(context);

        // Do something after the next middleware
        await context.Response.WriteAsync("After next middleware\n");
    }
}

How do I register this middleware in the Startup class?

You can register your custom middleware in the Configure method of the Startup class like this:

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    app.UseMiddleware<CustomMiddleware>();
    // Other middlewares
}