ASP — ASP.NET Middleware

What is Middleware?

Middleware components handle HTTP requests and responses.

Built-in Middleware

app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseRouting();
app.UseAuthentication();
app.UseAuthorization();
app.MapControllers();

Custom Middleware

app.Use(async (context, next) =>
{
    // Before request
    var start = DateTime.Now;
    
    await next();
    
    // After request
    var duration = DateTime.Now - start;
    Console.WriteLine($"Request took {duration.TotalMilliseconds}ms");
});

Middleware Class

public class RequestLoggingMiddleware
{
    private readonly RequestDelegate _next;
    
    public RequestLoggingMiddleware(RequestDelegate next)
    {
        _next = next;
    }
    
    public async Task InvokeAsync(HttpContext context)
    {
        // Before
        Console.WriteLine($"Request: {context.Request.Path}");
        
        await _next(context);
        
        // After
        Console.WriteLine($"Response: {context.Response.StatusCode}");
    }
}

Register Middleware

app.UseMiddleware<RequestLoggingMiddleware>();

Mini Practice

1. Add built-in middleware
2. Create custom middleware
3. Order middleware correctly
4. Log request information

Up Next

Continue with ASP.NET Authentication — authentication.