How is middleware configured?

Anubhav Sharma 458 19 May 2025

Ask by Anubhav Sharma

Updated 19 May 2025

1 Answers

Anubhav Sharma 19 May 2025

Middleware in ASP.NET Core is configured by adding it to the HTTP request pipeline inside the Startup.Configure method (or in Program.cs for .NET 6 and later). This pipeline is built using the IApplicationBuilder interface with a series of method calls like UseMiddleware(), UseRouting(), UseAuthentication(), and so on.

How to Configure Middleware — Step by Step

1. Inside `Startup.Configure` (Pre .NET 6 style)

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage(); // Exception handling middleware
    }
    else
    {
        app.UseExceptionHandler("/Home/Error");
        app.UseHsts();
    }

    app.UseHttpsRedirection();  // Redirect HTTP to HTTPS
    app.UseStaticFiles();       // Serve static files

    app.UseRouting();           // Adds routing middleware

    app.UseAuthentication();   // Add authentication middleware
    app.UseAuthorization();    // Add authorization middleware

    app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllers();  // Map controller routes
    });
}

Middleware components are executed in the order they are added.
You use .UseXyz() methods to add middleware that passes control to the next component.
.Run() can be used to terminate the pipeline early (not common except for very specific cases).

2. In `Program.cs` (Minimal Hosting Model — .NET 6 and later)

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddAuthentication();
builder.Services.AddAuthorization();
builder.Services.AddControllers();

var app = builder.Build();

if (app.Environment.IsDevelopment())
{
    app.UseDeveloperExceptionPage();
}
else
{
    app.UseExceptionHandler("/Error");
    app.UseHsts();
}

app.UseHttpsRedirection();
app.UseStaticFiles();

app.UseRouting();

app.UseAuthentication();
app.UseAuthorization();

app.MapControllers();

app.Run();

3. Adding Custom Middleware

You can add your own middleware with:

app.Use(async (context, next) =>
{
    // Code before next middleware runs
    Console.WriteLine("Request Incoming");

    await next();  // Call the next middleware

    // Code after next middleware runs
    Console.WriteLine("Response Outgoing");
});

Or create a class middleware and add it with:

app.UseMiddleware<MyCustomMiddleware>();

Summary

Middleware is configured by calling extension methods on IApplicationBuilder inside the Configure method or the minimal hosting Program.cs.
Order matters: The order you add middleware affects how requests and responses flow.
Use .Use...() for middleware that calls the next one, .Run() for terminal middleware.

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