⚙️ ASP.NET Core Fundamentals: Middleware, Routing & Controllers

Introduction

Now that you understand C# fundamentals, it’s time to see how .NET handles web requests.

ASP.NET Core is a high-performance, cross-platform web framework used to build:

• REST APIs

• Web applications

• Microservices

In this article, you’ll learn:

• How ASP.NET Core processes requests

• What middleware is

• How routing works

• How controllers handle HTTP requests

This is Week 4 of our .NET weekly blog series.

What Is ASP.NET Core?

ASP.NET Core is a modern web framework built on top of .NET.

Key Features

• Cross-platform

• Fast & lightweight

• Built-in Dependency Injection

• Cloud & container friendly

It replaces the older ASP.NET Framework.

Understanding the Request Pipeline

Every HTTP request in ASP.NET Core goes through a pipeline.

Request Flow

Client → Middleware → Routing → Controller → Response

Each component decides whether to:

• Process the request

• Modify it

• Pass it to the next component

Middleware Explained

Middleware is software that:

• Handles requests and responses

• Runs in sequence

• Can stop or forward requests

Common Middleware Examples

• Authentication

• Logging

• Exception handling

• CORS

Creating Custom Middleware