.NET
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The request lifecycle in a .NET 9 Minimal API / MVC application follows a series of steps from incoming request to response generation. Understanding this helps in performance tuning, debugging, and implementing middleware effectively.
1️⃣ Client Sends Request → (Browser/Postman/Frontend App)
2️⃣ Kestrel Web Server Receives Request
3️⃣ Middleware Pipeline Processes Request
4️⃣ Routing Determines Controller/Minimal API
5️⃣ Model Binding & Validation (if applicable)
6️⃣ Controller Action / Minimal API Executes
7️⃣ Service Layer Handles Business Logic
8️⃣ Database Interaction Occurs (via Repository/EF Core)
9️⃣ Response Is Generated
🔟 Middleware Pipeline Handles Response
🔟 Response Is Sent Back to Client
- Kestrel is the built-in cross-platform web server in ASP.NET.
- Listens for incoming HTTP requests and forwards them to the middleware pipeline.
🔹 Example:
GET https://localhost:5001/api/expenses
- Middleware components process requests in a sequential order.
- Can short-circuit requests (e.g., authentication, caching).
- Configured in
Program.cswithapp.UseMiddleware<>.
app.Use(async (context, next) =>
{
Console.WriteLine($"Request: {context.Request.Method} {context.Request.Path}");
await next(); // Pass request to next middleware
});
| Middleware | Purpose |
|---|---|
| UseExceptionHandler | Global error handling |
| UseRouting | Determines request path |
| UseAuthentication | Handles JWT, OAuth, etc. |
| UseAuthorization | Verifies user permissions |
| UseRateLimiter | Throttles requests |
- Understanding the request lifecycle helps optimize performance.
- Middleware placement is crucial for efficient request processing.
- Asynchronous programming improves scalability.
- Database optimizations prevent performance bottlenecks.
This ensures your .NET 9 API is efficient, scalable, and production-ready! 🚀 Let me know if you need further details! 😊
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In .NET DI, you can conditionally apply the Decorator Pattern based on configuration or runtime conditions using IServiceCollection.
public class LoggingExpenseServiceDecorator : IExpenseService
{
private readonly IExpenseService _inner;
private readonly ILogger<LoggingExpenseServiceDecorator> _logger;
public LoggingExpenseServiceDecorator(IExpenseService inner, ILogger<LoggingExpenseServiceDecorator> logger)
{
_inner = inner;
_logger = logger;
}
public async Task<string> ProcessExpenseAsync(decimal amount)
{
_logger.LogInformation($"Processing expense: {amount} USD");
var result = await _inner.ProcessExpenseAsync(amount);
_logger.LogInformation($"Expense processed successfully: {result}");
return result;
}
}
Conditionally Register the Decorator in Program.cs
var builder = WebApplication.CreateBuilder(args);
var services = builder.Services;
// Register the base service
services.AddScoped<IExpenseService, ExpenseService>();
// Conditionally apply the decorator
bool useLoggingDecorator = builder.Configuration.GetValue<bool>("UseLoggingDecorator");
if (useLoggingDecorator)
{
services.AddScoped<IExpenseService>(provider =>
{
var innerService = provider.GetRequiredService<ExpenseService>();
var logger = provider.GetRequiredService<ILogger<LoggingExpenseServiceDecorator>>();
return new LoggingExpenseServiceDecorator(innerService, logger);
});
}
var app = builder.Build();
Enable/Disable Decorator Using Configuration
{
"UseLoggingDecorator": true
}
* Set to true → Decorator will be applied.
* Set to false → Only the base service (ExpenseService) will be used.
read
- https://timdeschryver.dev/blog/the-decorator-pattern-using-nets-dependency-injection
- https://medium.com/@anderson.buenogod/mastering-the-decorator-pattern-in-c-net-8-advanced-use-cases-and-best-practices-378974abe9be
Approach 1
Approach 2
Approach 3 - Using Keyed Services to Register Multiple Implementations of the Same Interface
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In C#, record is a reference type introduced in C# 9 that is primarily used for immutable data models. It provides several benefits over traditional class and struct types, especially when dealing with data-centric applications.
-
recordtypes are designed to be immutable by default. - Unlike
class, properties cannot be changed after object creation unless explicitly marked asmutable.
public record Person(string Name, int Age);
var person1 = new Person("Alice", 30);
// person1.Age = 31; // ❌ Compilation Error: Properties are readonly by default.
- Reduces boilerplate code compared to
class. - Supports primary constructor syntax for easier initialization.
public record Employee(string Name, string Department);
Instead of writing:
public class Employee
{
public string Name { get; }
public string Department { get; }
public Employee(string name, string department)
{
Name = name;
Department = department;
}
}
- Unlike
class, where equality is reference-based,recordcompares by value. - Two records with the same property values are considered equal.
var e1 = new Employee("Bob", "IT");
var e2 = new Employee("Bob", "IT");
Console.WriteLine(e1 == e2); // ✅ True (Value-based equality)
Whereas, with a class:
public class Employee
{
public string Name { get; }
public string Department { get; }
public Employee(string name, string department)
{
Name = name;
Department = department;
}
}
var c1 = new Employee("Bob", "IT");
var c2 = new Employee("Bob", "IT");
Console.WriteLine(c1 == c2); // ❌ False (Reference-based equality)
-
recordsupports awithexpression for making shallow copies with modifications.
var emp1 = new Employee("Alice", "HR");
var emp2 = emp1 with { Department = "Finance" }; // Copy with modified property
Console.WriteLine(emp1); // Employee { Name = Alice, Department = HR }
Console.WriteLine(emp2); // Employee { Name = Alice, Department = Finance }
- This avoids manually cloning objects in class-based designs.
- Unlike
struct,recordsupports inheritance.
public record Person(string Name);
public record Employee(string Name, string Role) : Person(Name);
- Useful when defining domain models with hierarchical relationships.
| Use Case | record or class? |
|---|---|
| Immutable Data Models | ✅ record |
| DTOs (Data Transfer Objects) | ✅ record |
| Configuration Objects | ✅ record |
| Entity Framework Models | ❌ class (EF requires mutable properties) |
| Reference Equality (e.g., Cache, Dependency Injection) | ❌ class |
public record Product(string Name, decimal Price);
- Auto-generates properties with
getaccessors. - Provides a built-in
ToString(), equality, andwithexpression support.
public record Product
{
public string Name { get; init; } = "";
public decimal Price { get; init; }
}
-
initmakes properties settable only during initialization.
- Introduced in C# 10 for value-type record behavior.
public record struct Point(int X, int Y);
- More memory-efficient for small, frequently used structures.
✅ Use record when:
- You want immutable and value-based equality behavior.
- You need concise, readable code with less boilerplate.
- You require pattern matching and efficient copying with
with.
❌ Avoidrecordwhen: - You need mutable objects (prefer
class). - You work with Entity Framework (EF requires mutable properties).
Would you like a specific example of record usage in an application, such as ASP.NET Core or a REST API? 🚀