Architecture Overview

Relevant source files

The following files were used as context for generating this wiki page:

• Program.cs
• Data/UserDBContext.cs
• Controllers/Order/OrderController.cs
• Migrations/UserDBContextModelSnapshot.cs
• Configuration/OrderConfiguration.cs
• Dtos/CreateOrderRequest.cs
• Configuration/ProductConfiguration.cs
• Configuration/UserConfiguration.cs

This document provides a technical overview of the WEBAPI project architecture. It is a .NET Core Web API designed to serve as a backend for an e-commerce application. The architecture follows a standard layered pattern, separating concerns into API, Service, and Data Access layers. It uses Entity Framework Core for data persistence with a SQL Server database.

The core components include API controllers for handling HTTP requests, a service layer for business logic (inferred from dependency injection), and a data access layer managed by Entity Framework Core, which includes the DbContext, data models, and entity configurations.

System Components & Request Flow

The application is structured in a classic n-tier architecture. An incoming HTTP request is routed to a controller, which then utilizes a service to perform business operations. The service interacts with the UserDBContext to access the database.

This diagram illustrates the high-level request flow from client to database.

Application Startup & Services

The application's entry point is Program.cs, which configures and launches the web host. It is responsible for setting up dependency injection, middleware, and other essential services.

Service Registration

The following key services are registered in the dependency injection container:

Service	Registration Method	Purpose
Controllers	AddControllers()	Registers API controllers.
Swagger/OpenAPI	AddEndpointsApiExplorer(), AddSwaggerGen()	Enables API discovery and documentation.
DbContext	AddDbContext<UserDBContext>()	Registers the EF Core database context.
Session	AddDistributedMemoryCache(), AddSession()	Configures in-memory session management.
Custom Services	AddTransient<IUserService, ...>, AddScoped<IProductService, ...>, AddScoped<IOrderService, ...>	Registers the application's business logic services.
CORS	UseCors()	Configures Cross-Origin Resource Sharing to allow requests from any origin.

Sources: Program.cs:12-42, Program.cs:51-55

Middleware Pipeline

The HTTP request pipeline is configured to handle development-time exceptions, Swagger UI, CORS, authorization, and controller mapping.

API Layer (Controllers)

The API layer is implemented using ASP.NET Core MVC Controllers. These classes are responsible for handling incoming HTTP requests, validating input, and returning appropriate HTTP responses. The OrderController is a representative example.

Sources: Controllers/Order/OrderController.cs

Order API Endpoints

The OrderController exposes RESTful endpoints for managing orders.

Method	Route	Description	Request Body DTO
POST	api/v1/order	Creates a new order.	CreateOrderRequest
GET	api/v1/order	Retrieves all orders.	N/A
GET	api/v1/order/{id}	Retrieves a specific order by its ID.	N/A
GET	api/v1/order/user/{CustomerID}	Retrieves all orders for a specific customer.	N/A
PUT	api/v1/order/{id}	Updates an entire order.	UpdateOrderRequest
PATCH	api/v1/order/{id}	Partially updates an order's status, address, and delivery method.	UpdateOrderStatusRequest
DELETE	api/v1/order/{id}	Deletes an order by its ID.	N/A

Sources: Controllers/Order/OrderController.cs:18-129

Create Order Sequence

This diagram shows the sequence of operations when a client creates a new order. The controller receives a CreateOrderRequest DTO, maps it to an Order entity, and passes it to the IOrderService for processing.

Data Access Layer

The data access layer is built using Entity Framework Core. It is responsible for all database interactions.

DbContext

UserDBContext is the heart of the data layer. It represents a session with the database and allows querying and saving data. It defines DbSet properties for each entity, which map to database tables.

Sources: Data/UserDBContext.cs:7-36

Entity Configuration

Instead of using data annotations, the application uses the IEntityTypeConfiguration<T> interface to configure the entity models and their mapping to the database schema. This approach centralizes configuration and keeps the model classes clean. For example, OrderConfiguration defines the table name, primary key, and property constraints for the Order entity.

// Example from OrderConfiguration.cs
public void Configure(EntityTypeBuilder<Order> builder)
{
    builder.ToTable("Orders");
    builder.HasKey(o => o.OrderID);
    builder.Property(o => o.TotalAmount).HasColumnType("decimal(18,2)").IsRequired();
    builder.Property(o => o.OrderDate).IsRequired().HasDefaultValueSql("GETDATE()");
    // ... other configurations
}

Sources: Configuration/OrderConfiguration.cs:10-28, Data/UserDBContext.cs:15-21

Database Schema

The database schema is defined by the EF Core models and configurations. The following Entity-Relationship diagram illustrates the main tables and their relationships.

Key Data Models

Order Model

The Order entity represents a customer's order.

Property	Type	Constraints	Description
OrderID	int	Primary Key	Unique identifier for the order.
CustomerID	int	Required, Foreign Key to User	The ID of the customer who placed the order.
TotalAmount	decimal(18,2)	Required	The total cost of the order.
OrderDate	DateTime	Required, Default GETDATE()	The date and time the order was placed.
Status	string	Required, MaxLength(50)	The current status of the order (e.g., "Pending").
Address	string	Required, MaxLength(200)	The shipping address for the order.
DeliveryMethod	string	MaxLength(50)	The chosen delivery method.
PaymentMethod	string	MaxLength(50)	The chosen payment method.
OrderItems	ICollection<OrderItem>	Navigation Property	A collection of items included in the order.

Sources: Configuration/OrderConfiguration.cs:10-28, Migrations/UserDBContextModelSnapshot.cs:91-131

Product Model

The Product entity represents an item available for sale.

Property	Type	Constraints	Description
Id	int	Primary Key	Unique identifier for the product.
CategoryId	int?	Foreign Key to Category	The category this product belongs to.
Title	string	Required, MaxLength(100)	A short title for the product.
Name	string	Required, MaxLength(200)	The full name of the product.
Price	decimal(18,2)	Required	The price of the product.
Description	string	MaxLength(500)	A detailed description of the product.
ProductImageUrl	string	MaxLength(500)	URL for the product's image.

Sources: Configuration/ProductConfiguration.cs:11-38, Migrations/UserDBContextModelSnapshot.cs:176-221