Auto-Generating RESTful APIs in .NET with Plus.AutoApi

Sat, 30 Nov 2024 00:00:00 +0000

Introduction

In DDD (Domain-Driven Design) architectures, developers often need to manually create API controllers after implementing service layers. Plus.AutoApi eliminates this step by dynamically generating RESTful-style WebAPIs without requiring Controller classes.

Quick Start

1. Install NuGet Package

Add the package to your application service layer:

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Install-Package Plus.AutoApi

2. Service Registration

Configure in Startup.cs:

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public void ConfigureServices(IServiceCollection services)
{
 services.AddAutoApi(options => { });
}

3. Implement Service

Create service classes implementing IAutoApi with [AutoApi] attribute:

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[AutoApi]
public class WeatherService : IAutoApi
{
 private static readonly string[] Summaries = new[]
 {
 "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
 };

 // Auto-generated GET endpoint: /api/weather
 public IEnumerable<WeatherForecast> Get()
 {
 return GenerateForecast();
 }

 // Custom GET endpoint: /api/weather/{id}
 [HttpGet("{id}")]
 public IEnumerable<WeatherForecast> Get(int id)
 {
 return GenerateForecast();
 }

 private static IEnumerable<WeatherForecast> GenerateForecast()
 {
 var rng = new Random();
 return Enumerable.Range(1, 5).Select(index => new WeatherForecast
 {
 Date = DateTime.Now.AddDays(index),
 TemperatureC = rng.Next(-20, 55),
 Summary = Summaries[rng.Next(Summaries.Length)]
 });
 }
}

Key Features:

Naming Convention: Services ending with Service/ApplicationService auto-generate APIs
Custom Endpoints: Use standard ASP.NET Core attributes like [HttpGet("{id}")]
Opt-Out: Disable generation with [AutoApi(Disabled = true)]

Swagger Integration

Enable OpenAPI documentation:

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services.AddSwaggerGen(options =>
{
 options.SwaggerDoc("v1", new OpenApiInfo
 {
 Title = "AutoAPI Demo",
 Version = "v1.0.0"
 });
 options.DocInclusionPredicate((docName, description) => true); // Include all endpoints
});

HTTP Method Convention

Default verb mapping based on method names:

Method Prefix	HTTP Verb
Add/Create/Post	POST
Get/Find/Fetch	GET
Update/Put	PUT
Delete/Remove	DELETE

Example API Routes

Generated endpoints for the WeatherService:

GET /api/weather
GET /api/weather/{id}
POST /api/weather
PUT /api/weather/{id}
DELETE /api/weather/{id}

Resources

Key Benefits

Zero Controller Boilerplate Eliminate manual Controller class creation
Coexistence Support Works alongside traditional controllers
Customizable Rules Override default naming conventions through configuration options
Swagger Ready Full OpenAPI specification support
DDD Alignment Focus on domain logic rather than infrastructure code

Note: This approach works best for CRUD-heavy applications. Complex endpoints may still require traditional controllers.

WebApi on Allen's Dev Journal