Rest API in C#

1. What is an API?

An API, or Application Programming Interface, serves as the entry point into a project from external sources. Whether you're developing or consuming APIs, they act as connectors between different software components. In a microservices architecture, APIs play a pivotal role in enabling communication between various modules or projects.

2. Types of API in C#

In C#, there are two main options for creating APIs: SOAP (Simple Object Access Protocol) and REST (Representational State Transfer).

2.1 Differences between SOAP and REST

• Protocol: SOAP is a protocol, while REST is an architectural style operating on the HTTP protocol.

• Development: SOAP services typically require more development time for both clients and servers. In contrast, REST operates over the HTTP protocol, making API development faster.

• State Handling: SOAP can maintain state between requests, while REST treats each request independently. SOAP services are considered more secure due to XML-based (.wsdl) communication.

3. Creating an API in C#

When creating APIs, it's crucial to design endpoints with CRUD operations in mind.

3.1 What is CRUD?

CRUD stands for Create (POST), Read (GET), Update (PUT), and Delete (DELETE). These HTTP methods cover the majority of actions in API interactions.

In C#, the entry point is defined in the controllers. Ensure the Startup.cs class includes the service adding controllers:

public void ConfigureServices(IServiceCollection services) 
{ 
    services.AddControllers(); 
}

And in the Configure method, specify to look for these endpoints in the controllers:

app.UseEndpoints(endpoints => 
{ 
    endpoints.MapGet("/", async context => 
    { 
        await context.Response.WriteAsync("Hello World!"); 
    }); 
    endpoints.MapControllers(); 
});

3.2 Creating endpoints

In C#, endpoints are created in controllers. For example, consider an ExampleController:

[ApiController] 
public class ExampleController : Controller 
{ 
    // Methods  
}

• Creating a GET endpoint in C#

A GET endpoint is used for reading. Define a method with the [HttpGet] attribute:

[HttpGet("name/{id}")] 
public string ReadName(int id) 
{ 
    return id switch 
    { 
        1 => "Adri", 
        2 => "Codú", 
        _ => throw new System.NotImplementedException() 
    }; 
}

• Creating a POST endpoint in C#

A POST endpoint for updating data. Define the route with [HttpPost]:

[HttpPost("insertemployee")] 
public int InsertEmployee(Employee employee) 
{ 
    // Code to insert employee into the database 
    return 1; 
}

Configure Postman to send requests with the appropriate HTTP method, URL, headers, and JSON body.

Others

It's common to include the controller name as part of the URL. Use the [Route("[Controller]")] decorator in the controller class:

[ApiController] 
[Route("[Controller]")] 
public class ExampleController : Controller 
{ 
    // Methods  
}

Conclusion

In today's work environment, understanding APIs is crucial, whether working with microservices or consuming/providing API services. Recognizing the differences between SOAP and REST is essential for effective design. APIs facilitate development by reducing code complexity, aiding in testing, and streamlining bug fixes.