How to Use Refit to Consume APIs in ASP.NET Core

Introduction to Refit in ASP.NET Core

Refit is a powerful REST library for .NET. It simplifies API consumption by converting REST APIs into live interfaces. This article will guide you through using Refit in ASP.NET Core to consume APIs efficiently.

Setting Up Refit in Your ASP.NET Core Project

First, you need to add Refit to your project. Open your project in Visual Studio. Then, install the Refit package via NuGet Package Manager or the Package Manager Console.

bashCopy codeInstall-Package Refit

Creating an API Interface

Next, define an interface for your API. This interface will represent the endpoints of the API you want to consume. Use Refit attributes to map HTTP methods and routes.

csharpCopy codepublic interface IMyApi
{
    [Get("/api/values")]
    Task<List<string>> GetValuesAsync();

    [Post("/api/values")]
    Task AddValueAsync([Body] string value);
}

Configuring Refit in ASP.NET Core

After defining your interface, configure Refit in your Startup.cs file. Register the API client with the dependency injection container.

csharpCopy codepublic void ConfigureServices(IServiceCollection services)
{
    services.AddControllers();
    services.AddRefitClient<IMyApi>()
            .ConfigureHttpClient(c => c.BaseAddress = new Uri("https://example.com"));
}

Consuming the API in a Controller

Inject the API interface into your controller to consume the API. Use the methods defined in the interface to interact with the API.

csharpCopy code[ApiController]
[Route("[controller]")]
public class ValuesController : ControllerBase
{
    private readonly IMyApi _myApi;

    public ValuesController(IMyApi myApi)
    {
        _myApi = myApi;
    }

    [HttpGet]
    public async Task<IActionResult> GetValues()
    {
        var values = await _myApi.GetValuesAsync();
        return Ok(values);
    }

    [HttpPost]
    public async Task<IActionResult> AddValue([FromBody] string value)
    {
        await _myApi.AddValueAsync(value);
        return Ok();
    }
}

Handling Errors and Customizing Requests

Refit provides several ways to handle errors and customize requests. You can use attributes like [Header] to add custom headers or implement custom error handling.

csharpCopy codepublic interface IMyApi
{
    [Get("/api/values")]
    [Headers("Authorization: Bearer")]
    Task<List<string>> GetValuesAsync();

    [Post("/api/values")]
    Task AddValueAsync([Body] string value);
}

Advantages of Using Refit

Refit simplifies API consumption in several ways:

• Easy to Use: Converts REST APIs into live interfaces.
• Type-Safe: Provides compile-time validation of API contracts.
• Less Boilerplate Code: Reduces the amount of code needed to interact with APIs.

Conclusion

Using Refit in ASP.NET Core streamlines API consumption. By defining interfaces and leveraging Refit’s attributes, you can quickly and efficiently interact with APIs. This approach enhances code readability and maintainability, making your development process smoother.