YAFLHttp 1.0.8

YAFLHttp

Yet Another Fluent Library for Http client (YAFLHttp) is a fluent API for working with HTTP client class that seeks to provide a simply and intuitive devloper experience. Its fluent interface allows you send an HTTP request and parse the response by hiding away the details such as deserialisation, content negotiation, and URL encoding:

Installing YAFLHttp

You should install YAFLHttp with NuGet:

Install-Package YAFLHttp

Or via the .NET command line interface (.NET CLI):

dotnet add package YAFLHttp

Either commands, from Package Manager Console or .NET Core CLI, will allow download and installation of YAFLHttp and all its required dependencies.

How do I get started?

First, configure YAFLHttp by adding required http clients, in the startup of your application:

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddFluentHttp("identity-server", builder =>
{
    builder.WithTimeout(10);
}).AddFluentHttpClientFilter<MyCustomClientFilter>() //runs for all request
.AddFluentHttp<TodoController>(builder =>
 {
     builder.WithBaseUrl("https://localhost:18963/")
         .WithHeader("x-api-version", "1.0.0-beta")
         .AddFilter<TimerHttpClientFilter>() //runs only for this client
         .WithTimeout(20)
         .Register();
 }).AddFluentHttp("file-upload", builder =>
 {
     builder.WithBaseUrl("https://localhost:18963/")
        .WithTimeout(TimeSpan.FromMinutes(2));
 });

Inject the IFluentHttpClientFactory where you need to work with an HttpClient instance.

public class TodoController : Controller
{
    private readonly IFluentHttpClientFactory _clientFactory;

    public TodoController(IFluentHttpClientFactory clientFactory)
    {
        _clientFactory = clientFactory;
    }

    public async Task<IActionResult> Index(int pageNo = 1, int pageSize = 10)
    {
        var client = _clientFactory.Get<TodoController>();
        var bearer = await GetAuthToken();

        var items = await client
          .Endpoint("/api/v1/todos")
          .WithArguments(new { pageNo = pageNo, pageSize = pageSize })
          .WithGeneratedCorelationId()
          .UsingBearerToken(bearer.Token)
          .GetAsync<TodoItem[]>();

        return View(items);
    }
    
    private async Task<AccessToken> GetAuthToken()
    {
        var content = new FormUrlEncodedContent(new KeyValuePair<string?, string?>[]
        {
            new("client_id", "oauthClient"),
            new("client_secret", "SuperSecretPassword"),
            new("scope", "api1.read api1.write"),
            new("grant_type", "client_credentials")
        });

        var authToken = await _clientFactory.Get("identity-server").Endpoint("https://localhost:7094/connect/token")
            .PostAsync<AccessToken>(content);

        return authToken;
    }  
}

Register a fluent http client

You can sent a few properties on the http client during registration such as base url, http headers, request time and http filters. Http clients can be register by name or strongly type approach which makes selecting the correct client even easier.

builder.Services.AddFluentHttp("identity-server", builder =>
{
    builder.WithTimeout(10);
})

builder.Services.AddFluentHttp<TodoController>(builder =>
 {
     builder.WithBaseUrl("https://localhost:18963/")
         .WithHeader("x-api-version", "1.0.0-beta")
         .AddFilter<TimerHttpClientFilter>()
         .WithTimeout(20)
         .Register();
 })

When registering the fluent http client the Register method must be called to complete the process, however the library will automaticaly call the method if it is not explicitly called by your code.

Working with a fluent http client

To get and instance of a registerd fluent http client, you simply need to inject the IFluentHttpClientFactory and call its Get method using the named or strongly typed version.

public class TodoController : Controller
{
    private readonly IFluentHttpClientFactory _clientFactory;

    public TodoController(IFluentHttpClientFactory clientFactory)
    {
        _clientFactory = clientFactory;
    }

    public async Task<IActionResult> Index(int pageNo = 1, int pageSize = 10)
    {
        var client = _clientFactory.Get<TodoController>();

       //...
       
    }
 }

You can set request properties such as http headers, querystrings, correlation Id, content type,authentication scheme and attach files for upload to a remote server.

var client = _httpClientFactory.Get("file-upload");

var respMsg = await client
    .Endpoint("/api/v1/files")
    .WithHeader("x-request-client-type", "net60-aspnet")
    .WithCorrelationId("R5cCI6IkpXVCJ9.post")
    .AttachFile(file)
    .PostAsync();

The library has built in support for work with oauth2 client credentials flow which makes it much easier to integrate with many REST based APIs. You can also used bearer token or basic authentication when communicating with APIs.

//...

var client = _clientFactory.Get<TodoController>();
var cts = new CancellationTokenSource();

var respMsg = await client
    .Endpoint("/api/v1/todos")
    .WithHeader("x-request-client-type", "net60-aspnet")
    .WithCorrelationId("R5cCI6IkpXVCJ9.post")
    .UsingJsonFormat()
    .WithCancellationToken(cts.Token)
    .UsingIdentityServer("https://localhost:7094/connect/token", "oauthClient", "SuperSecretPassword", "api1.read", "api1.write")
    .PostAsync(todoItem);

//..

Retrying failed requests

You are able to check if a failed request can be retried and resend the request with relative ease.

//..

var respMsg = await client
   .Endpoint("/api/v1/todos")
   .WithHeader("x-request-client-type", "net60-aspnet")
   .WithCorrelationId("R5cCI6IkpXVCJ9.post")
   .UsingJsonFormat()
   .PostAsync(todoItem);
           
   var retryable = respMsg.StatusCode.IsRetryable();
   if(retryable)
   {
       //do some stuff
   }

   //or use the request objects to test if request is retryable

   var result = await respMsg.GetResultAsync<TodoItem>();

   if (result.Failure)
   {
       if (result.Retryable)
       {
           result = await respMsg.RetryResultAsync<TodoItem>(client);

           if (result.Success)
           {
               TempData["Message"] = $"Todo item created with id:{result.Data.Id}";
               return RedirectToAction("Index");
           }
       }

       ViewData["ErrorMessage"] = respMsg.ReasonPhrase;

       return View(todoItem);
   }