EasyApi

Introducing Easy Api – a new way to define and consume Web APIs for Blazor apps.

Why would you want to use it?

✅ Contract-First API development

• Bring order to your development process and gain a clear and consistent API structure.

✅ Shared data model

• Harness the true power of Blazor with a single data model for your server and client code.
• Forget about countless DTOs, mapping, versioning, and runtime errors.
• Welcome EasyApi's type-safe contract shared between both ends of your application.

✅ Unified logic across all Render Modes

• Stop worrying about where your client code is running.
• Just call your requests and let EasyApi do the rest.
• It does not matter if it is Wasm, SSR or prerendering – the job gets done.

✅ No boilerplate

• Save time and focus on what's important.
• EasyApi handles both client and server configuration for you.
• All you need to do is define the contract and handle your requests.

Sounds good?

Jump right into practice with EasyApi Website – an application that demonstrates how to set up and use EasyApi.

Want to know more?

The path to understanding EasyApi is straightforward and consists of getting to know the three key elements of the library - the contract, the server, and the client apps.

Contract

EasyApi Contract defines the API endpoints you want to expose and consume. Each endpoint is represented as a C# class that primarily defines the structure of incoming requests and the type of returned responses along with the HTTP medium details.

Setup

1️⃣ Add a new Class Library Project to your Solution.

2️⃣ Reference the BlazorUtils.EasyApi NuGet package.

<PackageReference Include="BlazorUtils.EasyApi" Version="[use the latest version here]" />

Defining the Contract

1️⃣ Create a class for your requests.

public class AddComment {}

2️⃣ Declare the HTTP Method you want to use by implementing one of the predefined interfaces.

public class AddComment : IPost {}

If the API endpoint is to respond with specific data, use a generic version of the interface and specify the expected response type.

public class AddComment : IPost<Guid> {}

The full list of available interfaces includes:

• IHead,
• IGet and IGet<ResponseType>,
• IPost and IPost<ResponseType>,
• IPut and IPut<ResponseType>,
• IPatch and IPatch<ResponseType>,
• IDelete and IDelete<ResponseType>.

3️⃣ Declare the API endpoint's route by using the RouteAttribute.

[Route("api/articles/{ArticleID}/comments")]
public class AddComment : IPost<Guid> {}

Use ProtectedRouteAttribute if the endpoint requires authorization.

[ProtectedRoute("api/articles/{ArticleID}/comments")]
public class AddComment : IPost<Guid> {}

Caution

Authorization is used only to protect the API endpoint. EasyApi requests are not authorized during pre-rendering and server-side rendering scenarios. Use Blazor authorization measures to protect your Client app.

4️⃣ Define the parameters that make up the request structure.

[ProtectedRoute("api/articles/{ArticleID}/comments")]
public class AddComment : IPost<Guid>
{
    [RouteParam]
    public Guid ArticleID { get; init; }

    [BodyParam]
    public string Author { get; init; } = default!;

    [BodyParam]
    public string Content { get; init; } = default!;
}

You can specify a different way of sending values for each of the parameters by using one of the predefined attributes:

• BodyParamAttribute - value sent in the body of a HTTP request (if the HTTP Method supports it),
• HeaderParamAttribute - value sent as a HTTP Header,
• QueryStringParamAttribute - value sent as an argument appended to the requested URL,
• RouteParamAttribute - value sent within the requested URL itself.

Note

When using route parameters, the route must contain matching {PropertyName} placeholders.

Server

The responsibility of the EasyApi Server app is to handle all requests defined in the Contract.

Setup

1️⃣ You should start with a Microsoft.NET.Sdk.Web SDK Project that is the Server for your application.

2️⃣ Reference the BlazorUtils.EasyApi.Server NuGet package.

<PackageReference Include="BlazorUtils.EasyApi.Server" Version="[use the latest version here]" />

3️⃣ Register EasyApi services.

using BlazorUtils.EasyApi;
using BlazorUtils.EasyApi.Server;

var contractAssembly = typeof(AddComment).Assembly;
var builder = WebApplication.CreateBuilder(args);

builder.Services
    .AddEasyApi()
    .WithContract(contractAssembly)
    .WithServer();

4️⃣ Map EasyApi endpoints.

var app = builder.Build();
// [...]
app.MapRequests();

Handling requests

1️⃣ Create the request handler class.

internal class AddCommentHandler : IHandle<AddComment, Guid> { }

2️⃣ Implement the IHandle interface.

internal class AddCommentHandler(ICommentsRepository CommentsRepository) : IHandle<AddComment, Guid>
{
    public async Task<HttpResult<Guid>> Handle(AddComment request, CancellationToken cancellationToken)
    {
        var newComment = new Comment(request);
        var newCommentID = await CommentsRepository.Add(newComment, cancellationToken);
        return HttpResult<Guid>.Created(newCommentID);
    }
}

Client

The EasyApi Client app creates requests defined in the Contract and sends them to the Server for processing.

Setup

1️⃣ You should start with a Microsoft.NET.Sdk.BlazorWebAssembly SDK Project that is your Client application.

2️⃣ Reference the BlazorUtils.EasyApi.Client NuGet package.

<PackageReference Include="BlazorUtils.EasyApi.Client" Version="[use the latest version here]" />

3️⃣ Register EasyApi services.

using BlazorUtils.EasyApi;
using BlazorUtils.EasyApi.Client;

var contractAssembly = typeof(AddComment).Assembly;
var builder = WebAssemblyHostBuilder.CreateDefault(args);

builder.Services
    .AddEasyApi()
    .WithContract(contractAssembly)
    .WithClient();

4️⃣ Setup the HttpClient.

Simply register it as a service,

builder.Services.AddScoped(provider => new HttpClient
{
    BaseAddress = new Uri(builder.HostEnvironment.BaseAddress)
});

or configure a provider for more control over the HttpClient.

Sending requests

1️⃣ Inject the caller of the endpoint you want to use.

@inject ICall<AddComment, Guid> AddComment

2️⃣ Create the request.

var request = new AddComment()
{
    ArticleID = Article.ID,
    Author = "EasyApi Enjoyer",
    Content = "This is very easy!"
};

3️⃣ Call the API endpoint.

Use the Call method to simply get the response,

Guid newCommentID = await AddComment.Call(request);

or turn to the CallHttp method if you need to access the HttpResult.

HttpResult<Guid> result = await AddComment.CallHttp(request);
if (result.StatusCode == HttpStatusCode.Created)
{
    Guid newCommentID = result.Response!;
}

Additional configuration

Response Persistence

Response Persistence allows you to seamlessly store and reuse EasyApi request responses for improved performance and user experience.

1️⃣ In order to use it, you must first configure one of the available persistence options.

• Prerendered Response Persistence
• In-memory Response Persistence

2️⃣ Then inject IPersistentCall as the caller of the endpoint you want to use.

@inject IPersistentCall<GetComments, IEnumerable<Comment>> GetComments

3️⃣ And provide a unique storage key for the request when calling the API endpoint.

var comments = await GetComments.Call("a-unique-request-identifier", request);

Once the initial request is completed and persisted, it will be used for subsequent calls according to the rules of the configured persistence options.

Forcing fresh calls

To ensure that fresh data is loaded from the server (e.g. after a user action), you can set the forceFreshCall flag to true when using IPersistentCall. It will bypass all persistence options and send the request directly to the server.

var comments = await GetComments.Call("a-unique-request-identifier", request, true);

Prerendered Response Persistence

Prerendered Response Persistence is a useful option when running your Blazor applications with prerendering.

It can be used to avoid repeated requests between prerendered and interactive sessions, improving performance and eliminating UI flicker.

easy-api-with-prerendered-response-persistence.mp4

Prerendered Response Persistence needs to be configured both in the Server...

builder.Services
    .AddEasyApi()
    .WithContract(contractAssembly)
    .WithServer()
    .Using<PrerenderedResponsePersistence>();

... and Client setup.

builder.Services
    .AddEasyApi()
    .WithContract(contractAssembly)
    .WithClient()
    .Using<PrerenderedResponsePersistence>();

After that, it can be used as described in Response Persistence.

Note

Prerendered Response Persistence is a one-time persistence option. It persists the request responses received during prerendering and discards them once they have been used again when the interactive session starts.

In-memory Response Persistence

In-memory Response Persistence can be used to increase the responsiveness of your application by reducing the number of backend calls within an interactive user session. It involves storing request responses in the application's memory and reusing them for repeated requests (e.g. when navigating to the same page multiple times).

You can configure it in your Client and/or Server setup depending on your needs.

builder.Services
    .AddEasyApi()
    .WithContract(contractAssembly)
    .With[Client/Server]()
    .Using<InMemoryResponsePersistence>();

After that, it can be used as described in Response Persistence.

Custom configuration

The default In-memory Response Persistence configuration does not include data expiration. Responses are persisted and reused for the duration of a single user session. Consider using custom configuration to set up expiration, or turn off persistence altogether for requests that contain highly dynamic data.

To do this, you can implement your custom persistence configuration.

internal class CustomInMemoryResponsePersistence : IInMemoryResponsePersistence
{
    public InMemoryResponsePersistenceOptions Configure(IRequest request)
    {
        if (responses should not be persisted for the request)
        {
            return new() { IsEnabled = false };
        }

        if (responses should expire for the request)
        {
            return new()
            {
                IsEnabled = true,
                AbsoluteExpiration = TimeSpan.FromMinutes(5),
                SlidingExpiration = TimeSpan.FromMinutes(1)
            };
        }

        return new() { IsEnabled = true };
    }
}

And configure it in your Client and/or Server setup.

builder.Services
    .AddEasyApi()
    .WithContract(contractAssembly)
    .With[Client/Server]()
    .Using<CustomInMemoryResponsePersistence>();

Client extensions

HTTP client provider

By default, EasyApi uses the HttpClient registered in the service collection of your Client app. Whenever you need more control over the HttpClient creation or need to manage different HttpClients for different API requests, you should set up your own provider.

1️⃣ Implement the IHttpClientProvider interface.

internal class HttpClientProvider : IHttpClientProvider
{
    public HttpClient GetClient(IRequest request)
    {
        // your logic goes here
    }
}

2️⃣ Register the HTTP client provider for your Client app.

builder.Services
    .AddEasyApi()
    .WithContract(contractAssembly)
    .WithClient()
    .Using<HttpClientProvider>();

Server extensions

API endpoints customization

EasyApi handles the basic API endpoint configuration for you. For advanced scenarios that require more configuration, you should set up your own API endpoint customization.

1️⃣ Implement the IEndpointsCustomization interface.

internal class EndpointsCustomization : IEndpointsCustomization
{
    public void Customize<Request>(RouteHandlerBuilder builder)
    {
        // your logic goes here
    }
}

2️⃣ Register the endpoints customization for your Server app.

builder.Services
    .AddEasyApi()
    .WithContract(contractAssembly)
    .WithServer()
    .Using<EndpointsCustomization>();

Change Log

v2.0.0

• .NET 9 upgrade

v1.1.0

• Introduced new overloads for IPersistentCall methods to allow forcing fresh request calls ignoring all persisted data
• Introduced absolute expiration of responses in in-memory persistence
• Introduced sliding expiration of responses in in-memory persistence
• Fixed intermittent loss of responses persisted during prerendering
• Fixed incorrect setup of custom response persistence

v1.0.0

• .NET 8 upgrade
• Introduced IPersistentCall
• Introduced PrerenderedResponsePersistence
• Introduced InMemoryResponsePersistence

v0.5.1

• Fixed incorrect HTTP method mapping for IPut requests.
• Fixed null string parameters being deserialized as empty strings.
• Query String and Header params are now skipped when sending null values.

v0.5.0

• Baseline version of the library.