Toolbelt.Blazor.HttpClientInterceptor 9.0.0

Blazor WebAssembly (client-side) HttpClient Interceptor

Summary

The class library that intercept all of the sending HTTP requests on a client side Blazor WebAssembly application.

Supported Blazor versions

"Blazor WebAssembly App (client-side) HttpClient Interceptor" ver.9.x supports Blazor WebAssembly App version 3.2 Preview 2~5, and Release Candidate 1.

How to install and use?

Step.1 Install the library via NuGet package, like this.

> dotnet add package Toolbelt.Blazor.HttpClientInterceptor

Step.2 Register "HttpClientInterceptor" service into the DI container, at Main() method in the Program class of your Blazor application.

using Toolbelt.Blazor.Extensions.DependencyInjection; // <- Add this, and...
...
public class Program
{
  public static async Task Main(string[] args)
  {
    var builder = WebAssemblyHostBuilder.CreateDefault(args);
    builder.RootComponents.Add<App>("app");
    builder.Services.AddHttpClientInterceptor(); // <- Add this!
    ...

Step.3 Add invoking EnableIntercept(IServiceProvider) extension method when registration of HttpClient as a transient service to DI container.

public class Program
{
  public static async Task Main(string[] args)
  {
    ...
    builder.Services.AddTransient(sp => new HttpClient { 
      BaseAddress = new Uri(builder.HostEnvironment.BaseAddress) 
    }.EnableIntercept(sp)); // <- Add this!
    ...

That's all.

You can subscribe the events that will occur before/after sending all of the HTTP requests, at anywhere you can get HttpClientInterceptor service from the DI container.

@using Toolbelt.Blazor
@inject HttpClientInterceptor Interceptor
...
@code {
  protected override void OnInitialized()
  {
    this.Interceptor.BeforeSend += Interceptor_BeforeSend;
    ...
  }

  void Interceptor_BeforeSend(object sender, HttpClientInterceptorEventArgs e)
  {
    // Do something here what you want to do.
  }
  ...

Note: Please remember that if you use HttpClientInterceptor to subscribe BeforeSend/AfterSend events in Blazor components (.razor), you should unsubscribe events when the components is discarded. To do it, you should implement IDisposable interface in that component, like this code:

@implements IDisposable
...
public void Dispose()
{
  this.Interceptor.BeforeSend -= Interceptor_BeforeSend;
}

The arguments of event handler

The event handler for BeforeSend/AfterSend events can be received HttpClientInterceptorEventArgs object.

The HttpClientInterceptorEventArgs object provides you to a request object and a response object that is come from an intercepted HttpClinet request.

void OnAfterSend(object sender, HttpClientInterceptorEventArgs args)
{
  if (!args.Response?.IsSuccessStatusCode) {
    // Do somthing here for handle all errors of HttpClient requests.
  }
}

Release Notes

Release notes is here.

License

Mozilla Public License Version 2.0