Blazor 添加 HttpClientHandler 以将 Jwt 添加到请求的 HTTP 标头

Question

我将Visual Studio 2019和.Net Core 3.0.0-preview-7与标准 Blazor 客户端、服务器和共享模板一起使用。在应用程序中，我们的服务器端 WebApi 应用程序将始终要求标头中存在 JWT 令牌以进行授权。从以下内容来看在 ASP.NET Core 中使用 IHttpClientFactory 发出 HTTP 请求我创建了以下处理程序；public class JwtTokenHeaderHandler : DelegatingHandler{    private readonly ILocalStorageService _localStorage;    public JwtTokenHeaderHandler(ILocalStorageService localStorage)    {        _localStorage = localStorage;    }    protected override async Task<HttpResponseMessage> SendAsync(        HttpRequestMessage request,        CancellationToken cancellationToken)    {        if (!request.Headers.Contains("bearer"))        {            var savedToken = await _localStorage.GetItemAsync<string>("authToken");            if (!string.IsNullOrWhiteSpace(savedToken))            {                request.Headers.Add("bearer", savedToken);            }        }        return await base.SendAsync(request, cancellationToken);    }}我用来Blazored.LocalStorage从本地存储获取保存的令牌并将其添加到标头。现在，此时我不确定该怎么做，就好像我将以下内容添加到Blazor.Client Startup.cs;services.AddTransient<JwtTokenHeaderHandler>();services.AddHttpClient("JwtTokenHandler")    .AddHttpMessageHandler<JwtTokenHeaderHandler>();我收到错误消息；“IServiceCollection”不包含“AddHttpClient”的定义，并且找不到接受“IServiceCollection”类型的第一个参数的可访问扩展方法“AddHttpClient”（您是否缺少 using 指令或程序集引用？）谁能指导我在这里做错了什么？

Answer 1

下面是一个摘录，在默认 http 客户端上设置默认请求标头（通过 DI）。然后，对您的 Web api 的所有调用都将包含不记名令牌：

public class ApiAuthenticationStateProvider : AuthenticationStateProvider

{

    private readonly HttpClient _httpClient;

    private readonly ILocalStorageService _localStorage;

    public ApiAuthenticationStateProvider(HttpClient httpClient, ILocalStorageService localStorage)

    {

        _httpClient = httpClient;

        _localStorage = localStorage;

    }

    public override async Task<AuthenticationState> GetAuthenticationStateAsync()

    {

        var savedToken = await _localStorage.GetItemAsync<string>("authToken");

        if (string.IsNullOrWhiteSpace(savedToken))

        {

            return new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity()));

        }

        // **************    Set JWT header       ****************

        _httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("bearer", savedToken);

        // *******************************************************

        return new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity(ParseClaimsFromJwt(savedToken), "jwt")));

    }

    // ...

}

Answer 2

目前您无法在客户端 Blazor 上使用 IHttpClientFactory。

而且您不必从 HttpMessageHandler (DelegatingHandler) 派生。Blazor 已经做到了。以下是扩展 HttpClient 服务功能的扩展类，以启用将 Jwt 令牌添加到请求消息标头的功能...

服务扩展.cs

    using System;

    using System.Collections.Generic;

    using System.Linq;

    using System.Net.Http;

    using System.Net.Http.Headers;

    using System.Security.Claims;

    using System.Text;

    using System.Text.Json.Serialization;

    using System.Threading.Tasks;

    using Microsoft.AspNetCore.Components;

    using Microsoft.Extensions.DependencyInjection;

 public static class ServiceExtensions

    {    

     public static async Task<T> GetJsonAsync<T>(this HttpClient httpClient, string url, AuthenticationHeaderValue authorization)

            {

                var request = new HttpRequestMessage(HttpMethod.Get, url);

                request.Headers.Authorization = authorization;

                var response = await httpClient.SendAsync(request);

                var responseBytes = await response.Content.ReadAsByteArrayAsync();

                return JsonSerializer.Parse<T>(responseBytes, new JsonSerializerOptions { PropertyNamingPolicy = JsonNamingPolicy.CamelCase });

            }

}

下面展示了如何调用 Web Api 上的端点，传递从 localStorage 读取的 Jwt 令牌。（顺便说一句，这些版本都没有数据保护）

索引剃刀

@page "/"

@inject ILocalStorageService localStorage

@inject HttpClient Http

<div class="mdc-card main-content-card">

    <h1 class="@MdcTypography.H4">Hello, world!</h1>

    Welcome to your new app.

</div>

// Razor content to display emloyees come here.....

@code {

Employee[] employees;

    protected override async Task OnInitAsync()

    {

        var token = await localStorage.GetTokenAsync();

        employees = await Http.GetJsonAsync<Employee[]>(

            "api/employees",

            new AuthenticationHeaderValue("Bearer", token));

    }

}

希望这有效...如果没有，并且您无法解决错误，请来这里告诉社区...

Answer 3

以下将 X-CSRF-TOKEN 标头添加到 http 请求中：

public class CustomHttpMessageHandler : DelegatingHandler

{

    private readonly IJSRuntime _js;

    public CustomHttpMessageHandler(IJSRuntime js)

    {

        _js = js;

    }

    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)

    {

        var afrt = await _js.InvokeAsync<string>("getCookie", ".AFRT");

        request.Headers.Add("X-CSRF-TOKEN", afrt);

        return await base.SendAsync(request, cancellationToken);

    }

}

在 Program.cs 中配置如下：

builder.Services.AddScoped<CustomHttpMessageHandler>();

builder.Services.AddHttpClient("ApiClient", client => client.BaseAddress = new Uri(builder.HostEnvironment.BaseAddress))

    .AddHttpMessageHandler<CustomHttpMessageHandler>();

builder.Services.AddScoped(sp => sp.GetRequiredService<IHttpClientFactory>().CreateClient("ApiClient"));

您需要将 Microsoft.Extensions.Http 包安装到 Blazor WebAssembly 客户端。

Answer 4

Microsoft.Extensions.Http您需要包含 AddHttpClient 方法的NuGet 包。使用以下命令安装它：Install-Package Microsoft.Extensions.Http -Version 3.0.0-preview7.19362.4

看起来，这个 NuGet 包是在服务器端 blazor 中自动提供的，但必须在客户端 blazor 中单独安装。