Blazor HttpClient卡在GetAsync中

编程入门行业动态更新时间:2024-10-20 05:28:09

本文介绍了Blazor HttpClient卡在GetAsync中的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！问题描述

我正在针对Blazor 3.0.0-preview4-19216-03的Client Blazor应用中进行测试

I'm making test in a Client Side Blazor app targeting Blazor 3.0.0-preview4-19216-03

剃须刀页面:

@page "/counter" @using BlazorServiceTest @inject IWebCrawlServiceAsync WebCrawler <h1>Counter</h1> <p>Current count: @debug</p> <button class="btn btn-primary" onclick="@IncrementCount">Click me</button> @functions { string debug = ""; async void IncrementCount() { debug = await WebCrawler.GetWeb(); } }

依赖注入:

using BlazorServiceTest; using Microsoft.AspNetCore.Components.Builder; using Microsoft.Extensions.DependencyInjection; namespace BlazorServicesTest { public class Startup { public void ConfigureServices(IServiceCollection services) { services.AddSingleton<IWebCrawlServiceAsync, WebCrawlServiceAsync>(); } public void Configure(IComponentsApplicationBuilder app) { app.AddComponent<App>("app"); } } }

服务:

using System; using System.Collections.Generic; using System.Linq; using System.Net.Http; using System.Threading.Tasks; namespace BlazorServiceTest { public interface IWebCrawlServiceAsync { Task<string> GetWeb(); } public class WebCrawlServiceAsync : IWebCrawlServiceAsync { private HttpClient _client; public WebCrawlServiceAsync(HttpClient client) { _client = client; } public async Task<string> GetWeb() { var response = await _client.GetAsync("postman-echo/response-headers?foo1=bar1&foo2=bar2"); var result = await response.Content.ReadAsStringAsync(); return result; } } }

每当我单击增量"时，都不会发生任何事情，并且对GetWeb的服务调用被卡在GetAsync调用中.

Whenever I click in Increment count nothing happens and the service call to GetWeb it's stuck in the GetAsync call.

更新

如果我在Chrome的WASM调试器中调试WebCrawler服务，则会发出他的请求

If I debug the service WebCrawler in Chrome's WASM debugger, he request is being made

但是响应部分为空:

推荐答案

在客户端应用中，您只能访问自己的来源或支持CORS的网站.

From a client-side app you can only acces your own origin or sites that support CORS.

为了验证这是您的问题，可以尝试使用postman-echo/response-headers?foo1=bar1&access-control-allow-origin=*，它可能会起作用.

In order to verify that this is your issue, you can try postman-echo/response-headers?foo1=bar1&access-control-allow-origin=*, that might work.

但是它仅适用于该站点.通常，您无法控制响应头.这不是解决方法.