CORS 策略已阻止从来源 'http://localhost:4200' 访问位于 'URL' 的 XMLHttpRequest：

Question

我以为我已经允许访问所有来源，但我仍然收到此错误。

Access to XMLHttpRequest at 'localhost:60248/api/page/1' from origin 'http://localhost:4200' has been blocked by CORS policy: Cross origin requests are only supported for protocol schemes: http, data, chrome, chrome-extension, https.

UPDATE 添加建议的代码更改后，错误现已更改。现在是这样的：

Access to XMLHttpRequest at 'http://localhost:60248/api/page/1' from origin 'http://localhost:4200' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: Redirect is not allowed for a preflight request.

在 Startup.cs 我有这个：

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddCors(options =>
        {
            options.AddPolicy(name: "AllowAll",
                builder =>
                {
                    builder.AllowAnyOrigin()
                        .WithMethods("PUT", "DELETE", "GET");
                });
        });

在我的控制器中我有这个：

[Route("api/[controller]")]
[ApiController]
public class PageController : ControllerBase
{
    ...

    [EnableCors("AllowAll")]
    [HttpGet("{id:int}")]
    public async Task<IActionResult> GetPageData(int id)
    {
       ...

这是调用端点的 Angular 服务：

export class PageContentService {
  constructor(private http: HttpClient) { }

  getContent(id: number): Observable<PageContent> {

    let headers = new HttpHeaders();
    headers = headers.set('Content-Type', 'application/json');
    const httpOptions = {
      headers: headers
    }

    return this.http.get<PageContent>(`http://localhost:60248/api/page/${id}`, httpOptions);
  }
}

我以为这样就可以了，但显然不行。

我还需要做什么？

Answer 1

您还需要添加中间件。

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
...

        app.UseCors();

...
    }

Answer 2

我想你还需要两件事：

如 vivek 所说，在您的 Configure 方法中将 .UseCors() 添加到您的请求管道。
将 .AllowAnyHeader() 添加到策略构建器中的 CORS-Config，我认为默认情况下不允许使用 Content-Type-Header。

CORS 策略已阻止从来源 'http://localhost:4200' 访问位于 'URL' 的 XMLHttpRequest：

Access to XMLHttpRequest at 'URL' from origin 'http://localhost:4200' has been blocked by CORS policy:

c#

asp.net-core-webapi

asp.net-core-3.1