c# - 使用 CORS 的应用程序无法在 Azure 中运行

Question

我已将我的应用程序配置为使用 CORS。一切都在我的本地环境中完美运行，但将应用程序部署到 Azure 后，我们收到以下错误:

No 'Access-Control-Allow-Origin' header is present on the requested resource.

当我在计算机上运行该应用程序并使用 DHC chrome 扩展创建原始 header 时，它确实有效:

Access-Control-Allow-Credentials:   true
Access-Control-Allow-Origin:        http://mysite.s3-website-eu-west-1.amazonaws.com
Access-Control-Expose-Headers:      Location,Finished

这是我使用的代码/配置:

Global.asax.cs

protected void Application_Start()
{
    GlobalConfiguration.Configure(WebApiConfig.Register);
}

WebApiConfig.cs

public static void Register(HttpConfiguration config)
{
    config.EnableCors(new MyCorsPolicyAttribute());
    config.MapHttpAttributeRoutes();
}

MyCorsPolicyAttribute.cs

public class MyCorsPolicyAttribute : Attribute, ICorsPolicyProvider
{
    private CorsPolicy _policy;

    public MyCorsPolicyAttribute()
    {
        _policy = new CorsPolicy
        {                
            AllowAnyMethod = true,
            AllowAnyHeader = true,
            SupportsCredentials = true
        };

        _policy.ExposedHeaders.Add("Location");
        _policy.ExposedHeaders.Add("Finished");

        // Add allowed origins.
        _policy.Origins.Add("http://mysite.s3-website-eu-west-1.amazonaws.com");
        _policy.Origins.Add("http://localhost:81");//for testing purposes; 
   }
    public Task<CorsPolicy> GetCorsPolicyAsync(HttpRequestMessage request)
    {
        return Task.FromResult(_policy);
    }

    public Task<CorsPolicy> GetCorsPolicyAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        return Task.FromResult(_policy);
    }   
}

最后是web.config

<system.webServer>
  <handlers>
    <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
    <remove name="WebDav" />
    <remove name="OPTIONSVerbHandler" />
    <remove name="TRACEVerbHandler" />
    <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
  </handlers>
</system.webServer>

为什么上面的方法在Azure环境中不起作用？

Answer 1

最近，Azure API 应用程序(现已过时并已统一到应用程序服务中)不再遵守代码定义的 CORS header 。部署到新的应用服务实例。