我正在尝试在我的ASP上启用跨起源资源共享。NET核心Web API,但我卡住了。

EnableCors属性接受字符串类型的policyName作为参数:

// Summary:
//     Creates a new instance of the Microsoft.AspNetCore.Cors.Core.EnableCorsAttribute.
//
// Parameters:
//   policyName:
//     The name of the policy to be applied.
public EnableCorsAttribute(string policyName);

policyName是什么意思,如何在ASP上配置CORS。NET核心Web API?


当前回答

在我设法在最琐碎的CORS问题上浪费了两个小时后,一些故障排除技巧:

If you see CORS policy execution failed logged... Don't assume that your CORS policy is not executing properly. In fact, the CORS middleware works, and your policy is executing properly. The only thing this badly worded message means is that the request's origin doesn't match any of the allowed origins (see source), i.e. the request is disallowed. The origin check (as of ASP.NET Core 5.0) happens in a very simple way... i.e. case-sensitive ordinal string comparison (see source) between the strings you provided via WithOrigins() and what exists in HttpContext.Request.Headers[Origin]. CORS can fail if you set an allowed origin with a trailing slash /, or if it contains uppercase letters. (In my case I did in fact accidentally copy the host with a trailing slash.)

其他回答

你必须在Startup.cs类中进行配置

services.AddCors(options =>
        {
            options.AddPolicy("CorsPolicy",
                builder => builder.AllowAnyOrigin()
                .AllowAnyMethod()
                .AllowAnyHeader()
                .AllowCredentials());
        });

如果你在IIS上托管,一个可能的原因是你得到这个是因为IIS阻塞选项动词。我为此花了将近一个小时:

一个明显的迹象是在OPTIONS请求期间出现404错误。

要解决这个问题,您需要显式地告诉IIS不要阻止OPTIONS请求。

进入请求过滤:

确保允许使用OPTIONS:

或者,只是做一张网。配置如下设置:

<system.webServer>
    <security>
        <requestFiltering>
            <verbs>
                <remove verb="OPTIONS" />
                <add verb="OPTIONS" allowed="true" />
            </verbs>
        </requestFiltering>
    </security>
</system.webServer>

得到这个工作与。net Core 3.1如下

确保你把UseCors代码放在app.UseRouting()之间;和app.UseAuthentication ();

app.UseHttpsRedirection();

app.UseRouting();
app.UseCors("CorsApi");

app.UseAuthentication();
app.UseAuthorization();

app.UseEndpoints(endpoints => {
    endpoints.MapControllers();
});

然后将此代码放在ConfigureServices方法中

services.AddCors(options =>
{
    options.AddPolicy("CorsApi",
        builder => builder.WithOrigins("http://localhost:4200", "http://mywebsite.com")
            .AllowAnyHeader()
            .AllowAnyMethod());
});

在基本控制器上面我放了这个

[EnableCors("CorsApi")]
[Route("api/[controller]")]
[ApiController]
public class BaseController : ControllerBase

现在我所有的控制器都将继承BaseController,并启用CORS

得到这个工作与。net Core 3.1如下:

在ConfigureServices()方法中:

 public void ConfigureServices(IServiceCollection services)
  {
   ...
   services.AddCors();
   ...
  }

在Configure()方法中:

 public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
  {
   ...
   app.UseCors(builder =>
          builder.AllowAnyOrigin()
          .AllowAnyHeader()
          .AllowAnyMethod()
        );
   ...
  }

步骤1:我们需要微软. aspnetcore . cors包在我们的项目。安装请进入“Tools -> NuGet Package Manager -> Manage NuGet Packages For Solution”。搜索“Microsoft.AspNetCore.Cors”,安装软件包。

步骤2:我们需要将CORS注入到容器中,以便应用程序可以使用它。在Startup.cs类中,让我们转到ConfigureServices方法并注册CORS。

因此,在我们的服务器应用程序中,让我们进入Controllers -> homeconcontroller .cs,并将EnableCors装饰器添加到Index方法(或您特定的控制器和动作):

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