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

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()
        );
   ...
  }

其他回答

对于“c# - ASP Net Core Web API (Net Core 3.1 LTS)”,它为我工作…

在Startup.cs文件:

在“ConfigureServices”函数中添加以下代码:

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

注意:在“CorsPolicy”的情况下,你可以改变你喜欢的或在“Startup”类中使用全局变量。

在“Configure”函数中添加以下代码:

app.UseCors("CorsPolicy");

检查函数的调用顺序,它应该是这样的:

if (env.IsDevelopment())
{
    app.UseDeveloperExceptionPage();
}

app.UseHttpsRedirection();
app.UseRouting();
app.UseCors("CorsPolicy");
app.UseAuthentication();
app.UseAuthorization();

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

最后,在你的控制器类中,将下面的代码添加到你的函数之上:

[EnableCors("CorsPolicy")]

例如:

[EnableCors("CorsPolicy")]
[HttpPost("UserLoginWithGoogle")]
public async Task<ActionResult<Result>> UserLoginWithGoogle([FromBody] TokenUser tokenUser)
{            
    Result result = await usersGoogleHW.UserLoginWithGoogle(tokenUser.Token);
    return new JsonResult(result);
}

注意:“CorsPolicy”必须在启动和控制器中匹配。

祝你好运……

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()
        );
   ...
  }

ASP。NET Core 6:

var  MyAllowSpecificOrigins = "_myAllowSpecificOrigins";

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddCors(options =>
{
    options.AddPolicy(name: MyAllowSpecificOrigins,
                      builder =>
                      {
                          builder.WithOrigins("http://example.com",
                                              "http://www.contoso.com");
                      });
});

// services.AddResponseCaching();

builder.Services.AddControllers();

var app = builder.Build();
app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseRouting();

app.UseCors(MyAllowSpecificOrigins);

app.UseAuthorization();

app.MapControllers();

app.Run();

更多样品请参考官方文档。


ASP。NET Core 3.1和5.0:

你必须在应用程序启动时在ConfigureServices方法中配置CORS策略:

public void ConfigureServices(IServiceCollection services)
{
    services.AddCors(o => o.AddPolicy("MyPolicy", builder =>
    {
        builder.WithOrigins("http://example.com")
               .AllowAnyMethod()
               .AllowAnyHeader();
    }));

    // ...
}

builder中的CorsPolicyBuilder允许您根据需要配置策略。你现在可以使用这个名字将策略应用到控制器和动作上:

[EnableCors("MyPolicy")]

或者把它应用到每一个请求上:

public void Configure(IApplicationBuilder app)
{
    app.UseCors("MyPolicy");

    // ...

    // This should always be called last to ensure that
    // middleware is registered in the correct order.
    app.UseMvc();
}

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.)

上面提到的所有解决办法都可能有效,也可能无效,在大多数情况下都行不通。我已经给出了答案

目前我正在研究Angular和Web API(.net Core),遇到了下面解释的CORS问题

上面提供的解决方案总是有效的。对于“OPTIONS”请求,真的有必要启用“匿名身份验证”。使用这里提到的解决方案,您不必执行上面提到的所有步骤,例如IIS设置。

不管怎样,有人把我上面的帖子标记为这篇帖子的副本,但我可以看到这篇帖子只是为了在ASP.net Core中启用CORS,但我的帖子与在ASP.net Core和Angular中启用和实现CORS有关。