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
public void ConfigureServices(IServiceCollection services)
{
services.AddCors(options =>
{
options.AddPolicy("AllowAnyOrigin",
builder => builder
.AllowAnyOrigin()
.AllowAnyMethod()
.AllowAnyHeader());
});
services.Configure<MvcOptions>(options => {
options.Filters.Add(new CorsAuthorizationFilterFactory("AllowAnyOrigin"));
});
}
其他回答
你有三种方式启用CORS:
在中间件中使用命名策略或默认策略。 使用端点路由。 使用[EnableCors]属性。
启用指定策略的CORS:
public class Startup
{
readonly string CorsPolicy = "_corsPolicy";
public void ConfigureServices(IServiceCollection services)
{
services.AddCors(options =>
{
options.AddPolicy(name: CorsPolicy,
builder =>
{
builder.AllowAnyOrigin()
.AllowAnyMethod()
.AllowAnyHeader()
.AllowCredentials();
});
});
// services.AddResponseCaching();
services.AddControllers();
}
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
app.UseRouting();
app.UseCors(CorsPolicy);
// app.UseResponseCaching();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
});
}
}
当使用UseResponseCaching时，UseCors必须在UseResponseCaching之前调用。
开启默认策略下的CORS:
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
services.AddCors(options =>
{
options.AddDefaultPolicy(
builder =>
{
builder.AllowAnyOrigin()
.AllowAnyMethod()
.AllowAnyHeader()
.AllowCredentials();
});
});
services.AddControllers();
}
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
app.UseRouting();
app.UseCors();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
});
}
}
启用带有端点的CORS
public class Startup
{
readonly string CorsPolicy = "_corsPolicy ";
public void ConfigureServices(IServiceCollection services)
{
services.AddCors(options =>
{
options.AddPolicy(name: CorsPolicy,
builder =>
{
builder.AllowAnyOrigin()
.AllowAnyMethod()
.AllowAnyHeader()
.AllowCredentials();
});
});
services.AddControllers();
}
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
app.UseRouting();
app.UseCors();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers()
.RequireCors(CorsPolicy)
});
}
}
启用带有属性的CORS
你有两个选择
[EnableCors]默认策略。 [EnableCors("{Policy String}")]指定命名策略。
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.)
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();
}
对于Web API(ASP。Net core 6.0) 在Program.cs中，只需在builder.Build()之前添加;
builder.Services.AddCors(p => p.AddPolicy("corsapp", builder =>
{
builder.WithOrigins("*").AllowAnyMethod().AllowAnyHeader();
}));
也添加
app.UseCors("corsapp");
