假设您有答案，但为了搜索者的利益，我在.NET Core Cors 上的标准教程中遇到了同样的问题。
遇到的许多错误之一：
XMLHttpRequest 无法加载 localhost:64633/api/blogs。回复
预检请求未通过访问控制检查：否
请求中存在“Access-Control-Allow-Origin”标头
资源。因此，不允许使用 Origin 'localhost:56573'
使用权。响应的 HTTP 状态代码为 500。
玩了之后，下面的代码工作了。完整的课程贴在下面，以帮助理解去哪里。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.EntityFrameworkCore;
using Microsoft.AspNetCore.Cors.Infrastructure;
namespace NetCoreWebApiTesting
{
public class Startup
{
public Startup(IHostingEnvironment env)
{
var builder = new ConfigurationBuilder()
.SetBasePath(env.ContentRootPath)
.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
.AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true);
if (env.IsEnvironment("Development"))
{
// This will push telemetry data through Application Insights pipeline faster, allowing you to view results immediately.
builder.AddApplicationInsightsSettings(developerMode: true);
}
builder.AddEnvironmentVariables();
Configuration = builder.Build();
}
public IConfigurationRoot Configuration { get; }
// This method gets called by the runtime. Use this method to add services to the container
public void ConfigureServices(IServiceCollection services)
{
// Add framework services.
services.AddApplicationInsightsTelemetry(Configuration);
services.AddMvc().AddJsonOptions(options => options.SerializerSettings.ReferenceLoopHandling =
Newtonsoft.Json.ReferenceLoopHandling.Ignore);
// ********************
// Setup CORS
// ********************
var corsBuilder = new CorsPolicyBuilder();
corsBuilder.AllowAnyHeader();
corsBuilder.AllowAnyMethod();
corsBuilder.AllowAnyOrigin(); // For anyone access.
//corsBuilder.WithOrigins("http://localhost:56573"); // for a specific url. Don't add a forward slash on the end!
corsBuilder.AllowCredentials();
services.AddCors(options =>
{
options.AddPolicy("SiteCorsPolicy", corsBuilder.Build());
});
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
loggerFactory.AddConsole(Configuration.GetSection("Logging"));
loggerFactory.AddDebug();
app.UseApplicationInsightsRequestTelemetry();
app.UseApplicationInsightsExceptionTelemetry();
app.UseMvc();
// ********************
// USE CORS - might not be required.
// ********************
app.UseCors("SiteCorsPolicy");
}
}
}
要使用它，您可以在控制器或方法上添加EnableCorsAttribute。例如
[EnableCors("SiteCorsPolicy")]
[Route("api/[controller]")]
public class BlogsController : Controller
{
}
或
// POST api/value
[EnableCors("SiteCorsPolicy")]
[HttpPost]
public HttpResponseMessage Post([FromBody]Blog value)
{
// Do something with the blog here....
var msg = new HttpResponseMessage(System.Net.HttpStatusCode.OK);
return msg;
}
当我使用以下代码调用它时（使用标准 js/jQuery 以便于复制和粘贴），通信停止被拒绝。
function HandleClick() {
var entityData = {
"blogId": 2,
"url": "http://blog.com/blog1",
"posts": [
{
"postId": 3,
"title": "Post 1-1",
"content": "This is post 1 for blog 1",
"blogId": 2
},
{
"postId": 4,
"title": "Post 1-2",
"content": "This is post 2 for blog 1",
"blogId": 2
}
]
};
$.ajax({
type: "POST",
url: "http://localhost:64633/api/blogs",
async: true,
cache: false,
crossDomain: true,
data: JSON.stringify(entityData),
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (responseData, textStatus, jqXHR) {
var value = responseData;
},
error: function (responseData, textStatus, errorThrown) {
alert('POST failed.');
}
});
}