即使遵循文档，.NET Web API 项目中也会出现 CORS 错误

Question

我正在尝试设置一个 API，并且在 swagger 中一切都工作得很好，但是当我尝试从我正在处理的 Angular 应用程序调用 API 时，我收到了 CORS 错误。两者都位于不同端口的本地主机上，但无论我做什么，即使在遵循启用 CORS 的文档后，我仍然会收到 CORS 错误。

这是我的启动配置的pastebin上的代码：https://pastebin.com/19V15Hf2

using System.Text;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.IdentityModel.Tokens;
using Microsoft.OpenApi.Models;
using Simple_RPG_API.BAL;

namespace Simple_RPG_API
{
    public class Startup
    {

        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddScoped<IUserService, UserService>();
            services.AddControllers();
            services.AddCors(options =>
            {
                options.AddDefaultPolicy(
                    builder =>
                    {
                        builder.WithOrigins("http://localhost:4200")
                                            .AllowAnyHeader()
                                            .AllowAnyMethod();
                    });
            });
            services.AddSwaggerGen(c =>
            {
                c.SwaggerDoc("v1", new OpenApiInfo { Title = "Simple_RPG_API", Version = "v1" });
            });

            services.AddScoped<IUserService, UserService>();

            var key = Encoding.ASCII.GetBytes(Configuration["AppSettings:Secret"]);
            services.AddAuthentication(x =>
            {
                x.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
                x.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
            })
            .AddJwtBearer(x =>
            {
                x.Events = new JwtBearerEvents
                {
                    OnTokenValidated = context =>
                    {
                        var userService = context.HttpContext.RequestServices.GetRequiredService<IUserService>();
                        var userId = int.Parse(context.Principal.Identity.Name);
                        var user = userService.GetById(userId);
                        if (user == null)
                        {
                            // return unauthorized if user no longer exists
                            context.Fail("Unauthorized");
                        }
                        return Task.CompletedTask;
                    }
                };
                x.RequireHttpsMetadata = false;
                x.SaveToken = true;
                x.TokenValidationParameters = new TokenValidationParameters
                {
                    ValidateIssuerSigningKey = true,
                    IssuerSigningKey = new SymmetricSecurityKey(key),
                    ValidateIssuer = false,
                    ValidateAudience = false
                };
            });
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseSwagger();
                app.UseSwaggerUI(c => c.SwaggerEndpoint("/swagger/v1/swagger.json", "Simple_RPG_API v1"));
            }
            app.UseHttpsRedirection();
            app.UseRouting();
            app.UseCors(x => x
                .AllowAnyOrigin()
                .AllowAnyMethod()
                .AllowAnyHeader());
            app.UseAuthorization();
            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }
    }
}

Answer 1

我遇到过这个问题几次，删除浏览器的缓存对我有用。希望它也适合你。