asp.net core api 跨域配置

項目先後端分離，前端請求接口例如使用axios發送請求時瀏覽器會提示跨域錯誤，須要後端配置容許接口跨域

配置步驟：

一、經過NuGet安裝Microsoft.AspNetCore.Cors.dll類庫

二、在Startup.cs中的ConfigureServices方法加入如下配置

            services.AddCors(options =>
            {
                options.AddPolicy("CorsPolicy", builder =>
                {
                    //builder.AllowAnyOrigin(); //客戶端不攜帶cookie時，能夠配置
                    builder.WithOrigins(ConfigHelper.GetSectionModel<List<string>>("CorsOrigins").ToArray()); //客戶端攜帶cookie、或者在請求報文定義其餘字段屬性時，必須指定域名
                    builder.AllowAnyHeader();
                    builder.AllowAnyMethod();
                    builder.AllowCredentials();
                    builder.SetPreflightMaxAge(TimeSpan.FromSeconds(60));  //若是接口已驗證過一次跨域，則在60分鐘內再次請求時，將不須要驗證跨域
                });

            });

三、在Startup.cs中的Configure方法加入如下配置

 app.UseCors("CorsPolicy");

注意：必需要加在app.UseMvc();前面

四、在appsettings.json配置能夠跨域的域名：

"CorsOrigins": [ "http://www.testseparateapi.com:8080", "http://localhost:8080" ]

ConfigHelper讀取appsettings.json工具類代碼：

 1     /// <summary>
 2     /// appsettings.json配置文件幫助類
 3     /// </summary>
 4     public class ConfigHelper
 5     {
 6         static ConfigHelper()
 7         {
 8             Microsoft.Extensions.Configuration.IConfiguration config = AutofacHelper.GetService<Microsoft.Extensions.Configuration.IConfiguration>();
 9             if (config == null)
10             {
11                 var builder = new Microsoft.Extensions.Configuration.ConfigurationBuilder().SetBasePath(AppContext.BaseDirectory).AddJsonFile("appsettings.json");
12 
13                 config = builder.Build();
14             }
15 
16             _config = config;
17         }
18 
19         private static Microsoft.Extensions.Configuration.IConfiguration _config { get; }
20 
21         #region 從appsettings.json獲取key的值
22         /// <summary>
23         /// 從appsettings.json獲取key的值
24         /// 
25         /// 列如：appsettings.json的格式以下
26         /// 
27         /// {
28         ///  
29         ///  "Logging": {
30         ///    "LogLevel": {
31         ///      "Default": "Warning"
32         ///    }
33         ///},
34         ///  "AllowedHosts": "*",
35         ///  "RabbitMQ": {
36         ///    "HostName": "111",
37         ///    "UserName": "11",
38         ///    "Password": "11",
39         ///    "ReTryCount": "5"
40         ///  }
41         ///}
42         ///
43         /// 取RabbitMQ下的HostName的值，則參數key爲 RabbitMQ:HostName
44         /// 
45         /// </summary>
46         /// <param name="key">key</param>
47         /// <returns></returns>
48         public static string GetValue(string key)
49         {
50             var rr = _config.GetSection(key).GetChildren();
51 
52             return _config[key];
53         }
54         #endregion
55 
56         #region appsettings.json 子節點轉實體
57         /// <summary>
58         /// appsettings.json 子節點轉實體
59         /// </summary>
60         /// <typeparam name="T"></typeparam>
61         /// <param name="key">節點名稱</param>
62         /// <returns></returns>
63         public static T GetSectionModel<T>(string key) where T : new()
64         {
65             var model = new T();
66             _config.GetSection(key).Bind(model);
67             return model;
68         }
69 
70         #endregion
71 
72         /// <summary>
73         /// 獲取鏈接字符串
74         /// </summary>
75         /// <param name="nameOfCon">鏈接字符串名</param>
76         /// <returns></returns>
77         public static string GetConnectionString(string nameOfCon)
78         {
79             return _config.GetConnectionString(nameOfCon);
80         }
81     }

 

配置容許全部域名經過跨域，builder.AllowAnyOrigin()，客戶端請求的時候攜帶cookie或者其餘參數的時候出現如下錯誤，必須經過builder.WithOrigins()指定域名