.NET中CORS跨域访问WebApi

我这里只写基本用法以作记录，具体为什么看下面的文章：

http://www.cnblogs.com/landeanfen/p/5177176.html

http://www.cnblogs.com/moretry/p/4154479.html

Nuget：microsoft.aspnet.webapi.cors，安装到WebApi项目上

web.config:

<appSettings>
    <add key="cors:allowedMethods" value="*"/>
    <add key="cors:allowedOrigin" value="http://localhost:63145"/>
    <add key="cors:allowedHeaders" value="*"/>
  </appSettings>

/App_Start/WebApiConfig修改一下：

引入命名空间：

using System.Web.Http.Cors;
using System.Configuration;

然后在Register函数里加入这段代码：这样以来就是全部的接口都具有跨域支持

#region 跨域配置
            var allowedMethods = ConfigurationManager.AppSettings["cors:allowedMethods"];//跨域支持的请求方式 get,post,put,delete; * 代表所有，多种方式用逗号隔开。
            var allowedOrigin = ConfigurationManager.AppSettings["cors:allowedOrigin"];//接受指定域名下的跨域请求，*表示接受任何来源的请求。
            var allowedHeaders = ConfigurationManager.AppSettings["cors:allowedHeaders"];//

            var geduCors = new EnableCorsAttribute(allowedOrigin, allowedHeaders, allowedMethods)
            {
                SupportsCredentials = true
            };
            config.EnableCors(geduCors);
            #endregion

另一个方法，在Controller上面加特性描述，这样只有这个接口支持跨域：

//[EnableCors(origins: "http://localhost:63145", headers: "*", methods: "GET,POST,PUT,DELETE")]//也可以这样用
    public class ChargingController : ApiController
    {
        /// <summary>
        /// api/Charging/GetAllChargingData
        /// </summary>
        /// <returns></returns>
        [HttpGet]
        public string GetAllChargingData()
        {
            //HttpResponseMessage result = new HttpResponseMessage { Content = new StringContent("success", Encoding.GetEncoding("UTF-8"), "application/json") };
            //return result;

            return ToJsonTran.ToJson2("success");
        }
    }

ToJsonTran是什么：

public class ToJsonTran
    {
        public static HttpResponseMessage ToJson(Object obj)
        {
            String str;
            if (obj is String || obj is Char)
            {
                str = obj.ToString();
            }
            else
            {
                JavaScriptSerializer serializer = new JavaScriptSerializer();
                str = serializer.Serialize(obj);
            }
            HttpResponseMessage result = new HttpResponseMessage { Content = new StringContent(str, Encoding.GetEncoding("UTF-8"), "application/json") };

            return result;
        }

        public static string ToJson2(Object obj)
        {
            String str;
            if (obj is String || obj is Char)
            {
                str = obj.ToString();
            }
            else
            {
                JavaScriptSerializer serializer = new JavaScriptSerializer();
                str = serializer.Serialize(obj);
            }
            return str;
        }
    }

页面上面的js测试跨域：

<script>
        jQuery.support.cors = true;
        var ApiUrl = "http://localhost:58068/";
        $(function () {
            $.ajax({
                type: "get",
                url: ApiUrl + "api/Charging/GetAllChargingData",
                data: {},
                success: function (data, status) {
                    debugger;
                    if (status == "success") {
                        $("#div_test").html(data);
                    }
                },
                error: function (e) {
                    debugger;
                    $("#div_test").html("Error");
                },
                complete: function () {

                }

            });
        });
    </script>

测试结果：<div id="div_test"></div>

POST请求：

function test1() {
            $.ajax({
                type: "POST",
                url: ApiUrl + "OfficialStoryInfo/GetJsonPDataByID",
                contentType: 'application/json',
                data: JSON.stringify({ ID: 711, callback: "" }),
                success: function (d, status) {
                    debugger;
                    if (status == "success") {
                        var StoryInfo = $.parseJSON(d).Data;
                        if (StoryInfo != null && StoryInfo != undefined) {
                            var Name = StoryInfo.Name;
                            var Description = StoryInfo.Description;
                            document.title = Name;
                            $("meta[name='apple-mobile-web-app-title']").attr('content', Name);
                            $("#div_test").html(Description);
                        }
                    }
                },
                error: function (e) {
                    debugger;
                    $("#div_test").html("Error");
                },
                complete: function () {

                }

            });
        }

这里的post请求，注意 contentType 和 data 里的 JSON.stringify() ，这样后台Api接口可以使用 dynamic 参数接收。注意看开头引用的那两篇文章。

注意：jQuery.support.cors = true;因为有些浏览器不支持js跨域，加上这句。

最近又发现了一个方法，只不过我还没试过，如下：

在web.config的<system.webServer>节点下面加入配置：

<!--跨域配置-->

<httpProtocol>

<customHeaders>

<add name="Access-Control-Allow-Origin" value="*" />

<add name="Access-Control-Max-Age" value="30"/>

<add name="Access-Control-Allow-Methods" value="GET,POST,OPTIONS"/>

<add name="Access-Control-Allow-Headers" value="Content-Type, Accept" />

</customHeaders>

</httpProtocol>