MVC跨域CORS扩展

CORS的原理：

     CORS定义一种跨域访问的机制，可以让AJAX实现跨域访问。CORS 允许一个域上的网络应用向另一个域提交跨域 AJAX 请求。实现此功能非常简单，只需由服务器发送一个响应标头即可。

     context.HttpContext.Response.AppendHeader("Access-Control-Allow-Origin", origin);

针对ASP.NET MVC，cors跨域访问，只需要在web.config中添加如下的内容即可

<system.webServer>

<httpProtocol>

<customHeaders>

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

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

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

</customHeaders>

</httpProtocol>

<handlers>

<remove name="ExtensionlessUrlHandler-Integrated-4.0" />

<remove name="OPTIONSVerbHandler" />

<remove name="TRACEVerbHandler" />

<add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />

</handlers>

</system.webServer>

但是这种全局设置存在局限性，因为你无法有选择性的设置可以跨域访问你本站的站点，所以就想到能不能通过特性标记控制器，或者标记控制器中的方法来设置跨域访问权限。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace IocTEST.Common
{
    public class AllowOriginAttribute
    {
        public static void onExcute(ControllerContext context, string[] AllowSites)
        {
            var origin = context.HttpContext.Request.Headers["Origin"];
            Action action = () =>
            {
                context.HttpContext.Response.AppendHeader("Access-Control-Allow-Origin", origin);

            };
            if (AllowSites != null && AllowSites.Any())
            {
                if (AllowSites.Contains(origin))
                {
                    action();
                }
            }
            

        }
    }

    public class ActionAllowOriginAttribute : ActionFilterAttribute
    {
        public string[] AllowSites { get; set; }
        public override void OnActionExecuting(System.Web.Mvc.ActionExecutingContext filterContext)
        {
            AllowOriginAttribute.onExcute(filterContext, AllowSites);
            base.OnActionExecuting(filterContext);
        }
    }
    public class ControllerAllowOriginAttribute : AuthorizeAttribute
    {
        public string[] AllowSites { get; set; }
        public override void OnAuthorization(System.Web.Mvc.AuthorizationContext filterContext)
        {
            AllowOriginAttribute.onExcute(filterContext, AllowSites);
        }

    }


  
}

 [ControllerAllowOrigin(AllowSites = new string[] { "http://www.cnblogs.com" })]
    public class HomeController : Controller
    {

    
        public JsonResult Test()
        {
            return Json(new { name = "aaa" }, JsonRequestBehavior.AllowGet);
        }

   }

 

 

  public class HomeController : Controller
    {

        [ActionAllowOrigin(AllowSites = new string[] { "http://www.cnbeta.com" })]
        public JsonResult Test()
        {
            return Json(new { name = "aaa" }, JsonRequestBehavior.AllowGet);
        }

   }

测试的时候，可以将需要跨域访问你本地localhost站点的网站打开，然后F12打开firebug，在console里面输入$.post('http://localhost:80/',{},function(){})或者

$.get('http://localhost:80/',{},function(){})  观察请求状态。