通过fetch访问后台C# Restful服务的时候，如果需要跨域，后台服务要设置支持CORS，否则会报错。
如果站点通过web服务器发布，会报如下错误：
Access to fetch at 'http://192.168.100.2:8080/Services/someAddress' from origin 'http://localhost:8080' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.
如果是通过本地文件系统直接访问，没有把文件放到web服务器上，错误如下
Access to fetch at 'http://192.168.100.2:8080/Services/someAddress' from origin 'null' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.
可以通过两种方式设置C# Restful WCF Services支持CORS.
1.修改web.config文件
在congfiguration中增加下面的节点，在Configuration里增加Access-Control-Allow-Origin等设置。
<?xml version="1.0"?> <configuration> <system.serviceModel> <behaviors> <endpointBehaviors> <behavior name="web"> <webHttp/> </behavior> </endpointBehaviors> </behaviors> <services> <service name="AXServices.MobileTransfer"> <endpoint address="" binding="webHttpBinding" contract="AXServices.MobileTransfer" behaviorConfiguration="web"/> </service> </services> </system.serviceModel> <system.webServer> <httpProtocol> <customHeaders> <add name="Access-Control-Allow-Origin" value="*"/> <add name="Access-Control-Allow-Headers" value="Content-Type, Accept" /> <add name="Access-Control-Allow-Methods" value="POST,GET,OPTIONS" /> <add name="Access-Control-Max-Age" value="1728000" /> </customHeaders> </httpProtocol> </system.webServer> </configuration>
不过这种设置对于直接通过文件系统访问的时候不起作用，尝试将Access-Control-Allow-Origin的节点设置成null也没作用，不知道哪里还需要设置，暂时没找到设置的方法，或者这个方法不支持从本地文件发起的访问。
通过web服务器的URL访问可以正常使用。
2.增加Global.asax和Global.asax.cs文件
在Global.asax.cs增加如下代码
protected void Application_BeginRequest(object sender, EventArgs e) { HttpContext.Current.Response.AddHeader("Access-Control-Allow-Origin", "*"); if (HttpContext.Current.Request.HttpMethod == "OPTIONS") { HttpContext.Current.Response.AddHeader("Access-Control-Allow-Methods", "POST, PUT, DELETE"); HttpContext.Current.Response.AddHeader("Access-Control-Allow-Headers", "Content-Type, Accept"); HttpContext.Current.Response.AddHeader("Access-Control-Max-Age", "1728000"); HttpContext.Current.Response.End(); } }
这种方法无论 通过web服务器还是文件访问都可以，将两个文件放到Services目录。
此内容由惯性聚合(RSS阅读器)自动聚合整理，仅供阅读参考。 原文来自 — 版权归原作者所有。