OPTIONS request processing webapi

1 error information

Access to XMLHttpRequest at 'http://localhost:4445/api/v/getmsg' from origin 'http://localhost:9528' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: The value of the 'Access-Control-Allow-Origin' header in the response must not be the wildcard '*' when the request's credentials mode is 'include'. The credentials mode of requests initiated by the XMLHttpRequest is controlled by the withCredentials attribute.

solution

References: https://segmentfault.com/q/1010000016765176 , the value change the value of a particular domain name.

  <system.webServer>   
    <httpProtocol>
      <customHeaders>
        <add name="Access-Control-Allow-Origin" value="http://localhost:9528" />
    </httpProtocol>    
  </system.webServer>

Error message 2

Access to XMLHttpRequest at 'http://localhost:4445/api/v/getmsg' from origin 'http://localhost:9528' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: The value of the 'Access-Control-Allow-Credentials' header in the response is '' which must be 'true' when the request's credentials mode is 'include'. The credentials mode of requests initiated by the XMLHttpRequest is controlled by the withCredentials attribute.

solution

Add a line profile

<add name="Access-Control-Allow-Credentials" value="true" />

3 error message

the reason

The browser sends a request interface to two requests, one for pre-request, equivalent to a confirmation request, the actual request is the second request you want to send, and this error message noted that the first OPTINOS request fails, the server does not handle this method is the OPTIONS request, you need to deal with it:

solution:

Reference: About Web API 2.0 The Options 405 issues a request to return

HTTP Module

    public class SpecialMethodModule : IHttpModule
    {
        public SpecialMethodModule()
        {
        }

        public void Init(HttpApplication app)
        {
            app.BeginRequest += new EventHandler(this.BeginRequest);
        }

        public void Dispose()
        {
        }

        public void BeginRequest(object resource, EventArgs e)
        {
            HttpApplication app = resource as HttpApplication;
            HttpContext context = app.Context;
            if (context.Request.HttpMethod.ToUpper() == "OPTIONS")
            {
                context.Response.StatusCode = 200;
                context.Response.End();
            }
        }
    }

Increase module node in web.config, refer to Microsoft's official documentation , depending on the version of IIS, added nodes in different ways, I was IIS10.0

<configuration>
  <system.webServer>
    <modules>
      <add name="HelloWorldModule" type="HelloWorldModule"/>
    </modules>
  </system.webServer>
</configuration>

This is my problem, resolve and order, there are other questions please communicate.