使用C＃后端服务器的跨域GET请求在jQuery中不起作用

Question

I have a separate HTTP server hosted on another domain that I use as my backend server (C#). It creates a TcpListener, and on connection creates a new thread to deal with the connection.

I use jQuery to make an ajax get request to this server, and jQuery sends an OPTIONS request instead. After some research, I added this segment into my program in hopes that it would continue with the HTTP request afterwards. (ns is an instance of NetworkStream, from TcpClient.GetStream())

if (req1.StartsWith("OPTIONS"))
            {
                //req1 = req1.Split('\n')[0].Substring(9);
                string headers = string.Format(
                    "HTTP/1.0 200 OK\r\n"+
               "Access-Control-Allow-Origin: *\r\n"+
               "Access-Control-Allow-Methods: *\r\n"+
               "Access-Control-Max-Age: 1728000\r\n"+
               "Access-Control-Allow-Headers: *\r\n"+
               "Connection: Keep-Alive\r\n"+
               "Content-Type: text/plain\r\n\r\n");
                ns.Write(Encoding.ASCII.GetBytes(headers), 0, Encoding.ASCII.GetBytes(headers).Length);
                ns.Close(); client.Close();  return;
            }

Unfortunately, the browser keeps sending OPTIONS requests to the server, even though the server sends back Access-Control headers that should let it have unlimited access.

Here are the network logs for 1 of these requests: http://pastebin.com/T07Whvem

Any suggestions to make this work? The javascript code is pretty trivial, but I'll include it:

//this is just a long-poll
function waitForMsg(){

    $.ajax({
        url: "http://127.0.0.1:6969/2|||ub",
        dataType: "text",

       async: true, 
       cache: true,
        timeout:50000, 

        success: function(data){ 
            addmsg("new", data); 
            setTimeout(
                'waitForMsg()', 
                1000 
            );
        },
        error: function(XMLHttpRequest, textStatus, errorThrown){
            addmsg("error", textStatus + " (" + errorThrown + ")");
            setTimeout(
                'waitForMsg()', 
                "1000"); 
        },
    });
};

$(document).ready(function(){
    waitForMsg(); /* Start the inital request */
});

I can't use an existing web-server because this is not really a standard webserver; merely a server that can take instructions via http.

Thanks!

Answer 1

You need to enable the below setting in jQuery

$(document).ready(function()
{
    $.support.cors = true;
});

see: http://api.jquery.com/jQuery.support/