Getting POST values with an ASHX file

Today I had this scenario where I wanted to post items from multiple HTML input elements to a generic handler (.ashx) file without using the action attribute of the form. Specifying the action meant that that you are navigated away from the page where the action is happening, which means re-creating UI logic. How did I achieve this? By using an XMLHttpRequest and using a POST method. GET places everything inside a querystring, which is ok, but I just wondered what would happen if the content was too long for the querystring. I guess the same can be said for POST, but it just seems POST uses a different way to transfer the data. So lets say you had this JavaScript:

    getXMLHTTPPostObject: function(url, elementName, parameters) {
        if (window.XMLHttpRequest) {
            // code for IE7+, Firefox, Chrome, Opera, Safari
            xmlhttp = new XMLHttpRequest();
        }
        else if (window.ActiveXObject) {
            // code for IE6, IE5
            xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
        }
        else {
            alert("Your browser does not support XMLHTTP!");
        }
        xmlhttp.onreadystatechange = function() {
            if (xmlhttp.readyState == 4) {
                document.getElementById(elementName).innerHTML = xmlhttp.responseText;
            }
        }
        xmlhttp.open("POST", url, true);
        xmlhttp.send(parameters);
    }

I use this function to create an XMLHttpRequest object by passing it:

• the URL for the AJAX call
• an elementName to put the result of request in
• A parameter list

I then have a function like this:

    addPost: function() {
        objXMLHTTP.getXMLHTTPPostObject("url to handler", "categoryTemp", "postTitle=" + document.getElementById("txtPostTitle").value + "&blogpost=" + document.getElementById("txtBlogPost").value);
    }

The function gets the values of two HTML input elements and passes it as parameters. The parameters are then used in the POST HTTPMethod. My next challenge was to get the data in the generic handler (.ashx) so that I can process it. I also wanted to return the data from the ASHX file to see that its processed successfully. So in my handler I created this code:

        context.Response.ContentType = "text/plain";
        System.IO.Stream body = context.Request.InputStream;
        System.Text.Encoding encoding = context.Request.ContentEncoding;
        System.IO.StreamReader reader = new System.IO.StreamReader(body, encoding);
        //if (context.Request.ContentType != null)
        //{
        //    context.Response.Write("Client data content type " + context.Request.ContentType);
        //}
        string s = reader.ReadToEnd();
        string[] content = s.Split('&');
        for (int i = 0; i < content.Length; i++)
        {
            string[] fields = content[i].Split('=');
            context.Response.Write("
" + fields[0] + "

");
            context.Response.Write("
" + fields[1] + "

");
        }
        //context.Response.Write(s);
        body.Close();
        reader.Close();

I first create a class of type Stream that is instantiated through the Response.InputStream property, after which I set the content encoding for the response object. I then create a StreamReader instance and call its ReadToEnd method. After this I do some string manipulation and return the text back to the XMLHttpRequest object, which then writes the content to an HTML Element.