Use Javascript objects like you do it in C#

Friday, July 16, 2004 5:19:00 AM

While developing websites (intranet applications) I had to save a lot of information on the client or for a user. First, I used cookies to save information. I noticed that I can only save up to 20 cookies with a lenght of about 192 chars I searched for a new way of saving cookies. While I am only developing intranet applications for the Internet Explorer, I decided to use a webservice to save cookies.

[WebMethod(Description="")]
public bool SetCookieEx(string AuthenticationTicket, string Name, string Value)
{
    MS.Security.Authentication auth = new MS.Security.Authentication(AuthenticationTicket);
    int UserID = auth.UserID;
    int DataSetID = auth.DataSetID;
    return ControlSettings.SaveSettingsObject(UserID, DataSetID, Name, Value);
}

[WebMethod(Description="")]
public string GetCookieEx(string AuthenticationTicket, string Name)
{
    MS.Security.Authentication auth = new MS.Security.Authentication(AuthenticationTicket);
    int UserID = auth.UserID;
    int DataSetID = auth.DataSetID;
    return ControlSettings.GetSettingsObject(UserID, DataSetID, Name);
}

Now, I took a look at my information to save. It would be nice to have objects in Javascript, allow to save these objects to the database for each user, and retreive a object again. I wrote a simple serializer/deserializer that will take my Javascript object, convert this object to a xml stream and save it as a string.

Here is my Javascript code (note: the script is not published complete here, contact me if you want to have my current version):

function Serializer()
{
    this._xml = new ActiveXObject("Microsoft.XMLDOM");
    this._xml.loadXML("<Serializer/>");
    this.serialize = Serializer_serialize;
    this.deserialize = Serializer_deserializeXml;
}

function Serializer_deserialize(node)
{
    var o = new Object();
    for(var i=0; i<node.childNodes.length; i++)
    {
        if(node.childNodes[i].tagName == "string")
        {
            return node.childNodes[i].text;
        }
        else if(node.childNodes[i].tagName == "number")
        {
            return node.childNodes[i].text;
        }
        else if(node.childNodes[i].tagName == "boolean")
        {
            return node.childNodes[i].text == "true";
        }
        else if(node.childNodes[i].tagName == "dateTime")
        {
            var d = new Date(parseInt(node.childNodes[i].text));
            d.setHours(d.getHours() + d.getTimezoneOffset() / 60);
            return d;
        }

        // else all other objects


    return o;
}

function Serializer_deserializeXml(xml)
{
    // deserialize code ...
}

function Serializer_serialize(obj, node, root)
{
    if(node == null && root == null)
    {
        node = this._xml.documentElement;
        root = this._xml;
    }
    if(obj == null)
    {
        var ele = root.createNode("element", "null", "");
        node.appendChild(ele);
    }
    else if(typeof(obj) == "string")
    {
        var ele = root.createNode("element", "string", "");
        ele.text = obj.valueOf();
        node.appendChild(ele);
    }
    else if(typeof(obj) == "number")
    {
        var ele = root.createNode("element", "number", "");
        ele.text = obj.valueOf();
        node.appendChild(ele);
    }

    // else all other objects

    return root.xml;

}

Now, you can use the code to save Javascript objects using ASP.NET (WebService) and a Database

<script>

var o = new Object();
o.OrderNumber = "615161";
o.CustomerName = "SIEMENS";
o.Quantity = 4000;
o.IsProduced = false;

var s = new Serializer();

SetCookieEx("currentorder", s.serialize(o));

// to get the object back from the webservice

var oo = GetCookieEx("currentorder");

if(oo.IsProduced)
    alert(oo.CustomerName + " " + oo.OrderNumber)

</script>

Currently we are developing a second serializer (is already working with all Microsoft's WSDLs generated by .NET) to use the same objects as you use in C# or Visual Basic.NET.

public class MyClass
{
    public string FirstName = "Michael";
    public string LastName = "Schwarz";
    public int Age = 0;
    public DateTime Birthday = DateTime.MinValue;
}

[WebMethod(Description="")]
public MyClass GetMyObject()
{
    return new MyClass();    // ok, very simple!   ;)
}

Now, in Javascript the code will look like this:

<script>

var s = new Serializer();

var o = GetMyObject();

alert(o.FirstName + " " + o.LastName);
alert("Age = " + o.Age + "\r\nBirth: " + o.Birthday.toLocaleString());

</script>

When finished the second serializer for WSDL standard classes I will post the code here!

3 Comments

  • Snorrk said

    Very nice.

    Take a look at the XMLHTTP thingy in IE and Moz. With a bit of tweaking you can call the webservice with client side code - no need to use cookies.

    &gt;S

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