A Simple AJAX App using SharePoint Web Services

In this era of Web 2.0 web applications, I think it was only a matter of time before I needed to investigate how I could apply AJAX to SharePoint. With a little JavaScript and SharePoint’s web services, you can build fancy apps that can easily be dropped into a document library. And after reading Glen Cooper’s blog post on the subject, I figured it was something definitely worth investigating.

I also took this opportunity to improve a process I have to do all the time: what are the internal column names in a list? To get the list information, I built a simple AJAX app that consumes the Lists.asmx web service. Please keep in mind that this code will have be uploaded into SharePoint in order to work (a document library will work) and will not run from your desktop.

Step 0: HTML for user input and displaying results

Since I will be calling the GetList method on Lists.asmx, I will need two parameters from the user: Site URL and List Name. Site URL gives the web service context to a particular web and List Name should be a list within that web. I also specify a DIV which is where I will display the list’s information.

Now that we have our HTML form, we can work on the JavaScript code.

Step 1: Building a SOAP Message

To communicate with the web service, we need to use SOAP. Luckily, Glen has already created a very handy class for taking care of these operations. It is also reusable so it will come in handy for other web service calls. I tweaked his code a little bit and then put it into SoapUtils.js (also, please note this code depends on Prototype.JS):

This utility class handles a lot of the grunt work for creating the SOAP message. It makes it pretty easy to grab the input, build the message, and then send it to the server. Next, I need to give it the specifics it needs to build the actual message. This is all contained inside my Execute function:

The Execute method is then bound to the “Get Columns” button on page load:

Step 2: Parsing the Web Service’s XML response

At this point, we are ready to handle the response from the web service. Unfortunately, parsing XML using JavaScript was not exactly the easiest experience. I haven’t found an easy way to do it, so if you have any ideas, please let me know in the comments.

In any case, if an error occurs, I simply want to print the error message:

A success message is a lot more complicated since we want to extract information out of the returned XML. In fact, if you look at the entire response from the webservice after calling GetList, the returned result for a simple Images library is something like 1100 lines of XML. The majority of this is taken up by the full description of each column in the list. There is a LOT of junk that we are simply going to be skipping over. For sanity sake, I’m not going to post the entire response, but useful snippets of interest.

Overall, the response will look something like:

Notice, the List node contains a LOT of useful information. Once we have that node, we can display a lot of it using this function:

function addListInformation(nodeList) {
var listTitle = nodeList.attributes.getNamedItem('Title').value;
var listImg = nodeList.attributes.getNamedItem('ImageUrl').value;
var listDesc = nodeList.attributes.getNamedItem('Description').value;
var listCount = nodeList.attributes.getNamedItem('ItemCount').value;
var listViewURL = nodeList.attributes.getNamedItem('DefaultViewUrl').value;

var output = ''
output +='';
output +='';
output +='

+ listViewURL + '">+ listImg + '" alt="' + listTitle + '" />

+ listViewURL + '">' + listTitle + '

# of items = ' + listCount + '

' + listDesc + '

';
Element.insert('result', {bottom:output});
}

Also, since we are interested in the internal column names, we want information about each of the fields. All of the columns are listed inside the Fields node (see above). A lot of them have attributes similar to below:

So, for each of the Field nodes, we are interested in the StaticName and DisplayName attributes:

And finally, to bring it all together, we are calling these functions inside our success function:

All together now: