Xdocument,Descendants in C#

Question

I have the below code to get alexa page rank.

private int GetAlexaRank(string domain)
{
    var alexaRank = 0;
    try
    {
        var url = string.Format("http://data.alexa.com/data?cli=10&dat=snbamz&url={0}", domain);

        var doc = XDocument.Load(url);

        var rank = doc.Descendants("POPULARITY").Select(node => node.Attribute("TEXT").Value).FirstOrDefault();

        if (!int.TryParse(rank, out alexaRank))
            alexaRank = -1;

    }
    catch (Exception e)
    {
        return -1;
    }

    return alexaRank;
}

But I truly don't understand how does that code work??? Would you tell me exactly, what is the "POPULARITY" and "TEXT" ? and where are they stored? I don't understand this syntax: doc.Descendants("POPULARITY").Select(node => node.Attribute("TEXT").Value).FirstOrDefault(); Please!!!!

Answer 1

I would recommend you navigating to the url you have in your code and take a look at the XML file structure. You should see tags with POPULARITY and TEXT , by the look of your code these are the nodes/attributes/values that you are selecting.

.Descendants returns a collection, and since you provide POPULARITY it will bring back the elements within the <POPULARITY> tag in your XML file.

You are then looking at each node in the Collection whose Descendants are Popularity and selecting an item with attribute TEXT . Your return the first value found, or null if the collection does not contain a node with attribute TEXT .