Adding a simple website hit counter using the Google Analytics API

Last time, I built a simple app to get the number of visitors to a site using the Google Analytics API. So the obvious next step is to get that data displayed on a web page. The simplest way to do this would be to add some server-side code to an ASP.NET page. But if you’ve run the code in the previous blog entry, you’ll notice it’s pretty slow, generally taking over a second to get the data back from Google. Adding a second to every page load isn’t such a good idea, so this is my slightly more complicated solution, which loads up the hit count via AJAX.

First we need a generic handler, looking something like this

<%@ WebHandler Language="C#" Class="visitorCounter" %>

using System;
using System.Web;
using Google.GData.Analytics;

public class visitorCounter : IHttpHandler 
{
  public void ProcessRequest (HttpContext context) 
  {
    AccountQuery feedQuery = new AccountQuery();
    AnalyticsService service = new AnalyticsService("DoogalAnalytics");
    service.setUserCredentials("email", "password");
    DataQuery pageViewQuery = new DataQuery("https://www.google.com/analytics/feeds/data");
    pageViewQuery.Ids = "ga:103173";
    pageViewQuery.Metrics = "ga:visits";
    pageViewQuery.GAStartDate = DateTime.Now.AddMonths(-1).ToString("yyyy-MM-dd");
    pageViewQuery.GAEndDate = DateTime.Now.ToString("yyyy-MM-dd");
    DataEntry pvEntry = service.Query(pageViewQuery).Entries[0] as DataEntry;

    context.Response.ContentType = "text/plain";
    context.Response.Write(pvEntry.Metrics[0].Value);
  }
 
  public bool IsReusable {
    get {
       return false;
    }
  }
}

Then we just need a bit of jQuery magic to show it on the page.

    <p>
      Visitors this month: <span id="visitorCount"></span>
      <script type="text/javascript">
        $(document).ready(function () {
          $.get('visitorCounter.ashx', function (data) {
            $('#visitorCount').html(data);
          });
        });

      </script>
    </p>

With a little work this could probably be wrapped up as an ASP.NET control, but I’ll leave that as an exercise for the reader.