General

Client side logging for your Ajax app. with Google Gears

Kevin — Fri, 06 Jul 2007 12:09:00 GMT

In today's Web 2.0 world developers are creating very rich clients with plenty of JavaScript code and little to no logging. With the tools available today there is no reason not to log on the client side.

Logging is an important tool in any developers toolbox. If done right logging gives the developer detailed context for application failures. Logging should not be confused with testing or debugging although in certain instances it can help with the later.

The following is a quick example of how logging on the client side can easily be acheived using Google Gears. There is potential to expand this small demo into a more sophisticated logging mechanismn with reporting features and server-side transfer of logs if desired.

The basic code and idea behind client side logging is very simple. Let's look at a little sample logger that uses Google Gears:

Sample Client Side Logger using Google Gears

To get client side logging running on your site all you need to do is include the following JavaScript files in your head section as follows:

  <script type="text/javascript"  src="gears_init.js"></script>
  <script type="text/javascript"  src="glogger.js"></script>

Then you are set to add client side logging in your scripts like this:

  // Log to Google Gears client side database
  log("INFO", "Hello World");

The client side database creation is done in the initialization function of the included glogger.js script. You can see here how it checks for existence of Google Gears and the database before it tries to create it.

  if (!window.google || !google.gears) {
    return;
  }
  try {
    db = google.gears.factory.create('beta.database', '1.0');
  } catch (ex) {
    setError('Could not create database: ' + ex.message);
  }
  if (db) {
    db.open('database-glogger');
    db.execute('create table if not exists glogger' +
               ' (level varchar(50), msg varchar(1024), timestamp int)');
  }

Inserting, selecting, and deleting from the log table is just as easy. There are examples of each of these in glogger.js.

The Code:
glogger.html - Web page that logs to client
glogger.js - Logging implementation
gears_init.js - Main Google Gears code

Helper Utilities:
sqlitebrowser.sourceforge.net - SQLiteDatabase Browser
dbquery.html - Web interface to SQLite query analyzer

Happy Client Side Logging!

Let me know if you make any extensions to this code...

Firefox Bookmarks

Kevin — Fri, 16 Feb 2007 20:02:00 GMT

If you're like me you have a ton of bookmarks. Some you go back to frequently and some you only use every so often. The problem is keeping them in sync on all your computers or remembering how to Google the page back. The answer is simple and easy to get used to. The answer is Foxmarks. If you don't use this extension go grab it. Try actually organizing your bookmarks and use ctrl-b to bring them up, and quickly search through them.

While I'm talking about Firefox extensions, if you are a web developer you have to try out Firebug.

For a more complete list of useful extensions, check out this list.

Windows is not the most important OS.

Kevin — Wed, 07 Apr 2004 08:31:00 GMT

Bill Hill explains on Channel9 how Windows is not the most important OS.

Office Update

Kevin — Wed, 24 Mar 2004 09:05:00 GMT

We all always run Windows update to make sure we have all the critical patches, but did you know there is also an Office update that has some good things on it like an updated junk-email filter.

Access Forbidden: Too many users are connected to Internet Information Services

Kevin — Mon, 22 Mar 2004 20:31:00 GMT

Thanks to a post by Omri Gazit I am able to minimize the number of 403.9's (Access Forbidden: Too many users are connected to Internet Information Services) I was seeing on my web server today. It turns out Windows XP Professional only allows 10 simultaneous connections by default (What were they thinking $$$). To top it off it turns out that many browsers will open more than one connection.

I bumped up the number of connections by running: adsutil set w3svc/MaxConnections 40

I also set my connection timeout to 120 seconds and turned off HTTP Keep alives. Not the best for performance, but better than an Access Forbidden error.

Hopefully this helps. I don't want to change servers.

New Blogger in Town.

Kevin — Sat, 20 Mar 2004 18:52:00 GMT

That's right people. There is a new blogger in town.

Welcome!

Kevin — Sat, 20 Mar 2004 17:36:00 GMT

Welcome to www.janetandkevin.com/blog. Hopefully this blog will keep you entertained with useful information.