Tech Blog

The ServerStats code wraps up a few undocumented methods for CF to make it easy to get information on the number of sessions active on a server as well as some basic information on memory usage.

Thanks to Charlie Arehart for mentioning it - keep up the good work.

I must have a look at updating it to support Railo when I get a moment.

Cheers, Mark

The find utility has an option to find a file newer than another file. By creating and empty file with a specific creation date we can do the search:

To show all files newer than 2010-01-01 use:

Or to create a tar archive of them use xargs like so:

Easy. Mark

Note - this was done with flexsdk-4.0.0.13875, which was the most recent stable build at the time.

Phase 1: Get Flex3 code compiling with Flex4

Fix up stylesheets:

If you have a current Flex3 project and you are migrating to Flex4 you need to add the following lines at the top of your stylesheet.

This makes the default non-namespaced items in your stylesheet refer to the MX components. eg:

To statically link or not?

Flex 4 defaults to dynamically linking runtime shared libraries. This produces smaller files, but if you are making desktop type applications or developing code while not connected to the internet you'll probably want to statically link the files. Add this to your compiler option:

You now should have a happily compiling app, however, to use all the new goodness of flex 4 there are still some more steps to be done.

Phase 2: Using all of flex 4

Update namespace to 2009

To update the namespace references for flex 4 I did the following search and replace:

Replace mx with fx namespace

Similarly for other tags like this:

Add Declarations for non visual components

Wrap tag around non visual compoents. The compiler will complain about all these errors so just follow through and wrap them in

Migrate States

This shows up as the following error:

So if you had something like this before:

It would now look something like this:

Migrate StyleManager References

Stylemanager is not called as a global class any more and you need to use fully qualified references so:

When these have all been converted, your application should compile.

Then you can start leveraging the new functionality of flex4 and begin migrating your components to spark if necessary.

These are:

• Logging to DB instead of log files
• Runtime configuration of logging.

Logging to DB instead of log files

Coming from a web development background rather than a sysadmin background I'm far more comfortable manipulating and analysing data using SQL. So to be able to log all the queries or just the slow queries for an application to the db during application development or load testing is a huge benefit.

To enable logging to DB you can add the following to your my.cnf

The logs will be written to the 'slow_log' and 'general_log' tables in the mysql database.

Note - logging to tables has more overhead than logging to file, so would suggest using it primarily for development purposes.

Full details of the options are on the mysql manual on log tables

Runtime configuration of logging.

This allows you to turn on and off logging without restarting MySQL - which just saves a little bit of time and makes it much nicer for debugging problems.

To turn on the logging of all queries run:

And to turn them both off use:

If you also want to see queries not using indexes in the slow query log you can set the following variable:

Hope it helps, Mark

To do this I used a SSH sock proxy like I have previously blogged about.

So I fired this up so that I could review the site I wanted to look at. It worked a charm through firefox but there is no where to set up the proxy in jmeter.

To make it work you need to let the JVM know what proxy to use like so:

No jmeter will use the socks proxy on port 8080 on my local machine. Nice.

I've just received a copy of the Tomcat 6 Developer's Guide from packt publishing to review.

It's nice timing as I've been working with Tomcat 6 a bit lately and in the new year plan to move some of our production systems over to running Railo on top of Tomcat.

After the extremely busy year Learnosity has had I'm looking forward to reading a few books over the break and coming back in the New Year with lots more ideas and technology to implement.

About Learnosity

Our service:

• Makes it practical for students to practice Oral and Aural skills
• Is efficient and effective for teachers, as they can listen to each student individually at a time to suit them
• Can be used for homework assignments or “High Stakes Assessments”

We are continuing to grow our core development team and we need another great developer to help us keep up with demand.

We need someone who can:

• Use Javascript or Actionscript to create great user interfaces
• Develop highly scalable web applications
• Cut code with the best in the world

You will also need to be:

• energetic with a butt kicking attitude
• ready to create cutting edge web 2.0 apps
• keen to continue learning new technologies
• able to have a conversation with non technical people

You'll need:

• 3 or more years of programming experience
• Expert in at least on Client side language (Actionscript or AJAX)
• Expert in at least one Server side language (eg PHP, Java, ColdFusion, etc)
• Understanding of Object Oriented design
• Understanding of XHTML and CSS

It would be good if you have:

• A degree in Computer Science, Engineering or similar.
• been working with open source tools
• been playing around with iPhone/Android applications
• experience with some of Linux/VOIP/SIP/Asterisk/Jabber/XMPP

This is a full time role and you will be working in a casual workplace with flexible hours in the Sydney CBD.

If this sounds like the job for you, email a covering letter explaining why you'll be great and your resume to mark@learnosity.com - no agencies please.

Seem to be on a roll with Sox tonight. Also figured out how to normalise audio files nicely.

The first thing to do with sox is to get it to calculate the max volume adjustment possible:

This will return a number like: 4.234

You can then call sox again using this number:

And if you're feeling particularly good you can put the whole command on a single line as follows:

Easy when you know how.

However, this time I finally managed to get past all the hurdles and jump through all the hoops to make this work.

Scenario is a follows. Audio file is comes in in alaw or ulaw format and we want to trim any silence before and after it.

First step is to convert it from alaw to pcm encoded wav file as SOX has issues filtering silence in alaw files

Then we do the trimming in one fell swoop.

A huge thanks to this article for giving such a thorough overview of the how silence detection works in sox.

Too easy, when you know how :-)

All the DB storage and application was using UTF8 throughout, but the PDF exports were showing nothing when they should have been showing Chinese characters.

To fix this up you need to do the following:

1. Need fonts installed on system:

2. Need fonts installed in CFAdmin

• Go to CFAdmin and Font Management
• Select directory /usr/share/fonts/truetype/arphic
• Select "Add" and you should see 2 new fonts added.

3: CFdocument Hotfix for CF7.0.2

Configure cffont.properties file

The cffont.properties file is located in /opt/jrun4/servers/{instance name}/cfusion.ear/cfusion.war/WEB-INF/cfusion/lib on the jrun multiserver version.

5. Restart CF

Once you restart CF you documents should be coming out with their Chinese fonts intact.

I'm sure there are additional fonts to add to get it working natively with all the other asian languages, so I'll add to this as and when I need/discover them. Please feel free to post a comment if you find any more font's that should be added to the list.