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PHP and MySQL 5 bit fields

Posted At : August 25, 2008 2:21 AM | Posted By : Mark Lynch
Related Categories: mysql, Open Source, PHP
While debugging some PHP code the other night I came across a particularly strange problem with MySQL Bit fields.

I was returning a query with some bit fields into my class but the it was not returning true or false when I switched the data.

A bit of hunting and it turned out the that it was being returned as a binary type and after a few failed attempts to convert it to an integer or boolean on the PHP side I found this bug report on it.

So the moral of the story is if you are selecting BIT types from a mysql DB in PHP don't do this:

SELECT myBit
FROM tbl_example
WHERE id = 1

Instead cast the bit to an integer in MySQL like so:

SELECT CAST(myBit AS unsigned integer) AS myBit,
FROM tbl_example
WHERE id = 1

Voila, it works like expected.

Cheers, Mark Lynch

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Howto refresh /dev/disk/by-uuid on Ubuntu

Posted At : August 15, 2008 11:08 PM | Posted By : Mark Lynch
Related Categories: HOWTO, Linux, Open Source, Ubuntu
I was recently setting up a Ubuntu server and was partitioning it after it had been installed.

There was lots of free space on the drives as the root partition was only using a small portion of the disk. After running fdisk to partition it and mkfs.ext3 on the partitions to format them I couldn't see them in /dev/disk/by-uuid.

A quick google presented the solution:

sudo udevtrigger

According to the man page this makes udev request the kernel device uevents, which in essence makes it read the disk info again and show it all up so you can mount it happily.

Cheers, Mark

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CF Sandbox Security Tricks and Tips

Posted At : August 13, 2008 1:07 AM | Posted By : Mark Lynch
Related Categories: Open Source, mysql, Linux, ColdFusion
I've been working on getting CF Sandbox security working. It's trickier than I first thought so here's how to do it for future reference:

Enable security Manager

Instructions from Steven Erat's blog:
Stop ColdFusion.
Locate the jvm.config file in jrun_root/bin.
Back up the file.
Open the file in a text editor.
Add the following lines to the java.args section:
-Djava.security.manager
"-Djava.security.policy=[cf_webapp_root]/WEB-INF/cfusion/lib/coldfusion.policy"
"-Djava.security.auth.policy=[cf_webapp_root]/WEB-INF/cfusion/lib/neo_jaas.policy"

NOTE the example from the adobe site has the quotes in the wrong place. Note you also need to change [cf_webapp_root] to match the location on your machine.

Datasources

After I enabled Datasource security I began to receive the following error, a bit of digging reminded me that the MySQL connector tries to do some autoconfiguration for coldfusion to optimise it.

Message: Can't find configuration template named 'coldFusion'
Type: java.sql.SQLException

It was failing to load the configuration file which is inside the mysql connector jar file /com/mysql/jdbc/configs/coldFusion.properties

I haven't gotten to the bottom of why it couldn't be loaded but adding the following to the datasource query string fixed it up:

autoConfigureForColdFusion=false

I would suggest adding some of the settings from this file as paramaters in your datasource settings as per previous post

Note: This was using the following:

  • ColdFusion 7.0.2 Cumulative Hotfix 1 Multiserver install
  • MySQL connector/J 5.0.8

Hope it helps. Cheers, Mark

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Evaluating Script blocks loaded from AJAX with Prototype

Posted At : August 6, 2008 1:48 AM | Posted By : Mark Lynch
Related Categories: Javascript
I'm working with protoype at the moment and here's a little gotcha I found when loading html snippets via ajax which contain script blocks. For example loading:

<script language="javascript" type="text/javascript">
   function sayHi(){
      alert('Hi');
   }
</script>
<input type="button" value="Click Me" onclick="sayHi()"/>

By default, prototype will not evaluate the script block so when you load this via an Update or Request call, clicking the button will result in a error.

To resolve this you need to do two things:

  • Add the 'evalScripts:true' parameter to the update request
  • Change the format of the functions as shown below

evalScripts : true

new Ajax.Updater('targetid',
   'http://www.example.com/myurl',
   { method: 'get', evalScripts: true });

Change the format of the functions:

<script language="javascript" type="text/javascript">
   sayHi = function(){
      alert('Hi');
   };
</script>

<input type="button" value="Click Me" onclick="sayHi()"/>

The way this get evaluated will make the functions exist correctly so that they can be called.

Many thanks to Sergio Pereira for this article on prototype that explained the problem.

Cheers, Mark

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Extracting from sound from Flash (aka NellyMoser)

Posted At : July 23, 2008 1:58 PM | Posted By : Mark Lynch
Related Categories: Ubuntu, Open Source, Linux, AIR, Actionscript
A current project that we are working on requires us to be able to record sound via a flash plugin. Initially I thought it would be nice and easy as I've seen demos of both video and audio broadcasting - however, the one big problem is that the current flash client only allows you to record video to a netstream, you can't get any access to it in the flash player.

So you need something like Flash Media Server or Red5 to record it.

However, once you record it to the server it is an flv and the audio codec is stored as a NellyMoser encoded audio portion. This codec is not supported by many applications and after a quick google found the nelly2pcm project on google code.

This will convert a flv sound file to a raw pcm file - which you can then do useful stuff with. So here's how to do it on a Ubuntu machine.

$ tar -xjvf nelly2pcm.tar.bz2
$ cd nelly2pcm
$ make
cc -Wall -c -o nelly2pcm.o nelly2pcm.c
cc -Wall -c -o nelly.o nelly.c
cc -Wall -c -o nelly_tables.o nelly_tables.c
cc -Wall nelly2pcm.o nelly.o nelly_tables.o -lm -o nelly2pcm
You should now have a nelly2pcm executable file in this directory.

You can run it as follows:

$ ./nelly2pcm test.flv > test.raw
mono Nellymoser stream with 16-bit samples at 44kHz

This will create a raw sound file with no headers and output the line above which you'll need for the next part.

To play this file back you can use sox (apt-get install sox)

$ play -r 44100 -c 1 -2 -s test.raw

If you've got all the options correct then this will play the file back. Once you got it correct you can then use sox to create a wav file which is essentially the same except that it has a header which contains all the settings (eg bitrate etc)

$ sox -r 44100 -c 1 -2 -s test.raw test.wav

From a wav you can convert to whatever you like. I'm looking forward to the Flash Player 10 release as this messing will no longer be necessary as it will support encoding with the free Speex codec.

Cheers, Mark

Update:

In the 12 hours since I wrote this post it appears that a DMCA takedown notice has been served on the nelly2pcm site and google have taken it down. I've no idea if it's related to this post or not and no details are available yet on the chillingeffects site but hopefully it will be updated shortly. As I mentioned earlier, I can't wait for flash 10 with the speex codec so we don't have to use Nellymoser, well done Adobe for including it.

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