Today I tried the same with my Ubuntu 10.04 installation and I encountered a few problems. This is how I got my webcam working with Skype:

• Check if your web cam is working in general. The program Cheese is quite suitable for this task.
• Test if Skype works with you cam. Open the options dialogue, go to “Video” and click test. If you see yourself, everything is fine
• Otherwise create a shell script with the following content:
  1. #!/bin/bash
  2. LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so  /usr/bin/skype

  This script forces Skype to use the Video4Linux drivers instead of the native ones.

• If you got this error like this:
  

  X Error, request 132, minor 18, error code 8 BadMatch (invalid parameter attributes)

  Modify you script this way:

  1. #!/bin/bash
  2. export XLIB_SKIP_ARGB_VISUALS=1 skype
  3. LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so  /usr/bin/skype
• Whenever you start Skype and want to use your web cam use this script to start Skype.

P.S.: If you are on a 64bit system you probably need to do this:

It took a while to get everything running and I pulled all the information I needed from many different sites. So pulled them all together in this blog entry:

1. Register at the VMware page. Download the package for VMware server as *.tar.gz. Extract the archive.
2. Current VMware products do not support the Linux kernel 2.6.32. Therefor you need a patch for the installation archive. Download the patch from the following link and extract it in the parent folder of you VMware download: VMware patch for Linux kernel 2.6.32. More information could found on this page and pages linked on this page.
3. Run the script with super-user rights. It is quite simple to install. Most of the times you could just hit enter for every question of the installer. At one point the installer ask for a system user which runs the Vmware instances. If you leave it at the default choice, root will be the user. Make sure you have password to log in as root user. (You can set a root password by running the following command on a terminal:
   

   sudo passwd root

4. If you are running a new Ubuntu system you might have get a Firefox version >= 3.6. In these versions the VMware console plugin for the browser won’t work, so download a older version of Firefox from this page (3.5.9 should be highest working version number).
   Extract it somewhere and run it:

   ./firefox -no-remote -P

   You might create a new Firefox profile (-P) and make sure a new instance of the Firefox is starting (-no-remote)

5. On a few guest operating systems you might have some trouble with some of the arrow keys of you keyboard. To get them working run this command from a terminal:
   

   sudo echo “xkeymap.nokeycodeMap = true” >> /etc/vmware/config

   You need to run this on the computer where you want to start the VMware console. More Informations could be found here.

6. Browse to you VMware administration panel (http://localhost:8222 or https://localhost:8333). Create and start a virtual machine. Install the browser plug-in. Launch the console.

VMware admin & console

Ok. That’s fine. Now we change the code a little bit to this one:

What do you expect? I was quite surprised:

global1: 10
foo1: NaN
foo2: 0
global2: 10

Why do we get a Not a Number? Why is JavaScript not using the global var as in the first example? Why is the global variable i not increased, the operation took place before the declaration of the local variable i? JavaScript has some “strange” rules about variable declaration. Every variable declared within a function is initialised at the beginning of the function, so our function actually would look like this:

Looking into the rules of JSLint which helps to verify JavaScript code to improve the quality of your JavaScript you get a few rules how to safely declare variables:

• JavaScript allows var definitions to occur anywhere within a function. JSLint is more strict.
• JSLint expects that a var will be declared only once, and that it will be declared before it is used.
• JSLint expects that a function will be declared before it is used.
• JSLint expects that parameters will not also be declared as vars.
• JSLint does not expect the arguments array to be declared as a var.
• JSLint does not expect that a var will be defined in a block. This is because JavaScript blocks do not have block scope. This can have unexpected consequences. Define all variables at the top of the function.

So Remember: Variables are not initialised when they are declared!

Links:

• all JSLint rules for quality JavaScript code.
• WTFJS.com, a page collection all kinds of JavaScript curiosities.

Yesterday I finally moved my two open source haXe libraries (hxJson2 and hxGD) to GitHub. (hxGD was hosted on Google Code before.) I really like the ideas of the work flow of git and seriously thinking about moving all my private Subversion repositories into git repositories, since there are well working tools to even import history and branches.

Today I found a really good working plug-in for Pidgin which allows you to use the most Skype features directly from Pidgin: http://code.google.com/p/skype4pidgin/

You still need Skype to be running, but you got all you contacts in you Pidgin list. If you make a call the standard Skype dialog appears, all message communication is done via the usual Pidgin conversation windows.

Skype 4 Pidgin

Skype 4 Pidgin

Downloading

I used a small python script youtube-dl for downloading the video data.

• It is available in the Ubuntu repositories

  sudo apt-get install youtube-dl

• If you encounter some problems you also could do a source checkout from BitBucket (requires that Mercurial is installed):

  hg clone http://bitbucket.org/rg3/youtube-dl/

• Download the video from a terminal:

   youtube-dl http://www.tube.com/watch?v=videoid

• After the download you will find a videoid.flv in your folder

Getting the audio data

For extracting the audio data I used ffmpeg.

• If you haven’t installed it already:

  sudo apt-get install ffmpeg

• We will extract the audio data to a simple wave file. This file is gonna be large, so make sure you delete it afterwards.

  ffmpeg -i videoid.flv output.wav

Converting to MP3

For converting the wav file to a mp3 file I used lame.

• Run (the “-b” arguments sets the bitrate of the mp3):

  lame -b 192 -h output.wav output.mp3

Notes

• There a lot of other ways to get the data. Instead of lame you could use mplayer, but this way I alway ended with broken mp3 files.
• Instead of converting to wave file you also could create a mpeg video and then create the mp3 file directly from this video.
• Lame and also ffmpeg have tons of options available from the command line, which could increase speed and quality of the conversation.

The offline alternative

A looked around for some alternatives and the first found was the MySQL Query Browser which is part of the MySQL GUI Tools. It is fast (okay, it is a installed application, but still its fast) and very comfortable for editing and creating tables and databases and also okay for just filling / editing some data inside the tables. Also nice is that is free.

MySQL Query Browser - result view

MySQL Query Browser - Table option view

In the MySQL GUI Tools there is also a so called MySQL Administrator which is nice for some statistics, setting up users and creating and restoring backups.

The online alternative

There is only one but a big con with the MySQL Query browser. I can not run it on my server, because therefore I needed to open the MySQL port and that one thing I definitely will not do.

So I searched for a while on the web and the tool which looked best for me was SQL Buddy:

• PHP-based
• makes heavy use of AJAX
• enough options for the most common operations
• size just 1 MB (instead of 11 MB for the full version of PHPMyAdmin)

SQL Buddy - result view

SQL Buddy - Table option view

For the most common tasks SQL Buddy is perfect. It is nearly as fast as installed application and easy to use.

But nobody is perfect, there are few thing I found out, that could not be archived with SQL Buddy. There is no option to create and import xx.sql.bz2 files, and currently no handling of the different storage engines, which means that you could not use foreign keys for example.

Conclusion

For you local computer you are okay with the MySQL GUI Tools and SQL Buddy, on the server I will use SQL Buddy but for the more complex tasks I will stick to PHPMyAdmin.

I make no secret of that I am a big fan of the Firefox web browser. Except of a few things that I will name later I am/was always impressed by the speed improvements that are made over the past few years, which seems very important to me, because many pages you use in you daily life are more and more based on heavy JavaScript functionalities. A few days ago I decided to give a try to the newest development version of the Firefox – named Minefield – and make some tests.

Building

Instead of using a nightly build I decided to to compile it by myself, which was not that hard. If you like to do it yourself could simply follow the instruction on that page: Simple Firefox build. I used slightly modified the mozconfig file in hope to get the best performance:

. $topsrcdir/browser/config/mozconfig
mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/objdir-ff-release
mk_add_options MOZ_MAKE_FLAGS="-j4"
ac_add_options --disable-tests
ac add_options --disable-crashreporter

Testing

As performance test I used the Sunspider JavaScript Benchmark from the Webkit developers. To make it short, here are the result for 3 versions of Firefox:

a

time in milliseconds, faster is better

time in milliseconds, faster is better

Results

When I switched from from Firefox 3.0.x to the 3.5 branch of Firefox I was really amazed by the performance boost gained through the new JavaScript engine Tracemonkey. As the results above show the next Firefox releases will get another boost. Good news!

P.S.: Other things I like Firefox for is because of all the very useful add-ons, I hardly could imagine a day as a web-developer without the use of Firebug. AdBlock saves my nerves every day. Linkification, TinyURL generator and Greasemonkey are just a few other I really like and needed to be named here.

So how to convert this gif animation into a swf file, which the Flash Player could play? (And of course I only want to use open source tools.) It was very easy:

• Make sure you have ImageMagick installed.
• Open a console and go to the directory where the gif file is located:

  convert +adjoin -coalesce loading.gif frame%02d.png

• Now we have a png for every frame of the gif animation. Why png? Because swfmill does not support gif as file format and png it the only available format with support for transparency.
• Create a XML file that look similar to this one:
  1. <?xml version="1.0" encoding="utf-8" ?>
  2. <movie width="32" height="32" framerate="25">
  3.         <background color="#ffffff"/>
  4.         <frame>
  5.                 <library>
  6.                         <clip id="frame00" import="frame00.png"/>
  7.                 </library>
  8.                 <place id="frame00" depth="1"/>
  9.         </frame>
  10.         <frame>
  11.                 <library>
  12.                         <clip id="frame01" import="frame01.png"/>
  13.                 </library>
  14.                 <place id="frame01" depth="1"/>
  15.         </frame>
  16.         <frame>
  17.                 <library>
  18.                         <clip id="frame02" import="frame02.png"/>
  19.                 </library>
  20.                 <place id="frame02" depth="1"/>
  21.         </frame>
  22. ….
  23. </movie>
• Finally merge the single frame images together with swfmill:

  swfmill simple input.xml output.swf

• That’s all.

HTTP/1.1 200 OK
Date: Sun, 06 Sep 2009 11:44:56 GMT
Server: Apache/2.2.8 (Ubuntu) DAV/2 SVN/1.4.6
X-Powered-By: PHP/5.2.4-2ubuntu5.7
Connection: close
Content-Type: text/html

Actually I think no one needs to know which PHP version is running on this machine and that there also a Subversion is running on that machine. Even the name of the operating system and the version of the Apache is not needed in most cases.

So how suppress these information?

Disable the “X-Powered-By”

• Log in to your server as root user.
• Open you php.ini file in a editor of you choice. My php.ini is located at /etc/php5/cgi/ (as I use mod_fcgid to server PHP content)
• Search and edit:

  ; Decides whether PHP may expose the fact that it is installed on the server
  ; (e.g. by adding its signature to the Web server header).  It is no security
  ; threat in any way, but it makes it possible to determine whether you use PHP
  ; on your server or not.
  expose_php = Off

  If you like you read in the official PHP documentation.

• Save and reload you Apache:

  /etc/init.d/apache2 force-reload

Disable the “Server”-header

After searching for while I figured out that disabling the “Server”-header is not possible, without recompiling the Apache. (The Apache developers claim this as a feature.)  But you could decide between some level of information that will be provided.

• If you are not logged in, log in as root user.
• Open you Apache configuration, for me it was /etc/apache2/apache2.conf
• Search for and edit the following lines:
  1. # ServerTokens
  2. # This directive configures what you return as the Server HTTP response
  3. # Header. The default is ‘Full’ which sends information about the OS-Type
  4. # and compiled in modules.
  5. # Set to one of:  Full | OS | Minor | Minimal | Major | Prod
  6. # where Full conveys the most information, and Prod the least.
  7. #
  8. ServerTokens Full
• Replace the Full with some of the options given in the comment. Here are some examples what these options are meaning:
  

  Full	Server: Apache/2.2.8 (Ubuntu) DAV/2 SVN/1.4.6
  OS	Server: Apache/2.2.8 (Ubuntu)
  Minor	Server: Apache/2.2.8
  Minimal	Server: Apache/2.2
  Major	Server: Apache/2
  Prod	Server: Apache

  If you like you could also read the official documentation.

• Save and reload you Apache:

  /etc/init.d/apache2 force-reload

Result

I had chosen Major in the last step. Now the headers look like this:

HTTP/1.1 200 OK
Date: Sun, 06 Sep 2009 12:16:40 GMT
Server: Apache/2
Connection: close
Content-Type: text/html

Important note: This does not improve the security of the server, because you are only hiding information. Maybe you want to read: Security through obscurity.