Art on Rails

sqlite3 won't load on Ruby Enterprise Edition - but there's a solution

2008-07-05T12:23:00.003+02:00

After several days runing mod_rails successfully on my server, I decided it was time to switch to Ruby Enterprise Edition from Phusion.
* It would provide the long outstanding correct bugfix for several security flaws in ruby (without breaking rails support [1,2,3]).
* It would also decrease the memory requirements on the server itself.

Here is my (old) configuration of mod_rails with standard ruby:


LoadModule passenger_module /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1/ext/apache2/mod_passenger.so
PassengerRoot /usr/lib/ruby/gems/1.8/gems/passenger-2.0.1
PassengerRuby /usr/bin/ruby1.8
RailsEnv production
RailsMaxPoolSize 10
RailsPoolIdleTime 120

So after installing Ruby Enterprise Edition for Ubuntu, I only had to change one line:


#PassengerRuby /usr/bin/ruby1.8
PassengerRuby /opt/ruby-enterprise-1.8.6-20080624/bin/ruby

I restarted apache (just to be sure).

The result was not what I actually expected:

sqlite3 won't load on REE

A quick check on the FAQ's on Pushion#s homepage revealed some hints - but I had already done that.

The actual problem
The problem wasn't the ruby enterprise edition (although only err shown the different behaviour), the source of the problem is the sqlite3-ruby gem itself. It doesn't contain read-rights on some files (oh dear maintainer!).


root@server:/opt/ruby-enterprise-1.8.6-20080624/lib/ruby/gems/1.8/gems# cd sqlite3-ruby-1.2.2/
root@server:/opt/ruby-enterprise-1.8.6-20080624/lib/ruby/gems/1.8/gems/sqlite3-ruby-1.2.2# find . -perm 0662 -exec ls -l {} \;

-rw-rw--w- 1 root root 3738 Jul 1 00:54 ./lib/sqlite3/translator.rb
-rw-rw--w- 1 root root 24774 Jul 1 00:54 ./lib/sqlite3/database.rb
-rw-rw--w- 1 root root 3174 Jul 1 00:54 ./doc/faq/faq.rb
-rw-rw--w- 1 root root 10744 Jul 1 00:54 ./ext/sqlite3_api/sqlite3_api.i
-rw-rw--w- 1 root root 457 Jul 1 00:54 ./ext/sqlite3_api/extconf.rb
-rw-rw--w- 1 root root 33308 Jul 1 00:54 ./test/tc_integration.rb
-rw-rw--w- 1 root root 541 Jul 1 00:54 ./test/tc_errors.rb

The fix
Just add read-permissions to the files:


root@server:/opt/ruby-enterprise-1.8.6-20080624/lib/ruby/gems/1.8/gems/sqlite3-ruby-1.2.2# find . -perm 0662 -exec chmod 664 {} \;

Everything is now up-and-running smoothly for 4 days now - thanks to mod_rails and Ruby Enterprise Edition from Phusion.

Productivity boost for Rails developers - or - How I work

2008-07-05T11:54:00.003+02:00

Here is the shell script I use to start my Rails development environment (requires iTerm and TextMate).
Just replace FULL_PATH_TO_PROJECT_ON_DISK with the path to your project and give it a name: PROJECT_NAME.

It will open iTerm with 4 shell, and it will run:
* Textmate in the root of the project, so that all project files are listed in textmate
* the rails server will be started
* the console will be launched
* the database console will be launched


#!/bin/sh
PROJECT_DIR=FULL_PATH_TO_PROJECT_ON_DISK
PROJECT_NAME=PROJECT_NAME
    
osascript <<-eof
  tell application "iTerm"
    make new terminal
    tell the last terminal
      activate current session

      launch session "Default Session"
      tell the last session
          set name to "$PROJECT_NAME-project-root"
          write text "cd \"$PROJECT_DIR\""
          write text "mate ."
          write text "clear; ls -lah"
      end tell

      launch session "Default Session"
      tell the last session
          set name to "$PROJECT_NAME-server"
          write text "cd \"$PROJECT_DIR\""
          write text "clear"
          write text "./script/server"
      end tell

      launch session "Default Session"
      tell the last session
          set name to "$PROJECT_NAME-console"
          write text "cd \"$PROJECT_DIR\""
          write text "clear"
          write text "./script/console"
      end tell

      launch session "Default Session"
      tell the last session
        set name to "$PROJECT_NAME-database"
        write text "cd \"$PROJECT_DIR\""
        write text "clear"
        write text "./script/dbconsole"
      end tell

    end tell
  end tell

  tell application "TextMate"
    activate
  end tell
eof

MySQL ENCRYPT function in Ruby (for Rails)

2008-07-04T16:57:00.001+02:00

Zhe backend system required that the password column used the MySQL ENCRYPT function. Since I didn't wanted to hack rails to much, I just aded the required code into the rails model directly - 5 minutes work, voila.

When the password get's assigned, it is automatically "MySQL encrypted". Here's ther code for reference:


  def password=(pw)
    self[:password] = mysql_encrypt(pw)
  end  
  
  private
  def mysql_encrypt(pw)
    salt = [Array.new(6){rand(256).chr}.join].pack("m").chomp
    return pw.crypt(salt)
  end

Today I bought an enterprise license of mod_rails (Phusion Passenger)

2008-05-22T16:10:00.000+02:00

I think it's the coolest piece of server software, right after apache and rails!

mod_rails
C'mon support those guys - they just made our lives (deployment-wise) much easier.

Getting Javascript and CSS files working with passenger (locally)

2008-05-22T14:02:00.000+02:00

After looking around why my .js or .css files won't load, I found that my Apache's error_log had a lot of these lines:


[Thu May 22 01:27:26 2008] [error] [client 127.0.0.1] client denied by server configuration: /Users/art/development/projects/rails/rchat/public/javascripts/application.js, referer: http://rchat_prod.local/

Adding AllowOverride and the Order directives, fixed it:


<VirtualHost *>
  ServerName rchat_prod.local
  DocumentRoot /Users/art/development/projects/rails/rchat/public
    <Directory "/Users/art/development/projects/rails/rchat/public"%gt;
      Options FollowSymLinks
      AllowOverride None
      Order allow,deny
      Allow from all
    </Directory>
</VirtualHost>

How to get a working Rails 1.2.5

2007-10-13T21:54:00.000+02:00

After today's


gem update

I repeatedly got the same annoying error message again and again:


Install required dependency activesupport? [Yn]  Y
ERROR:  While executing gem ... (Gem::GemNotFoundException)
    Could not find activesupport (= 1.4.3.7843) in any repository

The fix is however simply - just specifiy a source server for the packages (where Rails 1.2.5 can already be found):


gem install rails --version '= 1.2.5' --source http://gems.rubyonrails.org/ -y

Problem sovled - let's get back preparing Rails 1.2.x application for the migration to Rails 2.0

Update 1 - There are again failing updates!
To resolve this fully, just get rid of everything old and reinstall:


gem uninstall rails (select "all")
gem install rails -y --source http://gems.rubyonrails.org/

Classloader issues in rails

2007-08-23T18:25:00.000+02:00

Once upon a time, everybody gets hit by a train!
The classloader train on rails!

That's when everything works on your development workstation, in development and production mode, but it won't work on your production system.
That's when you check every line of your controllers code, every line of your models code.

But don't fear, there is an easy way to debug this and an easy way to prevent this in the future!

How to debug this:
Since ruby is a really really code language, try this:
Put a puts statement before and after your class!


puts 'start loading account_class'
class Account < ActiveRecord::Base  
# your code here
end

Once you're finished, just try this:


script/console

You will see something like this:


devws:/development/projects/demo art$ script/consoleLoading development environment.
start loading account
end loading account
start loading xxx
end loading xxx

Now login to your production, errr, integration system, and try this again.
One thing that really shocked me, was:
On Mac OSX (my workstation) every model was loaded.
On Linux (my production system) one model was missing!

Okay, I just had 19 models, so it was easy to track down the missing class :)

But, you can go even further - put a puts statement before and after your methods:


puts 'start loading account_class'
class Account < ActiveRecord::Base  
  puts 'before doSomethingWithADifferentClass'
  def doSomethingWithADifferentClass
  end
  puts 'after doSomethingWithADifferentClass'
end

That's how you can track down, if your methods get fully loaded.

How to prevent this in the future:
1) Put your requires where the belong (environments.rb could be loaded after your model class)
2) Put your require statements in the classes that need them
3) Be careful when you use memcached -> when you unmarshal an object (get it out of memcached) the class needs to be loaded first!

One additional info:
In development mode, all classes are reloaded everytime. In production mode classes are only loaded once :)

My models and even my controllers have now their require statements - I hope this help a bit!

As usual, once you know what hits you, you know how to search for more information and find these resources:
http://duncandavidson.com/archives/285
http://mojodna.net/2007/02/12/classloading-in-rails/

Everybody needs a javascript calendar (Calendariffic)

2007-07-01T22:08:00.002+02:00

Ever tried to write a web application where an user can create an account? You will probably have done this in the past.
You will also have faced the problem, that some information has a different formatting in different countries. Those date columns are a good example for this. Here is what I usually encouter:

dd/mm/yyyy
mm/dd/yyyy
yyyy/mm/dd

So, what you're going to do to satisfy everyone? Tell them the format, they should you? Try to guess what they mean by looking at the input?

Why not make this really easy (at least) for date input fields? Here is how:

Get a decent javascript calendar
Integrate it with ruby on rails
Make your users happy

Step 1: What is a decent javascript calendar?
Just google for "javascript calendar" and you will find: The coolest DHTML / Javascript calendar
A very nice and sexy javascript based calendar (LGPL).

Step 2: How to integrate this with a rails project?
How about: "script/plugin install http://opensvn.csie.org/calendariffic/calendariffic/"
And you're done?

Step 3: Help your users with your date fields
1. Add the javascript files to your view
<%= javascript_include_tag 'calendariffic/calendar.js', 'calendariffic/calendar-setup.js', 'calendariffic/lang/calendar-en.js' %>

2. Add the css files to your view (there are many precreated layouts available: aqua, winter, blue, sommer, green, win2k-1|2, win2k-cold-1|2, system)
<%= stylesheet_link_tag 'calendariffic/calendar-win2k-cold-1.css' %>

3. Create a (readonly) date field in your view
< % = calendariffic_input(false, 'date_field_name_goes_here', 'calendariffic/date.png', 'start_cal', '%m/%d/%y', date_field_value_or_nil_goes_here, {:class => 'myfavoriteclass', :readonly => 'true'}, {:class => 'borderless'}) %>

Why should the date field be readonly? That's how you "help" your users (and yourself), and tell them that they have to click on the nice little icon to input their date value :)

Caution:
If you use a language different then "../lang/calendar-en.js", you will have to define one javascript variable inside the language javascript file:
Calendar._FD = 1; // First day of the week. "0" means display Sunday first, "1" means display Monday first, etc.

Thanks to the author of calendariffic (Paul Danese), who helped me with the javascript language issue, I was able to add good looking and "user guiding" date fields to my web application within a few minutes.

Getting RMagick running on MAC OSX in 3 easy steps (with MacPorts)

2007-06-14T21:55:00.001+02:00

After figuring out (with some help) how to get RMagick running on debian, I had to get it running on my development notebook - a MacBook with Mac OSX 10.4 (Intel).

To keep things simple I really like to use MacPorts to install new software onto the Mac.

So here we go:
1. Install ImageMagick with MacPorts (this takes some time - get a coffee NOW):
sudo port instll ImageMagick +graphviz +gs +jbig +jpeg2+lcms +mpeg +nox11 +wmf

MacPorts just installed ImageMagick in /opt/local/lib. Mac OSX includes by default /lib, /usr/lib, and /usr/local/lib as library path.
2. All we have to do, is to "show" gem where we installed imagemagick:
export LD_LIBRARY_PATH=/opt/local/lib

3. Now we can install RMagick on the Mac without any problems:
sudo gem install RMagick

Now check that it did really worked:
irb -rubygems -r RMagick
(now enter) puts Magick::Long_version

Done :)

BTW: I don’t get - After the installation, I started a completely new terminal and check it again:
irb -rubygems -r RMagick
(now enter) puts Magick::Long_version

And it works – but this time the LD_LIBRARY_PATH variable is not set!

Getting RMagick installed on a debian machine

2007-06-14T20:41:00.002+02:00

After installing several packages with debian apt, I thought I just could do:

sudo gem install rmagick

But what I got was this:
Building native extensions. This could take a while...
ERROR: While executing gem ... (Gem::Installer::ExtensionBuildError)
ERROR: Failed to build gem native extension.

ruby gem_extconf.rb install rmagick

sh configure

Configuring RMagick 1.15.7
checking for gcc... gcc
checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables...
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ANSI C... none needed
checking for ruby... /usr/bin/ruby
checking for Magick-config... no
checking for GraphicsMagick-config... no
configure: error: Can't install RMagick. Can't find Magick-config or GraphicsMagick-config program.
RMagick configuration failed with status 1.

Gem files will remain installed in /usr/lib/ruby/gems/1.8/gems/rmagick-1.15.7 for inspection.
Results logged to /usr/lib/ruby/gems/1.8/gems/rmagick-1.15.7/gem_make.out

Not what I expected. Finally I decided to give the development version of imagemagick a try - it still didn't help. So I fired you firefox and search google for a solution and found this wonderful blog entry:
Quick Tip: Install Rmagick Gem on Ubuntu

And I did exactly what Vince W. wrote:
sudo apt-get remove --purge librmagick-ruby-doc librmagick-ruby1.8

after that:
sudo apt-get install libmagick9-dev ruby1.8-dev

and tried again:
sudo gem install rmagick

Guess what - it just worked!
Now check that it really works:

irb -rubygems -r RMagick
(then enter) puts Magick::Long_version

That's it! My thanks go to Vince W.