self.works_with_ruby?

Inlining CSS in ActionMailer 3 (Rails 3.0) July 8th, 2010

As most of you already know, a bunch of online mail readers (like Hotmail, Gmail, …) don’t handle stylesheets very well, they prefer inline styling (

TamTam is a gem created by Dave Hoover and Brian Tatnall that does all the dirty work for us. Before Rails 3 there was a plugin called inline_css (by the same authors) that used TamTam to automatically inlined all mails sent by ActionMailer. Since Rails 3, however, the ActionMailer internals have changed, and the plugin stopped working.

For my own use I created a module called InlineCss that I include in the mailers I need inlining for. This is the code:

module InlineCss
  def render(*args)
    if (template = args.first[:template]) && template.mime_type.html?
      # Be warned, this code expects a <style> tag in the head of your layout.
      TamTam.inline(:document => super)
    else
      super
    end
  end
end

This code sees if I am working with a template and if that template has a HTML MIME-type, it inline’s it with TamTam.

In my mailers I just include it. If you want to have this in all mailers, just add an initializer that includes InlineCss in ActionMailer::Base, and it should work

Railties Talk May 12th, 2010

Last ArrrrCamp I gave a talk about Railties and Engines.

You can get the PDF with my presenter notes on http://www.defv.be/railties.pdf

Environment specific files and gitignore March 1st, 2010

I love my Mac for doing development! Textmate and Passenger make it my all-time favorite environment to develop Ruby / Rails in. It does have some very specific “junk” files I don’t want in my git, though.

In the beginning I would include all those files in every project’s .gitignore file. This worked since all my colleagues also work on a Mac with Passenger & TextMate. Recently I’ve come across people with different setups, which made the project’s .gitignore look like this:

.DS_Store
Thumbs.db
tmp/restart.txt
.idea
.todo
.bundle
.rake_tasks~

After some searching I found you can easily setup a global .gitignore which ignores your environment specific files. Doing so is easy:

# ~/.gitignore
.DS_Store
tmp/restart.txt
.rake_tasks~
.idea

And added this to my global git config

git config --global core.excludesfile ~/.gitignore 

This all makes your .gitignore file much cleaner and more relevant for the project itself.

Compiling mongodb 'stable' as a debian lenny package January 14th, 2010

Today I had the pleasure of having to install MongoDb on one of our production servers. Pleasure because MongoDb is an awesome document database, and I also like new things.

Most of our production servers run Debian, and we try to keep all installed packages up to date with apt. Since Debian Lenny didn’t have a mongodb package (it does have a lot of other packages Mongolian language packs) I had to make my own. Luckily the mongodb git repository comes with a ‘debian’ folder, so making a .deb package should be easy as pie.

There are quite a few gotchas to get it to build, though. This is what you’ll need to do:

Get last mongodb ‘stable’ source

git clone git://github.com/mongodb/mongo.git
cd mongo
git checkout r1.2.1

The debian/control file lists all deps including one we can’t fulfill on Lenny, xulrunner-1.9-dev. We only have xulrunner-dev. So change the debian/control file:

# the Build-Depends line
-Build-Depends: debhelper (>= 7), libboost-dev, libpcre3, libpcre3-dev, scons, xulrunner-1.9-dev, libboost-thread-dev, libboost-filesystem-dev, libboost-program-options-dev, libboost-date-time-dev
+Build-Depends: debhelper (>= 7), libboost-dev, libpcre3, libpcre3-dev, scons, xulrunner-dev, libboost-thread-dev, libboost-filesystem-dev, libboost-program-options-dev, libboost-date-time-dev

# the Depends line
-Depends: ${shlibs:Depends}, ${misc:Depends}, xulrunner-1.9-dev
+Depends: ${shlibs:Depends}, ${misc:Depends}, xulrunner-dev

Also, be sure to install all these build-deps

apt-get install debhelper libboost-dev libpcre3 libpcre3-dev scons xulrunner-dev libboost-thread-dev libboost-filesystem-dev libboost-program-options-dev libboost-date-time-dev

Next up, we’ll need to change a script (buildscripts/hacks_ubuntu.py) which sets old-xulrunner-compatibility. Apparently the bug I encountered was already fixed but didn’t work on my system. I just deleted the condition since I was sure I needed the old-compatability mode.

diff --git a/buildscripts/hacks_ubuntu.py b/buildscripts/hacks_ubuntu.py
index 67c5d78..baebfe6 100644
--- a/buildscripts/hacks_ubuntu.py
+++ b/buildscripts/hacks_ubuntu.py
@@ -42,6 +42,5 @@ def foundxulrunner( env , options ):
                            incroot + "unstable/" ] )

     env.Append( CPPDEFINES=[ "XULRUNNER" , "OLDJS" ] )
-    if best.find( "1.9.0" ) >= 0:
-        env.Append( CPPDEFINES=[ "XULRUNNER190" ] )
+    env.Append( CPPDEFINES=[ "XULRUNNER190" ] )
     return True

That’s all changes needed to get it to compile. Next step is running dpkg-buildpackage and installing the package!

dpkg-buildpackage -rfakeroot -b
# <it builds..>
dpkg -i ../mongodb_1.2.1*.deb

Ruby and Rails beginner talk October 8th, 2009

Last night I gave a talk for Zeus about Ruby and Rails, talking about Ruby fundamentals and a short intro to the Rails philosophy and MVC.

I don’t know if you’ll be much with the slides without hearing the talk, but you can find them on http://defv.be/ruby.and.rails.pdf.

If you want to see the entire presentation you should come to ArrrrCamp, where I’ll be giving it again.

Ruby Hash coolness September 28th, 2009

Don’t shoot me if you already use this every day, but this is new to me.

In the past I’ve often had code like this

@hosts = {}

@accounts.each do |account|
  @hosts[account[:host]] ||= []
  @hosts[account[:host]] << account
end

But why do this hen you can just add some initializer code to your hash.

@hosts = Hash.new { |h, k| h[k] = [] }

@accounts.each do |account|
  @hosts[account[:host]] << account
end

Where Hash automatically invokes the block when an unknown hash key is called. Great!

Autoload JQuery Plugins August 5th, 2009

Rails has the convenient helper javascript_include_tag where you can give up :default, which automatically loads prototype / effects, or with the jrails plugin adds jquery, jquery-ui and jrails.

But when using jQuery you want to use more than those files, you want to use jQuery plugins, or write your own, all in small .

Loading this can be a pain in the ass. Thats why I wrote this little initializer which adds everything in public/javascripts/jquery/*.js to the defaults.

# config/initializers/add_jquery_to_defaults.rb
Dir[File.join(ActionView::Helpers::AssetTagHelper::JAVASCRIPTS_DIR,'jquery','*.js')].each do |js|
  ActionView::Helpers::AssetTagHelper.register_javascript_include_default "jquery/#{File.basename(js)}"
end

Rack::Cache and Lighttpd+FCGI July 15th, 2009

On some of the Openminds shared hosting servers we run a Lighttpd+FCGI stack for Ruby/Rails applications. This week we got a complaint from a user saying they had a problem with the latest Radiant 0.8. Every page he loaded was the same as the first page he opened since the last server restart.

When digging into the problem it was clear that it was a problem with Rack::Cache, which only created 1 meta-store entry and served that from there on. On investigation Rack::Cache::Key.call(@request) always returned http://example.com:80/dispatch.fcgi?. Apparently the last part of the key gets created by scriptname and pathinfo:

..snip..
      parts << @request.script_name
      parts << @request.path_info
..snip..

When looking at the request it seems Lighttpd+FCGI doesn’t fill in the env[‘PATH_INFO’], which results in always having the same cache key, thus the same page.

To solve this problem I’ve created a small Rack middleware that sets PATHINFO from REQUESTURI (Like Passenger does with Nginx)

module ::Rack
  class LighttpdFix
    def initialize(app)
      @app = app
    end     

    def call(env)
      env['PATH_INFO'] = env['REQUEST_URI'].split('?', 2).first
      @app.call(env)
    end     
  end
end

# in production.rb
config.middleware.insert_before ::Rack::Cache, ::Rack::LighttpdFix

# or for Radiant
config.middleware.insert_before ::Radiant::Cache, ::Rack::LighttpdFix

I’ll make a gem out of this tomorrow.I made a gem out of this, you can find it on GitHub and install it using RubyGems.

sudo gem install DefV-rack_lighttpd_fix

MySQL password hashing in Ruby May 12th, 2009

An old database used MySQL’s PASSWORD() hashing functionality for storing user credentials. We’re creating a Ruby app now to interface with that database, and wanted to hash the password in ruby. After looking at the code it looked like they just SHA1 hash the password twice and prepend a *. Implementation in Ruby is easy:

require 'digest/sha1'

def hash_mysql_password pass
  "*" + Digest::SHA1.hexdigest(Digest::SHA1.digest(pass)).upcase
end

Which gives us in MySQL

mysql> SELECT PASSWORD('foo');
+-------------------------------------------+
| PASSWORD('foo')                           |
+-------------------------------------------+
| *F3A2A51A9B0F2BE2468926B4132313728C250DBF | 
+-------------------------------------------+

And in Ruby

>> hash_mysql_password 'foo'
=> "*F3A2A51A9B0F2BE2468926B4132313728C250DBF"

Custom ActiveRecord timestamps April 27th, 2009

Some legacy databases have already defined their own created_at or updated_at fields. They can be easily filled in with ActiveRecord before_save filters, but after implementing this behaviour a few times the urge arose to write something reusable, so I created the custom_timestamps plugin.

With custom_timestamps you can easily define the columns you want to be updated on creation/change

class LegacyModel < ActiveRecord::Base
  set_create_column :creation_time
  set_update_column :change_time
end

The plugin can be found on github.

ArrrrCamp Belgium April 2nd, 2009

We have been talking between ourselves about hosting a Belgian Ruby conference since the last Railsconf Europe, and we have finally decided to proceed with the idea. Colleague Joren put things in motion and today we’re proud to announce Arrrrcamp, which stands for “About Ruby, Rails, Radiant and Rum Camp”.

The event will take place on friday, May 8th, in Ghent, Belgium. The idea is to have a barcamp-like organisation of talks, where everybody is encouraged to participate by either doing talks, taking pictures, do some hacking, … You can read all about the event on the website.

Radiant 0.7.x and Ruby 1.8.4 March 13th, 2009

A client of ours complained that Radiant 0.7.1 was not working out of the box on one of our shared servers. When running the radiant command he got an error:

/usr/lib/ruby/gems/1.8/gems/radiant-0.7.1/vendor/rails/railties/lib/initializer.rb:199:in `set_load_path': undefined method `load_paths' for nil:NilClass (NoMethodError)
  from /usr/lib/ruby/gems/1.8/gems/radiant-0.7.1/vendor/rails/railties/lib/initializer.rb:97:in `run'
  from /usr/lib/ruby/gems/1.8/gems/radiant-0.7.1/lib/radiant/initializer.rb:101:in `run'
  from /usr/lib/ruby/gems/1.8/gems/radiant-0.7.1/bin/../config/boot.rb:72:in `load_initializer'
  from /usr/lib/ruby/gems/1.8/gems/radiant-0.7.1/bin/../config/boot.rb:90:in `load_initializer'
  from /usr/lib/ruby/gems/1.8/gems/radiant-0.7.1/bin/../config/boot.rb:61:in `run'
  from /usr/lib/ruby/gems/1.8/gems/radiant-0.7.1/bin/../config/boot.rb:19:in `boot!'
  from /usr/lib/ruby/gems/1.8/gems/radiant-0.7.1/bin/../config/boot.rb:161
  from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
  from /usr/lib/ruby/gems/1.8/gems/radiant-0.7.1/bin/radiant:3
  from /usr/bin/radiant:19

It worked fine on our other servers, as well as on our local machines, the only thing that was different was the ruby version, which was 1.8.4 on that specific server. Apparently that version handles super a bit different. The solution was to change 1 line in /usr/lib/ruby/gems/1.8/gems/radiant-0.7.1/lib/radiant/initializer.rb:

# In /usr/lib/ruby/gems/1.8/gems/radiant-0.7.1/lib/radiant/initializer.rb line 101:
-     super
+     super(command, configuration)

Application-wide timeranges February 2nd, 2009

In some applications you need to work with time-ranges a lot. Displaying todays messages, a count of all messages that were posted this month, or last month, … ActiveRecord has pretty good support for times and ranges, so you could do it the default way.

Message.find(:all, :conditions => {:created_at => Time.now.beginning_of_month..Time.end_of_month})

And although this works perfectly it’s not very easy on the eyes. It’s also not very DRY since I need this on a lot of models. It’d be a lot better if I could have it in a scope, like this

Message.in(:this_month)

So how do we achieve this?

In our config/initializer folder we have a file called timeranges.rb.

# timeranges.rb
TimeRanges = {
  :today      => lambda { Time.now.beginning_of_day..Time.now.end_of_day },
  :yesterday  => lambda { 1.day.ago.beginning_of_day..1.day.ago.end_of_day },
  :this_week  => lambda { Time.now.beginning_of_week..Time.now.end_of_week },
  :last_week  => lambda { 1.week.ago.beginning_of_week..1.week.ago.end_of_week},
  :this_month => lambda { Time.now.beginning_of_month..Time.now.end_of_month },
  :last_month => lambda { 1.month.ago.beginning_of_month..1.month.ago.end_of_month }
}

Which gives us a constant TimeRanges we can use all over the application. So in our Message we define the named_scope in

class Message < ActiveRecord::Base
  named_scope :in, lambda { |period| 
      :conditions => {:created_at => TimeRanges[period].call}
  }
end

Now we could even make this more DRY and make a module that defines the named_scope when it’s included, but in my application I had a lot of different use-cases for the TimeRanges, and didn’t really need the scope a lot. Leave me a note if you want it in a module but don’t know how to, else it’s an exercise for the interested and easily challenged reader ;-)

Using Datamapper on legacy databases December 18th, 2008

Yesterday I had to map a legacy database schema to some Ruby classes. Just before that I had been looking into the advantages of DataMapper, and it looked like the perfect match for my current “challenge”.

from the DataMapper site:

DataMapper only issues updates or creates for the properties it knows about. So it plays well with others. You can use it in an Integration Database without worrying that your application will be a bad actor causing trouble for all of your other processes.

The system

The system is running with 2 databases. One database holds all the information for the legacy app, the other database holds all information for system management.

mysql app
mysql> desc cpClients;
+--------------+--------------+------+-----+---------+----------------+
| Field        | Type         | Null | Key | Default | Extra          |
+--------------+--------------+------+-----+---------+----------------+
| clientID     | int(255)     | NO   | PRI | NULL    | auto_increment | 
| login        | varchar(255) | NO   | UNI |         |                | 
| pass         | varchar(255) | NO   |     |         |                | 
| type         | int(2)       | NO   |     | 0       |                | 
| traffic      | bigint(255)  | NO   |     | 0       |                | 
<snip>
| VAT          | varchar(255) | YES  |     | NULL    |                | 
+--------------+--------------+------+-----+---------+----------------+
mysql> desc cpURL;
+----------+--------------+------+-----+---------+-------+
| Field    | Type         | Null | Key | Default | Extra |
+----------+--------------+------+-----+---------+-------+
| url      | varchar(255) | NO   | PRI |         |       | 
| clientID | int(255)     | NO   |     | 0       |       | 
+----------+--------------+------+-----+---------+-------+
> exit
mysql management
mysql> desc ftp_users;
+--------------+------------------+------+-----+-------------------+-------+
| Field        | Type             | Null | Key | Default           | Extra |
+--------------+------------------+------+-----+-------------------+-------+
| username     | varchar(60)      | NO   | PRI | NULL              |       | 
| password     | varchar(30)      | YES  |     | NULL              |       | 
<snip>
| homedir      | text             | YES  |     | NULL              |       | 
| shell        | varchar(15)      | NO   |     | /bin/false        |       | 
+--------------+------------------+------+-----+-------------------+-------+

One Client has many URL’s, One client also has many ftp_users, but the link in that can’t be captured in a simple has many relationship.

Solving it with DataMapper

Setting up the connections

Setting up 2 connections to the databases was quite easy and well documented. I chose the app database to be the default connection, and management as another.

DataMapper.setup(:default, 'mysql://localhost/app')
DataMapper.setup(:management, 'mysql://localhost/management')

Having different database names

The first problem I had was that I wanted the cpClient table to be mapped to the User class, and cpURL to be mapped to a Domain class. This can be solved with storage_names.

class User
    include DataMapper::Resource
    storage_names[:default] = 'cpClients'
end

class Domain
    include DataMapper::Resource
    storage_names[:default] = 'cpURL'
end

Defining primary keys

Defining the primary key of my cpURL table was quite easy since DataMapper does natural keys out of the box.

class Domain
  include DataMapper::Resource
  storage_names[:default] = 'cpURL'

  property :url, String, :key => true
end

Defining the primary key of the cpClients table was a tad more difficult since it was poorly documented. I wanted the property to be called ID, but it should still use clientID in the database. The magic option to this is :field, which allows you to set a custom field for a propery.

class User
    include DataMapper::Resource
    storage_names[:default] = 'cpClients'

    property :id,                    Serial, :field => 'clientID'
end

Defining associations

The hardest part was defining associations. When I’d just define them with has n without extra options, DataMapper would look for user_id, so I’d have to tell which key was used. Since it wasn’t very well documented I had some failed attempts

has n, :domains, :child_key => 'clientID'
# => +options[:child_key]+ should be Array, but was String (ArgumentError)

has n, :domains, :child_key => ['clientID']
# => ArgumentError: +name+ should be Symbol, but was String 

has n, :domains, :child_key => [:clientID]
# => MysqlError: Unknown column 'client_i_d' in 'field list' (mysql_error_code=0001)

So I need to use a symbol, but apparently DataMapper does some automatic magic to translate keys. When you have a key like me you can disable this magic by changing field_naming_convention’s proc to your own. In the proc we return the stringified value’s name (to_s is needed because the key is given as a symbol)

repository(:default).adapter.field_naming_convention = lambda { |value| value.name.to_s }

And then the association worked. Do note the :child_key option needs to be set at both sides.

class User
  has n, :domains, :child_key => [:clientID]
end

class Domain
  belongs_to :user, :child_key => [:clientID]
end

Setting models to automatically connect to another database

The FtpUser model automatically needs to connect to the :management database, and there doesn’t seem to be a function to set this. If you temporarily want to connect to another database you can do it with the repository command.

repository(:management) { FtpUser.first }

However, if you want a model to always connect to a database other then the default, defining self.default_repository_name with the correct repository works very well. (Databases are referred to as repositories)

class FtpUser
  include DataMapper::Resource

  def self.default_repository_name
      :services
  end
end

All of this was needed to get my legacy database mapped, I hope some of you find this information useful. If you see things I can do better / different, do let me know in the comments. I’ve only used DataMapper for about 2 hours so some of my assumptions may be way of.

small less-tip December 3rd, 2008

When you’re using less to view your Rails log, and you want your colours back, you can use less with the -R option, or you can automate this by setting the $LESS variable in your environment. So for a bash environment:

# ~/.profile
export LESS="-R"

Update!

Since setting $LESS in your environment affects git commands like status (git status automatically uses less) I updated by profile a bit:

# ~/.profile
# Disabled: Fucks up git status
# export LESS="-R"
alias less="less -R"