source.mihelac.org - Home

Programmable screencasts

2008-07-01T13:15:00Z

Here is screencast, how Gmaplocation Drupal module looks and feels on one website:

The video is created with Castanut, tool that allows one to write script that will move mouse, open webpages, enter text and record all this into the screencast. Castanaut scripts are written in Ruby and commands are scripts are relatively easy to write.

Here is excerpt of the script:

#!/usr/bin/env castanaut
ishowu_start_recording
move to_element('a[title="Adjust basic site configuration options."]')
click
pause PageLoadTime
move to_element('a[title="Configure Google Maps location."]')
click
pause PageLoadTime
move to_element('[id="edit-gmaplocation-address"]')
click

Please note, that it is MacOSX Leopard only tool (there is a fork on GitHub that allows it to be used with 10.4 thought).

I had some problems with dissapearing mouse cursor using Snapz Pro X capture tool and it draws up that Snapz Pro X is currently not ready to be used together with scripting yet. Guys in Ambrosia Software are working on the next generation and it would probably allow Snapz Pro X to be used with Castanaut . On the end of the day I bought iShowU which did not had any problems.

gmaplocation - Drupal module for geographic location via Google Maps

2008-06-05T09:44:00Z

The gmaplocation is Drupal 5.7 module that allow displaying of your geographic location via Google Maps. It has following features:

show Google Maps with marker on your location
editor can drag marker to fine-tune position in case when geolocating from address is not accurate
creates a block with static image of map and link to gmaplocationpage

Here are some screenshoots of gmaplocation in action:

gmaplocation page and static block in right sidebar

gmaplocation admin page

fine tuning location with drag and drop

Module page on Drupal.org

Static variables and unset()

2008-05-13T04:45:00Z

In Drupal many things are cached with static variables and this is often main source of headache. I just submitted small patch for bug where static cache does not work as it should. Bug report and this example shows that unset() should not be used with static variables:

<?php
function locale_supported_languages($reset = FALSE, $val = array()) {
  static $all = NULL;

  if ($reset) {
    // If a static variable is unset() inside of a function, unset() destroys the variable only in the context of the rest of a function. Following calls will restore the previous value of a variable.
    unset($all); // this would not work
    //$all = NULL; // this would work
  }

  if (is_null($all)) {
    $all = array();
    foreach ($val as $key => $value) {
      $all[$key] = $value;
    }
  }
  return $all;  
}

echo "\narray should have 'cached' element (PASS):";
print_r(locale_supported_languages(FALSE, array("first" => "cached")));

echo "\narray should have 'new' element (PASS):";
print_r(locale_supported_languages(TRUE, array("first" => "new")));

echo "\narray should have 'new' element but have 'cached' (FAILS):";
print_r(locale_supported_languages(FALSE));

Drupal - replace colors in buttons with color.module

2008-05-08T07:39:00Z

Drupal Color.module allows the admin to change the color scheme of a theme completely. Color module basically fill viewport with 5 choosen colors, layout transparent PNG on it and then makes image slices and update CSS with this colors.

I would like to share some code that customize color.module further. After color scheme is choosen specified images would be copied and colors updated to reflect current color scheme. This is especially useful for creating buttons that should be color aware.

/**
  * Form alter hook
  */
function mycolormodule_form_alter($form_id, &$form) { 
  if ($form_id == 'system_theme_settings') {
    $form['#submit']['mycolormodule_system_theme_settings'] = array();
  }
} 

/**
 * Copy PNG images and change color in images with color from palette. 
 * 
 * Settings in color.inc $info array:
 *
 *     'change_color' => array(
 *        'images/form_buttons.png' => array("#3CC6F5" => "bottom"), // Color #3CC6F5 will be updated with color of "header bottom" 
 *    ),
 */
function mycolormodule_system_theme_settings($form_id, $values) {

  $theme = $values['theme'];
  $target = variable_get('color_'. $theme .'_stylesheet', NULL);
  if (!$target) return;
  $files = variable_get('color_'. $theme .'_files', array());
  $target = dirname($target) . "/";
  $info = $values['info'];
  $source = drupal_get_path('theme', $theme) .'/';
  foreach ($info['change_color'] as $file => $replace_array) {
    $base = basename($file);
    $source = $source . $file;
    // NOTE: change color
    $im = imagecreatefrompng($source);
    foreach ($replace_array as $old => $new) {
      $old_arr = _color_unpack($old);
      $index = imagecolorexact($im, $old_arr[0], $old_arr[1], $old_arr[2]);
      $new_arr = _color_unpack($values['palette'][$new]);
      imagecolorset($im, $index ,$new_arr[0], $new_arr[1], $new_arr[2]);
      $files[] = $target . $base;
    }
    imagepng($im, $target . $base);
  }
  variable_set('color_'. $theme .'_files', $files);
}

Buttons from above image are based on Wii buttons demo. Using color.module is described in details here.

Drupal Forms - First argument is expected to be a valid callback

2008-04-22T17:25:00Z

While creating an installation profile for Drupal based websites I lost a day tracking what should look like a small error. This seems to be often error and it seems there are many possiblities why this and similiar errors can occur:

warning: call_user_func_array() [<a href='function.call-user-func-array'>function.call-user-func-array</a>]: First argument is expected to be a valid callback, 'page_node_form' was given in /Users/bmihelac/Sites/drupal/tsitedemo/includes/form.inc on line 221.

This error occure in drupal_retrieve_form function of form.inc and means that Drupal did not found callback_function for creating $form_id form.

How Drupal retrieves form:

drupal_retrieve_form function invokes hook_forms on all modules and statically cache returned forms
it execute callback for given $form_id is it exists, if callback does not exists drupal_retrieve_form calls function named $form_id
node.module defines hook_forms so every content type has form_id in format CONTENT-TYPE_node_form (page_node_type for example). Callback for all node forms is same and it is node_form. It is important to know that node_forms calls node_get_types to obtain available node types and this function statically cashes node types.

Possible solutions

In my case the error occured because I created custom node type and wanted to create nodes via drupal_execute_macro in same script. node_get_types returned caches node types and custom node was not in it. That also explains while same code worked if it was split in two scripts. Once the problem is found, solution is easy as reloading node types:

node_get_types(‘types’, NULL, TRUE);

If you have similiar problems you can:

check if you can retrieve form with drupal_retrieve_form($form_id)
check if $form_id is created in module_invoke_all(‘forms’)
check if module that should create form is loaded with module_list(FALSE, TRUE, FALSE)

Thanks for reading and hope this will save you some time.

UPDATE: I noticed that some other functions statically cache variables so similiar problems occured when creating multilanguage nodes. The best solution for now seems to create content types, blocks, etc in installation profile and create content in other script.

Breaking the silence

2008-02-16T20:40:00Z

Visited BarCamp Zagreb in december and I really liked it.

I like seeing new local ruby groups arise, we have Ruby Hrvatska and Ruby Slovenija groups.

We plan to do some unconference in Ljubljana or Maribor in march to exchange ruby knowledge, socialize and drink few beers. I plan to make short presentation about ruby/rails testing techniques in everyday work. If you are interested check us at Ruby Meetup.

RailsConf Berlin

2007-09-07T22:05:00Z

See ya there, friends!

PunBB to Beast converter

2007-08-14T15:56:00Z

Rails plugin punbb_to_beast would convert PunBB to Beast forum data.

Repository is here:

http://site-express.biz/svn/svn_r/plugins/punbb_to_beast/

To install and run assuming beast and punbb are in same database and punbb tables are prefixed with /punbb/:

ruby script/plugin install -x http://site-express.biz/svn/svn_r/plugins/punbb_to_beast/
rake punbb_to_beast:import SRC_PREFIX=punbb

See readme for more info.

This plugin is work in progress. It work for me and I tested it with latest clean PunBB installation but didn’t had time to test it throughly (so backup db before). Let me know if it works for you.

GetText to Gibberish rake task

2007-08-08T06:19:00Z

Here is a rake task to update your models and controllers to use Gibberish instead of GetText. It would change _s(“Title|MyTitle”) to “MyTitle”[] . It would use GetText default translation so if Title|MyTitle is translated to “My Beautiful Title” it would add this instead.

to_gibberish would overwrite files so backup files before.

Usage:

rake to_gibberish FILES=app/views/controller/index.rhtml rake to_gibberish FILES=app/views/*/.rhtml

Code


desc "Simple script to migrate gettext default lang to gibberish." 
task :to_gibberish do
  require 'rubygems'
  require 'gettext'
  GetText.bindtextdomain('myapp', :path => '/home/rails/myapp/locale')
  Dir.glob(ENV["FILES"]).each do |filename|
    str = File.open(filename) {|f| f.read }
    str = str.gsub(/s?_\(["']((?:[^\|"']+\|)*([^"']+))["']\)/) { |s|
      '"' + GetText.s_($2) + '"[]'
    }
    File.open(filename, "w") {|f| f.write(str) }
  end
end

Gettext to Gibberish

2007-08-08T05:57:00Z

For upgrade of old Rails project I decide to use Gibberish instead of GetText. Reasons are:

Gibberish seems very light and pure ruby. Installing GetText is not a problem with rubygems but it’s easier to install Gibberish. Especially If you have to ask administrator to update / reinstall GetText.
work with all PO, MO files and directories made me tired many times, rake updatepo, rake makemo, restart
few times, I jumped on Rails Edge and left out with GetText as thse two were not compatible in the moment – with GetText being compiled I couldn’t help but wait to be fixed

While GetText seems unmatched for translating standard aplications I am not sure if it is best fit for today web applications developed and changed rapidly.

Rails in practice - Compare records

2007-07-06T09:28:00Z

We have Travel object which defines travel_on attribute. Now, when I want to compare Travel objects, I can use:

raise "Cannot come before you leave" unless departure.travel_on > arrival.tavel_on

Or sort travel array with:

journeys.sort {|a,b| a.travel_on<=>b.travel_on}

This would work, but it is not very readable and DRY. If we include Comparable mixin in Travel , and define <=> operator we would get conventional comparison operators (<, <=, ==, >=, and >) including the method between? for free. Our code would now look:

class Travel < ActiveRecord::Base
  include Comparable

  def <=>(other)
    self.travel_on<=>other.travel_on
  end  
end
...
raise "Cannot come before you leave" unless departure > arrival
...
journeys.sort
...
some_other_travel.between?(arrival, departure)

Now on Mephisto

2007-06-20T09:05:00Z

Hello! Blog was down for almost a week. Sorry for that. Spam comments flooded all over the blog and I have to delete up to 50 comments a day. Suddenly blog stopped working, I am not sure what was the reason, nothing in rails log file, nothing in fast cgi log. It seemed to much work just to get it back on shared server, so I decided to host blog on VPS and to convert it from Typo to Mephisto engine with modified Lighter theme (thanks Brandon).

From the whole story I got few answers I was looking for some time:

Can Rails web site be hosted on shared server? No, even the smallest one or at least without a problems now and / or in the future. You need VPS and you need at least 30-40 MB per web site. If you want Apache, MySql and e-mail, by my experience VPS with 160 MB is minimum. VPS’s come without Cpanel / Plesk (if you are spare with memory and money at least), so you would need to learn some sysadmin as well. Webmin can surely make things easier.

Is it easy to migrate from Typo to Mephisto? Can Mephisto host multiple blogs? Yes and yes, very easy. I had two blogs, one running on Mephisto and one on Typo. I converted Typo blog to Mephisto and imported in same database in just few commands. Adding new theme to converted blog was easy too.

Rails in practice - Group records by condition

2007-05-12T04:12:00Z

Often, when it comes to views I have to group records and present it to the user grouped by some condition. For example, I would like to list all news articles grouped by year.

To accomplish this, I find it easiest that records are grouped in a hash, key should be year when article is published and value would be array of objects matching published on these year.

Before, I used custom function that would walk throught all elements of array calling custom block for each member and creating new hash with result value of the block as key and array of elements as value.

Today I discover classify method in Set class that would do just what I need (thanks to Ruby Cookbook for that).

So, the code to group all news articles by year published is:

@groups = NewsArticle.find(:all).to_set.classify {
  |article| article.published_on.year}

and view would be something like these:

<%@groups.each do |year, articles|%>
  <h1><%=year%></h1>
  <%=articles.collect {|a| \"<p>a.name</p>\"}.join%>
<%end%>

Short and sweet. Same method can be used to group anything, names by first letter, products by price range, etc.

Create URL's outside of controllers and views

2007-04-28T15:02:00Z

If you have a need to create URL’s outside of controllers and views include UrlWriter helper and set default_url_options.

include ActionController::UrlWriter
default_url_options = "www.example.com"

This way, you can create URL’s and use named routes from mailers, migrations, import scripts, etc. More info on Rails Framework Documentation

Customized Mongrel Startup Script

2007-03-27T15:25:00Z

This shell script allows to start and stop bunch of Rails application on Mongrel webserver. This is Tim Morgan’s script, while I added ability to customize port, rails environment and directory for every app while respecting default values.

I use it on linux development machine where there is no need for mongrel_cluster and I do not want to make extra configuration.

We can save this script as /etc/init.d/mongrel and start|restart|stop all mongrels with /etc/init.d/mongrel start (or stop|restart). And to configure for startup we can use:

# redhat
sudo /sbin/chkconfig --level 345 mongrel on
#debian/ubuntu
sudo /usr/sbin/update-rc.d -f mongrel defaults

And here is script:

#!/usr/bin/env ruby
#
# mongrel Startup script for Mongrel by Tim Morgan, modified by bmihelac
#
# chkconfig: - 85 15
# description: mongrel manages Mongrel
#

# this would add one mongrels for these two apps on 
# ports 8000 and 8001, mephisto would be started in production
apps = [
  {:app => 'myapp'},
  {:app => 'mephisto', :environment => 'production'},
]

default_port = 8000
default_options = {
  :app_dir => '/home/rails',
  :environment => 'production'
}

if ['stop', 'restart'].include? ARGV.first
  apps.each do |app|
    options = default_options.merge(app)
    path = File.join options[:app_dir], options[:app]
    puts "Stopping #{path}..." 
    `mongrel_rails stop -c #{path} -P log/mongrel.pid`
  end
end

if ['start', 'restart'].include? ARGV.first
  apps.each do |app|
    options = default_options.merge(app)
    path = File.join options[:app_dir], options[:app]
    port = options[:port] || default_port
    puts "Starting #{options[:app]} on #{port}..." 
    `mongrel_rails start -d -p #{port} -e #{options[:environment]} -c #{path} -P log/mongrel.pid`
    default_port = port + 1
  end
end

unless ['start', 'stop', 'restart'].include? ARGV.first
    puts "Usage: mongrel {start|stop|restart}" 
    exit
end