uninitialized constant ApplicationController

Upgrading from Rails 2.2.2 to later version namely Rails 2.3 and above, there is simple change which stop your Rails app from running. To update all the incompatibilities, namely changes due to application.rb to application_controller.rb, you can use this command:

rake rails:update

That's all.

Ruby Date Time

%a - The abbreviated weekday name (``Sun'')
%A - The full weekday name (``Sunday'')
%b - The abbreviated month name (``Jan'')
%B - The full month name (``January'')
%c - The preferred local date and time representation
%d - Day of the month (01..31)
%H - Hour of the day, 24-hour clock (00..23)
%I - Hour of the day, 12-hour clock (01..12)
%j - Day of the year (001..366)
%m - Month of the year (01..12)
%M - Minute of the hour (00..59)
%p - Meridian indicator (``AM'' or ``PM'')
%S - Second of the minute (00..60)
%U - Week number of the current year,
starting with the first Sunday as the first
day of the first week (00..53)
%W - Week number of the current year,
starting with the first Monday as the first
day of the first week (00..53)
%w - Day of the week (Sunday is 0, 0..6)
%x - Preferred representation for the date alone, no time
%X - Preferred representation for the time alone, no date
%y - Year without a century (00..99)
%Y - Year with century
%Z - Time zone name
%% - Literal ``%'' character

t = Time.now
t.strftime("Printed on %m/%d/%Y") #=> "Printed on 04/09/2003"
t.strftime("at %I:%M%p") #=> "at 08:56AM"

Hackintosh X61 (non-tablet) Upgrade to 10.5.7

Just upgraded my X61 hackintosh to 10.5.7. Upgrading process is easy. Nothing to take note all. No script required to run or delete any hidden kexts. Just use iDeneb 10.5.7 Upgrade Kit. Well done iDeneb team. It is similar to upgrading using Apple combo or delta update pack. Just run the installer and reboot twice and then 10.5.7 is installed.

To download iDeneb 10.5.7 Upgrade Kit, click here.

Rails link_to Previous Page

There is a useful shorthand in Ruby On Rails.

:back

< %= link_to "Back", :back % >

is equivalent to redirect_to(request.env["HTTP_REFERER"])

Rails Autocomplete Plugin

To enable Rails Autocomplete Plugin, you need the following steps:

1. Install plugin:

script/plugin install auto_complete

2. Add this line to the controller where auto_complete to be used:

auto_complete_for :contact, :name

3. < %= text_field_with_auto_complete :contact, :name, { :size => 10 }, { :skip_style => false,
:method => :get} % >

Using :method => :get overcomes the problem with InvalidAuthenticityToken.

4. To customize the result, you can override a method in your controller.

def auto_complete_for_contact_name
@user = User.find_by_id(session[:user_id])
re = Regexp.new("^#{params[:contact][:name]}", "i")
find_options = {:conditions => ['company_id = ?', "#{@user.company_id}"],:order => "name ASC" }
@organizations = Contact.find(:all, find_options).collect(&:name).select { |org| org.match re }

render :inline => "< %= content_tag(:ul, @organizations.map { |org| content_tag(:li, h(org)) }) % >"
end

The example above shows that the result will be filtered by company_id and sorted by name.

5. To beauty the autocomplete results, the css below can be helpful.

div.auto_complete {
position:absolute;
width:250px;
background-color:white;
border:1px solid #888;
margin:0px;
padding:0px;
}
li.selected { background-color: #ffb; }

Using ISAPI Rewrite on Rails App with IIS and Mongrel as Windows Service

In setting up a multiple production environment in a single server, IIS alone cannot do the redirection of url nicely. When a RAILS app runs in IIS, it requires port number and to redirect domain name to the particular port number, ISAPI Rewrite can help. Below are some sample of how to redirect a hostname to the port required.

RewriteCond %{HTTP:Host} ^(?:www\.)?domain name\.biz$
RewriteRule (.*) http://www.domain name.biz:3000$1 [R=301,L]

RewriteCond %{HTTP:Host} ^(?:www\.)?another domain name\.com$
RewriteRule (.*) http://www.another domain name.com:3001$1 [R=301,L]

Updated: 27th May 2009

Possible to do URL masking by using rewrite proxy

RewriteCond %{HTTP:Host} ^(?:www\.)?another domain name\.com$

RewriteProxy (.*) http://localhost:4002$1

Note: it will map to localhost:4002 and transparent to user as the url shown is www.anotherdomainname.com. You can point multiple domain name to a single web app.

To get this done:
1. Install ISAPI Rewrite.
2. Copy and replace domain name to your own domain name in ISAPI rewrite.
3. If you have more than one domain pointing to the same server, just add below the first domain.

Calendar Date Select for Ruby on Rails

CalendarDateSelect is semi-light-weight (about ~20k of javascript/css) and easy to use (but gets even lighter with bundle-fu)! It takes full advantage of the prototype.js library, resulting in less code, but maintaining a great deal of functionality.

Some of it's capabilities:

can pick a date, or a date-time, or a date with an optional time, as a popup selector or an embedded calendar!
speaks several different formats
is easy to localize
is extensible. Calendar Date Select doesn't do everything under the sun (which is a good thing), but you can build on top of it.
Installation / Usage

Install the calendar_date_select gem
sudo gem install calendar_date_select
Add a gem dependency to your rails project (in environment.rb)
config.gem "calendar_date_select"
Then, restart/start your rails project. All necessary files will be copied to your public folder.
Now include this at the top of your layout: (you'll also need to include prototype, if you haven't already!)
<%= calendar_date_select_includes "red" # or "blue", or "silver", or nil for the default! %>
# (if you want more control, you can get a list of stylesheets / javascripts via calendar_date_select_javascripts and calendar_date_select_stylesheets)
See the Demo for various uses of CalendarDateSelect.