no such file to load — readline (LoadError) – Rails 3.0.3 console – rvm

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Problem

When you try to run the console rails c in a new Rails 3.0.3 application, and when you use rvm, you get the following error:

no such file to load -- readline (LoadError)

Solution

It’s quite like likely that the readline libraries are missing from your installation. To find out which ones go to the directory that the error is indicating (ie):

cd ~/.rvm/rubies/ruby-1.8.7-p299

and then to the following:

cd ext/readline

then run the following:

ruby extconf.rb

If you get something like:
checking for readline/readline.h... no
checking for editline/readline.h... no

then you are probably missing the neccessary header files for readline.
so install them in your system (ie in Mandriva):

sudo urpmi readline-dev,

In Debian you will need to install libreadline5-dev and maybe libncurses5-dev (apt-get install).

When the package is installed successfully run the following again:

ruby extconf.rb
make
sudo make install

You should now be able to go back to your project and run rails c with no errors.

Internal 500 server error – Dreamhost – Rails 3.0.3 – Capistrano

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Problem
You want to deploy your Rails 3.0.3 in Dreamhost with capistrano, but even though you follow the steps from a previous post here, when you go to the application’s main page you still get an error:

500 Internal Server Error

Solution
Thanks to a blog post from Brendon Wilson here, the last missing piece from the puzzle in order to have your application running is to add the following line to the top of your deploy.rb file:

require 'bundler/capistrano'

and redo your cap deploy.

Thanks Brendon.

Rails 3 – Bundler – Dreamhost – Capistrano

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Problem
You want to deploy your Rails (3.0.3) application to Dreamhost using Capistrano, but you get errors like:

bundle command not found
or
Enter your password to install the bundled RubyGems to your system:

Solution
You may be able to see in your deploy.rb file a commented section that says the following:

As Capistrano executes in a non-interactive mode and therefore doesn’t cause
any of your shell profile scripts to be run ….

So in order for capistrano to be able to find your bundle command you should add in your deploy.rb file a line with your paths (ie):

default_environment['PATH']='/usr/lib/ruby/gems/1.8/bin:/home/your_name/.gems/bin:/usr/local/bin:/usr/bin:/bin'

If you have the previous line your bundle command can run, but if you try to do cap:deploy your bundler will probably give you an error as it would ask for your sudo password. In order to avoid this error and to make it work you have to add another line with your gem path (ie):

default_environment['GEM_PATH']='/home/your_name/.gems:/usr/lib/ruby/gems/1.8'

making sure that your home directory path for your gems is first in the list.

Webrat 0.7.2 problem with Rails 3.0.3

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Problem
You are trying to use Webrat with a new Rails 3.0.3 application but the redirection doesn’t work, and you get an error like:
You are being redirected. (RSpec::Expectations::ExpectationNotMetError)

Solution
According to a post here, there is a way to patch the webrat code so it follows the redirection.
After adding what is suggested above into your webrat/lib/core/session.rb, ie:

#starting at line 288
def current_host
- URI.parse(current_url).host || @custom_headers["Host"] ||
"www.example.com"
+ URI.parse(current_url).host || @custom_headers["Host"] ||
default_current_host
end

+ def default_current_host
+ adapter.class==Webrat::RackAdapter ? "example.org" :
"www.example.com"
+ end

and running your tests again, they should work.

Thanks yannnimac 🙂