Category Archives: ruby on rails

Ruby on Rails programming tips

Adding Webrat, Cucumber and RSpec to a new Rails 3 project

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Problem

You would like to start using BDD in a new Ruby on Rails 3 application, and would like to install Webrat, Cucumber and RSpec to your project.

Solution

Follow the steps below (taken from the RSpec Book), for creating a new Rails 3 application and adding the necessary testing frameworks:

  1. Create your new ruby on rails application: rails new my_app
  2. Go to your new application directory: cd my_app
  3. Edit your Gemfile to include the following:
    group :development, :test do
    gem "rspec-rails", ">= 2.0.0"
    gem "cucumber-rails", ">= 0.3.2"
    gem "webrat", ">= 0.7.2"
    end
  4. Use bundler to install all the gems and dependencies: bundle install
  5. Install the rspec files: script/rails generate rspec:install
  6. Install the cucumber files: script/rails generate cucumber:install
  7. Run the following and you shouldn’t be seeing any errors:
    rake db:migrate
    rake db:test:prepare
    rake spec
    rake cucumber

Creating a new git repository in Gitorious

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Problem
You would like to host a new git repository in Gitorius.

Solution
Assuming that you have created your initial ruby on rails application, and you have git installed, you can follow the steps below:

  1. Create a new account in Gitorious
  2. Copy your public ssh key (usually in ~./ssh) to your new account in Gitorius
  3. Create a new project in Gitorius (ie My Project)
  4. Add a new repository in Gitorius (ie My Git Repository)
  5. On your local development host initialise the git repository in your project’s directory: git init
  6. Add your remote hosting repository: git remote add origin git@gitorious.org:my-project-name/my-git-repo.git
  7. Add your project files: git add .
  8. Do your initial commit: git commit -m "Initial commit"
  9. Push your project to the Gitorious repository: git push origin master

Spree loading countries in production

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Problem
You have installed Spree in a production server but haven’t populated the database with the default seed data, and you want to add the countries (or any other seed data) that come as default in spree in the vendor/spree/db/default_countries.yml file.

Solution
On your production server, after logging in with ssh and going to the application directory run the following rake task:

rake db:load_file[vendor/spree/db/default/countries.yml] RAILS_ENV=production

Splitting big files (Rails log files) in Linux command line

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Problem
You want to examine some big log files (ie Rails production files), on the command line in Linux but they are quite big.

Solution
You can use cat and grep to look for a specific part in the log files. You can also use grep with the A and B parameters to specify how many lines you want to include before and after the search text, but maybe you want to have chunks of the logs to examine. In that case you can use split to split them up in smaller files:

split --bytes=10M input_log_file.log [output_files_or_directory]

In that case you will be splitting your log file on size (–bytes variable), so you can decide depending on the total size of the log file how many files you want. The output files or directory is optional and if you leave it empty it will create the files in your current directory.

You can also split by the number of lines you want in each file like:

split --lines=15000 input_log_file.log [output_files_or_directory]

no such file to load — pdfkit (LoadError)

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Problem
You are trying to use the pdfkit (here) in your rails application, and you configure it according to the configuration options for the rails 2.x in the config/environment.rb file. Although the application works, when you are trying to use the console you get the error:

no such file to load -- pdfkit (LoadError)

Solution
Make sure that:

require 'pdfkit'
in the config/environment.rb file comes after the line:

require File.join(File.dirname(__FILE__), 'boot')

capistrano deployment fails after dreamhost server move

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Problem
You have set up your capistrano recipe for deployment to dreamhost using password less logins, but after dreamhost moves your git repository server to a different server, the deployment breaks, with ‘permission denied’ when trying to get the git repository.

Solution
As the server was moved you would need to copy your ssh public key from the deployment server to the new server again for the password-less logins to work again.
Follow the details here how to copy your public key across, login in once with your password, and after that your capistrano recipe should be working again as normal.

NameError: uninitialized constant UserTest::Factory

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Problem
You are trying to use shoulda with factory_girl but you are getting the above error:

NameError: uninitialized constant UserTest::Factory

Solution
Insert the following to your config/environments/test.rb
config.gem 'shoulda', :lib => 'shoulda'

install the gem with:
sudo gem install shoulda

add the following to your test/test_helper.rb
require 'factory_girl'
require "factories"

in your test use the new syntax without the underscore, as in:
should belong_to(:model)

Create a rails app in a specific version

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Problem
You have installed various versions of rails (ie 3.0, 2.3.8, 2.3.5 etc). You want to create a new rails application for a specific version, and if you run rails app_name, it will create an application in the latest version you have installed.

Solution
Use the following if you want to create a specific rails (ie 2.3.8) application:

rails _2.3.8_ app_name