Rails cheatsheet

Rails_cheatsheet.md

Getting Started Reference

Rails new

Basic usage:

$ rails new <app_name>

This will create a directory named: <app_name> that contains a brand new rails app folder structure and boilerplate files.

There are lots of options, which you can view by running:

$ rails new -h

For our purposes, we want to use the Postgres database (easy to deploy to Heroku) and we'll skip Test::Unit (-T option):

$ rails new <app_name> -T -d postgresql  

Scaffolding

$ rails generate scaffold <Model> <element0>:<type0> ... <elementn>:<typen> 

Basic rake commands

$ rake db:migrate       #Runs all the migrations
$ rake db:rollback      #Returns to previous migration
$ rake db:schema:dump   #Dump the current db state
$ rake db:setup         #Creates the db, loads schema, & seed

Migrations commands

$ rails g migration Remove<Something>From<Table Name> something:type
$ rails g migration Add<Something>From<Table Name> something:type
$ rails g migration Drop<Table Name>Table

Change directory (cd) into your new project directory and configure the config/database.yml file to successfully connect your application to its database and then create the development environment database with $ rake db:create and $ rake db:migrate

Reference: Rails Guide - Getting Started

Check your Gemfile and install Rspec

After your Rails app is created, take a look at your Gemfile and make any edits necessary. In our work to date, we've removed the turbolinks gem and rearranged things without as many comments and also grouped gems by environment.

Install rspec-rails by adding the following to your Gemfile:

group :test do
  gem 'rspec-rails', '~> 3.0.0.beta'
end

Then, run $ bundle install and then $ rails generate rspec:install

We also added the following gems in the test group for more testing capabilities:

gem 'capybara'
gem 'factory_girl_rails'
gem 'database_cleaner'

Reference: rspec-rails on Github

PATH AND URL HELPERS

<application_plural>_path /<application_plural> new_<application_plural>_path /<application_plural>/new edit_<application_plural>_path /<application_plural>/:id/edit

<application_plural>_url http://localhost:3000/<application_plural> new_<application_plural>_url http://localhost:3000/<application_plural>/new edit_<application_plural>_url http://localhost:3000/<application_plural>/:id/edit <application_plural>_url http://localhost:3000/<application_plural>

Git and Github

At this point, with the boilerplate Rails app and bundle in place, you should get things committed to git:

$ git init
$ git add --all
$ git commit -m "Initial commit"  

This series of commands initializes a git repository locally, adds all the files and creates a new commit.

You can now create a remote repository at Github. If you're logged in there, you can create a new repository here: https://github.com/new. Once the repository is created at Github, the confirmation page there shows instructions on how to "Push an existing repository from the command line" and that's exactly what we need to do (since we already have a local repository):

$ git remote add origin <GIT URL FOR NEW REPOSITORY>
$ git push -u origin master

Start Application Development!

Start with something straightforward that is easy to test so that you can make sure that the testing framework runs. You should be able to run rake or rspec or rails server without error.

Generators

There are Rails generators for models, controllers, etc. I think that model generators are probably more useful since they generate the model file, migration file, etc. The model generator follows this form:

$ rails generate model <Model name> <attribute_name:type> <attribute_name: type>...

The "type" can be things like:

• "string" - text field with length limit (usually 255 characters)
• "text" - for a text area - lots of text
• "integer" - whole numbers
• "float" - decimal numbers
• "datetime"
• "boolean" - true/false (or 1/0 in the database)

Reference: Rails Guide - Migrations