Chapter 1 (with some of Chapter 6)

Question 1

How do you create a new gemset in rvm?

Answer 1

Example syntax:

$ rvm use ruby-2.1.5@rails4.2 –create

Once in the gemset, be sure to install rails!

Question 2

Who created Rails and when?

Answer 2

David Heinemeier Hansson in 2004

Question 3

What is the command to create a local development server?

Answer 3

$ rails server

Question 4

What is the first step in designing a new rails app?

Answer 4

Go to your workspace, and run the ‘rails new ‘ command

Question 5

What is the purpose of each folder generated by ‘rails new’?

Answer 5

app/ Core application (app) code, including models, views, controllers, and helpers

app/assets Applications assets such as cascading style sheets (CSS), JavaScript files, and images

bin/ Binary executable files

config/ Application
configuration

db/ Database files

doc/ Documentation for the application

lib/ Library modules

lib/assets Library assets such as cascading style sheets (CSS), JavaScript files, and images

log/ Application log files

public/ Data accessible to the

public (e.g., via web browsers), such as error pages

bin/rails A program for generating code, opening console sessions, or starting a local server

test/ Application tests

tmp/ Temporary files

vendor/ Third-party code such as plugins and gems

vendor/assets Third-party assets such as cascading style sheets (CSS), JavaScript files, and images

README.rdoc A brief description of the application

Rakefile Utility tasks available via the rake command

Gemfile Gem requirements for this app

Gemfile.lock A list of gems used to ensure that all copies of the app use the same gem versions

config.ru A configuration file for Rack middleware

.gitignore Patterns for files that should be ignored by Git

Question 6

What does ‘bundle install’ do?

Answer 6

It installs and includes the gems needed by the app according to the Gemfile

Question 7

T/F: ‘bundle install’ is not run at the end of ‘rails new’

Answer 7

F; it is

Question 8

How can we specify ranges in the Gemfile, and why might we do this?

Answer 8

’>=’ installs the gem as long as it is greater than or equal to the specified version

’~>’ installs the gem as long as it’s newer than the version specified and NOT newer than the next major point release (i.e. 4.0.0 to 4.0.1, NOT 4.0.0 to 4.1.0)

gem ‘uglifier’, ‘>= 1.3.0’
gem ‘coffee-rails’, ‘~> 4.0.0’

It is important that any change in gem can break an application, so this is to be done carefully.

Question 9

If we change our Gemfile, how can we update the app to reflect the changes?

Answer 9

run ‘$ bundle install’ or, if that fails, ‘$ bundle update’

Question 10

How can we see our app running on the rails server?

Answer 10

Point your browser to the url given by the server (usually localhost:3000)

Question 11

What is the MVC architectural pattern?

Answer 11

The “model-view-controller” architectural pattern, which separates “domain logic” from the GUI (input and presentation logic)

Question 12

What is “domain logic”? What does the GUI refer to?

Answer 12

Also called business logic, it typically consists of data models for things like users, articles, and products, and the GUI is just a web page in a web browser.

Question 13

Articulate the process of how a rails app interacts with a web browser? What is the difference between a view and a model?

Answer 13

The web browser sends a request, which is received by a web server and passed on to a Rails controller, which is in charge of what to do next. In some cases, the controller will immediately render a view, which is a template that gets converted to HTML and sent back to the browser. More commonly for dynamic sites, the controller interacts with a model, which is a Ruby object that represents an element of the site (such as a user) and is in charge of communicating with the database. After invoking the model, the controller then renders the view and returns the complete web page to the browser as HTML.

Question 14

Where can we find controllers, and what are they for?

Answer 14

In the app/controllers directory. They are used for defining controller actions, which is part of what the webpage does.

Question 15

When defining a controller action (function), what function must be included to return text?

Answer 15

‘render text: “”’

Question 16

Where can we change where to send browser requests? Why is this important?

Answer 16

By changing the route in config/routes.rb

We can change the page that is served. For example, we can change the page sent by the root URL with the function: ‘root ‘application#’

Question 17

How do we create a new Git repo?

Answer 17

Navigate to the root directory of the project and run ‘$ git init’

Question 18

What is the command to add all files to the repo?

Answer 18

$ git add -A

Question 19

What does ‘$ git status’ do, and how does it relate to the ‘add’ command?

Answer 19

All files that are ‘added’ are placed in a staging area for pending changes, and the status command shows the contents of this staging area

Question 20

How do we confirm changes with Git?

Answer 20

’$ git commit -m “”’

Question 21

How do we revert to the last commit?

Answer 21

$ git checkout -f

Question 22

What is the first step in making a new BitBucket repo?

Answer 22

Create a new private Git repo with a name matching your root directory

Question 23

What is the command to connect to your repo?

Answer 23

$ git remote add origin git@bitbucket.org:/.git

Question 24

How do we create a new branch?

Answer 24

$ git checkout -b `

Question 25

With the ‘$ git branch’ command, what does the ‘*’ in the results indicate?

Answer 25

The current branch

Question 26

What is the syntax for the first time we push up to our repo?

Answer 26

$ git push -u origin –all

Question 27

What do the -a and -m flags do in the commit command?

Answer 27

-m sets a message to describe the commit, and -a commits changes to all EXISTING files (files MUST be added with ‘git add -A’ first).

Question 28

What does ‘git checkout branch’ do?

Answer 28

Switches the active branch.

Question 29

How do we merge the changes of one test branch to the master branch?

Answer 29

$ git merge

MUST BE IN MASTER BRANCH!

Question 30

What is the cleanest thing to do once you’ve finished merging a branch?

Answer 30

Delete the branch with ‘$ git branch -d ‘

Question 31

What needs to be added to the Gemfile in order to use Heroku?

Answer 31

group :production do
gem ‘pg’, ‘0.17.1’
gem ‘rails_12factor’, ‘0.0.2’
end

Question 32

How do we add out commit to BitBucket?

Answer 32

$ git push

Question 33

What is the point of the following command?

$ bundle install –without production

Answer 33

It does not install the production gems in the Gemfile, but it adds them to Gemfile.lock. This is mainly for deployment to a production environment, since these gems are not needed for development.

Question 34

How do we create space for a new application on Heroku?

Answer 34

$ heroku create

Question 35

How do we deploy to Heroku?

Answer 35

$ git push heroku master

Question 36

What is the command to change the name of our Heroku deployment, and what will the resulting address be?

Answer 36

$ heroku rename newname.herokuapp.com

Question 37

How can we view our live site directly from the command line?

Answer 37

$ heroku open

Question 38

Why is storing hashed values instead of passwords advantageous?

Answer 38

If a database is compromised, user passwords will still be secure.

Question 39

What does #has_secure_password do, and what does it require to work?

Answer 39

The ability to save a securely hashed password_digest attribute to the database
A pair of virtual attributes (password and password_confirmation), including presence validations upon object creation and a validation requiring that they match
An authenticate method that returns the user when the password is correct (and false otherwise)

The only requirement for has_secure_password to work its magic is for the corresponding model to have an attribute called password_digest.

Question 40

T/F: The following code is valid:

@user.password = @user.password_confirmation = “a” * 5

Answer 40

T; it is a case of compact multiple assignment

Question 41

What is a last step when deploying to heroku?

Answer 41

$ heroku run rake db:migrate