Controller generation in Ruby on Rails - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to generate a new controller named 'Posts'.

Ruby on Rails

rails generate [1] Posts

Drag options to blanks, or click blank then click option'

Acontroller

Bmodel

Cmigration

Dscaffold

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'model' instead of 'controller' will generate a model, not a controller.

Using 'migration' creates a database migration, not a controller.

Use controller to generate a new controller in Rails.

2fill in blank

medium

Complete the code to generate a controller with an action named 'index'.

Ruby on Rails

rails generate controller Posts [1]

Drag options to blanks, or click blank then click option'

Ashow

Bedit

Cindex

Ddelete

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'show' or 'edit' will create different actions, not the list action.

Using 'delete' is not a valid action name for generation.

The index action is commonly used to list all records.

3fill in blank

hard

Fix the error in the command to generate a controller named 'Users' with actions 'new' and 'create'.

Ruby on Rails

rails generate controller Users [1] [2]

Drag options to blanks, or click blank then click option'

Anew

Bnew create

Ccreate

Attempts:

3 left

💡 Hint

Common Mistakes

Putting multiple actions in one blank causes syntax errors.

Not providing both actions separately.

Each action must be a separate argument; you cannot combine them in one option.

4fill in blank

hard

Fill both blanks to generate a controller named 'Articles' with actions 'show' and 'edit'.

Ruby on Rails

rails generate controller Articles [1] [2]

Drag options to blanks, or click blank then click option'

Ashow

Bindex

Cedit

Ddelete

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up action names or combining them in one argument.

Using invalid action names.

Actions are listed separately after the controller name.

5fill in blank

hard

Fill all three blanks to generate a controller named 'Comments' with actions 'create', 'destroy', and 'update'.

Ruby on Rails

rails generate controller Comments [1] [2] [3]

Drag options to blanks, or click blank then click option'

Ashow

Bcreate

Cdestroy

Dupdate

Attempts:

3 left

💡 Hint

Common Mistakes

Combining multiple actions in one argument.

Using actions not relevant to the controller.

List all desired actions separately after the controller name.

Practice

1. What does the rails generate controller command do in a Rails application?

easy

A. Compiles the Rails application for production.

B. Generates a new database table for storing data.

C. Deletes an existing controller and its views.

D. Creates a new controller file with specified actions and related view files.

Solution

1. Step 1: Understand the purpose of the command

   The rails generate controller command is used to create a new controller in a Rails app.

2. Step 2: Identify what files are created

   This command creates a controller file and also generates view files for the actions specified.

3. Final Answer:

   Creates a new controller file with specified actions and related view files. -> Option D

4. Quick Check:

   Controller generation = creates controller and views [OK]

Hint: Controller generator creates controller and views together [OK]

Common Mistakes:

• Confusing controller generation with database migration
• Thinking it compiles or deletes files
• Assuming it only creates views without controller

2. Which of the following is the correct syntax to generate a controller named Products with actions index and show?

easy

A. rails generate controller Products index show

B. rails create controller Products index show

C. rails generate model Products index show

D. rails generate controller products index show

Solution

1. Step 1: Identify the correct command keyword

   The correct command to generate a controller is rails generate controller.

2. Step 2: Check the controller name and actions

   Controller names are capitalized (e.g., Products) and actions follow after the name.

3. Final Answer:

   rails generate controller Products index show -> Option A

4. Quick Check:

   Correct syntax = rails generate controller + ControllerName + actions [OK]

Hint: Use 'rails generate controller' with capitalized controller name [OK]

Common Mistakes:

• Using 'create' instead of 'generate'
• Using 'model' instead of 'controller'
• Using lowercase controller name

3. Given the command rails generate controller Articles new edit, which files will be created?

medium

A. Only the controller file articles_controller.rb without views.

B. Model file article.rb and migration for articles table.

C. Controller file articles_controller.rb and views new.html.erb and edit.html.erb.

D. Database schema file and routes for articles.

Solution

1. Step 1: Understand what the generate controller command creates

   It creates a controller file named after the pluralized controller name and view files for each action.

2. Step 2: Identify the files created for actions

   Actions new and edit generate corresponding view files new.html.erb and edit.html.erb.

3. Final Answer:

   Controller file articles_controller.rb and views new.html.erb and edit.html.erb. -> Option C

4. Quick Check:

   Controller + views for actions = Controller file articles_controller.rb and views new.html.erb and edit.html.erb. [OK]

Hint: Controller generator creates views for each action named [OK]

Common Mistakes:

• Confusing controller generation with model generation
• Expecting database files to be created
• Thinking views are not created automatically

4. You run rails generate controller users show but get an error. Which of the following is the most likely cause?

medium

A. Controller name should be capitalized as Users.

B. The action show is not allowed in controllers.

C. You must create a model before generating a controller.

D. The command should be rails create controller users show.

Solution

1. Step 1: Check the controller name capitalization

   Rails expects controller names to be capitalized (e.g., Users), lowercase causes errors.

2. Step 2: Verify command correctness

   The command rails generate controller Users show is correct; show is a valid action.

3. Final Answer:

   Controller name should be capitalized as Users. -> Option A

4. Quick Check:

   Capitalized controller name required [OK]

Hint: Always capitalize controller names in generate command [OK]

Common Mistakes:

• Using lowercase controller names
• Thinking actions are restricted
• Confusing generate with create command

5. You want to generate a controller named Admin::Dashboard with actions index and stats. Which command correctly creates the controller and places it in the admin folder?

hard

A. rails generate controller admin/dashboard index stats

B. rails generate controller Admin::Dashboard index stats

C. rails generate controller Admin_Dashboard index stats

D. rails generate controller admin_dashboard index stats

Solution

1. Step 1: Understand namespacing in Rails controllers

   Using :: in the controller name creates a folder structure for namespacing (e.g., Admin::Dashboard creates admin/dashboard_controller.rb).

2. Step 2: Identify the correct command syntax

   The correct syntax uses capitalized names with :: to separate namespace and controller name.

3. Final Answer:

   rails generate controller Admin::Dashboard index stats -> Option B

4. Quick Check:

   Namespace with :: and capitalized names [OK]

Hint: Use :: for namespaced controllers with capitalized parts [OK]

Common Mistakes:

• Using underscores instead of :: for namespaces
• Using lowercase names for namespaces
• Confusing folder path with command syntax