Image and file handling in Ruby on Rails - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to attach an image file to a Rails model using Active Storage.

Ruby on Rails

class User < ApplicationRecord
  has_one_attached :[1]
end

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

Aphoto

Bimage

Cavatar

Dfile

Attempts:

3 left

💡 Hint

Common Mistakes

Using plural form like 'avatars' instead of singular 'avatar'.

Using generic names like 'file' which are less descriptive.

The has_one_attached method defines a one-to-one attachment for the model. Here, avatar is the common name used for user profile images.

2fill in blank

medium

Complete the code to permit the image attachment parameter in a Rails controller.

Ruby on Rails

def user_params
  params.require(:user).permit(:name, [1])
end

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

A:avatar

B:image

C:photo

D:file

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to permit the attachment parameter causes the file not to be saved.

Using string instead of symbol for the parameter.

To allow file uploads, the attachment name (here :avatar) must be permitted in strong parameters.

3fill in blank

hard

Fix the error in the view code to display the attached image if it exists.

Ruby on Rails

<% if @user.[1].attached? %>
  <%= image_tag @user.avatar %>
<% end %>

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

Aavatar

Bimage

Cphoto

Dfile

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different attachment name causes a runtime error.

Calling attached? on the model instead of the attachment.

The method attached? checks if the named attachment exists. It must match the attachment name defined in the model.

4fill in blank

hard

Fill both blanks to create a variant of the attached image resized to 100x100 pixels.

Ruby on Rails

<%= image_tag @user.avatar.variant([1]: [2]) %>

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

Aresize_to_limit

B[100, 100]

C[200, 200]

Dresize_to_fill

Attempts:

3 left

💡 Hint

Common Mistakes

Using resize_to_fill crops the image, which may not be desired.

Passing size as a string instead of an array.

The variant method creates a resized version of the image. resize_to_limit resizes the image to fit within the given dimensions without cropping.

5fill in blank

hard

Fill all three blanks to create a hash of filenames and their byte sizes for all attached files.

Ruby on Rails

files_info = @document.files.each_with_object({}) do |file, hash|
  hash[[1]] = file.blob.[2]
end

files_info.keys.first == [3]

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

Afile.filename.to_s

Bbyte_size

Cfile.filename

Dsize

Attempts:

3 left

💡 Hint

Common Mistakes

Using file.filename directly as a hash key causes issues because it is not a string.

Using size instead of byte_size returns nil.

To get the filename as a string, use file.filename.to_s. The file size in bytes is accessed with blob.byte_size.