Question

My Tag model has some validations for attribute name. It’s wroking fine in all other cases. But when I call find_or_create_by_name by this way:

# The last value of this string (by coma) is empty.
# So this record should not be saved.
tags_line = 'ruby, javascript, '

tags_line.split(',').each do |tag_name|
  tag = Tag.find_or_create_by_name(tag_name.strip) do |new_tag|
    new_tag.update_attribute :user_id, member.user.id
  end

  # Just append tag to this model
  # through `has_and_belongs_to_many :tags`
  tags << tag if tag
end

But this empty tag is even being saved. So, can be something wrong in this code?

NOTE: When I remove the block, it works:

...
tags_line.split(',').each do |tag_name|
  # This way, invalid tag will not be created.
  tag = Tag.find_or_create_by_name(tag_name.strip)
  tags << tag if tag
end

Answer 1

The problem was caused by the fact that attribute :name is protected in model. So, as the Rails Doc says:

The same dynamic finder style can be used to create the object if it
doesn’t already exist. This dynamic finder is called with
find_or_create_by_ and will return the object if it already exists and
otherwise creates it, then returns it. Protected attributes won’t be
set unless they are given in a block.

The fixed code is…

tags_field.split(',').each do |tag_name|
  tag_name.strip!

  tag = General::Tag.find_or_create_by_name(tag_name) do |new_tag|
    # :name is attr_protected
    new_tag.name = tag_name
    new_tag.user_id = member.user.id
  end

  tags << tag if tag
end