rails friendly_id and check if entry exists

Question

How to check if friendly_id entry exists before get it?

For example:

  def book
   @book = Book.find(params[:book_id])
  end

It's ok, but i want check before if friendly_id exists, something like:

def book
  if Book.exists?(params[:book_id])
    @book = Book.find(params[:book_id])
  else
    #404 not found
  end

score 17 · Answer 1 · answered Oct 01 '14 at 05:13

17

As of the latest version of the friendly_id gem, you can say:

Book.friendly.exists? params[:book_id]

answered Oct 01 '14 at 05:13

Hamed

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2

This is so much better than the accepted answer. Exceptions should only be for things you can't easily predict - not things you expect to happen. – marksiemers Feb 27 '15 at 18:12
if you use :finders you can probably omit friendly, resulting in `Book.exists? params[:book_id]` – AndreiMotinga Mar 26 '16 at 15:53
Dangerous. Any slug that starts with a number will return false positives since it will fall back on ActiveRecord's finder, and "1something".to_i == 1 – Stephen Corwin Jun 17 '21 at 16:01
1

@StephenCorwin Yes, that's why I don't mix in the "finders" module into my model. – Hamed Jun 17 '21 at 20:29

Deepak N · Accepted Answer · 2011-03-13T19:06:27.907

5

Rescue from RecordNotFound exception ==>

def book
  @book = Book.find(params[:book_id])
  #OK
rescue ActiveRecord::RecordNotFound => e
  head :not_found
end

edited Mar 13 '11 at 19:06

answered Mar 13 '11 at 17:27

Deepak N

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`find_by_id` will return instance or nil. While `find` or `find_by_id` will raise exception – fl00r Mar 13 '11 at 18:39
thanks, corrected the answer. Copy paste always leads to trouble!! – Deepak N Mar 13 '11 at 19:07

score 2 · Answer 3 · answered Mar 20 '12 at 15:18

I suggest you to move Deepak N's solution to model like I did:

def self.find_by_friendly_id(friendly_id)
  find(friendly_id)
rescue ActiveRecord::RecordNotFound => e
  nil
end

So now it will fetch your books by both id and slug and won't throw exception, just like standard AR method #find_by_id.
BTW, according the documentation #exists? method now is right way to check record existance!

score -2 · Answer 4 · answered Mar 13 '11 at 15:24

-2

@book = Book.find_by_id(params[:book_id])
if @book
  # OK
else
  #404 not found
enв

answered Mar 13 '11 at 15:24

fl00r

82,987
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rails friendly_id and check if entry exists

4 Answers4