10

Hey... how would you validate a full_name field (name surname).

xpepermint
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  • need some good reg for validates_format_of – xpepermint Apr 13 '10 at 12:24
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    What are the acceptable values, and what are not? To my mind you can check only, that there should not be any special chars like `#@%...`, numbers and should be at least 1 space. – Draco Ater Apr 13 '10 at 12:25
  • Some people go by a single name, so even looking for a space can be problematic. Ask yourself: *Why* am I validating a name field? What problem are you trying to prevent from occurring? – Larry K Apr 13 '10 at 17:14

3 Answers3

33

Consider names like:

  • Ms. Jan Levinson-Gould
  • Dr. Martin Luther King, Jr.
  • Brett d'Arras-d'Haudracey
  • Brüno

Instead of validating the characters that are there, you might just want to ensure some set of characters is not present.

For example:

class User < ActiveRecord::Base

  validates_format_of :full_name, :with => /\A[^0-9`!@#\$%\^&*+_=]+\z/
  # add any other characters you'd like to disallow inside the [ brackets ]
  # metacharacters [, \, ^, $, ., |, ?, *, +, (, and ) need to be escaped with a \

end

Tests

Ms. Jan Levinson-Gould         # pass
Dr. Martin Luther King, Jr.    # pass
Brett d'Arras-d'Haudracey      # pass
Brüno                          # pass
John Doe                       # pass
Mary-Jo Jane Sally Smith       # pass
Fatty Mc.Error$                # fail
FA!L                           # fail
#arold Newm@n                  # fail
N4m3 w1th Numb3r5              # fail

Regular expression explanation

NODE                     EXPLANATION
--------------------------------------------------------------------------------
  \A                       the beginning of the string
--------------------------------------------------------------------------------
  [^`!@#\$%\^&*+_=\d]+     any character except: '`', '!', '@', '#',
                           '\$', '%', '\^', '&', '*', '+', '_', '=',
                           digits (0-9) (1 or more times (matching
                           the most amount possible))
--------------------------------------------------------------------------------
  \z                       the end of the string
maček
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  • I found this issue on Rails 4.0.1 The provided regular expression is using multiline anchors (^ or $), which may present a security risk. Did you mean to use \A and \z, or forgot to add the :multiline => true option? But it was solved with adding :multiline => true ``validates_format_of :name, :with => /^[^0-9`!@#\$%\^&*+_=]+$/, :multiline => true`` – barek2k2 Oct 23 '14 at 10:56
  • @barek2k2, I should be using `\A` and `\z` here. Thanks for the comment. – maček Oct 23 '14 at 16:46
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    Bit late though... However keep in mind that this regex approves of the name being `------` – ExcellentAverage May 02 '16 at 17:20
  • Consider non-English speakers (names in Cyrillic etc.). It's a mess. – Serge Vinogradov Jun 05 '21 at 04:12
1

At least one space and at least 4 char (including the space)

\A(?=.* )[^0-9`!@#\\\$%\^&*\;+_=]{4,}\z
montrealmike
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1

Any validation you perform here is likely to break down unless it is extremely general. For instance, enforcing a minimum length of 3 is probably about as reasonable as you can get without getting into the specifics of what is entered.

When you have names like "O'Malley" with an apostrophe, "Smith-Johnson" with a dash, "Andrés" with accented characters or extremely short names such as "Vo Ly" with virtually no characters at all, how do you validate without excluding legitimate cases? It's not easy.

tadman
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