Fully custom validation error message with Rails

Question

Using Rails I m trying to get an error message like  The song field can t be empty  on save  Doing the following   validates presence of  song rep xyz   message   gt   can t be empty        only displays  Song Rep XYW can t be empty   which is not good because the title of the field is not user friendly  How can I change the title of the field itself   I could change the actual name of the field in the database  but I have multiple  song  fields and I do need to have specific field names   I don t want to hack around rails  validation process and I feel there should be a way of fixing that

User · Answer

Related to the accepted answer and another answer down the list:

I'm confirming that nanamkim's fork of custom-err-msg works with Rails 5, and with the locale setup.

You just need to start the locale message with a caret and it shouldn't display the attribute name in the message.

A model defined as:

class Item < ApplicationRecord
  validates :name, presence: true
end

with the following en.yml:

en:
  activerecord:
    errors:
      models:
        item:
          attributes:
            name:
              blank: "^You can't create an item without a name."

item.errors.full_messages will display:

You can't create an item without a name

instead of the usual Name You can't create an item without a name

User · Answer

In your model   validates presence of  address1  message   Put some address please     In your view   lt   m errors each do  attr  msg     gt    lt    msg   gt   lt   end   gt    If you do instead   lt    attr   gt   lt    msg   gt    you get this error message with the attribute name    address1 Put some address please   if you want to get the error message for one single attribute    lt     model errors  address1    gt

User · Answer

Now  the accepted way to set the humanized names and custom error messages is to use locales     config locales en yml en    activerecord      attributes        user          email   E-mail address      errors        models          user            attributes              email                blank   is required    Now the humanized name and the presence validation message for the  email  attribute have been changed   Validation messages can be set for a specific model attribute  model  attribute  or globally

User · Answer

If you want to list them all in a nice list but without using the cruddy non human friendly name  you can do this     object errors each do  attr message    puts   lt li gt   message   lt  li gt   end

User · Answer

In your view  object errors each do  attr msg    if msg is a  String     if attr     base       content tag  li  msg     elsif msg 0               content tag  li  msg 1  -1      else       content tag  li     object class human attribute name attr     msg       end   end end   When you want to override the error message without the attribute name  simply prepend the message with   like so   validates  last name    uniqueness        scope    first name   course id   user id       case sensitive  false      message    This student has already been registered

User · Answer

In the custom validation method use   errors add  base   Custom error message    as add to base has been deprecated   errors add to base  Custom error message

User · Answer

Rails3 Code with fully localized messages   In the model user rb define the validation  validates  email   presence   gt  true   In config locales en yml  en      activerecord      models         user   Customer      attributes        user          email   Email address      errors        models          user            attributes              email                blank   cannot be empty

User · Answer

Here is another way   If you use this template    lt   if  thing errors any    gt     lt ul gt       lt    thing errors full messages each do  message    gt         lt li gt  lt    message   gt  lt  li gt       lt   end   gt     lt  ul gt   lt   end   gt    You can write you own custom message like this   class Thing  lt  ActiveRecord  Base    validate  custom validation method with message    def custom validation method with message     if some model attribute blank        errors add      My custom message       end   end   This way  because of the underscore  the full message becomes   My custom message   but the extra space in the beginning is unnoticeable  If you really don t want that extra space at the beginning just add the  lstrip method    lt   if  thing errors any    gt     lt ul gt       lt    thing errors full messages each do  message    gt         lt li gt  lt    message lstrip   gt  lt  li gt       lt   end   gt     lt  ul gt   lt   end   gt    The String lstrip method will get rid of the extra space created by      and will leave any other error messages unchanged   Or even better  use the first word of your custom message as the key     def custom validation method with message     if some model attribute blank        errors add  my   custom message       end   end   Now the full message will be  My custom message  with no extra space   If you want the full message to start with a word capitalized like  URL can t be blank  it cannot be done  Instead try adding some other word as the key     def custom validation method with message     if some model attribute blank        errors add  the   URL can t be blank       end   end   Now the full message will be  The URL can t be blank

User · Answer

I recommend installing the custom error message gem  or as a plugin  originally written by David Easley  It lets you do stuff like   validates presence of  non friendly field name   message   gt    Friendly field name is blank

User · Answer

Just do it the normal way   validates presence of  email   message   gt   Email is required     But display it like this instead   lt   if  user errors any    gt     lt    user errors messages each do  message    gt       lt div class  message  gt  lt    message last last html safe   gt  lt  div gt     lt   end   gt   lt   end   gt    Returns   Email is required     The localization method is definitely the  proper  way to do this  but if you re doing a little  non-global project and want to just get going fast - this is definitely easier than file hopping    I like it for the ability to put the field name somewhere other than the beginning of the string   validates uniqueness of  email   message   gt   There is already an account with that email

User · Answer

A unique approach I haven t seen anyone mention    The only way I was able to get all the customisation I wanted was to use an after validation callback to allow me to manipulate the error message    Allow the validation message to be created as normal  you don t need to try and change it in the validation helper  create an after validation callback that will replace that validation message in the back-end before it gets to the view  In the after validation method you can do anything you want with the validation message  just like a normal string  You can even use dynamic values and insert them into the validation message       this could be any validation validates presence of  song rep xyz   message   gt   whatever you want - who cares - we will replace you later   after validation  replace validation message  def replace validation message     custom value    any value you would like     errors messages  name of the attribute       This is the replacement message where      you can now add your own dynamic values      custom value    end   The after validation method will have far greater scope than the built in rails validation helper  so you will be able to access the object you are validating like you are trying to do with object file name  Which does not work in the validation helper where you are trying to call it   Note  we use the   to get rid of the attribute name at the beginning of the validation as  Rystraum pointed out referencing this gem

User · Answer

graywh s answer is the best if it actually locales different in displaying the field name  In the case of a dynamic field name  based on other fields to display   I would do something like this    lt   object errors each do  attr  msg    gt   lt li gt     lt   case attr to sym   gt     lt   when  song rep xyz   gt       lt     display error how you want here   gt     lt   else   gt       lt    object errors full message attr  msg    gt     lt   end   gt   lt  li gt   lt   end   gt    the full message method on the else is what rails use inside of full messages method  so it will give out the normal Rails errors for other cases  Rails 3 2 and up

User · Answer

One solution might be to change the i18n default error format   en    errors      format     message     Default is format    attribute    message

User · Answer

I tried following  worked for me     1 job rb  class Job  lt  ApplicationRecord     validates  description  presence  true     validates  title                  presence   gt  true                  length   gt     minimum   gt  5   message   gt   Must be at least 5 characters   end   2 jobs controller rb  def create        job   Job create job params        if  job valid          redirect to jobs path       else         render new job path       end          end   3  form html erb    lt    form for  job do  f    gt     lt   if  job errors any    gt       lt h2 gt Errors lt  h2 gt       lt ul gt         lt    job errors full messages each do  message   gt           lt li gt  lt    message   gt  lt  li gt         lt   end   gt         lt  ul gt     lt   end   gt     lt div gt       lt    f label  title   gt       lt    f text field  title   gt     lt  div gt     lt div gt       lt    f label  description   gt       lt    f text area  description  size   60x6    gt      lt  div gt     lt div gt       lt    f submit   gt     lt  div gt   lt   end   gt

User · Answer

Here is my code that can be useful for you in case you still need it   My model    validates  director  acceptance   message    Please confirm that you are a director of the company     on   create  if   is director    Then I have created a helper to show messages    module ErrorHelper   def error messages      return    unless error messages      messages   resource errors full messages map    msg         if msg present   amp  amp   msg index      nil           content tag  p  msg slice  msg index      1   -1          else          content tag  p  msg         end       join      html    lt  lt -HTML        lt div class  general-error alert show  gt            messages         lt  div gt      HTML      html html safe   end    def error messages       resource errors empty    end end

User · Answer

Try this  class User  lt  ActiveRecord  Base   validate do  user      user errors add to base  quot Country can t be blank quot   if user country iso blank    end end  I found this here  Update for Rails 3 to 6  validate do  user    user errors add  base   quot Country can t be blank quot   if user country iso blank  end  Here is another way to do it  What you do is define a human attribute name method on the model class  The method is passed the column name as a string and returns the string to use in validation messages  class User  lt  ActiveRecord  Base    HUMANIZED ATTRIBUTES          email   gt   quot E-mail address quot         def self human attribute name attr      HUMANIZED ATTRIBUTES attr to sym     super   end  end  The above code is from here

User · Answer

Yes  there s a way to do this without the plugin  But it is not as clean and elegant as using the mentioned plugin  Here it is   Assuming it s Rails 3  I don t know if it s different in previous versions    keep this in your model   validates presence of  song rep xyz   message   gt   can t be empty    and in the view  instead of leaving   instance errors full messages   as it would be when we use the scaffold generator  put    instance errors first 1    And you will get just the message you specified in the model  without the attribute name   Explanation    returns an hash of messages  one element foreach field error  in this particular case would be just one element in the hash   instance errors      gt    song rep xyz  gt  can t be empty     this returns the first element of the hash as an array like   key  value    instance errors first     gt    song rep xyz   can t be empty     by doing the following  you are telling ruby to take just the second element of that array  which is the message   instance errors first 1    So far we are just displaying only one message  always for the first error  If you wanna display all errors you can loop in the hash and show the values   Hope that helped

[ruby-on-rails] Fully custom validation error message with Rails

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