When using Rails validations, a standard error message will be provided whenever there is a violation. Consider the scenario when there is a uniqueness validation on the email attribute and it is violated:
# User model
validates_uniqueness_of :email
# Users controller
new_user.errors.full_messages
#=> ["Email has already been taken"]Sometimes you don't want the default validation message. The validation
declaration can be given a message option to specify an alternate
validation message.
# User model
validates_uniqueness_of :email, message: 'is not available'
# Users controller
new_user.errors.full_messages
#=> ["Email is not available"]Keep in mind that full_messages will prepend the model name to the front
of the message. You'll want to ensure that the resulting message is
coherent.