Custom Validations Rails Model - ruby-on-rails

I have a contact form and would like to show individual messages depending on what has failed.I would like to use flash messages. So from what i have read so far i can create a custom method (or i think it just overrides the one in place?)
So for example, i want to validate the presence of the name field
Class Message
attr_accessor :name
validates :name, :presence => true
def validate
if self.name < 0
errors.add(:name, "Name cannot be blank")
end
end
end
Within my controller i normally use a generic message
flash.now.alert = "Please Ensure all Fields are filled in"
Is there a way to call the particular message that failed validation?
Thanks

There is a plugin available, u can follow the below url
https://github.com/jeremydurham/custom-err-msg

Check the method validates because you can pass a message argument with the desired message.
validates :name, :presence => {:message => 'The name can't be blank.'}

Related

Validating a existence of a beta code before creating a User

model: User
has_one :beta_invite
before_save :beta_code_must_exist
def beta_code_must_exist
if beta_invite_id == beta_invite.find_by_name(beta_invite.id)
user
else
nil
end
end
model: BetaInvite
has_many :users
What I`m trying to do is check for the existence of a beta invite in DB, before allowing the user to be saved.
Since the User will be passing in the BetaInvite name into the field, I would like to check if it matches any existing Codes in the DB.
Hope I didn`t mix things up too much.
Would appreciate any help with this problem.
Add a text field to the form for :beta_code
Add an attr_accessor for that field: attr_accessor :beta_code
Then add the following line to the model (Assumes you only want to do this check on user creation):
validate :beta_code_must_exist, :on => :create
Change beta_code_must_exist to add an error to the form. Also be sure to properly cast :beta_code into the correct type.
Warning untested code below
def beta_code_must_exist
#invite = BetaInvite.find_by_name(beta_code)
if #invite.empty?
errors.add(:beta_code, "is not a valid invite code")
else
beta_invite_id = #invite.id
end
end
Use :inclusion with the :in option. You can supply :in with any enumerable:
validates :beta_invite, :inclusion => { :in => BetaInvite.all,
:message => "%{value} is not a valid beta invite code" }
Source: Rails Active Record Validation

Validate presence of one of multiple attributes in rails

In an multilingual application, a user can input their Chinese and English names. The user can input either or both, but must input at least one name.
class Person < ActiveRecord::Base
validates :zh_name, :presence => true
validates :en_name, :presence => true
validates :fr_name, :presence => true
end
Since the built-in :validates_presence_of method can only validate both attributes at once, is there a way to validate the presence of at least one of many attributes in rails?
Like a magical, validates_one_of :zh_name, :en_name, :fr_name
Thank you in advance,
validate :at_least_one_name
def at_least_one_name
if [self.zh_name, self.en_name, self.fr_name].reject(&:blank?).size == 0
errors[:base] << ("Please choose at least one name - any language will do.")
end
end
Taking #micapam's answer a step futher, may I suggest:
validate :has_a_name
def has_a_name
unless [zh_name?, en_name?, fr_name?].include?(true)
errors.add :base, 'You need at least one name in some language!'
end
end
just a quick shot out, you can pass a "if" or "unless" to the validator, maybe you can get it working this way. i have something like this in mind
validates :zh_name, :presence => { :if => (fr_name.blank? && en_name.blank?) }
validate :has_a_name
def has_a_name
unless [zh_name, en_name, fr_name].any?{|val| val.present? }
errors.add :base, 'You need at least one name in some language!'
end
end
Max Williams' answer is fine, but I didn't see the need to count hits when any? returns a boolean.

preventing rails validation based on previous validation

I have a model with 2 validations on the 'name' attribute. It goes something like this:
validates :name, :uniqueness => true
validate do
errors.add(:name, "is dumb") if name_is_dumb?
end
I don't want the 2nd validation to run if the first validation fails (the name is not unique).
What's the best and cleanest way to do this?
According to the documentation:
Callbacks are generally run in the
order they are defined, with the
exception of callbacks defined as
methods on the model, which are called
last.
So the following snippet should work:
validates :name, :uniqueness => true
validate do
errors.add(:name, "is dumb") unless errors[:name].nil?
end

How do I set a Rails validation to ensure that two attributes can't have the same value?

I have a form on my site that lets users direct a message at other users, but I want to ensure that they can't direct a message at themselves.
The class has attributes :username and :target_user, and I just want to set a validation that checks to make sure that these attributes can't have the same value, before anything gets saved.
I figured it would look something like this:
validates_presence_of :user_id, :username, :target_user, :message, :tag
validate :username != :target_user
But clearly don't know enough Ruby to do it correctly.
Up at the top with your validations:
validate :username_does_not_equal_target
and then a private/protected method within your model code:
def username_does_not_equal_target
#errors.add(:base, "The username should not be the same as the target user") if self.username == self.target_user
end
OR to attach the error to a specific attribute:
def username_does_not_equal_target
#errors.add(:username, "should not be the same as the target user") if self.username == self.target_user
end
You can change the text of your error message or the name of your method.
to read more on errors: http://api.rubyonrails.org/classes/ActiveRecord/Errors.html
to read more on validations: http://api.rubyonrails.org/classes/ActiveRecord/Validations/ClassMethods.html
I hope this helps, happy coding!
Use validate
def validate
if self.username == self.target_user
self.errors.add :base, "You can't send message to yourself."
end
end

Rails 2.3 uniqueness validation - how can I capture the value causing the error

I'm trying to capture the value that's throwing a uniqueness error (or for that matter, any other type of built-in validation) to display it in the :message option. Here's what I tried (didn't work)
# inside the model
validate_uniqueness_of :name, :message => "#{name} has already been taken" # also tried using #{:name}
I could use a custom validation, but this beats the point of using something that's already integrated into AR. Any thoughts? thanks.
Try this interpolation technique:
validate_uniqueness_of :name, :message => "%{value} has already been taken"
The RailsGuide for Active Record Validations and Callbacks shows an example where %{value} is interpolated in a custom error message:
:message => "%{value} is not a valid size"
I looked at the validates_each documentation and can see the validate block is passed three properties: |record, attr, value|. All three can be accessed with %{model}, %{attribute} and %{value}.
While this is limited, since it only gives you access to three properties, thankfully that is all you need.
Try self.name
validates_uniqueness_of :name, :message => "#{self.name} has already been taken" # also tried using #{:name}
Also validate_uniqueness_of is wrong it should be validates_uniqueness_of
If this not works use validate method and comment line validates_uniqueness_of
def validate
name= User.find_by_name(self.name) #Assuming User is your Model Name
unless name.blank?
self.errors.add :base, "#{self.name} has already been taken"
end
end

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