How to write database specific custom validator in Rails 3.0? - ruby-on-rails

I need to write a custom validator to check if a record exists in the database or not. Sort of like the opposite of validate uniqueness, however I couldn't find something that could achieve what I wanted in the built in validators.
What I'm attempting to do is check if the referrer exists or not in the Users table. If the referrer's username is "testuser", I want to check in the Users table whether "testuser" actually exists.
I have created a custom validator:
class ReferrerExistsValidator < ActiveModel::EachValidator
However I'm unsure how to proceed to fetch details from there database, any pointers?

Write the following validation class
class ReferrerExistsValidator < ActiveModel::EachValidator
def validate_each(object, attribute, value)
unless User.find_by_username(value)
object.errors[attribute] << (options[:message] || "referrer does not exist")
end
end
end
Add the following to the relevant model
validates :referrer_exists => true

I'm new to rails/coding, and I may misunderstand you, but couldnt you just do something like:
#user.each do |user|
unless #user.username == current_user.referral_name
:alert "no user found"
else whatever
end
end
EDIT: that wouldn't work at all - ignore that, let me think about it for a sec ;)

Related

PostgreSQL check whether timestamp field is empty

I followed these instructions to check whether a user has been soft-deleted or not when logging in. In the example below I can check for a boolean value:
Class User < ActiveRecord::Base
def self.find_for_authentication(conditions)
super(conditions.merge(:deleted_flag => false))
end
I would prefer a timestamp (created_at) field. How can I check whether such a field is empty? The database throws errors for the following checks:
super(conditions.merge(:deleted_at => false)) # also tried nil, "NULL" and "IS NULL"
You can't using this solution, without modifying devise of course. Devise will send your conditions directly to the database, so no way of calling a method or using a library like squeel (that will allow something like where{created_at == nil}.
You could use the solution provided in How to "soft delete" user with Devise, but the error message will be: "You have to confirm your account before continuing."
Add this to your resource model:
def inactive_message
!!deleted_at ? :deleted : super
end
And add a message to your locales:
en:
devise:
failure:
deleted: "Your account was deleted."
I hope it helps!

Customizing Devise gem (Rails)

I am trying to add a new field "registration code" along with the email/password in sign up form. (i have the registration code field in a separate database, only a valid registration code/email pair will have to work with the sign up)
I could not able to find any controller for actions done by devise gem.
How do i customize devise to achieve this?
Thanks in advance.
It seems like your question basically has nothing to do with Devise itself (besides the views). To validate your registration code/email pairs, you surely need to add this as validation.
The easy way to validate registration code could be:
class User
validate :validate_registration_code
private
def validate_registration_code
reg_code = RegistrationCode.find_by_code(registration_code)
unless reg_code.email == record.email
errors.add(:registration_code, "Invalid registration code for #{record.email}")
end
end
end
You also might want to write simple custom validator:
class RegistrationCodeValidator < ActiveModel::Validator
def validate(record)
# actual reg code validation
# might look like:
reg_code = RegistrationCode.find_by_code(record.registration_code)
unless reg_code.email == record.email
record.errors[:registration_code] << "Invalid registration code for #{record.email}"
end
end
end
# in your User model
class User
# include registration code validator
include RegistrationCodeValidator
validates_with MyValidator
end
Devise keeps it's controllers behind the scenes inside the gem. If you want to add an action or modify one, you have to subclass it and do a little work in routes to get the action to your controller.
However you shouldn't need to do that to add a field. See goshakkk's answer

Bind paramerts in Object if those present there

I am receiving an API call at my server with parameters
first_name , :last_name , :age
etc
I want to bind those params to my object against which user is having attribute with same name , like i want to have these in user[first_name] , user[:last_name]
so that I can just put the complete user object into database in following way ,
User.new(params[:user]) or User.new(some_hash)
I dont want to use the following ,
User.new(:first_name=>params[:first_name],:last_name=>params[:last_name])
thanks in advance for you help :)
Something like this may work:
user = User.new
params.each do |key,value|
user[key] = value if user.attribute_names.include?(key.to_s)
end
Note, however, that you should protect sensitive attributes of your User model with attr_protected or attr_accessible in this case.
Writing that functionality into User.initialize can take care of this:
def initialize(args={})
args.each_with_key do |key,val|
instance_variable_set("##{key}", val)
end
end
This of course has no validation and does not protect your object from bad data. For example, if you want to make sure only valid accessible attributes are being set, add if respond_to? key to end end of line 3.

How to setup default attributes in a ruby model

I have a model User and when I create one, I want to pragmatically setup some API keys and what not, specifically:
#user.apikey = Digest::MD5.hexdigest(BCrypt::Password.create("jibberish").to_s)
I want to be able to run User.create!(:email=>"something#test.com") and have it create a user with a randomly generated API key, and secret.
I currently am doing this in the controller, but when I tried to add a default user to the seeds.rb file, I am getting an SQL error (saying my apikey is null).
I tried overriding the save definition, but that seemed to cause problems when I updated the model, because it would override the values. I tried overriding the initialize definition, but that is returning a nil:NilClass and breaking things.
Is there a better way to do this?
use callbacks and ||= ( = unless object is not nil ) :)
class User < ActiveRecord::Base
before_create :add_apikey #or before_save
private
def add_apikey
self.apikey ||= Digest::MD5.hexdigest(BCrypt::Password.create(self.password).to_s)
end
end
but you should definitely take a look at devise, authlogic or clearance gems
What if, in your save definition, you check if the apikey is nil, and if so, you set it?
Have a look at ActiveRecord::Callbacks & in particular before_validation.
class User
def self.create_user_with_digest(:options = { })
self.create(:options)
self.apikey = Digest::MD5.hexdigest(BCrypt::Password.create("jibberish").to_s)
self.save
return self
end
end
Then you can call User.create_user_with_digest(:name => "bob") and you'll get a digest created automatically and assigned to the user, You probably want to generate the api key with another library than MD5 such as SHA256 you should also probably put some user enterable field, a continuously increasing number (such as the current date-time) and a salt as well.
Hope this helps
I believe this works... just put the method in your model.
def apikey=(value)
self[:apikey] = Digest::MD5.hexdigest(BCrypt::Password.create("jibberish").to_s)
end

ActiveRecord custom validation problem

I'm having a problem with validation in my RoR Model:
def save
self.accessed = Time.now.to_s
self.modified = accessed
validate_username
super
end
def validate_username
if User.find(:first, :select => :id, :conditions => ["userid = '#{self.userid}'"])
self.errors.add(:userid, "already exists")
end
end
As you can see, I've replaced the Model's save method with my own, calling validate_username before I call the parent .save method. My Problem is, that, even though the error is being added, Rails still tries to insert the new row into the database, even if the user name is a duplicate. What am I doing wrong here?
PS: I'm not using validate_uniqueness_of because of the following issue with case sensitivity: https://rails.lighthouseapp.com/projects/8994/tickets/2503-validates_uniqueness_of-is-horribly-inefficient-in-mysql
Update: I tried weppos solution, and it works, but not quite as I'd like it to. Now, the field gets marked as incorrect, but only if all other fields are correct. What I mean is, if I enter a wrong E-Mail address for example, the email field is marked es faulty, the userid field is not. When I submit a correct email address then, the userid fields gets marked as incorrect. Hope you guys understand what I mean :D
Update2: The data should be validated in a way, that it should not be possible to insert duplicate user ids into the database, case insensitive. The user ids have the format "user-domain", eg. "test-something.net". Unfortunately, validates_uniqueness_of :userid does not work, it tries to insert "test-something.net" into the database even though there already is an "Test-something.net". validate_username was supposed to be my (quick) workaround for this problem, but it didn't work. weppos solution did work, but not quite as I want it to (as explained in my first update).
Haven't figured this out yet... anyone?
Best regards,
x3ro
Why don't you use a callback and leave the save method untouched?
Also, avoid direct SQL value interpolation.
class ... < ActiveRecord::Base
before_save :set_defaults
before_create :validate_username
protected
def set_defaults
self.accessed = Time.now.to_s
self.modified = accessed
end
def validate_username
errors.add(:userid, "already exists") if User.exists?(:userid => self.userid)
errors.empty?
end
end
How about calling super only if validate_username returns true or something similar?
def save
self.accessed = Time.now.to_s
self.modified = accessed
super if validate_username
end
def validate_username
if User.find(:first, :select => :id, :conditions => ["userid = '#{self.userid}'"])
self.errors.add(:userid, "already exists")
return false
end
end
... I think that you could also remove totally the super call. Not sure, but you could test it out.

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