Say I have two fields in a new or edit form:
<%= f.text_field :email %>
<%= f.text_field :parent_email %>
How, in my model, can I validate that parent_email is different from email? The exclusion option seems like it might work, but I can't figure out how to access the email field's value within the model. Do I need to implement this in the controller instead?
validates :parent_email, exclusion: self.email # doesn't work, nor does :email
The following should work (but I guess there are cooler solutions out there):
class User
validate :email_differs_from_parent_email
private
def email_differs_from_parent_email
if email == parent_email
errors.add(:parent_email, "parent_email must differ from email")
end
end
end
Related
I have a form and I have made some inputs required. After submitting the form that value will be sent to an API. I know that the validations are put into model file but since I do not have a database, how can I use the rails validation?
Right now I am validating the code inside a controller using if else.
if !params[:groups][:name].blank? && !params[:groups][:make].blank? && !params[:groups][:model].blank? && !params[:groups][:firmware].blank?
This does the work but it is not very elegant.
Take a look at ActiveModel, it lets you do "model things" without the database. There were some limitations that made me not use it in the end (I think related to associations) but for simple stuff it's great (and it's a part of how ActiveRecord works.
Example code from docs
class Person
include ActiveModel::Model
attr_accessor :name, :age
validates :name, :age, presence: true
end
this is easy. On the form input fields that you NEED, add required: true For example:
<%= form.for #something do |f| %>
<%= f.text_field :title, placeholder: 'Title', required: true %>
<% end %>
The user gets an error if the required fields are not filled out correctlty.
Is this what you mean?
Justin
EDIT
I guess I would look at using the gem
client_side_validations
Let us know how you go
First question: how to validate a model relation and mark it in form when validation failed.
I have a subject model:
class Subject < ActiveRecord::Base
belongs_to :semester
validates_presence_of :semester
end
In my view (form):
<%= select_tag :semester, options_from_collection_for_select(#semesters,"id","name") %>
The validates_presence_of works fine. But when the validation fails (user forgot to enter semester ). The semester input is not marked in red.
Second question: how to validate an input field.
In my view, I also have a university input field, but model subject has no relationship with university, no field university in subject table. So how to validate it and mark it in red.
Thanks in advance.
If you want to get the fields with error displayed in red "out of the box", you must use a form builder. The code will looks like f.select ... instead of using select_tag.
With the form builder, the fields with errors are created inside a <div class="field_with_errors">...</div>. The css file generated by scaffolding displays these fields in red; if you're not using it, you must add the css rules to your css.
# app/models/subject.rb
class Subject < ActiveRecord::Base
belongs_to :semester
validates :semester, :university, presence: true # new syntax http://api.rubyonrails.org/classes/ActiveModel/Validations/ClassMethods.html#method-i-validates
end
# app/views/subjects/_form.html.erb
<%= form_for #subject do |f| %>
Semestr: <%= f.collection_select :semester_id, Semestr.all, :id, :name, prompt: true %>
University: <%= f.text_field :univercity %>
<% end %>
For more information about building forms in rails (with validations enabled) you could find there http://api.rubyonrails.org/classes/ActionView/Helpers/FormBuilder.html
Those "red errors" that you hope for are probably coming from a form helper gem like formtastic, feel free to check that out.
I have literally no idea what your second question is asking, but if you're looking for a custom validation. Check out the rails docs on them for help.
If you'd like more help, (please) edit your question to be more clear (thanks)
I have a Rails model (persisted with Mongoid) that can be collaboratively edited by any registered user. However, I want to allow editing any particular attribute only if it was previously blank or nil.
For example, say someone created an object, and set its title attribute to "Test Product". Then another user comes along and wants to add a value for price, which until now has been nil.
What's the best way to do this, while locking an attribute that has previously been entered?
Look into the ActiveRecord::Dirty module for some nice utility methods you can use to do something like this:
NON_UPDATABLE_ATTRIBUTES = [:name, :title, :price]
before_validation :check_for_previously_set_attributes
private
def check_for_previously_set_attributes
NON_UPDATABLE_ATTRIBUTES.each do |att|
att = att.to_s
# changes[att] will be an array of [prev_value, new_value] if the attribute has been changed
errors.add(att, "cannot be updated because it has previously been set") if changes[att] && changes[att].first.present?
end
end
The easiest way, i think, is by checking for it in the form itself.
Just say add :disabled => true to the input field if the person cannot edit it.
<% if #my_object.name %>
<%= f.text_field :name, :disabled => true %>
<% else %>
<%= f.text_field :name, :disabled => true %>
<% end %>
(i think there is a prettier way to write this code)
But by using this the user has a visual feed back that he can't do something, it is always better to not allor something than to give an error message
I'm trying to fill out an array with values from checkboxes. It works just fine when creating a record, but fails validation when editing. The params look right, which is what really confuses me:
"record"=>{... "type_array"=>["accounting"], ...}
It looks the same as the params from creating a new record. The fields in New.html.erb and Edit.html.erb also use the same markup.
Edit.html.erb
<div class="field">
<%= f.label :type_array, "What type of record?" %><br />
<% ["accounting", "agriculture", "automotive"].each do |type| %>
<%= check_box_tag 'record[type_array][]', type, (true if #record.type_list.include? type),
:id => type %>
<%= label_tag type, type.titleize, :class => type %><br />
<% end %>
</div>
Parts of Record.rb
validates :type_array, :presence => true
attr_accessor :type_array
attr_accessible :type_array
before_validation :set_type_list
private
def set_type_list
self.type_list = type_array.join ',' if type_array.present?
end
Am I missing something? When I remove the type_array validation and fill out the form, it acts like type_array is empty. Somewhere along the line, it must be lost or something.
I appreciate any help.
(Sidenote: if anyone has a better way to do the list of checkboxes, let me know)
Delete the line attr_accessor :type_array.
This creates accessor methods to a new instance variable, not to the model attribute type_array, which means that #record.type_array now refers to that instance variable instead of the attribute.
You almost never use attr_accessor or it's siblings attr_reader and attr_writer in Rails because you want to deal with model attributes, not instance variables.
Edit: You're using type_array as a virtual attribute.
class Record < ActiveRecord::Base
validates :type_array, :presence => true
attr_accessible :type_array
def type_array=(val)
self.type_list = val.join ','
end
def type_array
self.type_list.split ','
end
def type_array_before_type_cast
type_array
end
end
For the reason why you need that last function definition, see this question.
I was just wondering: How can i make an attribute "write once" ?
To be more precise, I'm using Devise and I want the user to be able to register with this email but then, once it's done, I want this email locked.
I read that forms can easily be bypass, so I want to make sure my model does that.
Also, i'm using in one of my form that: <%= f.email_field :email, :id => "email", :disabled => "disabled" %>
Is there any risks that an user can modify his email after being registered?
Thanks for your answers!
attr_readonly allows setting a value at creation time, then prevents modifying it on updates.
class MyModel < ActiveRecord::Base
attr_readonly :email
end