Rails - Combining Variables and Saving them in the Controller - ruby-on-rails

I have a "Word" model that has 3 string variables: "word_a" , "word_b" , "word_ab".
A form in my view collects the values for "word_a" and "word_b":
<%= f.text_field :word_a %>
<%= f.text_field :word_b %>
What is the best way to save the value for "word_ab" which will be made automatically from a combo of "word_a" and "word_b"?
The way Im doing it now seems really really wrong. After submitting the first form, I have the controller redirect to another edit page with a 'word_ab' form that has a value that combines 'word_a' and 'word_b'.
<%= f.text_field :word_ab, :value => #word.word_a+"_"+#word.word_b %>
The user then has to resubmit the form to save 'word_ab' into the database. Can't I do this is a controller?

Are you sure you want to save concated value to db? What about editing?
If you still want to do it - best idea is to add attr_accessor in model
attr_accessible :word_a, :word_b
attr_accessor :word_a, :word_b
First line allows yo perform mass assign, second one creates setter and getter methods.
Then, still in a model do
before_validation(:on => :create) do
self.word_ab = word_a + word_b
end
You may perform this on before_save as well, and you may validate word_a and word_b separately with regular validators.
Pro tip: create getter method that returns concated string
def word_ab
self.word_a + self.word_b
end
Associated models
class User
has_one :profile_picture
def word_ab
self.profile_picture.url + self.word_a + self.word_b
end
end

Related

ActiveAdmin passing variable in controller

I have a permit and vehicle model. I am trying to update the AA create controller to work how I have it in my rails app. That is taking the vehicle license_number entered and inputting it into the permit table, then also taking the inputted permit_id and inputting it into the permits attribute of the vehicle it is related to in the vehicle table.
admin/permit.rb
permit_params :permit_id, :vehicle, :date_issued, :issued_by, :date_entered, :entered_by
form do |f|
f.inputs do
f.input :permit_id
f.input :vehicle, :collection => Vehicle.all.map{ |vehicle| [vehicle.license_number]}
f.input :date_issued, as: :date_picker
f.input :issued_by
end
f.actions
end
controller do
def new
#permit = Permit.new
#vehicle = #permit.build_vehicle
#vehicle = Vehicle.all
super
end
def create
vehicle = Vehicle.find_by(license_number: permit_params[:vehicle_attributes][:license_number])
#permit = current_user.permit.build(permit_params.merge(date_entered: Date.today,
entered_by: current_user_admin.email))
super
end
end
My errors that I am getting, is that it is inputting the license_number in for the permit_id and then it is also saying the permit_params is not a defined variable. Any help would be great, thanks!
You have an interesting case here: it is confusing because you have a model called Permit, and usually in Rails you name the params method something like permit_params. Turns out, permit_params is the general method signature for ActiveRecord to implement strong params: https://activeadmin.info/2-resource-customization.html
With that, instead of calling permit_params in your create action, you need to call permitted_params[:vehicle_attributes][:license_number]. That’s why it’s considering permit_params as an undefined variable. Again, those two method signatures will be the same for all your ActiveAdmin forms.
Additionally, I’m not sure if this is a typo but you define #vehicle twice in your new method. I’m not sure you need to build a vehicle for the permit form unless you’re doing nested forms. Either way, I think the last line should read #vehicles = Vehicle.all Then you can use that in your form, which also could use an update in the collection part of your form field:
form do |f|
f.inputs do
f.input :permit_id
f.input :vehicle, collection: #vehicles.map { |vehicle| [vehicle.license_number, vehicle.id] }
f.input :date_issued, as: :date_picker
f.input :issued_by
end
f.actions
end
The collection_select form tag will take the first item in the array as the value that appears in the form, and the second value will be the value passed through in the params (https://apidock.com/rails/ActionView/Helpers/FormOptionsHelper/collection_select).
Then in your create action, you can find the Vehicle with the id:
Vehicle.find(permitted_params[:vehicle_attributes][:vehicle_id])
I would avoid Permit as a model name, try using VehiclePermit.

getter not getting values for new record on validation rails 4

I have a form_for for creating a new record. I have set getter and setter methods to access form field in my view. Below are my getter ans setter methods with my form view,
Getter & Setter Methods respectively :
def manufacturer_model_name
self.manufacturer_models.pluck(:name).join(', ') unless self.manufacturer_models.blank?
end
def manufacturer_model_name=(names)
names = names.split(',').map{|n| n.strip}.delete_if(&:empty?) if names.present?
names.uniq.each do |name|
id = ManufacturerModel.where(:name => name, :manufacturer_id => manufacturer.id).first_or_create.id
if self.new_record?
self.user_skill_manufacturer_models.build(:user_skill_id => self.id, :manufacturer_model_id => id)
else
self.user_skill_manufacturer_models.where(:user_skill_id => self.id, :manufacturer_model_id => id).first_or_create.id
end
end if names.present?
end
Form View:
= f.text_field :manufacturer_model_name, :class => 'form-control
My problem is that, my input field is autocomplete with multiple set to true, to get multiple values. when user enters multiple comma separated values and submits form and if there are any errors on the form, my new action is rendered and user losts all the entered values forcing him to reenter all again. How can I solve this problem?
It would be better to make a manufacturer_model_name_form field or some such via attr_accessor, and then parse that in validate. It would look something like this:
class ManufacturerModel < ActiveRecord::Base
attr_accessor :manufacturer_model_name_form
validate :validate_manufacturer_model_name
def validate_manufacturer_model_name
errors.add(:manufacturer_model_name, 'not a valid manufacturer model name') if !!true # perform your validation here in place of `!!true`
end
end
Then, in your form, you would use manufacturer_model_name_form instead of manufacturer_model_name:
= f.text_field :manufacturer_model_name_form, :class => 'form-control'

Accept Rails model attribute only if it was previously blank

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

Validating field's presence fails even though the field is not blank

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.

How can I format the value shown in a Rails edit field?

I would like to make editing form fields as user-friendly as possible. For example, for numeric values, I would like the field to be displayed with commas (like number_with_precision).
This is easy enough on the display side, but what about editing? Is there a good way to do this?
I am using the Rails FormBuilder. Upon investigation, I found that it uses InstanceTag, which gets the values for fields by using <attribute>_value_before_type_cast which means overriding <attribute> won't get called.
The best I have come up with so far is something like this:
<%= f.text_field :my_attribute, :value => number_with_precision(f.object.my_attribute) %>
Or my_attribute could return the formatted value, like this:
def my_attribute
ApplicationController.helpers.number_with_precision(read_attribute(:my_attribute))
end
But you still have to use :value
<%= f.text_field :my_attribute, :value => f.object.my_attribute %>
This seems like a lot of work.
I prefer your first answer, with the formatting being done in the view. However, if you want to perform the formatting in the model, you can use wrapper methods for the getter and setter, and avoid having to use the :value option entirely.
You'd end up with something like this.
def my_attribute_string
foo_formatter(myattribute)
end
def my_attribute_string=(s)
# Parse "s" or do whatever you need to with it, then set your real attribute.
end
<%= f.text_field :my_attribute_string %>
Railscasts covered this with a Time object in a text_field in episode #32. The really clever part of this is how they handle validation errors. It's worth watching the episode for that alone.
This is an old question, but in case anyone comes across this you could use the number_to_X helpers. They have all of the attributes you could ever want for displaying your edit value:
<%= f.text_field :my_number, :value => number_to_human(f.object.my_number, :separator => '', :unit => '', :delimiter => '', :precision => 0) %>
There are more attributes available too: http://api.rubyonrails.org/classes/ActionView/Helpers/NumberHelper.html
If you want a format to be created or maintained during editing, you will need to add Javascript to implement "masks." Here is a demo.
It was the first hit in these results.
You can use the number_format plugin. By specifying a number_format for an existing numeric attribute inside your model, the attribute will now appear as formatted to Rails in all forms and views. It will also be parsed back from that format (when assigned via forms) prior to insertion into the database. (The plugin also creates purely numeric unformatted_<attribute-name> accessors which can continue to be used for arithmetic, or for direct numerical assignment or retrieval by you for seamless integration.)
class MyModel < ActiveRecord::Base
# this model has the balance attribute, which we
# want to display using formatting in views,
# although it is stored as a numeric in the database
number_format :balance,
:precision => 2,
:delimiter => ',',
:strip_trailing_zeros => false
def increment_balance
unformatted_balance += 10
end
You can also combine the above with a Javascript solution, which can force the user to maintain the decimal point and thousands separators in place while editing, although this is really not necessary.
I have done something similar. We format times and lengths using a custom form builder. It makes use of the existing text_field, but wraps it so the value can be customized:
class SuperFormBuilder < ActionView::Helpers::FormBuilder
include ApplicationHelper
include FormHelper
include ActionView::Helpers::TagHelper
include ActionView::Helpers::FormTagHelper
def length_field(label,*args)
scale = 'medium'
args.each do |v|
if v.has_key?(:scale)
scale = v[:scale]
v.delete(:scale)
end
end
value = length_conversion(#object.send(label.to_sym),scale)
options = (args.length > 0) ? args.pop : {}
return has_error(label, text_field_tag(field_name(label),value,*args) + ' ' + length_unit(scale))
end
private
def field_name(label)
return #object_name + "[#{label}]"
end
def has_error(label, output)
return "<div class='fieldWithErrors'>#{output}</div>" if #object.errors[label]
return output
end
And it is used like this:
<%= form_for( #section, {:action => 'save', :id => #section.id}, :builder => SuperFormBuilder) do |sf| %>
<%= sf.length_field :feed_size_min_w, :size => 3, :scale => 'small' %>
<% end %>
The end result is a value in the appropriate unit based off their choice on system (Metric, Imperial) and scale IE small = inches or millimeters.
I basically copied the text_field method from the existing form builder, which uses the text_field_tag itself.
There are two gotchas: 1) Knowing the name of the object field and how to access the object to get the value which you want to format. 2) Getting the name right so when the form is submitted it is part of the correct params hash.
The form builder is given a class variable #object. You can get the value of the field using the .send method. In my case I send the label :feed_size_min_w to the #object and get its length back. I then convert it to my desired format, and give it to the text_field_tag.
The name of the field is key to having it end up in the params hash, in my instance the params[:sections] one. I made a little helper function called field_name that takes care of this.
Finally the has_error wraps the field in an error div if there are errors on that label.
I needed "nicer" format on some specified text fields, resolved it by adding this to my initializers. Seems to work nicely on Rails ~= 5.2 and it should be easy to customize.
class ActionView::Helpers::Tags::TextField
private
def value_before_type_cast # override method in ActionView::Helpers::Tags::Base
v = super
# format as you like, when you like
if #options.delete(:nice_decimal)
v = v.to_s.gsub('.', ',') if v.is_a?(BigDecimal)
end
v
end
end
Usage in form f
<%= f.text_field :foo, nice_decimal: true %>

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