How to extract info from input field in ruby - ruby-on-rails

Question

I'm a frontend + PHP dev, trying to fix [] in a project built in Rails.
[] = Fetch color, show a slightly darker color.
This row:
<%= f.text_field attribute %>
creates an input field with a value that can be translated into a color. I'm at loss as to where to look for how it adds that value. I'm trying to use the value that this input field generates.
this is code from the file select_a_color_input.html.erb inside the app/views/shared folder. Any ideas on where to continue my treasure hunt? :)
update: I found this!
def app_text_field(attribute, args = {})
render_field 'text_field', field_locals(attribute, args)
end
Does that help? ^__^
update:
The form builder
class AppFormBuilder < ActionView::Helpers::FormBuilder
def form_fields(partial = nil , options = {})
partial ||= 'form'
fields = ''
unless options.delete(:without_error_messages)
fields << #template.render('shared/error_messages', :target => Array(#object).last)
end
fields << #template.render(partial, options.merge(:f => self))
end
def app_text_field(attribute, args = {})
render_field 'text_field', field_locals(attribute, args)
end
def app_file_field(attribute, args = {})
render_field 'file_field', field_locals(attribute, args)
end
private
def render_field(name, locals)
#template.render field_path(name), locals
end
def field_locals(attribute, args = {})
help_options = args[:help_options] || {}
field_options = args[:field_options] || {}
html_options = args[:html_options] || {}
{ :f => self, :attribute => attribute, :help_options => help_options, :field_options => field_options, :html_options => html_options, :object => object }
end
def field_path(value)
"shared/app_form/#{value}"
end
end
update:
When I tried to add
<%= content_tag(:p, attribute) %>
It does not give me the values, but instead the id/name of the item, not the colour.

Answer 1

<%= f.text_field attribute %>
This by itself is not very useful to help us gather context. What's the surrounding markup look like? attribute is a ruby variable in this instance. If it were f.text_field :attribute, then :attribute is now a symbol instead of a variable and this would indicate that it maps to the attribute method on X model. This all depends on what your form_for looks like though. I'll give an example:
<%= form_for #user do |f| %>
<%= f.text_field :attribute %>
In this case, we have a form for the User model, and our text_field maps to #user.attribute. The field itself looks something like this:
<input type='text' name='user[attribute]'>
And in the controller's #update or #create action (depending on if this is a new record or an existing record you're editing) the value would be accessible in this fashion:
params[:user][:attribute]
However, it's impossible to say what exactly the params will look like in your particular case. What action is being run? What's the name of the file that this is being loaded from? "app/views/users/new" would indicate the #new action handles this page, and the #create action will handle the form submission.
Things we need to know to fully solve your problem:
Name and relevant code of the controller that's handling this action.
Full view path that this is being rendered from
The rest of the markup starting at form_for and ending at this field attribute
What value does attribute hold? It's a variable, so it must be holding a symbol value or something that will indicate which field is being mapped to this input.