Rails validating with two models - ruby-on-rails

Question

Ok, bit confused on how to solve this issue.
I have one form and two models. Here is my form:
<% if #booking.errors.any? %>
<% #booking.errors.full_messages.each do |msg| %>
<p class="error"><%= msg %></p>
<% end %>
<% end %>
<% if #guest.errors.any? %>
<% #guest.errors.full_messages.each do |msg| %>
<p class="error"><%= msg %></p>
<% end %>
<% end %>
<%= form_for :booking, url: bookings_path do |f| %>
<%= label_tag :email, "Guest's Email Address" %>
<%= text_field_tag :email %>
<%= f.label :nights, "Nights" %>
<%= f.text_field :nights %>
<%= f.label :nights, "People" %>
<%= f.text_field :people %>
<%= f.label :nights, "Arrival Date" %>
<%= f.text_field :arrival %>
<% end %>
As you can see, the email field isn't part of the form builder. The email address will be used to create a new Guest record if the email doesn't already exist. Once I have the ID of the guest then the booking record can be made also.
Here is the code for create action in my BookingController - where the form is submitted to...
...
def create
accommodation = current_user.accommodation
guest = Guest.find_or_create_by(:email => params[:email])
#booking = accommodation.bookings.new(post_params.merge(:guest_id => guest.id))
if #booking.save
flash[:success] = 'The booking has been added successfully.'
redirect_to :controller => 'bookings', :action => 'index'
else
render 'new'
end
end
...
I do realise this question isn't new but I can't find a good solution anywhere to my problem - I want to be able to set the form up properly (if necessary) and validate all fields using the two models. Then I need to display the error messages. At the moment, my email is ignored during validation and I'm not sure what to do next.
Any help much appreciated.

Answer 1

It seems to me that the easiest way to is to validate the email in the controller itself and add any validation error to the booking variable. Something like this:
def create
accommodation = current_user.accommodation
guest = Guest.find_or_create_by(:email => params[:email])
#booking = accommodation.bookings.new(post_params.merge(:guest_id => guest.id))
if #booking.save
flash[:success] = 'The booking has been added successfully.'
redirect_to :controller => 'bookings', :action => 'index'
else
<% if params[:email].blank> %>
#booking.errors.add(:email, "can't be blank.")
<% end %>
#You can do the same thing for whatever other validation errors you have
render 'new'
end
end
Note: I did not test the code
This is probably not the best way possible but it gets the job done and is easy. You could use accept_nested_attributes_for but it seems to me a little bit unnecessary considering that you are only validating an email. Nevertheless, if you want to do it the cleanest way, stick with accept_nested_attributes_for.
EDIT
Actually, your code is the right track. You just made a syntax error. The real reason your guests errors are not being shown is that you used a local variable instead of a instance variable. Try this:
#guest = Guest.find_or_create_by(:email => params[:email])
Your error messages should be displayed with the code you already have
<% if #guest.errors.any? %>
<% #guest.errors.full_messages.each do |msg| %>
<p class="error"><%= msg %></p>
<% end %>
<% end %>
EDIT 2
In order to avoid a booking instance from beings saved in case the guest email is invalid you can do something like this:
if !#guest.errors.any? && #booking.save
flash[:success] = 'The booking has been added successfully.'
redirect_to :controller => 'bookings', :action => 'index'
else
Therefore, if the guest has any errors, the if statement will terminate before the #booking.save statement is executed.

Answer 2

You can try to do a transaction. If one of them is invalid, rails will do a rollback and you can render the errors.
Follow this question code, see if it helps.