Rails relationships that is
I am doing something wrong, and can’t figure out what and where.
I have 3 models - Command, Contact, and a joined CommandsContact via has_many through relationship, because commands_contacts table holds an extra column - notification_type, which could be either set to host of *service. *
**Models **
contact.rb
This one is a special case, because it has 2 extra “virtual” relationships**:host_notification_commands and :service_notification_commands, which gives me an ability to selectively get either host or service commands for a user (contact) like this:
Contact.first.host_notification_commands or
Contact.find(3).service_notification_commands etc.
class Contact < ActiveRecord::Base
has_many :commands_contacts, :inverse_of => : contact
has_many :commands, :through => :
commands_contacts
has_many :host_notification_commands, -> { where commands_contacts: { :notification_type => 'host' } },
:through => :commands_contacts,
:class_name => 'Command',
:source => :
command
has_many :service_notification_commands, -> { where commands_contacts: { notification_type: 'service' } },
:through => :commands_contacts,
:class_name => 'Command',
:source => :
command
accepts_nested_attributes_for : host_notification_commands
accepts_nested_attributes_for :
service_notification_commands
end
command.rb
class Command < ActiveRecord::Base
has_many :commands_contacts, :inverse_of => :command
has_many :contacts, :through => :
commands_contacts
accepts_nested_attributes_for :
commands_contacts
end
commands_contracts.rb
class CommandsContact < ActiveRecord::Base
belongs_to : command
belongs_to :
contact
accepts_nested_attributes_for : command
accepts_nested_attributes_for :
contact
end
So far. So good. This works as expected (i think?) as I am able to manually create relationships, as long as i have a contact and a command already.
contact = Contact.first
command = Command.find(7)
contact.host_notification_commands << command
Aaand after this things start to go down south, because a Controller, strong_parameters and accepts_nested_attributes_for come into play, and this is where I fail.
My assumption is that Rails will be able to handle this for me and establish the relationship, right?
def create
contact = Contact.new safe_params
contact.save
end
Because I use accepts_nested_attributes_for, I have to append _attributes to the names of nested objects, right? So i do a simple re-assignment here and then permit them with strong_parameters.
private
def safe_params
params[:contact][:host_notification_commands_attributes] = params[:contact][:host_notification_commands]
params[:contact][:service_notification_commands_attributes] = params[:contact][:service_notification_commands]
params.require(:contact)
.permit(:contact_name,
:host_notification_commands_attributes => [ :id, :command_name, :command_line, :command_description ],
:service_notification_commands_attributes => [ :id, :command_name, :command_line, :command_description ])
As far as I understand, this is all that needs to be done and Rails should handle the rest, right? The problem is that it does not even try to to establish a relationship. It does a SELECT and immediately fails.
When I try to create a new record, it fails with:
ActiveRecord::RecordNotFound (Couldn’t find Command with ID=1 for Contact with ID=):
Because it hasn’t yet created a user a hasn’t established a relationship.
When I try to edit and existing contact and establish a relationship with existing command, it fails with
(0.1ms) BEGIN
Command Load (0.2ms) SELECT commands.* FROM commands INNER JOIN commands_contacts ON commands.id = commands_contacts.command_id WHERE commands_contacts.contact_id = 3 AND commands_contacts.notification_type = ‘host’ AND commands.id = 1
(0.1ms) ROLLBACK
Completed 404 Not Found in 6ms
ActiveRecord::RecordNotFound (Couldn’t find Command with ID=1 for Contact with ID=3):
Uhm… Of course this relationship record is not found. I am trying to create it! Why does it run SELECT instead of UPDATE / INSERT ?
So, something tells me I have this relationship defined incorrectly somewhere in my models… but where? How do i troubleshoot this?