从Rails引擎模型继承时的关联问题

Question

I have a shared engine that I keep shared AR models and bunch of other stuff. Below is my User AR model

module Shared
  class User < ApplicationRecord
    validates_presence_of :password, on: :create
    # validates_uniqueness_of :email
    # validates_uniqueness_of :phone_number

    has_many :apps
  end
end

And I have a child User in the main rails app ( Analytics ) as follows:

class User < Shared::User
  self.table_name = 'users'
end

When I mount this engine to a rails app, I dynamically find the "correct" ( Analytics::User ) using below method:

def model_const(const)
  # shell_app is set to 'Analytics' somewhere else
  shell_app.constantize.const_get const
rescue
  Shared.const_get const
end

With above, I can insert, find records in the database, but problems start when I use associations and AR validators (above validates_uniqueness_of calls for instance)

user = model_const('User').create ... # works, returns a Analytics::User instance
user.apps # fails with below error

(Same error if I un-comment validators in the Shared::User model and try to create a new record)

ActiveRecord::StatementInvalid (PG::UndefinedTable: ERROR:  relation "shared_apps" does not exist
LINE 8:                WHERE a.attrelid = '"shared_apps"'::regclas...
                                      ^
:               SELECT a.attname, format_type(a.atttypid, a.atttypmod),
                 pg_get_expr(d.adbin, d.adrelid), a.attnotnull,     a.atttypid, a.atttypmod,
         (SELECT c.collname FROM pg_collation c, pg_type t
           WHERE c.oid = a.attcollation AND t.oid = a.atttypid AND a.attcollation <> t.typcollation),
                 col_description(a.attrelid, a.attnum) AS comment
            FROM pg_attribute a LEFT JOIN pg_attrdef d
              ON a.attrelid = d.adrelid AND a.attnum = d.adnum
           WHERE a.attrelid = '"shared_apps"'::regclass
             AND a.attnum > 0 AND NOT a.attisdropped
           ORDER BY a.attnum
):

Also, please note that I'm creating and trying to access apps in the shared engine code, not sure if that matters.

Thanks in advance!

Answer 1

After spending a good couple of hours, here is the solution that I came up with. (This is actually what I should have done in the first place, so blame me )

1. Nest outer User class inside Analytics module:

   module Analytics class User.... end end

2. add this to the lib/shared.rb file :

   def self.table_name_prefix end

Hope this could be helpful to someone else..