Class: Priloo::Preloaders::BmInjectorPreloader

Inherits:
BasePreloader show all
Defined in:
lib/priloo/preloaders/bm_injector_preloader.rb

Overview

This class implements preloading for Bannerman’s custom ActiveRecord injectors

Instance Attribute Summary collapse

Attributes inherited from BasePreloader

#merge_key

Instance Method Summary collapse

Methods inherited from BasePreloader

#dependencies, #multiplicity

Constructor Details

#initialize(ar_class, name) ⇒ BmInjectorPreloader

Returns a new instance of BmInjectorPreloader.



9
10
11
12
13
14
 
# File 'lib/priloo/preloaders/bm_injector_preloader.rb', line 9

def initialize(ar_class, name)
    super([self.class, ar_class, name])

    @name = name
    @ar_class = ar_class
end

Instance Attribute Details

#ar_class ⇒ Object (readonly)

Returns the value of attribute ar_class.



7
8
9
 
# File 'lib/priloo/preloaders/bm_injector_preloader.rb', line 7

def ar_class
  @ar_class
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



7
8
9
 
# File 'lib/priloo/preloaders/bm_injector_preloader.rb', line 7

def name
  @name
end

Instance Method Details

#extract(target) ⇒ Object 



36
37
38
 
# File 'lib/priloo/preloaders/bm_injector_preloader.rb', line 36

def extract(target)
    target.instance_variable_get(:@attributes).[](name).value
end

#inject(target, value) ⇒ Object 



28
29
30
 
# File 'lib/priloo/preloaders/bm_injector_preloader.rb', line 28

def inject(target, value)
    target._preloadable_target.send(:write_attribute_without_type_cast, name, value)
end

#injected?(target) ⇒ Boolean

Returns:

  • (Boolean) 


32
33
34
 
# File 'lib/priloo/preloaders/bm_injector_preloader.rb', line 32

def injected?(target)
    target.has_attribute?(name)
end

#preload(ar_list) ⇒ Object 



16
17
18
19
20
21
22
23
24
25
26
 
# File 'lib/priloo/preloaders/bm_injector_preloader.rb', line 16

def preload(ar_list)
    ids = ar_list.map { |ar| ar.send(primary_key) }
    injector_sql = ar_class.send("#{name}_sql")
    sql_query = Arel.sql <<~SQL
        #{quote_table_column(ar_class.table_name, primary_key)} AS id,
        (#{injector_sql}) AS val
    SQL

    fetched_data = ar_class.where(primary_key => ids.uniq).pluck(sql_query).to_h
    ar_list.map { |ar| fetched_data[ar.send(primary_key)] }
end