module Pluckers::Features::Base::BelongsToPolymorphicReflections
This module implements plucking belongs_to polymorphic relationships in a recursive way.
The options used in this feature are:
* reflections: A hash of the reflections we will pluck recursively. The key of this hash will be the name of the reflection and the value is another hash of options. In the case of a polymorphic relationship, this options will be a hash where you will set the plucking options for each different available model. Keys of the hash wil be names of the models and the values will be the regular options for a standard reflection: - scope: You can limit the scope of the objects plucked. E.g, you could use Author.active instead of Author.all. Notice that .all is the default. - plucker: You can use a custom plucker instead of Pluckers::Base in case you want any specific logic. Pluckers::Base is the default one. - Any other option will be passed to the plucker, so you can send any other regular option such as attributes, custom ones or even more reflections. Recursivity FTW!! (even in polymorphic relations)
Public Instance Methods
build_results()
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In this method we get the reflections and for each one creates and executes a new plucker.
This pluck gives the whole process a recursive character and options for that plucker may be passed in the options hash.
Calls superclass method
# File lib/pluckers/features/base/belongs_to_polymorphic_reflections.rb, line 92 def build_results super return if @belongs_to_polymorphic_reflections.blank? # For each reflection @belongs_to_polymorphic_reflections.each do |name, reflection| # As an example we will imagine that we are plucking BlogPosts and # this relation is the Subject # First, we get the meta information about the reflection klass_reflection = @klass_reflections[name] reflection_primary_key = klass_reflection.active_record_primary_key.to_sym reflection_foreign_key = klass_reflection.foreign_key.to_sym reflection_foreign_type = klass_reflection.foreign_type.to_sym # Now, we group all the already plucked _type and _id attributes, so # we can pluck the polymorphic models polymporphic_models = {} @results.each do |_, r| next if r[reflection_foreign_type].nil? || r[reflection_foreign_key].nil? polymporphic_models[r[reflection_foreign_type]] ||= [] polymporphic_models[r[reflection_foreign_type]] << r[reflection_foreign_key] end # Now we have a hash like { # "Category" => [1, 2, 3], "Author" => [4, 2, 8] # } # We initialize so we return a nil if there are no record related @results.each do |_,result| result[name] = nil end polymporphic_models.each do |model_name, model_ids| model_options = reflection[model_name.to_sym] # If there are no options for a model we don't pluck them next if model_options.nil? # initialize some options such as the plucker or the scope of the pluck scope = model_options[:scope] || model_name.constantize.send(all_method) plucker = model_options[:plucker] || Pluckers::Base # And now we create the plucker. Notice that we add a where to the # scope, so we filter the records to pluck as we only get those with # an id in the set of the foreign keys of the records already # plucked by the base plucker # # In our Example we would be doing something like # Author.all.where(id: author_ids) reflection_plucker = plucker.new scope.where( reflection_primary_key => model_ids ), model_options # And now pluck the related class and process the results reflection_plucker.pluck.each do |r| # For each related result (Author or Category) we search those # records (BlogPost) that are related (post.subject_id == # author.id o post.subject_id == category.id) and insert them in # the relationship attributes @results.each do |_,result| if result[reflection_foreign_key] == r[reflection_primary_key] && result[reflection_foreign_type] == model_name result[name] = r end end end end end end
configure_query()
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Here we obtain the belongs_to reflections to include in the pluck operation and also include the relation foreign key in the attributes to pluck for this model.
Calls superclass method
# File lib/pluckers/features/base/belongs_to_polymorphic_reflections.rb, line 47 def configure_query super pluck_reflections = @options[:reflections] || {} return if pluck_reflections.blank? @belongs_to_polymorphic_reflections = { } # We iterate through the class reflections passed as options @klass_reflections.slice(*pluck_reflections.keys). # And select those that are BelongsTo select{|_, r| active_record_belongs_to_polymorphic_reflection?(r) }. # And store them in the belongs_to_reflection hash that will be used later each do |name, reflection| name = name.to_sym @belongs_to_polymorphic_reflections[name] = pluck_reflections[name] end # First thing we do is to include the foreign key in the attributes to # pluck array, so the base plucker plucks them @belongs_to_polymorphic_reflections.each do |name, _| foreign_key_name = @klass_reflections[name].foreign_key @attributes_to_pluck << { name: foreign_key_name.to_sym, sql: foreign_key_name } foreign_type = @klass_reflections[name].foreign_type @attributes_to_pluck << { name: foreign_type.to_sym, sql: foreign_type } end end