module PolymorphicJoin::ClassMethods
Public Instance Methods
query_ref_polymorphic(type, refs)
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# File lib/polymorphic_join.rb, line 13 def query_ref_polymorphic(type, refs) polymorphic = if refs.nil? { refs: retrieve_all_polymorphic_types(type), map_columns: {} } else process_input_refs(refs) end columns = polymorphic[:refs] .first .to_s .classify .constantize .column_names polymorphic[:refs].each do |p| columns &= p.to_s.classify.constantize.column_names end polymorphic[:map_columns].values.each do |value| columns += value.values end columns.uniq! selectable_columns = {} types = type.to_s.pluralize polymorphic[:refs].each do |p| map_columns = polymorphic[:map_columns][p] || {} selectable_columns[p] = [] p.to_s.classify.constantize.column_names.each do |column_name| if (alias_name = map_columns[column_name.to_sym]).present? selectable_columns[p] << "#{types}.#{column_name} AS #{alias_name}" elsif columns.index(column_name) selectable_columns[p] << "#{types}.#{column_name}" end end end table = arel_table joins_statements = polymorphic[:refs].map do |join_type| join_table = join_type.to_s.classify.constantize.arel_table.alias(types) arel_table .project(*(selectable_columns[join_type])) .join( join_table, Arel::Nodes::InnerJoin ) .on( table["#{type}_type".to_sym] .eq(join_type.to_s.classify) .and( table["#{type}_id".to_sym].eq(join_table[:id]) ) ) end polymorphic_union_scope( type, polymorphic[:refs], *joins_statements ) end
Protected Instance Methods
add_ref_polymorphic_scope()
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# File lib/polymorphic_join.rb, line 136 def add_ref_polymorphic_scope scope :ref_polymorphic, lambda { |type, refs = nil| query_ref_polymorphic(type, refs) } end
build_union(left, right)
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# File lib/polymorphic_join.rb, line 83 def build_union(left, right) if right.length > 1 Arel::Nodes::Union.new(left, build_union(right[0], right[1..-1])) else Arel::Nodes::Union.new(left, right[0]) end end
polymorphic_union_scope(type, refs, *scopes)
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# File lib/polymorphic_join.rb, line 91 def polymorphic_union_scope(type, refs, *scopes) union = scopes[0] t2 = arel_table union = build_union(scopes[0], scopes[1..-1]) if scopes.length > 1 types = type.to_s.pluralize t1 = arel_table.create_table_alias(union, types) from( t2.create_join( t1, t2.create_on( t1[:id].eq(t2["#{type}_id".to_sym]).and( t2["#{type}_type"].in( refs.collect { |x| x.to_s.singularize.classify } ) ) ) ) ).distinct end
process_input_refs(refs)
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# File lib/polymorphic_join.rb, line 118 def process_input_refs(refs) poly_refs = [] refs.each do |ref| poly_refs << (ref.is_a?(Symbol) ? ref : ref.keys.first) end { refs: poly_refs, map_columns: refs.each_with_object({}) do |el, hash| if el.is_a?(Symbol) hash[el] = {} else hash[el.keys.first] = el[el.keys.first] end end } end
retrieve_all_polymorphic_types(type)
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# File lib/polymorphic_join.rb, line 112 def retrieve_all_polymorphic_types(type) distinct.pluck("#{type}_type").collect do |x| x.underscore.tableize.to_sym end end