Class: ForestAdminDatasourceMongoid::Utils::Pipeline::LookupGenerator

Inherits:
Object
  • Object
show all
Includes:
Schema
Defined in:
lib/forest_admin_datasource_mongoid/utils/pipeline/lookup_generator.rb

Class Method Summary collapse

Class Method Details

.add_fields(name, projection, options) ⇒ Object 



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# File 'lib/forest_admin_datasource_mongoid/utils/pipeline/lookup_generator.rb', line 34

def self.add_fields(name, projection, options)
  return {} if options[:include] && !options[:include].include?(name)
  return {} if options[:exclude]&.include?(name)

  projection.filter { |field| field.include?('@@@') }
            .map { |field_name| "#{name}.#{field_name.tr(":", ".")}" }
            .each_with_object({}) do |curr, acc|
              acc[curr] = "$#{curr.gsub("@@@", ".")}"
            end
end

.lookup(model, stack, projection, options) ⇒ Object

Transform a forest admin projection into a mongo pipeline that performs the lookups and transformations to target them



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# File 'lib/forest_admin_datasource_mongoid/utils/pipeline/lookup_generator.rb', line 9

def self.lookup(model, stack, projection, options)
  schema_stack = stack.each_with_index.reduce([MongoidSchema.from_model(model)]) do |acc, (_, index)|
    [
      *acc,
      MongoidSchema.from_model(model).apply_stack(stack.slice(0..(index + 1)), skip_as_models: true)
    ]
  end

  lookup_projection(nil, schema_stack.map(&:fields), projection, options)
end

.lookup_projection(current_path, schema_stack, projection, options) ⇒ Object 



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# File 'lib/forest_admin_datasource_mongoid/utils/pipeline/lookup_generator.rb', line 20

def self.lookup_projection(current_path, schema_stack, projection, options)
  pipeline = []
  fields = {}
  projection.relations.each do |name, relation_projection|
    pipeline.push(*lookup_relation(current_path, schema_stack, name, relation_projection, options))
    # pipeline = [*pipeline, *lookup_relation(current_path, schema_stack, name, relation_projection, options)]
    fields.merge!(add_fields(name, relation_projection, options))
  end

  pipeline.push({ '$addFields' => fields }) unless fields.empty?

  pipeline
end

.lookup_relation(current_path, schema_stack, name, projection, options) ⇒ Object

Raises:

  • (ForestAdminDatasourceToolkit::Exceptions::ForestException) 


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# File 'lib/forest_admin_datasource_mongoid/utils/pipeline/lookup_generator.rb', line 45

def self.lookup_relation(current_path, schema_stack, name, projection, options)
  models = ObjectSpace
           .each_object(Class)
           .select { |klass| klass < Mongoid::Document && klass.name && !klass.name.start_with?('Mongoid::') }
           .to_h { |klass| [klass.name, klass] }

  as = current_path ? "#{current_path}.#{name}" : name

  last_schema = schema_stack[schema_stack.length - 1]
  previous_schema = schema_stack.slice(0..(schema_stack.length - 1))

  return {} if options[:include] && !options[:include].include?(as)
  return {} if options[:exclude]&.include?(as)

  # Native many to one relation
  identifier = '__many_to_one'
  if name.end_with?(identifier)
    foreign_key_name = name[0..(name.length - identifier.length - 1)]
    model = models[last_schema[foreign_key_name].options[:association].class_name]

    from = model.name.gsub('::', '__')
    local_field = current_path ? "#{current_path}.#{foreign_key_name}" : foreign_key_name
    foreign_field = '_id'
    sub_schema = MongoidSchema.from_model(model).fields

    return [
      # Push lookup to pipeline
      {
        '$lookup' => { 'from' => from, 'localField' => local_field, 'foreignField' => foreign_field,
                       'as' => as }
      },
      { '$unwind' => { 'path' => "$#{as}", 'preserveNullAndEmptyArrays' => true } },

      # Recurse to get relations of relations
      *lookup_projection(as, [*schema_stack, sub_schema], projection, options)
    ]
  end

  # inverse of fake relation
  if name == 'parent' && !previous_schema.empty?
    return lookup_projection(as, previous_schema, projection, options)
  end

  # fake relation
  return lookup_projection(as, [*schema_stack, last_schema[name]], projection, options) if last_schema[name]

  # We should have handled all possible cases.
  raise ForestAdminDatasourceToolkit::Exceptions::ForestException, "Unexpected relation: '#{name}'"
end