Module: Mongoid::Matcher Private

Defined in:
lib/mongoid/matcher.rb,
lib/mongoid/matcher/eq.rb,
lib/mongoid/matcher/gt.rb,
lib/mongoid/matcher/in.rb,
lib/mongoid/matcher/lt.rb,
lib/mongoid/matcher/ne.rb,
lib/mongoid/matcher/or.rb,
lib/mongoid/matcher/all.rb,
lib/mongoid/matcher/and.rb,
lib/mongoid/matcher/gte.rb,
lib/mongoid/matcher/lte.rb,
lib/mongoid/matcher/nin.rb,
lib/mongoid/matcher/nor.rb,
lib/mongoid/matcher/not.rb,
lib/mongoid/matcher/size.rb,
lib/mongoid/matcher/regex.rb,
lib/mongoid/matcher/exists.rb,
lib/mongoid/matcher/eq_impl.rb,
lib/mongoid/matcher/elem_match.rb,
lib/mongoid/matcher/expression.rb,
lib/mongoid/matcher/field_operator.rb,
lib/mongoid/matcher/field_expression.rb,
lib/mongoid/matcher/eq_impl_with_regexp.rb,
lib/mongoid/matcher/expression_operator.rb,
lib/mongoid/matcher/elem_match_expression.rb

This module is part of a private API. You should avoid using this module if possible, as it may be removed or be changed in the future.

Defined Under Namespace

Modules: All, And, ElemMatch, ElemMatchExpression, Eq, EqImpl, EqImplWithRegexp, Exists, Expression, ExpressionOperator, FieldExpression, FieldOperator, Gt, Gte, In, Lt, Lte, Ne, Nin, Nor, Not, Or, Regex, Size

Class Method Summary collapse

Class Method Details

.extract_attribute(document, key) ⇒ Array<true | false, Object | Array, true | false>

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Extracts field values in the document at the specified key.

The document can be a Hash or a model instance.

The key is a valid MongoDB dot notation key. The following use cases are supported:

  • Simple field traversal (foo) - retrieves the field foo in the current document.

  • Hash/embedded document field traversal (foo.bar) - retrieves the field foo in the current document, then retrieves the field bar from the value of foo. Each path segment could descend into an embedded document or a hash field.

  • Array element retrieval (foo.N) - retrieves the Nth array element from the field foo which must be an array. N must be a non-negative integer.

  • Array traversal (foo.bar) - if foo is an array field, and the elements of foo are hashes or embedded documents, this returns an array of values of the bar field in each of the hashes in the foo array.

The return value is a two-element array. The first element is the value retrieved, or an array of values. The second element is a boolean flag indicating whether an array was expanded at any point during the key traversal (because the respective document field was an array).

Parameters:

  • document (Document | Hash) —

    The document to extract from.

  • key (String) —

    The key path to extract.

Returns:

  • (Array<true | false, Object | Array, true | false>) —

    Whether the value existed in the document, the extracted value and the array expansion flag.



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# File 'lib/mongoid/matcher.rb', line 38

module_function def extract_attribute(document, key)
  if document.respond_to?(:as_attributes, true)
    # If a document has hash fields, as_attributes would keep those fields
    # as Hash instances which do not offer indifferent access.
    # Convert to BSON::Document to get indifferent access on hash fields.
    document = BSON::Document.new(document.send(:as_attributes))
  end

  current = [document]

  key.to_s.split('.').each do |field|
    new = []
    current.each do |doc|
      case doc
      when Hash
        if doc.key?(field)
          new << doc[field]
        end
      when Array
        if (index = field.to_i).to_s == field
          if doc.length > index
            new << doc[index]
          end
        end
        doc.each do |subdoc|
          if Hash === subdoc
            if subdoc.key?(field)
              new << subdoc[field]
            end
          end
        end
      end
    end
    current = new
    break if current.empty?
  end

  current
end