Class: Parse::Constraint::ObjectIdConstraint

Inherits:
Constraint
  • Object
show all
Defined in:
lib/parse/query/constraints.rb

Overview

A constraint for matching by a specific objectId value.

where this Parse object equals the object in the column field.

q.where :field => Parse::Pointer("Field", "someObjectId")

alias, shorthand when we infer :field maps to Field parse class.

q.where :field.id => "someObjectId"

"field":"__type":"Pointer","className":"Field","objectId":"someObjectId"}

class Artist < Parse::Object end

class Song < Parse::Object belongs_to :artist end

artist = Artist.first # get any artist artist_id = artist.id # ex. artist.id

find all songs for this artist object

Song.all :artist => artist

In some cases, you do not have the Parse object, but you have its objectId. You can use the objectId in the query as follows:

shorthand if you are using convention. Will infer class Artist

Song.all :artist.id => artist_id

other approaches, same result

Song.all :artist.id => artist # safely supported Parse::Pointer Song.all :artist => Artist.pointer(artist_id) Song.all :artist => Parse::Pointer.new("Artist", artist_id)

Instance Method Summary collapse

Instance Method Details

#build ⇒ Hash

Returns the compiled constraint.

Returns:

  • (Hash) —

    the compiled constraint.



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# File 'lib/parse/query/constraints.rb', line 109

def build
  className = operand.to_parse_class
  value = formatted_value
  # if it is already a pointer value, just return the constraint. Allows for
  # supporting strings, symbols and pointers.
  return { @operation.operand => value } if value.is_a?(Parse::Pointer)

  begin
    klass = className.constantize
  rescue NameError
    klass = Parse::Model.find_class className
  end

  unless klass.present? && klass.is_a?(Parse::Object) == false
    raise ArgumentError, "#{self.class}: No Parse class defined for #{operand} as '#{className}'"
  end

  # allow symbols
  value = value.to_s if value.is_a?(Symbol)

  unless value.is_a?(String) && value.strip.present?
    raise ArgumentError, "#{self.class}: value must be of string type representing a Parse object id."
  end
  value.strip!
  return { @operation.operand => klass.pointer(value) }
end

#id ⇒ ObjectIdConstraint

A registered method on a symbol to create the constraint.

Examples:

q.where :field.id => "someObjectId"
q.where :field.id => pointer # safely supported

Returns:



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# File 'lib/parse/query/constraints.rb', line 106

register :id