class Mongoid::Criteria

The Criteria class is the core object needed in Mongoid to retrieve objects from the database. It is a DSL that essentially sets up the selector and options arguments that get passed on to a Mongo::Collection in the Ruby driver. Each method on the Criteria returns self to they can be chained in order to create a readable criterion to be executed against the database.

Constants

CHECK

Static array used to check with method missing - we only need to ever instantiate once.

@since 4.0.0

Attributes

embedded[RW]
klass[RW]

Public Class Methods

new(klass) click to toggle source

Initialize the new criteria.

@example Init the new criteria.

Criteria.new(Band)

@param [ Class ] klass The model class.

@since 1.0.0

Calls superclass method Mongoid::Criteria::Modifiable#new
# File lib/mongoid/criteria.rb, line 193
def initialize(klass)
  @klass = klass
  klass ? super(klass.aliased_fields, klass.fields) : super({}, {})
end

Public Instance Methods

==(other) click to toggle source

Returns true if the supplied Enumerable or Criteria is equal to the results of this Criteria or the criteria itself.

@note This will force a database load when called if an enumerable is passed.

@param [ Object ] other The other Enumerable or Criteria to compare to.

@return [ true, false ] If the objects are equal.

@since 1.0.0

Calls superclass method
# File lib/mongoid/criteria.rb, line 46
def ==(other)
  return super if other.respond_to?(:selector)
  entries == other
end
as_json(options = nil) click to toggle source

Needed to properly get a criteria back as json

@example Get the criteria as json.

Person.where(:title => "Sir").as_json

@param [ Hash ] options Options to pass through to the serializer.

@return [ String ] The JSON string.

# File lib/mongoid/criteria.rb, line 59
def as_json(options = nil)
  entries.as_json(options)
end
cache() click to toggle source

Tells the criteria that the cursor that gets returned needs to be cached. This is so multiple iterations don’t hit the database multiple times, however this is not advisable when working with large data sets as the entire results will get stored in memory.

@example Flag the criteria as cached.

criteria.cache

@return [ Criteria ] The cloned criteria.

# File lib/mongoid/criteria.rb, line 72
def cache
  crit = clone
  crit.options.merge!(cache: true)
  crit
end
cached?() click to toggle source

Will return true if the cache option has been set.

@example Is the criteria cached?

criteria.cached?

@return [ true, false ] If the criteria is flagged as cached.

# File lib/mongoid/criteria.rb, line 84
def cached?
  options[:cache] == true
end
documents() click to toggle source

Get the documents from the embedded criteria.

@example Get the documents.

criteria.documents

@return [ Array<Document> ] The documents.

@since 3.0.0

# File lib/mongoid/criteria.rb, line 96
def documents
  @documents ||= []
end
documents=(docs) click to toggle source

Set the embedded documents on the criteria.

@example Set the documents.

@param [ Array<Document> ] docs The embedded documents.

@return [ Array<Document> ] The embedded documents.

@since 3.0.0

# File lib/mongoid/criteria.rb, line 109
def documents=(docs)
  @documents = docs
end
embedded?() click to toggle source

Is the criteria for embedded documents?

@example Is the criteria for embedded documents?

criteria.embedded?

@return [ true, false ] If the criteria is embedded.

@since 3.0.0

# File lib/mongoid/criteria.rb, line 121
def embedded?
  !!@embedded
end
extract_id() click to toggle source

Extract a single id from the provided criteria. Could be in an $and query or a straight _id query.

@example Extract the id.

criteria.extract_id

@return [ Object ] The id.

@since 2.3.0

# File lib/mongoid/criteria.rb, line 134
def extract_id
  selector.extract_id
end
extras(extras) click to toggle source

Adds a criterion to the Criteria that specifies additional options to be passed to the Ruby driver, in the exact format for the driver.

@example Add extra params to the criteria. criteria.extras(:limit => 20, :skip => 40)

@param [ Hash ] extras The extra driver options.

@return [ Criteria ] The cloned criteria.

@since 2.0.0

# File lib/mongoid/criteria.rb, line 149
def extras(extras)
  crit = clone
  crit.options.merge!(extras)
  crit
end
field_list() click to toggle source

Get the list of included fields.

@example Get the field list.

criteria.field_list

@return [ Array<String> ] The fields.

@since 2.0.0

# File lib/mongoid/criteria.rb, line 163
def field_list
  if options[:fields]
    options[:fields].keys.reject{ |key| key == "_type" }
  else
    []
  end
end
for_js(javascript, scope = {}) click to toggle source

Find documents by the provided javascript and scope. Uses a $where but is different from +Criteria#where+ in that it will pass a code object to the query instead of a pure string. Safe against Javascript injection attacks.

@example Find by javascript.

Band.for_js("this.name = param", param: "Tool")

@param [ String ] javascript The javascript to execute in the $where. @param [ Hash ] scope The scope for the code.

@return [ Criteria ] The criteria.

@since 3.1.0

# File lib/mongoid/criteria.rb, line 430
def for_js(javascript, scope = {})
  js_query(Moped::BSON::Code.new(javascript, scope))
end
freeze() click to toggle source

When freezing a criteria we need to initialize the context first otherwise the setting of the context on attempted iteration will raise a runtime error.

@example Freeze the criteria.

criteria.freeze

@return [ Criteria ] The frozen criteria.

@since 2.0.0

Calls superclass method
# File lib/mongoid/criteria.rb, line 181
def freeze
  context and inclusions and super
end
includes(*relations) click to toggle source

Eager loads all the provided relations. Will load all the documents into the identity map who’s ids match based on the extra query for the ids.

@note This will only work if Mongoid’s identity map is enabled. To do

so set identity_map_enabled: true in your mongoid.yml

@note This will work for embedded relations that reference another

collection via belongs_to as well.

@note Eager loading brings all the documents into memory, so there is a

sweet spot on the performance gains. Internal benchmarks show that
eager loading becomes slower around 100k documents, but this will
naturally depend on the specific application.

@example Eager load the provided relations.

Person.includes(:posts, :game)

@param [ Array<Symbol> ] relations The names of the relations to eager

load.

@return [ Criteria ] The cloned criteria.

@since 2.2.0

# File lib/mongoid/criteria.rb, line 222
def includes(*relations)
  relations.flatten.each do |name|
    metadata = klass.reflect_on_association(name)
    raise Errors::InvalidIncludes.new(klass, relations) unless metadata
    inclusions.push(metadata) unless inclusions.include?(metadata)
  end
  clone
end
inclusions() click to toggle source

Get a list of criteria that are to be executed for eager loading.

@example Get the eager loading inclusions.

Person.includes(:game).inclusions

@return [ Array<Metadata> ] The inclusions.

@since 2.2.0

# File lib/mongoid/criteria.rb, line 239
def inclusions
  @inclusions ||= []
end
inclusions=(value) click to toggle source

Set the inclusions for the criteria.

@example Set the inclusions.

criteria.inclusions = [ meta ]

@param [ Array<Metadata> ] The inclusions.

@return [ Array<Metadata> ] The new inclusions.

@since 3.0.0

# File lib/mongoid/criteria.rb, line 253
def inclusions=(value)
  @inclusions = value
end
merge(other) click to toggle source
criteria.merge({
  klass: Band,
  where: { name: "Depeche Mode" },
  order_by: { name: 1 }
})

@param [ Criteria ] other The other criterion to merge with.

@return [ Criteria ] A cloned self.

# File lib/mongoid/criteria.rb, line 277
def merge(other)
  crit = clone
  crit.merge!(other)
  crit
end
merge!(other) click to toggle source

Merge the other criteria into this one.

@example Merge another criteria into this criteria.

criteria.merge(Person.where(name: "bob"))

@param [ Criteria ] other The criteria to merge in.

@return [ Criteria ] The merged criteria.

@since 3.0.0

# File lib/mongoid/criteria.rb, line 293
def merge!(other)
  criteria = other.to_criteria
  selector.merge!(criteria.selector)
  options.merge!(criteria.options)
  self.documents = criteria.documents.dup unless criteria.documents.empty?
  self.scoping_options = criteria.scoping_options
  self.inclusions = (inclusions + criteria.inclusions.dup).uniq
  self
end
only(*args) click to toggle source

Overriden to include _type in the fields.

@example Limit the fields returned from the database.

Band.only(:name)

@param [ Array<Symbol> ] args The names of the fields.

@return [ Criteria ] The cloned criteria.

@since 1.0.0

Calls superclass method
# File lib/mongoid/criteria.rb, line 313
def only(*args)
  return clone if args.flatten.empty?
  args = args.flatten
  if klass.hereditary?
    super(*args.push(:_type))
  else
    super(*args)
  end
end
respond_to?(name, include_private = false) click to toggle source

Returns true if criteria responds to the given method.

@example Does the criteria respond to the method?

crtiteria.respond_to?(:each)

@param [ Symbol ] name The name of the class method on the Document. @param [ true, false ] include_private Whether to include privates.

@return [ true, false ] If the criteria responds to the method.

Calls superclass method
# File lib/mongoid/criteria.rb, line 332
def respond_to?(name, include_private = false)
  super || klass.respond_to?(name) || CHECK.respond_to?(name, include_private)
end
to_criteria() click to toggle source

Convenience for objects that want to be merged into a criteria.

@example Convert to a criteria.

criteria.to_criteria

@return [ Criteria ] self.

@since 3.0.0

# File lib/mongoid/criteria.rb, line 346
def to_criteria
  self
end
to_proc() click to toggle source

Convert the criteria to a proc.

@example Convert the criteria to a proc.

criteria.to_proc

@return [ Proc ] The wrapped criteria.

@since 3.0.0

# File lib/mongoid/criteria.rb, line 358
def to_proc
  ->{ self }
end
type(types) click to toggle source

Adds a criterion to the Criteria that specifies a type or an Array of types that must be matched.

@example Match only specific models.

criteria.type('Browser')
criteria.type(['Firefox', 'Browser'])

@param [ Array<String> ] types The types to match against.

@return [ Criteria ] The cloned criteria.

# File lib/mongoid/criteria.rb, line 372
def type(types)
  any_in(_type: Array(types))
end
where(expression) click to toggle source

This is the general entry point for most MongoDB queries. This either creates a standard field: value selection, and expanded selection with the use of hash methods, or a $where selection if a string is provided.

@example Add a standard selection.

criteria.where(name: "syd")

@example Add a javascript selection.

criteria.where("this.name == 'syd'")

@param [ String, Hash ] criterion The javascript or standard selection.

@raise [ UnsupportedJavascript ] If provided a string and the criteria

is embedded.

@return [ Criteria ] The cloned selectable.

@since 1.0.0

Calls superclass method
# File lib/mongoid/criteria.rb, line 394
def where(expression)
  if expression.is_a?(::String) && embedded?
    raise Errors::UnsupportedJavascript.new(klass, expression)
  end
  super
end
without_options() click to toggle source

Get a version of this criteria without the options.

@example Get the criteria without options.

criteria.without_options

@return [ Criteria ] The cloned criteria.

@since 3.0.4

# File lib/mongoid/criteria.rb, line 410
def without_options
  crit = clone
  crit.options.clear
  crit
end

Private Instance Methods

check_for_missing_documents!(result, ids) click to toggle source

Are documents in the query missing, and are we configured to raise an error?

@api private

@example Check for missing documents.

criteria.check_for_missing_documents!([], [ 1 ])

@param [ Array<Document> ] result The result. @param [ Array<Object> ] ids The ids.

@raise [ Errors::DocumentNotFound ] If none are found and raising an

error.

@since 3.0.0

# File lib/mongoid/criteria.rb, line 451
def check_for_missing_documents!(result, ids)
  if (result.size < ids.size) && Mongoid.raise_not_found_error
    raise Errors::DocumentNotFound.new(klass, ids, ids - result.map(&:_id))
  end
end
initialize_copy(other) click to toggle source

Clone or dup the current Criteria. This will return a new criteria with the selector, options, klass, embedded options, etc intact.

@api private

@example Clone a criteria.

criteria.clone

@example Dup a criteria.

criteria.dup

@param [ Criteria ] other The criteria getting cloned.

@return [ nil ] nil.

@since 1.0.0

Calls superclass method
# File lib/mongoid/criteria.rb, line 473
def initialize_copy(other)
  @inclusions = other.inclusions.dup
  @scoping_options = other.scoping_options
  @documents = other.documents.dup
  @context = nil
  super
end
merge_type_selection() click to toggle source

For models where inheritance is at play we need to add the type selection.

@example Add the type selection.

criteria.merge_type_selection

@return [ true, false ] If type selection was added.

@since 3.0.3

# File lib/mongoid/criteria.rb, line 514
def merge_type_selection
  selector.merge!(type_selection) if type_selectable?
end
method_missing(name, *args, &block) click to toggle source

Used for chaining Criteria scopes together in the for of class methods on the Document the criteria is for.

@example Handle method missing.

criteria.method_missing(:name)

@param [ Symbol ] name The method name. @param [ Array ] args The arguments.

@return [ Object ] The result of the method call.

@since 1.0.0

Calls superclass method
# File lib/mongoid/criteria.rb, line 493
def method_missing(name, *args, &block)
  if klass.respond_to?(name)
    klass.send(:with_scope, self) do
      klass.send(name, *args, &block)
    end
  elsif CHECK.respond_to?(name)
    return entries.send(name, *args, &block)
  else
    super
  end
end
selector_with_type_selection() click to toggle source

Get a new selector with type selection in it.

@api private

@example Get a selector with type selection.

criteria.selector_with_type_selection

@return [ Hash ] The selector.

@since 3.0.3

# File lib/mongoid/criteria.rb, line 558
def selector_with_type_selection
  type_selectable? ? selector.merge(type_selection) : selector
end
type_selectable?() click to toggle source

Is the criteria type selectable?

@api private

@example If the criteria type selectable?

criteria.type_selectable?

@return [ true, false ] If type selection should be added.

@since 3.0.3

# File lib/mongoid/criteria.rb, line 528
def type_selectable?
  klass.hereditary? &&
    !selector.keys.include?("_type") &&
    !selector.keys.include?(:_type)
end
type_selection() click to toggle source

Get the selector for type selection.

@api private

@example Get a type selection hash.

criteria.type_selection

@return [ Hash ] The type selection.

@since 3.0.3

# File lib/mongoid/criteria.rb, line 544
def type_selection
  { _type: { "$in" => klass._types }}
end