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
Public Class Methods
Initialize the new criteria.
@example Init the new criteria.
Criteria.new(Band)
@param [ Class ] klass The model class.
@since 1.0.0
Mongoid::Criteria::Modifiable#new
# File lib/mongoid/criteria.rb, line 250 def initialize(klass) @klass = klass @embedded = nil @none = nil klass ? super(klass.aliased_fields, klass.fields) : super({}, {}) end
Public Instance Methods
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
Mongoid::Criteria::Queryable#==
# File lib/mongoid/criteria.rb, line 61 def ==(other) return super if other.respond_to?(:selector) entries == other end
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 116 def as_json(options = nil) entries.as_json(options) end
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 129 def cache crit = clone crit.options.merge!(cache: true) crit end
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 141 def cached? options[:cache] == true end
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 153 def documents @documents ||= [] end
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 166 def documents=(docs) @documents = docs end
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 178 def embedded? !!@embedded end
Is the criteria an empty but chainable criteria?
@example Is the criteria a none criteria?
criteria.empty_and_chainable?
@return [ true, false ] If the criteria is a none.
@since 4.0.0
# File lib/mongoid/criteria.rb, line 324 def empty_and_chainable? !!@none end
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 191 def extract_id selector.extract_id end
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 206 def extras(extras) crit = clone crit.options.merge!(extras) crit end
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 220 def field_list if options[:fields] options[:fields].keys.reject{ |key| key == klass.discriminator_key } else [] end end
Finds one or many documents given the provided _id values, or filters the documents in the current scope in the application process space after loading them if needed.
If this method is not given a block, it delegates to +Findable#find+ and finds one or many documents for the provided _id values.
If this method is given a block, it delegates to +Enumerable#find+ and returns the first document of those found by the current Crieria object for which the block returns a truthy value.
Note that the “default proc” argument of Enumerable is not specially treated by Mongoid
- the decision between delegating to Findable
vs Enumerable
is made solely based on whether find
is passed a block.
@example Finds a document by its _id, invokes Findable#find
.
critera.find("1234")
@example Finds the first matching document using a block, invokes Enumerable#find.
criteria.find { |item| item.name == "Depeche Mode" }
@example Finds the first matching document using a block using the default Proc, invokes Enumerable#find.
criteria.find(-> { "Default Band" }) { |item| item.name == "Milwaukee Mode" }
@example Tries to find a document whose _id is the stringification of the provided Proc, typically failing.
enumerator = criteria.find(-> { "Default Band" })
@return [ Document
| Array<Document> | nil ] A document or matching documents.
@raise Errors::DocumentNotFound
If the parameters were _id values and
not all documents are found and the +raise_not_found_error+ Mongoid configuration option is truthy.
@see ruby-doc.org/core/Enumerable.html#method-i-find
# File lib/mongoid/criteria.rb, line 100 def find(*args, &block) if block_given? _enumerable_find(*args, &block) else _findable_find(*args) end end
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 501 def for_js(javascript, scope = {}) code = if scope.empty? # CodeWithScope is not supported for $where as of MongoDB 4.4 BSON::Code.new(javascript) else BSON::CodeWithScope.new(javascript, scope) end js_query(code) end
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
# File lib/mongoid/criteria.rb, line 238 def freeze context and inclusions and super end
Merges another object with this Criteria
and returns a new criteria. The other object may be a Criteria
or a Hash
. This is used to combine multiple scopes together, where a chained scope situation may be desired.
@example Merge the criteria with another criteria.
criteri.merge(other_criteria)
@example Merge the criteria with a hash. The hash must contain a klass
key and the key/value pairs correspond to method names/args. 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 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).uniq self end
Returns a criteria that will always contain zero results and never hits the database.
@example Return a none criteria.
criteria.none
@return [ Criteria
] The none criteria.
@since 4.0.0
# File lib/mongoid/criteria.rb, line 312 def none @none = true and self end
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
# File lib/mongoid/criteria.rb, line 338 def only(*args) args = args.flatten return clone if args.empty? if (args & Fields::IDS).empty? args.unshift(:_id) end if klass.hereditary? args.push(klass.discriminator_key.to_sym) end super(*args) end
Set the read preference for the criteria.
@example Set the read preference.
criteria.read(mode: :primary_preferred)
@param [ Hash ] value The mode preference.
@return [ Criteria
] The cloned criteria.
@since 5.0.0
# File lib/mongoid/criteria.rb, line 360 def read(value = nil) clone.tap do |criteria| criteria.options.merge!(read: value) end end
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.
# File lib/mongoid/criteria.rb, line 390 def respond_to?(name, include_private = false) super || klass.respond_to?(name) || CHECK.respond_to?(name, include_private) end
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 404 def to_criteria self end
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 416 def to_proc ->{ self } end
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 430 def type(types) any_in(self.discriminator_key.to_sym => Array(types)) end
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 ] expression 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
# File lib/mongoid/criteria.rb, line 452 def where(*args) # Historically this method required exactly one argument. # As of https://jira.mongodb.org/browse/MONGOID-4804 it also accepts # zero arguments. # The underlying where implemetation that super invokes supports # any number of arguments, but we don't presently allow mutiple # arguments through this method. This API can be reconsidered in the # future. if args.length > 1 raise ArgumentError, "Criteria#where requires zero or one arguments (given #{args.length})" end if args.length == 1 expression = args.first if expression.is_a?(::String) && embedded? raise Errors::UnsupportedJavascript.new(klass, expression) end end super end
Overriden to exclude _id from the fields.
@example Exclude fields returned from the database.
Band.without(:name)
@param [ Array<Symbol> ] args The names of the fields.
@return [ Criteria
] The cloned criteria.
@since 4.0.3
# File lib/mongoid/criteria.rb, line 376 def without(*args) args -= id_fields super(*args) end
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 481 def without_options crit = clone crit.options.clear crit end
Private Instance Methods
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 528 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
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
Mongoid::Criteria::Queryable#initialize_copy
# File lib/mongoid/criteria.rb, line 550 def initialize_copy(other) @inclusions = other.inclusions.dup @scoping_options = other.scoping_options @documents = other.documents.dup @context = nil super end
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 591 def merge_type_selection selector.merge!(type_selection) if type_selectable? end
# File lib/mongoid/criteria.rb, line 570 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
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 640 def selector_with_type_selection type_selectable? ? selector.merge(type_selection) : selector end
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 605 def type_selectable? klass.hereditary? && !selector.keys.include?(self.discriminator_key) && !selector.keys.include?(self.discriminator_key.to_sym) end
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 621 def type_selection klasses = klass._types if klasses.size > 1 { klass.discriminator_key.to_sym => { "$in" => klass._types }} else { klass.discriminator_key.to_sym => klass._types[0] } end end