# -- # Copyright (C) 2008-2010 10gen Inc. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. # ++ module Mongo # A named collection of documents in a database. class Collection attr_reader :db, :name, :pk_factory, :hint # Initialize a collection object. # # @param [DB] db a MongoDB database instance. # @param [String, Symbol] name the name of the collection. # # @raise [InvalidNSName] # if collection name is empty, contains '$', or starts or ends with '.' # # @raise [TypeError] # if collection name is not a string or symbol # # @return [Collection] # # @core collections constructor_details def initialize(db, name, pk_factory=nil) case name when Symbol, String else raise TypeError, "new_name must be a string or symbol" end name = name.to_s if name.empty? or name.include? ".." raise Mongo::InvalidNSName, "collection names cannot be empty" end if name.include? "$" raise Mongo::InvalidNSName, "collection names must not contain '$'" unless name =~ /((^\$cmd)|(oplog\.\$main))/ end if name.match(/^\./) or name.match(/\.$/) raise Mongo::InvalidNSName, "collection names must not start or end with '.'" end @db, @name = db, name @connection = @db.connection @pk_factory = pk_factory || BSON::ObjectID @hint = nil end # Return a sub-collection of this collection by name. If 'users' is a collection, then # 'users.comments' is a sub-collection of users. # # @param [String] name # the collection to return # # @raise [Mongo::InvalidNSName] # if passed an invalid collection name # # @return [Collection] # the specified sub-collection def [](name) name = "#{self.name}.#{name}" return Collection.new(db, name) if !db.strict? || db.collection_names.include?(name) raise "Collection #{name} doesn't exist. Currently in strict mode." end # Set a hint field for query optimizer. Hint may be a single field # name, array of field names, or a hash (preferably an [OrderedHash]). # If using MongoDB > 1.1, you probably don't ever need to set a hint. # # @param [String, Array, OrderedHash] hint a single field, an array of # fields, or a hash specifying fields def hint=(hint=nil) @hint = normalize_hint_fields(hint) self end # Query the database. # # The +selector+ argument is a prototype document that all results must # match. For example: # # collection.find({"hello" => "world"}) # # only matches documents that have a key "hello" with value "world". # Matches can have other keys *in addition* to "hello". # # If given an optional block +find+ will yield a Cursor to that block, # close the cursor, and then return nil. This guarantees that partially # evaluated cursors will be closed. If given no block +find+ returns a # cursor. # # @param [Hash] selector # a document specifying elements which must be present for a # document to be included in the result set. # # @option opts [Array, Hash] :fields field names that should be returned in the result # set ("_id" will always be included). By limiting results to a certain subset of fields, # you can cut down on network traffic and decoding time. If using a Hash, keys should be field # names and values should be either 1 or 0, depending on whether you want to include or exclude # the given field. # @option opts [Integer] :skip number of documents to skip from the beginning of the result set # @option opts [Integer] :limit maximum number of documents to return # @option opts [Array] :sort an array of [key, direction] pairs to sort by. Direction should # be specified as Mongo::ASCENDING (or :ascending / :asc) or Mongo::DESCENDING (or :descending / :desc) # @option opts [String, Array, OrderedHash] :hint hint for query optimizer, usually not necessary if using MongoDB > 1.1 # @option opts [Boolean] :snapshot ('false') if true, snapshot mode will be used for this query. # Snapshot mode assures no duplicates are returned, or objects missed, which were preset at both the start and # end of the query's execution. For details see http://www.mongodb.org/display/DOCS/How+to+do+Snapshotting+in+the+Mongo+Database # @option opts [Boolean] :timeout ('true') when +true+, the returned cursor will be subject to # the normal cursor timeout behavior of the mongod process. When +false+, the returned cursor will never timeout. Note # that disabling timeout will only work when #find is invoked with a block. This is to prevent any inadvertant failure to # close the cursor, as the cursor is explicitly closed when block code finishes. # # @raise [ArgumentError] # if timeout is set to false and find is not invoked in a block # # @raise [RuntimeError] # if given unknown options # # @core find find-instance_method def find(selector={}, opts={}) fields = opts.delete(:fields) fields = ["_id"] if fields && fields.empty? skip = opts.delete(:skip) || skip || 0 limit = opts.delete(:limit) || 0 sort = opts.delete(:sort) hint = opts.delete(:hint) snapshot = opts.delete(:snapshot) if opts[:timeout] == false && !block_given? raise ArgumentError, "Timeout can be set to false only when #find is invoked with a block." end timeout = block_given? ? (opts.delete(:timeout) || true) : true if hint hint = normalize_hint_fields(hint) else hint = @hint # assumed to be normalized already end raise RuntimeError, "Unknown options [#{opts.inspect}]" unless opts.empty? cursor = Cursor.new(self, :selector => selector, :fields => fields, :skip => skip, :limit => limit, :order => sort, :hint => hint, :snapshot => snapshot, :timeout => timeout) if block_given? yield cursor cursor.close() nil else cursor end end # Return a single object from the database. # # @return [OrderedHash, Nil] # a single document or nil if no result is found. # # @param [Hash, ObjectID, Nil] spec_or_object_id a hash specifying elements # which must be present for a document to be included in the result set or an # instance of ObjectID to be used as the value for an _id query. # If nil, an empty selector, {}, will be used. # # @option opts [Hash] # any valid options that can be send to Collection#find # # @raise [TypeError] # if the argument is of an improper type. def find_one(spec_or_object_id=nil, opts={}) spec = case spec_or_object_id when nil {} when BSON::ObjectID {:_id => spec_or_object_id} when Hash spec_or_object_id else raise TypeError, "spec_or_object_id must be an instance of ObjectID or Hash, or nil" end find(spec, opts.merge(:limit => -1)).next_document end # Save a document to this collection. # # @param [Hash] doc # the document to be saved. If the document already has an '_id' key, # then an update (upsert) operation will be performed, and any existing # document with that _id is overwritten. Otherwise an insert operation is performed. # # @return [ObjectID] the _id of the saved document. # # @option opts [Boolean] :safe (+false+) # If true, check that the save succeeded. OperationFailure # will be raised on an error. Note that a safe check requires an extra # round-trip to the database. def save(doc, options={}) if doc.has_key?(:_id) || doc.has_key?('_id') id = doc[:_id] || doc['_id'] update({:_id => id}, doc, :upsert => true, :safe => options.delete(:safe)) id else insert(doc, :safe => options.delete(:safe)) end end # Insert one or more documents into the collection. # # @param [Hash, Array] doc_or_docs # a document (as a hash) or array of documents to be inserted. # # @return [ObjectID, Array] # the _id of the inserted document or a list of _ids of all inserted documents. # Note: the object may have been modified by the database's PK factory, if it has one. # # @option opts [Boolean] :safe (+false+) # If true, check that the save succeeded. OperationFailure # will be raised on an error. Note that a safe check requires an extra # round-trip to the database. # # @core insert insert-instance_method def insert(doc_or_docs, options={}) doc_or_docs = [doc_or_docs] unless doc_or_docs.is_a?(Array) doc_or_docs.collect! { |doc| @pk_factory.create_pk(doc) } result = insert_documents(doc_or_docs, @name, true, options[:safe]) result.size > 1 ? result : result.first end alias_method :<<, :insert # Remove all documents from this collection. # # @param [Hash] selector # If specified, only matching documents will be removed. # # @option opts [Boolean] :safe [false] run the operation in safe mode, which # will call :getlasterror on the database and report any assertions. # # @example remove all documents from the 'users' collection: # users.remove # users.remove({}) # # @example remove only documents that have expired: # users.remove({:expire => {"$lte" => Time.now}}) # # @return [True] # # @raise [Mongo::OperationFailure] an exception will be raised iff safe mode is enabled # and the operation fails. # # @core remove remove-instance_method def remove(selector={}, opts={}) # Initial byte is 0. message = BSON::ByteBuffer.new([0, 0, 0, 0]) BSON::BSON_RUBY.serialize_cstr(message, "#{@db.name}.#{@name}") message.put_int(0) message.put_array(BSON::BSON_CODER.serialize(selector, false, true).to_a) if opts[:safe] @connection.send_message_with_safe_check(Mongo::Constants::OP_DELETE, message, @db.name, "#{@db.name}['#{@name}'].remove(#{selector.inspect})") # the return value of send_message_with_safe_check isn't actually meaningful -- # only the fact that it didn't raise an error is -- so just return true true else @connection.send_message(Mongo::Constants::OP_DELETE, message, "#{@db.name}['#{@name}'].remove(#{selector.inspect})") end end # Update a single document in this collection. # # @param [Hash] selector # a hash specifying elements which must be present for a document to be updated. Note: # the update command currently updates only the first document matching the # given selector. If you want all matching documents to be updated, be sure # to specify :multi => true. # @param [Hash] document # a hash specifying the fields to be changed in the selected document, # or (in the case of an upsert) the document to be inserted # # @option [Boolean] :upsert (+false+) if true, performs an upsert (update or insert) # @option [Boolean] :multi (+false+) update all documents matching the selector, as opposed to # just the first matching document. Note: only works in MongoDB 1.1.3 or later. # @option opts [Boolean] :safe (+false+) # If true, check that the save succeeded. OperationFailure # will be raised on an error. Note that a safe check requires an extra # round-trip to the database. # # @core update update-instance_method def update(selector, document, options={}) # Initial byte is 0. message = BSON::ByteBuffer.new([0, 0, 0, 0]) BSON::BSON_RUBY.serialize_cstr(message, "#{@db.name}.#{@name}") update_options = 0 update_options += 1 if options[:upsert] update_options += 2 if options[:multi] message.put_int(update_options) message.put_array(BSON::BSON_CODER.serialize(selector, false, true).to_a) message.put_array(BSON::BSON_CODER.serialize(document, false, true).to_a) if options[:safe] @connection.send_message_with_safe_check(Mongo::Constants::OP_UPDATE, message, @db.name, "#{@db.name}['#{@name}'].update(#{selector.inspect}, #{document.inspect})") else @connection.send_message(Mongo::Constants::OP_UPDATE, message, "#{@db.name}['#{@name}'].update(#{selector.inspect}, #{document.inspect})") end end # Create a new index. # # @param [String, Array] spec # should be either a single field name or an array of # [field name, direction] pairs. Directions should be specified # as Mongo::ASCENDING, Mongo::DESCENDING, or Mongo::GEO2D. # # Note that geospatial indexing only works with versions of MongoDB >= 1.3.3+. Keep in mind, too, # that in order to geo-index a given field, that field must reference either an array or a sub-object # where the first two values represent x- and y-coordinates. Examples can be seen below. # # Also note that it is permissible to create compound indexes that include a geospatial index as # long as the geospatial index comes first. # # @param [Boolean] unique if true, this index will enforce a uniqueness constraint. DEPRECATED. Future # versions of this driver will specify the uniqueness constraint using a hash param. # # @option opts [Boolean] :unique (false) if true, this index will enforce a uniqueness constraint. # @option opts [Boolean] :background (false) indicate that the index should be built in the background. This # feature is only available in MongoDB >= 1.3.2. # @option opts [Boolean] :dropDups If creating a unique index on a collection with pre-existing records, # this option will keep the first document the database indexes and drop all subsequent with duplicate values. # @option opts [Integer] :min specify the minimum longitude and latitude for a geo index. # @option opts [Integer] :max specify the maximum longitude and latitude for a geo index. # # @example Creating a compound index: # @posts.create_index([['subject', Mongo::ASCENDING], ['created_at', Mongo::DESCENDING]]) # # @example Creating a geospatial index: # @restaurants.create_index([['location', Mongo::GEO2D]]) # # # Note that this will work only if 'location' represents x,y coordinates: # {'location': [0, 50]} # {'location': {'x' => 0, 'y' => 50}} # {'location': {'latitude' => 0, 'longitude' => 50}} # # @example A geospatial index with alternate longitude and latitude: # @restaurants.create_index([['location', Mongo::GEO2D]], :min => 500, :max => 500) # # @return [String] the name of the index created. # # @core indexes create_index-instance_method def create_index(spec, opts={}) opts.assert_valid_keys(:min, :max, :background, :unique, :dropDups) if opts.is_a?(Hash) field_spec = OrderedHash.new if spec.is_a?(String) || spec.is_a?(Symbol) field_spec[spec.to_s] = 1 elsif spec.is_a?(Array) && spec.all? {|field| field.is_a?(Array) } spec.each { |f| field_spec[f[0].to_s] = f[1] } else raise MongoArgumentError, "Invalid index specification #{spec.inspect}; " + "should be either a string, symbol, or an array of arrays." end name = generate_index_name(field_spec) if opts == true || opts == false warn "For Collection#create_index, the method for specifying a unique index has changed." + "Please pass :unique => true to the method instead." end sel = { :name => name, :ns => "#{@db.name}.#{@name}", :key => field_spec, :unique => (opts == true ? true : false) } sel.merge!(opts) if opts.is_a?(Hash) begin response = insert_documents([sel], Mongo::DB::SYSTEM_INDEX_COLLECTION, false, true) rescue Mongo::OperationFailure raise Mongo::OperationFailure, "Failed to create index #{sel.inspect} with the following errors: #{response}" end name end # Drop a specified index. # # @param [String] name # # @core indexes def drop_index(name) @db.drop_index(@name, name) end # Drop all indexes. # # @core indexes def drop_indexes # Note: calling drop_indexes with no args will drop them all. @db.drop_index(@name, '*') end # Drop the entire collection. USE WITH CAUTION. def drop @db.drop_collection(@name) end # Perform a map/reduce operation on the current collection. # # @param [String, BSON::Code] map a map function, written in JavaScript. # @param [String, BSON::Code] reduce a reduce function, written in JavaScript. # # @option opts [Hash] :query ({}) a query selector document, like what's passed to #find, to limit # the operation to a subset of the collection. # @option opts [Array] :sort ([]) an array of [key, direction] pairs to sort by. Direction should # be specified as Mongo::ASCENDING (or :ascending / :asc) or Mongo::DESCENDING (or :descending / :desc) # @option opts [Integer] :limit (nil) if passing a query, number of objects to return from the collection. # @option opts [String, BSON::Code] :finalize (nil) a javascript function to apply to the result set after the # map/reduce operation has finished. # @option opts [String] :out (nil) the name of the output collection. If specified, the collection will not be treated as temporary. # @option opts [Boolean] :keeptemp (false) if true, the generated collection will be persisted. default is false. # @option opts [Boolean ] :verbose (false) if true, provides statistics on job execution time. # # @return [Collection] a collection containing the results of the operation. # # @see http://www.mongodb.org/display/DOCS/MapReduce Offical MongoDB map/reduce documentation. # # @core mapreduce map_reduce-instance_method def map_reduce(map, reduce, opts={}) map = BSON::Code.new(map) unless map.is_a?(BSON::Code) reduce = BSON::Code.new(reduce) unless reduce.is_a?(BSON::Code) hash = OrderedHash.new hash['mapreduce'] = self.name hash['map'] = map hash['reduce'] = reduce hash.merge! opts result = @db.command(hash) unless result["ok"] == 1 raise Mongo::OperationFailure, "map-reduce failed: #{result['errmsg']}" end @db[result["result"]] end alias :mapreduce :map_reduce # Perform a group aggregation. # # @param [Array, String, BSON::Code, Nil] :key either 1) an array of fields to group by, # 2) a javascript function to generate the key object, or 3) nil. # @param [Hash] condition an optional document specifying a query to limit the documents over which group is run. # @param [Hash] initial initial value of the aggregation counter object # @param [String, BSON::Code] reduce aggregation function, in JavaScript # @param [String, BSON::Code] finalize :: optional. a JavaScript function that receives and modifies # each of the resultant grouped objects. Available only when group is run # with command set to true. # # @return [Array] the grouped items. def group(key, condition, initial, reduce, finalize=nil) reduce = BSON::Code.new(reduce) unless reduce.is_a?(BSON::Code) group_command = { "group" => { "ns" => @name, "$reduce" => reduce, "cond" => condition, "initial" => initial } } unless key.nil? if key.is_a? Array key_type = "key" key_value = {} key.each { |k| key_value[k] = 1 } else key_type = "$keyf" key_value = key.is_a?(BSON::Code) ? key : BSON::Code.new(key) end group_command["group"][key_type] = key_value end finalize = BSON::Code.new(finalize) if finalize.is_a?(String) if finalize.is_a?(BSON::Code) group_command['group']['finalize'] = finalize end result = @db.command group_command if result["ok"] == 1 result["retval"] else raise OperationFailure, "group command failed: #{result['errmsg']}" end end # Return a list of distinct values for +key+ across all # documents in the collection. The key may use dot notation # to reach into an embedded object. # # @param [String, Symbol, OrderedHash] key or hash to group by. # @param [Hash] query a selector for limiting the result set over which to group. # # @example Saving zip codes and ages and returning distinct results. # @collection.save({:zip => 10010, :name => {:age => 27}}) # @collection.save({:zip => 94108, :name => {:age => 24}}) # @collection.save({:zip => 10010, :name => {:age => 27}}) # @collection.save({:zip => 99701, :name => {:age => 24}}) # @collection.save({:zip => 94108, :name => {:age => 27}}) # # @collection.distinct(:zip) # [10010, 94108, 99701] # @collection.distinct("name.age") # [27, 24] # # # You may also pass a document selector as the second parameter # # to limit the documents over which distinct is run: # @collection.distinct("name.age", {"name.age" => {"$gt" => 24}}) # [27] # # @return [Array] an array of distinct values. def distinct(key, query=nil) raise MongoArgumentError unless [String, Symbol].include?(key.class) command = OrderedHash.new command[:distinct] = @name command[:key] = key.to_s command[:query] = query @db.command(command)["values"] end # Rename this collection. # # Note: If operating in auth mode, the client must be authorized as an admin to # perform this operation. # # @param [String] new_name the new name for this collection # # @raise [Mongo::InvalidNSName] if +new_name+ is an invalid collection name. def rename(new_name) case new_name when Symbol, String else raise TypeError, "new_name must be a string or symbol" end new_name = new_name.to_s if new_name.empty? or new_name.include? ".." raise Mongo::InvalidNSName, "collection names cannot be empty" end if new_name.include? "$" raise Mongo::InvalidNSName, "collection names must not contain '$'" end if new_name.match(/^\./) or new_name.match(/\.$/) raise Mongo::InvalidNSName, "collection names must not start or end with '.'" end @db.rename_collection(@name, new_name) end # Get information on the indexes for this collection. # # @return [Hash] a hash where the keys are index names. # # @core indexes def index_information @db.index_information(@name) end # Return a hash containing options that apply to this collection. # For all possible keys and values, see DB#create_collection. # # @return [Hash] options that apply to this collection. def options @db.collections_info(@name).next_document['options'] end # Get the number of documents in this collection. # # @return [Integer] def count find().count() end alias :size :count protected def normalize_hint_fields(hint) case hint when String {hint => 1} when Hash hint when nil nil else h = OrderedHash.new hint.to_a.each { |k| h[k] = 1 } h end end private # Sends a Mongo::Constants::OP_INSERT message to the database. # Takes an array of +documents+, an optional +collection_name+, and a # +check_keys+ setting. def insert_documents(documents, collection_name=@name, check_keys=true, safe=false) # Initial byte is 0. message = BSON::ByteBuffer.new([0, 0, 0, 0]) BSON::BSON_RUBY.serialize_cstr(message, "#{@db.name}.#{collection_name}") documents.each { |doc| message.put_array(BSON::BSON_CODER.serialize(doc, check_keys, true).to_a) } if safe @connection.send_message_with_safe_check(Mongo::Constants::OP_INSERT, message, @db.name, "#{@db.name}['#{collection_name}'].insert(#{documents.inspect})") else @connection.send_message(Mongo::Constants::OP_INSERT, message, "#{@db.name}['#{collection_name}'].insert(#{documents.inspect})") end documents.collect { |o| o[:_id] || o['_id'] } end def generate_index_name(spec) indexes = [] spec.each_pair do |field, direction| indexes.push("#{field}_#{direction}") end indexes.join("_") end end end