mongo-ruby-driver/lib/mongo/collection.rb

616 lines
23 KiB
Ruby

# --
# Copyright (C) 2008-2009 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 [InvalidName]
# if collection name is empty, contains '$', or starts or ends with '.'
#
# @raise [TypeError]
# if collection name is not a string or symbol
#
# @return [Collection]
def initialize(db, name, pk_factory=nil)
case name
when Symbol, String
else
raise TypeError, "new_name must be a string or symbol"
end
name = name.to_s
if name.empty? or name.include? ".."
raise InvalidName, "collection names cannot be empty"
end
if name.include? "$"
raise InvalidName, "collection names must not contain '$'" unless name =~ /((^\$cmd)|(oplog\.\$main))/
end
if name.match(/^\./) or name.match(/\.$/)
raise InvalidName, "collection names must not start or end with '.'"
end
@db, @name = db, name
@connection = @db.connection
@pk_factory = pk_factory || 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 [InvalidName]
# 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] :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.
# @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
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 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.
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.
#
# @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}})
def remove(selector={})
message = ByteBuffer.new
message.put_int(0)
BSON_RUBY.serialize_cstr(message, "#{@db.name}.#{@name}")
message.put_int(0)
message.put_array(BSON.serialize(selector, false).unpack("C*"))
@connection.send_message(Mongo::Constants::OP_DELETE, message,
"db.#{@db.name}.remove(#{selector.inspect})")
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.
def update(selector, document, options={})
message = ByteBuffer.new
message.put_int(0)
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.serialize(selector, false).unpack("C*"))
message.put_array(BSON.serialize(document, false).unpack("C*"))
if options[:safe]
@connection.send_message_with_safe_check(Mongo::Constants::OP_UPDATE, message, @db.name,
"db.#{@name}.update(#{selector.inspect}, #{document.inspect})")
else
@connection.send_message(Mongo::Constants::OP_UPDATE, message,
"db.#{@name}.update(#{selector.inspect}, #{document.inspect})")
end
end
# Create a new index.
#
# @param [String, Array] field_or_spec
# should be either a single field name or an array of
# [field name, direction] pairs. Directions should be specified as Mongo::ASCENDING or Mongo::DESCENDING.
#
# @param [Boolean] unique if true, this index will enforce a uniqueness constraint.
#
# @return [String] the name of the index created.
def create_index(field_or_spec, unique=false)
field_h = OrderedHash.new
if field_or_spec.is_a?(String) || field_or_spec.is_a?(Symbol)
field_h[field_or_spec.to_s] = 1
else
field_or_spec.each { |f| field_h[f[0].to_s] = f[1] }
end
name = generate_index_names(field_h)
sel = {
:name => name,
:ns => "#{@db.name}.#{@name}",
:key => field_h,
:unique => unique }
insert_documents([sel], Mongo::DB::SYSTEM_INDEX_COLLECTION, false)
name
end
# Drop a specified index.
#
# @param [String] name
def drop_index(name)
@db.drop_index(@name, name)
end
# Drop all 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, Code] map a map function, written in JavaScript.
# @param [String, 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, 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.
def map_reduce(map, reduce, opts={})
map = Code.new(map) unless map.is_a?(Code)
reduce = Code.new(reduce) unless reduce.is_a?(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, 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, Code] reduce aggregation function, in JavaScript
# @param [String, 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.
# @param [Boolean] command if true, run the group as a command instead of in an
# eval. Note: Running group as eval has been DEPRECATED.
#
# @return [Array] the grouped items.
def group(key, condition, initial, reduce, command=false, finalize=nil)
if command
reduce = Code.new(reduce) unless reduce.is_a?(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?(Code) ? key : Code.new(key)
end
group_command["group"][key_type] = key_value
end
# only add finalize if specified
if finalize
finalize = Code.new(finalize) unless finalize.is_a?(Code)
group_command['group']['finalize'] = finalize
end
result = @db.command group_command
if result["ok"] == 1
return result["retval"]
else
raise OperationFailure, "group command failed: #{result['errmsg']}"
end
else
warn "Collection#group must now be run as a command; you can do this by passing 'true' as the command argument."
raise OperationFailure, ":finalize can be specified only when " +
"group is run as a command (set command param to true)" if finalize
raise OperationFailure, "key must be an array of fields to group by. If you want to pass a key function,
run group as a command by passing 'true' as the command argument." unless key.is_a? Array || key.nil?
case reduce
when Code
scope = reduce.scope
else
scope = {}
end
scope.merge!({
"ns" => @name,
"keys" => key,
"condition" => condition,
"initial" => initial })
group_function = <<EOS
function () {
var c = db[ns].find(condition);
var map = new Map();
var reduce_function = #{reduce};
while (c.hasNext()) {
var obj = c.next();
var key = {};
for (var i = 0; i < keys.length; i++) {
var k = keys[i];
key[k] = obj[k];
}
var aggObj = map.get(key);
if (aggObj == null) {
var newObj = Object.extend({}, key);
aggObj = Object.extend(newObj, initial);
map.put(key, aggObj);
}
reduce_function(obj, aggObj);
}
return {"result": map.values()};
}
EOS
@db.eval(Code.new(group_function, scope))["result"]
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 [InvalidName] 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 InvalidName, "collection names cannot be empty"
end
if new_name.include? "$"
raise InvalidName, "collection names must not contain '$'"
end
if new_name.match(/^\./) or new_name.match(/\.$/)
raise InvalidName, "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.
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)
message = ByteBuffer.new
message.put_int(0)
BSON_RUBY.serialize_cstr(message, "#{@db.name}.#{collection_name}")
documents.each { |doc| message.put_array(BSON.serialize(doc, check_keys).unpack("C*")) }
if safe
@connection.send_message_with_safe_check(Mongo::Constants::OP_INSERT, message, @db.name,
"db.#{collection_name}.insert(#{documents.inspect})")
else
@connection.send_message(Mongo::Constants::OP_INSERT, message,
"db.#{collection_name}.insert(#{documents.inspect})")
end
documents.collect { |o| o[:_id] || o['_id'] }
end
def generate_index_names(spec)
indexes = []
spec.each_pair do |field, direction|
indexes.push("#{field}_#{direction}")
end
indexes.join("_")
end
end
end