523 lines
19 KiB
Ruby
523 lines
19 KiB
Ruby
# --
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# Copyright (C) 2008-2009 10gen Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# ++
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require 'socket'
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require 'digest/md5'
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require 'mutex_m'
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require 'mongo/collection'
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require 'mongo/message'
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require 'mongo/query'
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require 'mongo/util/ordered_hash.rb'
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require 'mongo/admin'
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module XGen
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module Mongo
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module Driver
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# A Mongo database.
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class DB
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SYSTEM_NAMESPACE_COLLECTION = "system.namespaces"
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SYSTEM_INDEX_COLLECTION = "system.indexes"
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SYSTEM_PROFILE_COLLECTION = "system.profile"
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SYSTEM_USER_COLLECTION = "system.users"
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SYSTEM_COMMAND_COLLECTION = "$cmd"
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# Strict mode enforces collection existence checks. When +true+,
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# asking for a collection that does not exist or trying to create a
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# collection that already exists raises an error.
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#
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# Strict mode is off (+false+) by default. Its value can be changed at
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# any time.
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attr_writer :strict
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# Returns the value of the +strict+ flag.
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def strict?; @strict; end
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# The name of the database.
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attr_reader :name
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# Host to which we are currently connected.
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attr_reader :host
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# Port to which we are currently connected.
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attr_reader :port
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# An array of [host, port] pairs.
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attr_reader :nodes
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# The database's socket. For internal (and Cursor) use only.
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attr_reader :socket
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def slave_ok?; @slave_ok; end
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def auto_reconnect?; @auto_reconnect; end
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# A primary key factory object (or +nil+). See the README.doc file or
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# DB#new for details.
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attr_reader :pk_factory
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def pk_factory=(pk_factory)
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raise "error: can not change PK factory" if @pk_factory
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@pk_factory = pk_factory
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end
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# Instances of DB are normally obtained by calling Mongo#db.
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#
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# db_name :: The database name
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#
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# nodes :: An array of [host, port] pairs. See Mongo#new, which offers
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# a more flexible way of defining nodes.
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#
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# options :: A hash of options.
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#
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# Options:
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#
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# :strict :: If true, collections must exist to be accessed and must
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# not exist to be created. See #collection and
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# #create_collection.
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#
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# :pk :: A primary key factory object that must respond to :create_pk,
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# which should take a hash and return a hash which merges the
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# original hash with any primary key fields the factory wishes
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# to inject. (NOTE: if the object already has a primary key,
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# the factory should not inject a new key; this means that the
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# object is being used in a repsert but it already exists.) The
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# idea here is that when ever a record is inserted, the :pk
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# object's +create_pk+ method will be called and the new hash
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# returned will be inserted.
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#
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# :slave_ok :: Only used if +nodes+ contains only one host/port. If
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# false, when connecting to that host/port we check to
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# see if the server is the master. If it is not, an error
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# is thrown.
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#
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# :auto_reconnect :: If the connection gets closed (for example, we
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# have a server pair and saw the "not master"
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# error, which closes the connection), then
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# automatically try to reconnect to the master or
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# to the single server we have been given. Defaults
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# to +false+.
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#
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# When a DB object first connects to a pair, it will find the master
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# instance and connect to that one. On socket error or if we recieve a
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# "not master" error, we again find the master of the pair.
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def initialize(db_name, nodes, options={})
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raise "Invalid DB name \"#{db_name}\" (must be non-nil, non-zero-length, and can not contain \".\")" if !db_name || (db_name && db_name.length > 0 && db_name.include?("."))
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@name, @nodes = db_name, nodes
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@strict = options[:strict]
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@pk_factory = options[:pk]
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@slave_ok = options[:slave_ok] && @nodes.length == 1 # only OK if one node
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@auto_reconnect = options[:auto_reconnect]
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@semaphore = Object.new
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@semaphore.extend Mutex_m
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@socket = nil
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connect_to_master
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end
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def connect_to_master
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close if @socket
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@host = @port = nil
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@nodes.detect { |hp|
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@host, @port = *hp
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begin
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@socket = TCPSocket.new(@host, @port)
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@socket.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1)
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# Check for master. Can't call master? because it uses mutex,
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# which may already be in use during this call.
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semaphore_is_locked = @semaphore.locked?
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@semaphore.unlock if semaphore_is_locked
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is_master = master?
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@semaphore.lock if semaphore_is_locked
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break if @slave_ok || is_master
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rescue SocketError, SystemCallError, IOError => ex
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close if @socket
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end
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@socket
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}
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raise "error: failed to connect to any given host:port" unless @socket
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end
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# Returns true if +username+ has +password+ in
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# +SYSTEM_USER_COLLECTION+. +name+ is username, +password+ is
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# plaintext password.
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def authenticate(username, password)
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doc = db_command(:getnonce => 1)
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raise "error retrieving nonce: #{doc}" unless ok?(doc)
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nonce = doc['nonce']
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auth = OrderedHash.new
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auth['authenticate'] = 1
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auth['user'] = username
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auth['nonce'] = nonce
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auth['key'] = Digest::MD5.hexdigest("#{nonce}#{username}#{hash_password(username, password)}")
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ok?(db_command(auth))
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end
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# Deauthorizes use for this database for this connection.
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def logout
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doc = db_command(:logout => 1)
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raise "error logging out: #{doc.inspect}" unless ok?(doc)
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end
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# Returns an array of collection names. Each name is of the form
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# "database_name.collection_name".
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def collection_names
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names = collections_info.collect { |doc| doc['name'] || '' }
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names.delete('')
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names
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end
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# Returns a cursor over query result hashes. Each hash contains a
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# 'name' string and optionally an 'options' hash. If +coll_name+ is
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# specified, an array of length 1 is returned.
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def collections_info(coll_name=nil)
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selector = {}
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selector[:name] = full_coll_name(coll_name) if coll_name
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query(Collection.new(self, SYSTEM_NAMESPACE_COLLECTION), Query.new(selector))
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end
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# Create a collection. If +strict+ is false, will return existing or
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# new collection. If +strict+ is true, will raise an error if
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# collection +name+ already exists.
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#
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# Options is an optional hash:
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#
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# :capped :: Boolean. If not specified, capped is +false+.
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#
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# :size :: If +capped+ is +true+, specifies the maximum number of
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# bytes. If +false+, specifies the initial extent of the
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# collection.
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#
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# :max :: Max number of records in a capped collection. Optional.
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def create_collection(name, options={})
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# First check existence
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if collection_names.include?(full_coll_name(name))
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if strict?
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raise "Collection #{name} already exists. Currently in strict mode."
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else
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return Collection.new(self, name)
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end
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end
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# Create new collection
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oh = OrderedHash.new
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oh[:create] = name
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doc = db_command(oh.merge(options || {}))
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ok = doc['ok']
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return Collection.new(self, name) if ok.kind_of?(Numeric) && (ok.to_i == 1 || ok.to_i == 0)
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raise "Error creating collection: #{doc.inspect}"
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end
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def admin
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Admin.new(self)
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end
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# Return a collection. If +strict+ is false, will return existing or
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# new collection. If +strict+ is true, will raise an error if
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# collection +name+ does not already exists.
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def collection(name)
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return Collection.new(self, name) if !strict? || collection_names.include?(full_coll_name(name))
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raise "Collection #{name} doesn't exist. Currently in strict mode."
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end
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# Drop collection +name+. Returns +true+ on success or if the
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# collection does not exist, +false+ otherwise.
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def drop_collection(name)
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return true unless collection_names.include?(full_coll_name(name))
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ok?(db_command(:drop => name))
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end
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# Returns the error message from the most recently executed database
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# operation for this connection, or +nil+ if there was no error.
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#
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# Note: as of this writing, errors are only detected on the db server
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# for certain kinds of operations (writes). The plan is to change this
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# so that all operations will set the error if needed.
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def error
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doc = db_command(:getlasterror => 1)
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raise "error retrieving last error: #{doc}" unless ok?(doc)
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doc['err']
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end
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# Returns +true+ if an error was caused by the most recently executed
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# database operation.
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#
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# Note: as of this writing, errors are only detected on the db server
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# for certain kinds of operations (writes). The plan is to change this
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# so that all operations will set the error if needed.
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def error?
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error != nil
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end
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# Returns true if this database is a master (or is not paired with any
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# other database), false if it is a slave.
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def master?
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doc = db_command(:ismaster => 1)
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is_master = doc['ismaster']
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ok?(doc) && is_master.kind_of?(Numeric) && is_master.to_i == 1
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end
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# Returns a string of the form "host:port" that points to the master
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# database. Works even if this is the master database.
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def master
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doc = db_command(:ismaster => 1)
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is_master = doc['ismaster']
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raise "Error retrieving master database: #{doc.inspect}" unless ok?(doc) && is_master.kind_of?(Numeric)
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case is_master.to_i
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when 1
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"#@host:#@port"
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else
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doc['remote']
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end
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end
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# Close the connection to the database.
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def close
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if @socket
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s = @socket
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@socket = nil
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s.close
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end
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end
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def connected?
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@socket != nil
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end
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def receive_full(length)
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message = ""
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while message.length < length do
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chunk = @socket.recv(length - message.length)
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raise "connection closed" unless chunk.length > 0
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message += chunk
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end
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message
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end
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# Send a MsgMessage to the database.
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def send_message(msg)
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send_to_db(MsgMessage.new(msg))
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end
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# Returns a Cursor over the query results.
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#
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# Note that the query gets sent lazily; the cursor calls
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# #send_query_message when needed. If the caller never requests an
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# object from the cursor, the query never gets sent.
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def query(collection, query)
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Cursor.new(self, collection, query)
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end
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# Used by a Cursor to lazily send the query to the database.
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def send_query_message(query_message)
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@semaphore.synchronize {
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send_to_db(query_message)
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}
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end
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# Remove the records that match +selector+ from +collection_name+.
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# Normally called by Collection#remove or Collection#clear.
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def remove_from_db(collection_name, selector)
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@semaphore.synchronize {
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send_to_db(RemoveMessage.new(@name, collection_name, selector))
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}
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end
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# Update records in +collection_name+ that match +selector+ by
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# applying +obj+ as an update. Normally called by Collection#replace.
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def replace_in_db(collection_name, selector, obj)
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@semaphore.synchronize {
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send_to_db(UpdateMessage.new(@name, collection_name, selector, obj, false))
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}
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end
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# Alias for #replace_in_db. Normally called by Collection.modify.
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alias_method :modify_in_db, :replace_in_db
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# Update records in +collection_name+ that match +selector+ by
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# applying +obj+ as an update. If no match, inserts (???). Normally
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# called by Collection#repsert.
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def repsert_in_db(collection_name, selector, obj)
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@semaphore.synchronize {
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obj = @pk_factory.create_pk(obj) if @pk_factory
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send_to_db(UpdateMessage.new(@name, collection_name, selector, obj, true))
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obj
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}
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end
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# Return the number of records in +collection_name+ that match
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# +selector+. If +selector+ is +nil+ or an empty hash, returns the
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# count of all records. Normally called by Collection#count.
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def count(collection_name, selector={})
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oh = OrderedHash.new
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oh[:count] = collection_name
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oh[:query] = selector || {}
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doc = db_command(oh)
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return doc['n'].to_i if ok?(doc)
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raise "Error with count command: #{doc.inspect}"
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end
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# Evaluate a JavaScript expression on MongoDB.
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# +code+ should be a string or Code instance containing a JavaScript
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# expression. Additional arguments will be passed to that expression
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# when it is run on the server.
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def eval(code, *args)
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if not code.is_a? Code
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code = Code.new(code)
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end
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oh = OrderedHash.new
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oh[:$eval] = code
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oh[:args] = args
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doc = db_command(oh)
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return doc['retval'] if ok?(doc)
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raise "Error with eval command: #{doc.inspect}"
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end
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# Drop index +name+ from +collection_name+. Normally called from
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# Collection#drop_index or Collection#drop_indexes.
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def drop_index(collection_name, name)
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oh = OrderedHash.new
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oh[:deleteIndexes] = collection_name
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oh[:index] = name
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doc = db_command(oh)
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raise "Error with drop_index command: #{doc.inspect}" unless ok?(doc)
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end
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# Return an array of hashes, one for each index on +collection_name+.
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# Normally called by Collection#index_information. Each hash contains:
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#
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# :name :: Index name
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#
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# :keys :: Hash whose keys are the names of the fields that make up
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# the key and values are integers.
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#
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# :ns :: Namespace; same as +collection_name+.
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def index_information(collection_name)
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sel = {:ns => full_coll_name(collection_name)}
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query(Collection.new(self, SYSTEM_INDEX_COLLECTION), Query.new(sel)).collect { |row|
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h = {:name => row['name']}
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raise "Name of index on return from db was nil. Coll = #{full_coll_name(collection_name)}" unless h[:name]
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h[:keys] = row['key']
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raise "Keys for index on return from db was nil. Coll = #{full_coll_name(collection_name)}" unless h[:keys]
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h[:ns] = row['ns']
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raise "Namespace for index on return from db was nil. Coll = #{full_coll_name(collection_name)}" unless h[:ns]
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h[:ns].sub!(/.*\./, '')
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raise "Error: ns != collection" unless h[:ns] == collection_name
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h
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}
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end
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# Create a new index on +collection_name+. +field_or_spec+
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# should be either a single field name or a Array of [field name,
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# direction] pairs. Directions should be specified as
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# XGen::Mongo::ASCENDING or XGen::Mongo::DESCENDING. Normally called
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# by Collection#create_index. If +unique+ is true the index will
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# enforce a uniqueness constraint.
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def create_index(collection_name, field_or_spec, unique=false)
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field_h = OrderedHash.new
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if field_or_spec.is_a? String
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field_h[field_or_spec] = 1
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else
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field_or_spec.each { |f| field_h[f[0]] = f[1] }
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end
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name = gen_index_name(field_h)
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sel = {
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:name => name,
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:ns => full_coll_name(collection_name),
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:key => field_h,
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:unique => unique
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}
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@semaphore.synchronize {
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send_to_db(InsertMessage.new(@name, SYSTEM_INDEX_COLLECTION, sel))
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}
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name
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end
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# Insert +objects+ into +collection_name+. Normally called by
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# Collection#insert. Returns a new array containing +objects+,
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# possibly modified by @pk_factory.
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def insert_into_db(collection_name, objects)
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@semaphore.synchronize {
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objects.collect { |o|
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o = @pk_factory.create_pk(o) if @pk_factory
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send_to_db(InsertMessage.new(@name, collection_name, o))
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o
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}
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}
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end
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def send_to_db(message)
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connect_to_master if !connected? && @auto_reconnect
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begin
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@socket.print(message.buf.to_s)
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@socket.flush
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rescue => ex
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close
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raise ex
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end
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end
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def full_coll_name(collection_name)
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"#{@name}.#{collection_name}"
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end
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# Return +true+ if +doc+ contains an 'ok' field with the value 1.
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def ok?(doc)
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ok = doc['ok']
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ok.kind_of?(Numeric) && ok.to_i == 1
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end
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# DB commands need to be ordered, so selector must be an OrderedHash
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# (or a Hash with only one element). What DB commands really need is
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# that the "command" key be first.
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#
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# Do not call this. Intended for driver use only.
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def db_command(selector)
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if !selector.kind_of?(OrderedHash)
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if !selector.kind_of?(Hash) || selector.keys.length > 1
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raise "db_command must be given an OrderedHash when there is more than one key"
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end
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end
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q = Query.new(selector)
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q.number_to_return = 1
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query(Collection.new(self, SYSTEM_COMMAND_COLLECTION), q).next_object
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end
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private
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|
def hash_password(username, plaintext)
|
|
Digest::MD5.hexdigest("#{username}:mongo:#{plaintext}")
|
|
end
|
|
|
|
def gen_index_name(spec)
|
|
temp = []
|
|
spec.each_pair { |field, direction|
|
|
temp = temp.push("#{field}_#{direction}")
|
|
}
|
|
return temp.join("_")
|
|
end
|
|
end
|
|
end
|
|
end
|
|
end
|