mongo-ruby-driver/lib/mongo/db.rb
2010-01-08 19:11:49 -05:00

469 lines
16 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.
# ++
require 'socket'
require 'timeout'
require 'digest/md5'
require 'thread'
module Mongo
# A MongoDB database.
class DB
SYSTEM_NAMESPACE_COLLECTION = "system.namespaces"
SYSTEM_INDEX_COLLECTION = "system.indexes"
SYSTEM_PROFILE_COLLECTION = "system.profile"
SYSTEM_USER_COLLECTION = "system.users"
SYSTEM_COMMAND_COLLECTION = "$cmd"
# Counter for generating unique request ids.
@@current_request_id = 0
# Strict mode enforces collection existence checks. When +true+,
# asking for a collection that does not exist, or trying to create a
# collection that already exists, raises an error.
#
# Strict mode is disabled by default, but enabled (+true+) at any time.
attr_writer :strict
# Returns the value of the +strict+ flag.
def strict?; @strict; end
# The name of the database.
attr_reader :name
# The Mongo::Connection instance connecting to the MongoDB server.
attr_reader :connection
# An array of [host, port] pairs.
attr_reader :nodes
# The logger instance if :logger is passed to initialize.
attr_reader :logger
# Instances of DB are normally obtained by calling Mongo#db.
#
# db_name :: The database name
#
# nodes :: An array of [host, port] pairs. See Connection#new, which offers
# a more flexible way of defining nodes.
#
# options :: A hash of options.
#
# Options:
#
# :strict :: If true, collections must exist to be accessed and must
# not exist to be created. See #collection and #create_collection.
#
# :pk :: A primary key factory object that must respond to :create_pk,
# which should take a hash and return a hash which merges the
# original hash with any primary key fields the factory wishes
# to inject. (NOTE: if the object already has a primary key,
# the factory should not inject a new key; this means that the
# object is being used in a repsert but it already exists.) The
# idea here is that when ever a record is inserted, the :pk
# object's +create_pk+ method will be called and the new hash
# returned will be inserted.
#
# :slave_ok :: Only used if +nodes+ contains only one host/port. If
# false, when connecting to that host/port we check to
# see if the server is the master. If it is not, an error
# is thrown.
#
# :logger :: Optional Logger instance to which driver usage information
# will be logged.
#
# :auto_reconnect :: DEPRECATED. See http://www.mongodb.org/display/DOCS/Replica+Pairs+in+Ruby
def initialize(db_name, connection, options={})
@name = validate_db_name(db_name)
@connection = connection
@strict = options[:strict]
@pk_factory = options[:pk]
end
# Returns true if +username+ has +password+ in
# +SYSTEM_USER_COLLECTION+. +name+ is username, +password+ is
# plaintext password.
def authenticate(username, password)
doc = command(:getnonce => 1)
raise "error retrieving nonce: #{doc}" unless ok?(doc)
nonce = doc['nonce']
auth = OrderedHash.new
auth['authenticate'] = 1
auth['user'] = username
auth['nonce'] = nonce
auth['key'] = Digest::MD5.hexdigest("#{nonce}#{username}#{hash_password(username, password)}")
ok?(command(auth))
end
# Deauthorizes use for this database for this connection.
def logout
doc = command(:logout => 1)
return true if ok?(doc)
raise "error logging out: #{doc.inspect}"
end
# Returns an array of collection names in this database.
def collection_names
names = collections_info.collect { |doc| doc['name'] || '' }
names = names.delete_if {|name| name.index(@name).nil? || name.index('$')}
names.map {|name| name.sub(@name + '.', '')}
end
# Retuns an array of Collection instances, one for each collection in this
# database.
def collections
collection_names.map do |collection_name|
Collection.new(self, collection_name)
end
end
# Returns a cursor over query result hashes. Each hash contains a
# 'name' string and optionally an 'options' hash. If +coll_name+ is
# specified, an array of length 1 is returned.
def collections_info(coll_name=nil)
selector = {}
selector[:name] = full_collection_name(coll_name) if coll_name
Cursor.new(Collection.new(self, SYSTEM_NAMESPACE_COLLECTION), :selector => selector)
end
# Create a collection. If +strict+ is false, will return existing or
# new collection. If +strict+ is true, will raise an error if
# collection +name+ already exists.
#
# Options is an optional hash:
#
# :capped :: Boolean. If not specified, capped is +false+.
#
# :size :: If +capped+ is +true+, specifies the maximum number of
# bytes. If +false+, specifies the initial extent of the
# collection.
#
# :max :: Max number of records in a capped collection. Optional.
def create_collection(name, options={})
# First check existence
if collection_names.include?(name)
if strict?
raise "Collection #{name} already exists. Currently in strict mode."
else
return Collection.new(self, name)
end
end
# Create new collection
oh = OrderedHash.new
oh[:create] = name
doc = command(oh.merge(options || {}))
ok = doc['ok']
return Collection.new(self, name, @pk_factory) if ok.kind_of?(Numeric) && (ok.to_i == 1 || ok.to_i == 0)
raise "Error creating collection: #{doc.inspect}"
end
# @deprecated all the admin methods are now included in the DB class.
def admin
warn "DB#admin has been DEPRECATED. All the admin functions are now available in the DB class itself."
Admin.new(self)
end
# Return a collection. If +strict+ is false, will return existing or
# new collection. If +strict+ is true, will raise an error if
# collection +name+ does not already exists.
def collection(name)
return Collection.new(self, name, @pk_factory) if !strict? || collection_names.include?(name)
raise "Collection #{name} doesn't exist. Currently in strict mode."
end
alias_method :[], :collection
# Drop collection +name+. Returns +true+ on success or if the
# collection does not exist, +false+ otherwise.
def drop_collection(name)
return true unless collection_names.include?(name)
ok?(command(:drop => name))
end
# Returns the error message from the most recently executed database
# operation for this connection, or +nil+ if there was no error.
def error
doc = command(:getlasterror => 1)
raise "error retrieving last error: #{doc}" unless ok?(doc)
doc['err']
end
# Get status information from the last operation on this connection.
def last_status
command(:getlasterror => 1)
end
# Returns +true+ if an error was caused by the most recently executed
# database operation.
def error?
error != nil
end
# Get the most recent error to have occured on this database
#
# Only returns errors that have occured since the last call to
# DB#reset_error_history - returns +nil+ if there is no such error.
def previous_error
error = command(:getpreverror => 1)
if error["err"]
error
else
nil
end
end
# Reset the error history of this database
#
# Calls to DB#previous_error will only return errors that have occurred
# since the most recent call to this method.
def reset_error_history
command(:reseterror => 1)
end
# Returns a Cursor over the query results.
#
# Note that the query gets sent lazily; the cursor calls
# #send_query_message when needed. If the caller never requests an
# object from the cursor, the query never gets sent.
def query(collection, query, admin=false)
Cursor.new(self, collection, query, admin)
end
# Dereference a DBRef, getting the document it points to.
def dereference(dbref)
collection(dbref.namespace).find_one("_id" => dbref.object_id)
end
# Evaluate a JavaScript expression on MongoDB.
# +code+ should be a string or Code instance containing a JavaScript
# expression. Additional arguments will be passed to that expression
# when it is run on the server.
def eval(code, *args)
if not code.is_a? Code
code = Code.new(code)
end
oh = OrderedHash.new
oh[:$eval] = code
oh[:args] = args
doc = command(oh)
return doc['retval'] if ok?(doc)
raise OperationFailure, "eval failed: #{doc['errmsg']}"
end
# Rename collection +from+ to +to+. Meant to be called by
# Collection#rename.
def rename_collection(from, to)
oh = OrderedHash.new
oh[:renameCollection] = "#{@name}.#{from}"
oh[:to] = "#{@name}.#{to}"
doc = command(oh, true)
raise "Error renaming collection: #{doc.inspect}" unless ok?(doc)
end
# Drop index +name+ from +collection_name+. Normally called from
# Collection#drop_index or Collection#drop_indexes.
def drop_index(collection_name, name)
oh = OrderedHash.new
oh[:deleteIndexes] = collection_name
oh[:index] = name
doc = command(oh)
raise "Error with drop_index command: #{doc.inspect}" unless ok?(doc)
end
# Get information on the indexes for the collection +collection_name+.
# Normally called by Collection#index_information. Returns a hash where
# the keys are index names (as returned by Collection#create_index and
# the values are lists of [key, direction] pairs specifying the index
# (as passed to Collection#create_index).
def index_information(collection_name)
sel = {:ns => full_collection_name(collection_name)}
info = {}
Cursor.new(Collection.new(self, SYSTEM_INDEX_COLLECTION), :selector => sel).each { |index|
info[index['name']] = index['key'].map {|k| k}
}
info
end
# Create a new index on +collection_name+. +field_or_spec+
# should be either a single field name or a Array of [field name,
# direction] pairs. Directions should be specified as
# Mongo::ASCENDING or Mongo::DESCENDING. Normally called
# by Collection#create_index. If +unique+ is true the index will
# enforce a uniqueness constraint.
def create_index(collection_name, field_or_spec, unique=false)
self.collection(collection_name).create_index(field_or_spec, unique)
end
# Return +true+ if +doc+ contains an 'ok' field with the value 1.
def ok?(doc)
ok = doc['ok']
ok.kind_of?(Numeric) && ok.to_i == 1
end
# DB commands need to be ordered, so selector must be an OrderedHash
# (or a Hash with only one element). What DB commands really need is
# that the "command" key be first.
def command(selector, use_admin_db=false, sock=nil)
if !selector.kind_of?(OrderedHash)
if !selector.kind_of?(Hash) || selector.keys.length > 1
raise "command must be given an OrderedHash when there is more than one key"
end
end
cursor = Cursor.new(Collection.new(self, SYSTEM_COMMAND_COLLECTION), :admin => use_admin_db, :limit => -1, :selector => selector, :socket => sock)
cursor.next_document
end
# Sends a command to the database.
#
# :selector (required) :: An OrderedHash, or a standard Hash with just one
# key, specifying the command to be performed.
#
# :admin (optional) :: If true, the command will be executed on the admin
# collection.
#
# :check_response (optional) :: If true, will raise an exception if the
# command fails.
#
# Note: DB commands must start with the "command" key. For this reason,
# any selector containing more than one key must be an OrderedHash.
def command(selector, admin=false, check_response=false, sock=nil)
raise MongoArgumentError, "command must be given a selector" unless selector.is_a?(Hash) && !selector.empty?
if selector.class.eql?(Hash) && selector.keys.length > 1
raise MongoArgumentError, "DB#command requires an OrderedHash when hash contains multiple keys"
end
result = Cursor.new(system_command_collection, :admin => admin,
:limit => -1, :selector => selector, :socket => sock).next_document
if check_response && !ok?(result)
raise OperationFailure, "Database command '#{selector.keys.first}' failed."
else
result
end
end
# @deprecated please use DB#command instead.
def db_command(*args)
warn "DB#db_command has been DEPRECATED. Please use DB#command instead."
command(args[0], args[1])
end
def full_collection_name(collection_name)
"#{@name}.#{collection_name}"
end
# The primary key factory object (or +nil+).
def pk_factory
@pk_factory
end
# Specify a primary key factory if not already set.
#
# @raise [MongoArgumentError] if the primary key factory has already been set.
def pk_factory=(pk_factory)
if @pk_factory
raise MongoArgumentError, "Cannot change primary key factory once it's been set"
end
@pk_factory = pk_factory
end
# Return the current database profiling level.
#
# @return [Symbol] :off, :slow_only, or :all
def profiling_level
oh = OrderedHash.new
oh[:profile] = -1
doc = command(oh)
raise "Error with profile command: #{doc.inspect}" unless ok?(doc) && doc['was'].kind_of?(Numeric)
case doc['was'].to_i
when 0
:off
when 1
:slow_only
when 2
:all
else
raise "Error: illegal profiling level value #{doc['was']}"
end
end
# Set database profiling level to :off, :slow_only, or :all.
def profiling_level=(level)
oh = OrderedHash.new
oh[:profile] = case level
when :off
0
when :slow_only
1
when :all
2
else
raise "Error: illegal profiling level value #{level}"
end
doc = command(oh)
raise "Error with profile command: #{doc.inspect}" unless ok?(doc)
end
# Returns an array containing current profiling information.
def profiling_info
Cursor.new(Collection.new(self, DB::SYSTEM_PROFILE_COLLECTION), :selector => {}).to_a
end
# Validate a named collection by raising an exception if there is a
# problem or returning an interesting hash (see especially the
# 'result' string value) if all is well.
def validate_collection(name)
doc = command(:validate => name)
raise "Error with validate command: #{doc.inspect}" unless ok?(doc)
result = doc['result']
raise "Error with validation data: #{doc.inspect}" unless result.kind_of?(String)
raise "Error: invalid collection #{name}: #{doc.inspect}" if result =~ /\b(exception|corrupt)\b/i
doc
end
private
def hash_password(username, plaintext)
Digest::MD5.hexdigest("#{username}:mongo:#{plaintext}")
end
def system_command_collection
Collection.new(self, SYSTEM_COMMAND_COLLECTION)
end
def validate_db_name(db_name)
unless [String, Symbol].include?(db_name.class)
raise TypeError, "db_name must be a string or symbol"
end
[" ", ".", "$", "/", "\\"].each do |invalid_char|
if db_name.include? invalid_char
raise InvalidName, "database names cannot contain the character '#{invalid_char}'"
end
end
raise InvalidName, "database name cannot be the empty string" if db_name.empty?
db_name
end
end
end