150 lines
5.4 KiB
Python
150 lines
5.4 KiB
Python
# Copyright 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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"""Wrapper class for a Mongo database connection.
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Adds some nice functionality."""
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import socket
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import types
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import traceback
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import struct
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import database
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from connection import Connection
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from son import SON
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from son_manipulator import NamespaceInjector
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from objectid import ObjectId
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from dbref import DBRef
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from cursor_manager import BatchCursorManager
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ASCENDING = database.ASCENDING
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DESCENDING = database.DESCENDING
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class Mongo(database.Database):
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"""A connection to a Mongo database.
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"""
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def __init__(self, name, host="localhost", port=27017, settings={}):
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"""Open a new connection to the database at host:port.
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Raises TypeError if name or host is not an instance of string or port is
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not an instance of int. Raises ConnectionFailure if the connection
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cannot be made.
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Settings are passed in as a dictionary. Possible settings, along with
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their default values (in parens), are listed below:
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- "auto_dereference" (False): automatically dereference any `DBRef`s
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contained within SON objects being returned from queries
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- "auto_reference" (False): automatically create `DBRef`s out of any
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sub-objects that have already been saved in the database
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Arguments:
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- `name`: the name of the database to connect to
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- `host` (optional): the hostname or IPv4 address of the database to
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connect to
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- `port` (optional): the port number on which to connect
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- `settings` (optional): a dictionary of settings
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"""
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if not isinstance(settings, types.DictType):
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raise TypeError("settings must be an instance of dict")
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self.__auto_dereference = settings.get("auto_dereference", False)
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self.__auto_reference = settings.get("auto_reference", False)
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connection = Connection(host, port)
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connection.set_cursor_manager(BatchCursorManager)
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database.Database.__init__(self, connection, name)
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self.add_son_manipulator(NamespaceInjector(self))
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def __repr__(self):
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return "Mongo(%r, %r, %r)" % (self.name(), self.connection().host(), self.connection().port())
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def dereference(self, dbref):
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"""Dereference a DBRef, getting the SON object it points to.
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Raises TypeError if dbref is not an instance of DBRef. Returns a SON
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object or None if the reference does not point to a valid object.
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Arguments:
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- `dbref`: the reference
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"""
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if not isinstance(dbref, DBRef):
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raise TypeError("cannot dereference a %s" % type(dbref))
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return self[dbref.collection()].find_one(dbref.id())
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# TODO these should just be a SONManipulator, so we don't need to override
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# these two methods. I haven't done this yet because we aren't spending any
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# time on DBRef code right now.
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def _fix_outgoing(self, son, collection):
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"""Fixes an object coming out of the database.
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Used to do things like auto dereferencing, if the option is enabled.
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Arguments:
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- `son`: a SON object coming out of the database
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- `collection`: collection this object is being retrieved from
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"""
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son = database.Database._fix_outgoing(self, son, collection)
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if not self.__auto_dereference:
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return son
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def fix_value(value):
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if isinstance(value, DBRef):
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deref = self.dereference(value)
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if deref is None:
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return value
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return self._fix_outgoing(deref, collection)
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elif isinstance(value, (SON, types.DictType)):
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return self._fix_outgoing(value, collection)
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elif isinstance(value, types.ListType):
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return [fix_value(v) for v in value]
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return value
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for (key, value) in son.items():
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son[key] = fix_value(value)
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return son
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def _fix_incoming(self, to_save, collection):
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"""Fixes an object going in to the database.
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Used to do things like auto referencing, if the option is enabled.
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Will also add _id and _ns if they are missing and desired (as specified
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by add_meta).
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Arguments:
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- `to_save`: a SON object going into the database
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- `collection`: collection into which this object is being saved
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"""
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to_save = database.Database._fix_incoming(self, to_save, collection)
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if not self.__auto_reference:
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return to_save
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# make a copy, so only what is being saved gets auto-ref'ed
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to_save = SON(to_save)
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def fix_value(value):
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if isinstance(value, (SON, types.DictType)):
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if "_id" in value and not value["_id"].is_new() and "_ns" in value:
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return DBRef(value["_ns"], value["_id"])
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return value
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for (key, value) in to_save.items():
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to_save[key] = fix_value(value)
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return to_save
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