database.py

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# Copyright 2009-2010 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.

"""Database level operations."""

import warnings

from bson.code import Code
from bson.dbref import DBRef
from bson.son import SON
from pymongo import helpers
from pymongo.collection import Collection
from pymongo.errors import (CollectionInvalid,
                            InvalidName,
                            OperationFailure)
from pymongo.son_manipulator import ObjectIdInjector


def _check_name(name):
    """Check if a database name is valid.
    """
    if not name:
        raise InvalidName("database name cannot be the empty string")

    for invalid_char in [" ", ".", "$", "/", "\\"]:
        if invalid_char in name:
            raise InvalidName("database names cannot contain the "
                              "character %r" % invalid_char)


class Database(object):
    """A Mongo database.
    """

    def __init__(self, connection, name):
        """Get a database by connection and name.

        Raises :class:`TypeError` if `name` is not an instance of
        :class:`basestring`. Raises
        :class:`~pymongo.errors.InvalidName` if `name` is not a valid
        database name.

        :Parameters:
          - `connection`: a :class:`~pymongo.connection.Connection`
            instance
          - `name`: database name

        .. mongodoc:: databases
        """
        if not isinstance(name, basestring):
            raise TypeError("name must be an instance of basestring")

        _check_name(name)

        self.__name = unicode(name)
        self.__connection = connection

        self.__incoming_manipulators = []
        self.__incoming_copying_manipulators = []
        self.__outgoing_manipulators = []
        self.__outgoing_copying_manipulators = []
        self.add_son_manipulator(ObjectIdInjector())
        self.__system_js = SystemJS(self)

    def add_son_manipulator(self, manipulator):
        """Add a new son manipulator to this database.

        Newly added manipulators will be applied before existing ones.

        :Parameters:
          - `manipulator`: the manipulator to add
        """
        def method_overwritten(instance, method):
            return getattr(instance, method) != \
                getattr(super(instance.__class__, instance), method)

        if manipulator.will_copy():
            if method_overwritten(manipulator, "transform_incoming"):
                self.__incoming_copying_manipulators.insert(0, manipulator)
            if method_overwritten(manipulator, "transform_outgoing"):
                self.__outgoing_copying_manipulators.insert(0, manipulator)
        else:
            if method_overwritten(manipulator, "transform_incoming"):
                self.__incoming_manipulators.insert(0, manipulator)
            if method_overwritten(manipulator, "transform_outgoing"):
                self.__outgoing_manipulators.insert(0, manipulator)

    @property
    def system_js(self):
        """A :class:`SystemJS` helper for this :class:`Database`.

        See the documentation for :class:`SystemJS` for more details.

        .. versionadded:: 1.5
        """
        return self.__system_js

    @property
    def connection(self):
        """The :class:`~pymongo.connection.Connection` instance for this
        :class:`Database`.

        .. versionchanged:: 1.3
           ``connection`` is now a property rather than a method.
        """
        return self.__connection

    @property
    def name(self):
        """The name of this :class:`Database`.

        .. versionchanged:: 1.3
           ``name`` is now a property rather than a method.
        """
        return self.__name

    def __cmp__(self, other):
        if isinstance(other, Database):
            return cmp((self.__connection, self.__name),
                       (other.__connection, other.__name))
        return NotImplemented

    def __repr__(self):
        return "Database(%r, %r)" % (self.__connection, self.__name)

    def __getattr__(self, name):
        """Get a collection of this database by name.

        Raises InvalidName if an invalid collection name is used.

        :Parameters:
          - `name`: the name of the collection to get
        """
        return Collection(self, name)

    def __getitem__(self, name):
        """Get a collection of this database by name.

        Raises InvalidName if an invalid collection name is used.

        :Parameters:
          - `name`: the name of the collection to get
        """
        return self.__getattr__(name)

    def create_collection(self, name, options=None, **kwargs):
        """Create a new :class:`~pymongo.collection.Collection` in this
        database.

        Normally collection creation is automatic. This method should
        only be used to specify options on
        creation. :class:`~pymongo.errors.CollectionInvalid` will be
        raised if the collection already exists.

        Options should be passed as keyword arguments to this
        method. Any of the following options are valid:

          - "size": desired initial size for the collection (in
            bytes). must be less than or equal to 10000000000. For
            capped collections this size is the max size of the
            collection.
          - "capped": if True, this is a capped collection
          - "max": maximum number of objects if capped (optional)

        :Parameters:
          - `name`: the name of the collection to create
          - `options`: DEPRECATED options to use on the new collection
          - `**kwargs` (optional): additional keyword arguments will
            be passed as options for the create collection command

        .. versionchanged:: 1.5
           deprecating `options` in favor of kwargs
        """
        opts = {"create": True}
        if options is not None:
            warnings.warn("the options argument to create_collection is "
                          "deprecated and will be removed. please use "
                          "kwargs instead.", DeprecationWarning)
            opts.update(options)
        opts.update(kwargs)

        if name in self.collection_names():
            raise CollectionInvalid("collection %s already exists" % name)

        return Collection(self, name, **opts)

    def _fix_incoming(self, son, collection):
        """Apply manipulators to an incoming SON object before it gets stored.

        :Parameters:
          - `son`: the son object going into the database
          - `collection`: the collection the son object is being saved in
        """
        for manipulator in self.__incoming_manipulators:
            son = manipulator.transform_incoming(son, collection)
        for manipulator in self.__incoming_copying_manipulators:
            son = manipulator.transform_incoming(son, collection)
        return son

    def _fix_outgoing(self, son, collection):
        """Apply manipulators to a SON object as it comes out of the database.

        :Parameters:
          - `son`: the son object coming out of the database
          - `collection`: the collection the son object was saved in
        """
        for manipulator in reversed(self.__outgoing_manipulators):
            son = manipulator.transform_outgoing(son, collection)
        for manipulator in reversed(self.__outgoing_copying_manipulators):
            son = manipulator.transform_outgoing(son, collection)
        return son

    def command(self, command, value=1,
                check=True, allowable_errors=[], **kwargs):
        """Issue a MongoDB command.

        Send command `command` to the database and return the
        response. If `command` is an instance of :class:`basestring`
        then the command {`command`: `value`} will be sent. Otherwise,
        `command` must be an instance of :class:`dict` and will be
        sent as is.

        Any additional keyword arguments will be added to the final
        command document before it is sent.

        For example, a command like ``{buildinfo: 1}`` can be sent
        using:

        >>> db.command("buildinfo")

        For a command where the value matters, like ``{collstats:
        collection_name}`` we can do:

        >>> db.command("collstats", collection_name)

        For commands that take additional arguments we can use
        kwargs. So ``{filemd5: object_id, root: file_root}`` becomes:

        >>> db.command("filemd5", object_id, root=file_root)

        :Parameters:
          - `command`: document representing the command to be issued,
            or the name of the command (for simple commands only).

            .. note:: the order of keys in the `command` document is
               significant (the "verb" must come first), so commands
               which require multiple keys (e.g. `findandmodify`)
               should use an instance of :class:`~bson.son.SON` or
               a string and kwargs instead of a Python `dict`.

          - `value` (optional): value to use for the command verb when
            `command` is passed as a string
          - `check` (optional): check the response for errors, raising
            :class:`~pymongo.errors.OperationFailure` if there are any
          - `allowable_errors`: if `check` is ``True``, error messages
            in this list will be ignored by error-checking
          - `**kwargs` (optional): additional keyword arguments will
            be added to the command document before it is sent

        .. versionchanged:: 1.6
           Added the `value` argument for string commands, and keyword
           arguments for additional command options.
        .. versionchanged:: 1.5
           `command` can be a string in addition to a full document.
        .. versionadded:: 1.4

        .. mongodoc:: commands
        """

        if isinstance(command, basestring):
            command = SON([(command, value)])

        command.update(kwargs)

        result = self["$cmd"].find_one(command,
                                       _must_use_master=True,
                                       _is_command=True)

        if check:
            msg = "command %r failed: %%s" % command
            helpers._check_command_response(result, self.connection.disconnect,
                                            msg, allowable_errors)

        return result

    def collection_names(self):
        """Get a list of all the collection names in this database.
        """
        results = self["system.namespaces"].find(_must_use_master=True)
        names = [r["name"] for r in results]
        names = [n[len(self.__name) + 1:] for n in names
                 if n.startswith(self.__name + ".")]
        names = [n for n in names if "$" not in n]
        return names

    def drop_collection(self, name_or_collection):
        """Drop a collection.

        :Parameters:
          - `name_or_collection`: the name of a collection to drop or the
            collection object itself
        """
        name = name_or_collection
        if isinstance(name, Collection):
            name = name.name

        if not isinstance(name, basestring):
            raise TypeError("name_or_collection must be an instance of "
                            "(Collection, str, unicode)")

        self.__connection._purge_index(self.__name, name)

        self.command("drop", unicode(name), allowable_errors=["ns not found"])

    def validate_collection(self, name_or_collection):
        """Validate a collection.

        Returns a string of validation info. Raises CollectionInvalid if
        validation fails.
        """
        name = name_or_collection
        if isinstance(name, Collection):
            name = name.name

        if not isinstance(name, basestring):
            raise TypeError("name_or_collection must be an instance of "
                            "(Collection, str, unicode)")

        result = self.command("validate", unicode(name))

        info = result["result"]
        if info.find("exception") != -1 or info.find("corrupt") != -1:
            raise CollectionInvalid("%s invalid: %s" % (name, info))
        return info

    def profiling_level(self):
        """Get the database's current profiling level.

        Returns one of (:data:`~pymongo.OFF`,
        :data:`~pymongo.SLOW_ONLY`, :data:`~pymongo.ALL`).

        .. mongodoc:: profiling
        """
        result = self.command("profile", -1)

        assert result["was"] >= 0 and result["was"] <= 2
        return result["was"]

    def set_profiling_level(self, level):
        """Set the database's profiling level.

        Raises :class:`ValueError` if level is not one of
        (:data:`~pymongo.OFF`, :data:`~pymongo.SLOW_ONLY`,
        :data:`~pymongo.ALL`).

        :Parameters:
          - `level`: the profiling level to use

        .. mongodoc:: profiling
        """
        if not isinstance(level, int) or level < 0 or level > 2:
            raise ValueError("level must be one of (OFF, SLOW_ONLY, ALL)")

        self.command("profile", level)

    def profiling_info(self):
        """Returns a list containing current profiling information.

        .. mongodoc:: profiling
        """
        return list(self["system.profile"].find())

    def error(self):
        """Get a database error if one occured on the last operation.

        Return None if the last operation was error-free. Otherwise return the
        error that occurred.
        """
        error = self.command("getlasterror")
        if error.get("err", 0) is None:
            return None
        if error["err"] == "not master":
            self.__connection.disconnect()
        return error

    def last_status(self):
        """Get status information from the last operation.

        Returns a SON object with status information.
        """
        return self.command("getlasterror")

    def previous_error(self):
        """Get the most recent error to have occurred on this database.

        Only returns errors that have occurred since the last call to
        `Database.reset_error_history`. Returns None if no such errors have
        occurred.
        """
        error = self.command("getpreverror")
        if error.get("err", 0) is None:
            return None
        return error

    def reset_error_history(self):
        """Reset the error history of this database.

        Calls to `Database.previous_error` will only return errors that have
        occurred since the most recent call to this method.
        """
        self.command("reseterror")

    def __iter__(self):
        return self

    def next(self):
        raise TypeError("'Database' object is not iterable")

    def add_user(self, name, password):
        """Create user `name` with password `password`.

        Add a new user with permissions for this :class:`Database`.

        .. note:: Will change the password if user `name` already exists.

        :Parameters:
          - `name`: the name of the user to create
          - `password`: the password of the user to create

        .. versionadded:: 1.4
        """
        pwd = helpers._password_digest(name, password)
        self.system.users.update({"user": name},
                                 {"user": name,
                                  "pwd": pwd},
                                 upsert=True, safe=True)

    def remove_user(self, name):
        """Remove user `name` from this :class:`Database`.

        User `name` will no longer have permissions to access this
        :class:`Database`.

        :Parameters:
          - `name`: the name of the user to remove

        .. versionadded:: 1.4
        """
        self.system.users.remove({"user": name}, safe=True)

    def authenticate(self, name, password):
        """Authenticate to use this database.

        Once authenticated, the user has full read and write access to
        this database. Raises :class:`TypeError` if either `name` or
        `password` is not an instance of ``(str,
        unicode)``. Authentication lasts for the life of the database
        connection, or until :meth:`logout` is called.

        The "admin" database is special. Authenticating on "admin"
        gives access to *all* databases. Effectively, "admin" access
        means root access to the database.

        .. note:: Currently, authentication is per
           :class:`~socket.socket`. This means that there are a couple
           of situations in which re-authentication is necessary:

           - On failover (when an
             :class:`~pymongo.errors.AutoReconnect` exception is
             raised).

           - After a call to
             :meth:`~pymongo.connection.Connection.disconnect` or
             :meth:`~pymongo.connection.Connection.end_request`.

           - When sharing a :class:`~pymongo.connection.Connection`
             between multiple threads, each thread will need to
             authenticate separately.

        .. warning:: Currently, calls to
           :meth:`~pymongo.connection.Connection.end_request` will
           lead to unpredictable behavior in combination with
           auth. The :class:`~socket.socket` owned by the calling
           thread will be returned to the pool, so whichever thread
           uses that :class:`~socket.socket` next will have whatever
           permissions were granted to the calling thread.

        :Parameters:
          - `name`: the name of the user to authenticate
          - `password`: the password of the user to authenticate

        .. mongodoc:: authenticate
        """
        if not isinstance(name, basestring):
            raise TypeError("name must be an instance of basestring")
        if not isinstance(password, basestring):
            raise TypeError("password must be an instance of basestring")

        nonce = self.command("getnonce")["nonce"]
        key = helpers._auth_key(nonce, name, password)
        try:
            self.command("authenticate", user=unicode(name),
                         nonce=nonce, key=key)
            return True
        except OperationFailure:
            return False

    def logout(self):
        """Deauthorize use of this database for this connection.

        Note that other databases may still be authorized.
        """
        self.command("logout")

    def dereference(self, dbref):
        """Dereference a :class:`~bson.dbref.DBRef`, getting the
        document it points to.

        Raises :class:`TypeError` if `dbref` is not an instance of
        :class:`~bson.dbref.DBRef`. Returns a document, or ``None`` if
        the reference does not point to a valid document.  Raises
        :class:`ValueError` if `dbref` has a database specified that
        is different from the current database.

        :Parameters:
          - `dbref`: the reference
        """
        if not isinstance(dbref, DBRef):
            raise TypeError("cannot dereference a %s" % type(dbref))
        if dbref.database is not None and dbref.database != self.__name:
            raise ValueError("trying to dereference a DBRef that points to "
                             "another database (%r not %r)" % (dbref.database,
                                                               self.__name))
        return self[dbref.collection].find_one({"_id": dbref.id})

    def eval(self, code, *args):
        """Evaluate a JavaScript expression in MongoDB.

        Useful if you need to touch a lot of data lightly; in such a
        scenario the network transfer of the data could be a
        bottleneck. The `code` argument must be a JavaScript
        function. Additional positional arguments will be passed to
        that function when it is run on the server.

        Raises :class:`TypeError` if `code` is not an instance of
        (str, unicode, `Code`). Raises
        :class:`~pymongo.errors.OperationFailure` if the eval
        fails. Returns the result of the evaluation.

        :Parameters:
          - `code`: string representation of JavaScript code to be
            evaluated
          - `args` (optional): additional positional arguments are
            passed to the `code` being evaluated
        """
        if not isinstance(code, Code):
            code = Code(code)

        result = self.command("$eval", code, args=args)
        return result.get("retval", None)

    def __call__(self, *args, **kwargs):
        """This is only here so that some API misusages are easier to debug.
        """
        raise TypeError("'Database' object is not callable. If you meant to "
                        "call the '%s' method on a 'Connection' object it is "
                        "failing because no such method exists." % self.__name)


class SystemJS(object):
    """Helper class for dealing with stored JavaScript.
    """

    def __init__(self, database):
        """Get a system js helper for the database `database`.

        An instance of :class:`SystemJS` is automatically created for
        each :class:`Database` instance as :attr:`Database.system_js`,
        manual instantiation of this class should not be necessary.

        :class:`SystemJS` instances allow for easy manipulation and
        access to server-side JavaScript:

        .. doctest::

          >>> db.system_js.add1 = "function (x) { return x + 1; }"
          >>> db.system.js.find({"_id": "add1"}).count()
          1
          >>> db.system_js.add1(5)
          6.0
          >>> del db.system_js.add1
          >>> db.system.js.find({"_id": "add1"}).count()
          0

        .. note:: Requires server version **>= 1.1.1**

        .. versionadded:: 1.5
        """
        # can't just assign it since we've overridden __setattr__
        object.__setattr__(self, "_db", database)

    def __setattr__(self, name, code):
        self._db.system.js.save({"_id": name, "value": Code(code)}, safe=True)

    def __delattr__(self, name):
        self._db.system.js.remove({"_id": name}, safe=True)

    def __getattr__(self, name):
        return lambda *args: self._db.eval("function() { return %s.apply(this,"
                                           "arguments); }" % name, *args)

    def list(self):
        """Get a list of the names of the functions stored in this database.

        .. versionadded:: 1.9
        """
        return [x["_id"] for x in self._db.system.js.find(fields=["_id"])]

---

pymongo
Author(s): Bhaskara Marthi
autogenerated on Fri Jan 11 10:09:03 2013