# Copyright 2009-present MongoDB, 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. """Cursor class to iterate over Mongo query results.""" import copy import datetime import warnings from collections import deque from bson import RE_TYPE from bson.code import Code from bson.py3compat import (iteritems, integer_types, string_type) from bson.son import SON from pymongo import helpers from pymongo.common import validate_boolean, validate_is_mapping from pymongo.collation import validate_collation_or_none from pymongo.errors import (AutoReconnect, ConnectionFailure, InvalidOperation, NotMasterError, OperationFailure) from pymongo.message import (_convert_exception, _CursorAddress, _GetMore, _RawBatchGetMore, _Query, _RawBatchQuery) from pymongo.read_preferences import ReadPreference _QUERY_OPTIONS = { "tailable_cursor": 2, "slave_okay": 4, "oplog_replay": 8, "no_timeout": 16, "await_data": 32, "exhaust": 64, "partial": 128} class CursorType(object): NON_TAILABLE = 0 """The standard cursor type.""" TAILABLE = _QUERY_OPTIONS["tailable_cursor"] """The tailable cursor type. Tailable cursors are only for use with capped collections. They are not closed when the last data is retrieved but are kept open and the cursor location marks the final document position. If more data is received iteration of the cursor will continue from the last document received. """ TAILABLE_AWAIT = TAILABLE | _QUERY_OPTIONS["await_data"] """A tailable cursor with the await option set. Creates a tailable cursor that will wait for a few seconds after returning the full result set so that it can capture and return additional data added during the query. """ EXHAUST = _QUERY_OPTIONS["exhaust"] """An exhaust cursor. MongoDB will stream batched results to the client without waiting for the client to request each batch, reducing latency. """ # This has to be an old style class due to # http://bugs.jython.org/issue1057 class _SocketManager: """Used with exhaust cursors to ensure the socket is returned. """ def __init__(self, sock, pool): self.sock = sock self.pool = pool self.__closed = False def __del__(self): self.close() def close(self): """Return this instance's socket to the connection pool. """ if not self.__closed: self.__closed = True self.pool.return_socket(self.sock) self.sock, self.pool = None, None class Cursor(object): """A cursor / iterator over Mongo query results. """ _query_class = _Query _getmore_class = _GetMore def __init__(self, collection, filter=None, projection=None, skip=0, limit=0, no_cursor_timeout=False, cursor_type=CursorType.NON_TAILABLE, sort=None, allow_partial_results=False, oplog_replay=False, modifiers=None, batch_size=0, manipulate=True, collation=None, hint=None, max_scan=None, max_time_ms=None, max=None, min=None, return_key=False, show_record_id=False, snapshot=False, comment=None, session=None): """Create a new cursor. Should not be called directly by application developers - see :meth:`~pymongo.collection.Collection.find` instead. .. mongodoc:: cursors """ # Initialize all attributes used in __del__ before possibly raising # an error to avoid attribute errors during garbage collection. self.__id = None self.__exhaust = False self.__exhaust_mgr = None self.__killed = False if session: self.__session = session self.__explicit_session = True else: self.__session = None self.__explicit_session = False spec = filter if spec is None: spec = {} validate_is_mapping("filter", spec) if not isinstance(skip, int): raise TypeError("skip must be an instance of int") if not isinstance(limit, int): raise TypeError("limit must be an instance of int") validate_boolean("no_cursor_timeout", no_cursor_timeout) if cursor_type not in (CursorType.NON_TAILABLE, CursorType.TAILABLE, CursorType.TAILABLE_AWAIT, CursorType.EXHAUST): raise ValueError("not a valid value for cursor_type") validate_boolean("allow_partial_results", allow_partial_results) validate_boolean("oplog_replay", oplog_replay) if modifiers is not None: warnings.warn("the 'modifiers' parameter is deprecated", DeprecationWarning, stacklevel=2) validate_is_mapping("modifiers", modifiers) if not isinstance(batch_size, integer_types): raise TypeError("batch_size must be an integer") if batch_size < 0: raise ValueError("batch_size must be >= 0") if projection is not None: if not projection: projection = {"_id": 1} projection = helpers._fields_list_to_dict(projection, "projection") self.__collection = collection self.__spec = spec self.__projection = projection self.__skip = skip self.__limit = limit self.__batch_size = batch_size self.__modifiers = modifiers and modifiers.copy() or {} self.__ordering = sort and helpers._index_document(sort) or None self.__max_scan = max_scan self.__explain = False self.__comment = comment self.__max_time_ms = max_time_ms self.__max_await_time_ms = None self.__max = max self.__min = min self.__manipulate = manipulate self.__collation = validate_collation_or_none(collation) self.__return_key = return_key self.__show_record_id = show_record_id self.__snapshot = snapshot self.__set_hint(hint) # Exhaust cursor support if cursor_type == CursorType.EXHAUST: if self.__collection.database.client.is_mongos: raise InvalidOperation('Exhaust cursors are ' 'not supported by mongos') if limit: raise InvalidOperation("Can't use limit and exhaust together.") self.__exhaust = True # This is ugly. People want to be able to do cursor[5:5] and # get an empty result set (old behavior was an # exception). It's hard to do that right, though, because the # server uses limit(0) to mean 'no limit'. So we set __empty # in that case and check for it when iterating. We also unset # it anytime we change __limit. self.__empty = False self.__data = deque() self.__address = None self.__retrieved = 0 self.__codec_options = collection.codec_options # Read preference is set when the initial find is sent. self.__read_preference = None self.__read_concern = collection.read_concern self.__query_flags = cursor_type if no_cursor_timeout: self.__query_flags |= _QUERY_OPTIONS["no_timeout"] if allow_partial_results: self.__query_flags |= _QUERY_OPTIONS["partial"] if oplog_replay: self.__query_flags |= _QUERY_OPTIONS["oplog_replay"] @property def collection(self): """The :class:`~pymongo.collection.Collection` that this :class:`Cursor` is iterating. """ return self.__collection @property def retrieved(self): """The number of documents retrieved so far. """ return self.__retrieved def __del__(self): self.__die() def rewind(self): """Rewind this cursor to its unevaluated state. Reset this cursor if it has been partially or completely evaluated. Any options that are present on the cursor will remain in effect. Future iterating performed on this cursor will cause new queries to be sent to the server, even if the resultant data has already been retrieved by this cursor. """ self.__data = deque() self.__id = None self.__address = None self.__retrieved = 0 self.__killed = False return self def clone(self): """Get a clone of this cursor. Returns a new Cursor instance with options matching those that have been set on the current instance. The clone will be completely unevaluated, even if the current instance has been partially or completely evaluated. """ return self._clone(True) def _clone(self, deepcopy=True, base=None): """Internal clone helper.""" if not base: if self.__explicit_session: base = self._clone_base(self.__session) else: base = self._clone_base(None) values_to_clone = ("spec", "projection", "skip", "limit", "max_time_ms", "max_await_time_ms", "comment", "max", "min", "ordering", "explain", "hint", "batch_size", "max_scan", "manipulate", "query_flags", "modifiers", "collation") data = dict((k, v) for k, v in iteritems(self.__dict__) if k.startswith('_Cursor__') and k[9:] in values_to_clone) if deepcopy: data = self._deepcopy(data) base.__dict__.update(data) return base def _clone_base(self, session): """Creates an empty Cursor object for information to be copied into. """ return self.__class__(self.__collection, session=session) def __die(self, synchronous=False): """Closes this cursor. """ already_killed = self.__killed self.__killed = True if self.__id and not already_killed: if self.__exhaust and self.__exhaust_mgr: # If this is an exhaust cursor and we haven't completely # exhausted the result set we *must* close the socket # to stop the server from sending more data. self.__exhaust_mgr.sock.close() else: address = _CursorAddress( self.__address, self.__collection.full_name) if synchronous: self.__collection.database.client._close_cursor_now( self.__id, address, session=self.__session) else: # The cursor will be closed later in a different session. self.__collection.database.client._close_cursor( self.__id, address) if self.__exhaust and self.__exhaust_mgr: self.__exhaust_mgr.close() if self.__session and not self.__explicit_session: self.__session._end_session(lock=synchronous) self.__session = None def close(self): """Explicitly close / kill this cursor. """ self.__die(True) def __query_spec(self): """Get the spec to use for a query. """ operators = self.__modifiers.copy() if self.__ordering: operators["$orderby"] = self.__ordering if self.__explain: operators["$explain"] = True if self.__hint: operators["$hint"] = self.__hint if self.__comment: operators["$comment"] = self.__comment if self.__max_scan: operators["$maxScan"] = self.__max_scan if self.__max_time_ms is not None: operators["$maxTimeMS"] = self.__max_time_ms if self.__max: operators["$max"] = self.__max if self.__min: operators["$min"] = self.__min if self.__return_key: operators["$returnKey"] = self.__return_key if self.__show_record_id: # This is upgraded to showRecordId for MongoDB 3.2+ "find" command. operators["$showDiskLoc"] = self.__show_record_id if self.__snapshot: operators["$snapshot"] = self.__snapshot if operators: # Make a shallow copy so we can cleanly rewind or clone. spec = self.__spec.copy() # White-listed commands must be wrapped in $query. if "$query" not in spec: # $query has to come first spec = SON([("$query", spec)]) if not isinstance(spec, SON): # Ensure the spec is SON. As order is important this will # ensure its set before merging in any extra operators. spec = SON(spec) spec.update(operators) return spec # Have to wrap with $query if "query" is the first key. # We can't just use $query anytime "query" is a key as # that breaks commands like count and find_and_modify. # Checking spec.keys()[0] covers the case that the spec # was passed as an instance of SON or OrderedDict. elif ("query" in self.__spec and (len(self.__spec) == 1 or next(iter(self.__spec)) == "query")): return SON({"$query": self.__spec}) return self.__spec def __check_okay_to_chain(self): """Check if it is okay to chain more options onto this cursor. """ if self.__retrieved or self.__id is not None: raise InvalidOperation("cannot set options after executing query") def add_option(self, mask): """Set arbitrary query flags using a bitmask. To set the tailable flag: cursor.add_option(2) """ if not isinstance(mask, int): raise TypeError("mask must be an int") self.__check_okay_to_chain() if mask & _QUERY_OPTIONS["exhaust"]: if self.__limit: raise InvalidOperation("Can't use limit and exhaust together.") if self.__collection.database.client.is_mongos: raise InvalidOperation('Exhaust cursors are ' 'not supported by mongos') self.__exhaust = True self.__query_flags |= mask return self def remove_option(self, mask): """Unset arbitrary query flags using a bitmask. To unset the tailable flag: cursor.remove_option(2) """ if not isinstance(mask, int): raise TypeError("mask must be an int") self.__check_okay_to_chain() if mask & _QUERY_OPTIONS["exhaust"]: self.__exhaust = False self.__query_flags &= ~mask return self def limit(self, limit): """Limits the number of results to be returned by this cursor. Raises :exc:`TypeError` if `limit` is not an integer. Raises :exc:`~pymongo.errors.InvalidOperation` if this :class:`Cursor` has already been used. The last `limit` applied to this cursor takes precedence. A limit of ``0`` is equivalent to no limit. :Parameters: - `limit`: the number of results to return .. mongodoc:: limit """ if not isinstance(limit, integer_types): raise TypeError("limit must be an integer") if self.__exhaust: raise InvalidOperation("Can't use limit and exhaust together.") self.__check_okay_to_chain() self.__empty = False self.__limit = limit return self def batch_size(self, batch_size): """Limits the number of documents returned in one batch. Each batch requires a round trip to the server. It can be adjusted to optimize performance and limit data transfer. .. note:: batch_size can not override MongoDB's internal limits on the amount of data it will return to the client in a single batch (i.e if you set batch size to 1,000,000,000, MongoDB will currently only return 4-16MB of results per batch). Raises :exc:`TypeError` if `batch_size` is not an integer. Raises :exc:`ValueError` if `batch_size` is less than ``0``. Raises :exc:`~pymongo.errors.InvalidOperation` if this :class:`Cursor` has already been used. The last `batch_size` applied to this cursor takes precedence. :Parameters: - `batch_size`: The size of each batch of results requested. """ if not isinstance(batch_size, integer_types): raise TypeError("batch_size must be an integer") if batch_size < 0: raise ValueError("batch_size must be >= 0") self.__check_okay_to_chain() self.__batch_size = batch_size return self def skip(self, skip): """Skips the first `skip` results of this cursor. Raises :exc:`TypeError` if `skip` is not an integer. Raises :exc:`ValueError` if `skip` is less than ``0``. Raises :exc:`~pymongo.errors.InvalidOperation` if this :class:`Cursor` has already been used. The last `skip` applied to this cursor takes precedence. :Parameters: - `skip`: the number of results to skip """ if not isinstance(skip, integer_types): raise TypeError("skip must be an integer") if skip < 0: raise ValueError("skip must be >= 0") self.__check_okay_to_chain() self.__skip = skip return self def max_time_ms(self, max_time_ms): """Specifies a time limit for a query operation. If the specified time is exceeded, the operation will be aborted and :exc:`~pymongo.errors.ExecutionTimeout` is raised. If `max_time_ms` is ``None`` no limit is applied. Raises :exc:`TypeError` if `max_time_ms` is not an integer or ``None``. Raises :exc:`~pymongo.errors.InvalidOperation` if this :class:`Cursor` has already been used. :Parameters: - `max_time_ms`: the time limit after which the operation is aborted """ if (not isinstance(max_time_ms, integer_types) and max_time_ms is not None): raise TypeError("max_time_ms must be an integer or None") self.__check_okay_to_chain() self.__max_time_ms = max_time_ms return self def max_await_time_ms(self, max_await_time_ms): """Specifies a time limit for a getMore operation on a :attr:`~pymongo.cursor.CursorType.TAILABLE_AWAIT` cursor. For all other types of cursor max_await_time_ms is ignored. Raises :exc:`TypeError` if `max_await_time_ms` is not an integer or ``None``. Raises :exc:`~pymongo.errors.InvalidOperation` if this :class:`Cursor` has already been used. .. note:: `max_await_time_ms` requires server version **>= 3.2** :Parameters: - `max_await_time_ms`: the time limit after which the operation is aborted .. versionadded:: 3.2 """ if (not isinstance(max_await_time_ms, integer_types) and max_await_time_ms is not None): raise TypeError("max_await_time_ms must be an integer or None") self.__check_okay_to_chain() # Ignore max_await_time_ms if not tailable or await_data is False. if self.__query_flags & CursorType.TAILABLE_AWAIT: self.__max_await_time_ms = max_await_time_ms return self def __getitem__(self, index): """Get a single document or a slice of documents from this cursor. Raises :class:`~pymongo.errors.InvalidOperation` if this cursor has already been used. To get a single document use an integral index, e.g.:: >>> db.test.find()[50] An :class:`IndexError` will be raised if the index is negative or greater than the amount of documents in this cursor. Any limit previously applied to this cursor will be ignored. To get a slice of documents use a slice index, e.g.:: >>> db.test.find()[20:25] This will return this cursor with a limit of ``5`` and skip of ``20`` applied. Using a slice index will override any prior limits or skips applied to this cursor (including those applied through previous calls to this method). Raises :class:`IndexError` when the slice has a step, a negative start value, or a stop value less than or equal to the start value. :Parameters: - `index`: An integer or slice index to be applied to this cursor """ self.__check_okay_to_chain() self.__empty = False if isinstance(index, slice): if index.step is not None: raise IndexError("Cursor instances do not support slice steps") skip = 0 if index.start is not None: if index.start < 0: raise IndexError("Cursor instances do not support " "negative indices") skip = index.start if index.stop is not None: limit = index.stop - skip if limit < 0: raise IndexError("stop index must be greater than start " "index for slice %r" % index) if limit == 0: self.__empty = True else: limit = 0 self.__skip = skip self.__limit = limit return self if isinstance(index, integer_types): if index < 0: raise IndexError("Cursor instances do not support negative " "indices") clone = self.clone() clone.skip(index + self.__skip) clone.limit(-1) # use a hard limit clone.__query_flags &= ~CursorType.TAILABLE_AWAIT # PYTHON-1371 for doc in clone: return doc raise IndexError("no such item for Cursor instance") raise TypeError("index %r cannot be applied to Cursor " "instances" % index) def max_scan(self, max_scan): """**DEPRECATED** - Limit the number of documents to scan when performing the query. Raises :class:`~pymongo.errors.InvalidOperation` if this cursor has already been used. Only the last :meth:`max_scan` applied to this cursor has any effect. :Parameters: - `max_scan`: the maximum number of documents to scan .. versionchanged:: 3.7 Deprecated :meth:`max_scan`. Support for this option is deprecated in MongoDB 4.0. Use :meth:`max_time_ms` instead to limit server side execution time. """ self.__check_okay_to_chain() self.__max_scan = max_scan return self def max(self, spec): """Adds `max` operator that specifies upper bound for specific index. :Parameters: - `spec`: a list of field, limit pairs specifying the exclusive upper bound for all keys of a specific index in order. .. versionadded:: 2.7 """ if not isinstance(spec, (list, tuple)): raise TypeError("spec must be an instance of list or tuple") self.__check_okay_to_chain() self.__max = SON(spec) return self def min(self, spec): """Adds `min` operator that specifies lower bound for specific index. :Parameters: - `spec`: a list of field, limit pairs specifying the inclusive lower bound for all keys of a specific index in order. .. versionadded:: 2.7 """ if not isinstance(spec, (list, tuple)): raise TypeError("spec must be an instance of list or tuple") self.__check_okay_to_chain() self.__min = SON(spec) return self def sort(self, key_or_list, direction=None): """Sorts this cursor's results. Pass a field name and a direction, either :data:`~pymongo.ASCENDING` or :data:`~pymongo.DESCENDING`:: for doc in collection.find().sort('field', pymongo.ASCENDING): print(doc) To sort by multiple fields, pass a list of (key, direction) pairs:: for doc in collection.find().sort([ ('field1', pymongo.ASCENDING), ('field2', pymongo.DESCENDING)]): print(doc) Beginning with MongoDB version 2.6, text search results can be sorted by relevance:: cursor = db.test.find( {'$text': {'$search': 'some words'}}, {'score': {'$meta': 'textScore'}}) # Sort by 'score' field. cursor.sort([('score', {'$meta': 'textScore'})]) for doc in cursor: print(doc) Raises :class:`~pymongo.errors.InvalidOperation` if this cursor has already been used. Only the last :meth:`sort` applied to this cursor has any effect. :Parameters: - `key_or_list`: a single key or a list of (key, direction) pairs specifying the keys to sort on - `direction` (optional): only used if `key_or_list` is a single key, if not given :data:`~pymongo.ASCENDING` is assumed """ self.__check_okay_to_chain() keys = helpers._index_list(key_or_list, direction) self.__ordering = helpers._index_document(keys) return self def count(self, with_limit_and_skip=False): """**DEPRECATED** - Get the size of the results set for this query. The :meth:`count` method is deprecated and **not** supported in a transaction. Please use :meth:`~pymongo.collection.Collection.count_documents` instead. Returns the number of documents in the results set for this query. Does not take :meth:`limit` and :meth:`skip` into account by default - set `with_limit_and_skip` to ``True`` if that is the desired behavior. Raises :class:`~pymongo.errors.OperationFailure` on a database error. When used with MongoDB >= 2.6, :meth:`~count` uses any :meth:`~hint` applied to the query. In the following example the hint is passed to the count command: collection.find({'field': 'value'}).hint('field_1').count() The :meth:`count` method obeys the :attr:`~pymongo.collection.Collection.read_preference` of the :class:`~pymongo.collection.Collection` instance on which :meth:`~pymongo.collection.Collection.find` was called. :Parameters: - `with_limit_and_skip` (optional): take any :meth:`limit` or :meth:`skip` that has been applied to this cursor into account when getting the count .. note:: The `with_limit_and_skip` parameter requires server version **>= 1.1.4-** .. versionchanged:: 3.7 Deprecated. .. versionchanged:: 2.8 The :meth:`~count` method now supports :meth:`~hint`. """ warnings.warn("count is deprecated. Use Collection.count_documents " "instead.", DeprecationWarning, stacklevel=2) validate_boolean("with_limit_and_skip", with_limit_and_skip) cmd = SON([("count", self.__collection.name), ("query", self.__spec)]) if self.__max_time_ms is not None: cmd["maxTimeMS"] = self.__max_time_ms if self.__comment: cmd["$comment"] = self.__comment if self.__hint is not None: cmd["hint"] = self.__hint if with_limit_and_skip: if self.__limit: cmd["limit"] = self.__limit if self.__skip: cmd["skip"] = self.__skip return self.__collection._count( cmd, self.__collation, session=self.__session) def distinct(self, key): """Get a list of distinct values for `key` among all documents in the result set of this query. Raises :class:`TypeError` if `key` is not an instance of :class:`basestring` (:class:`str` in python 3). The :meth:`distinct` method obeys the :attr:`~pymongo.collection.Collection.read_preference` of the :class:`~pymongo.collection.Collection` instance on which :meth:`~pymongo.collection.Collection.find` was called. :Parameters: - `key`: name of key for which we want to get the distinct values .. seealso:: :meth:`pymongo.collection.Collection.distinct` """ options = {} if self.__spec: options["query"] = self.__spec if self.__max_time_ms is not None: options['maxTimeMS'] = self.__max_time_ms if self.__comment: options['$comment'] = self.__comment if self.__collation is not None: options['collation'] = self.__collation return self.__collection.distinct( key, session=self.__session, **options) def explain(self): """Returns an explain plan record for this cursor. .. mongodoc:: explain """ c = self.clone() c.__explain = True # always use a hard limit for explains if c.__limit: c.__limit = -abs(c.__limit) return next(c) def __set_hint(self, index): if index is None: self.__hint = None return if isinstance(index, string_type): self.__hint = index else: self.__hint = helpers._index_document(index) def hint(self, index): """Adds a 'hint', telling Mongo the proper index to use for the query. Judicious use of hints can greatly improve query performance. When doing a query on multiple fields (at least one of which is indexed) pass the indexed field as a hint to the query. Hinting will not do anything if the corresponding index does not exist. Raises :class:`~pymongo.errors.InvalidOperation` if this cursor has already been used. `index` should be an index as passed to :meth:`~pymongo.collection.Collection.create_index` (e.g. ``[('field', ASCENDING)]``) or the name of the index. If `index` is ``None`` any existing hint for this query is cleared. The last hint applied to this cursor takes precedence over all others. :Parameters: - `index`: index to hint on (as an index specifier) .. versionchanged:: 2.8 The :meth:`~hint` method accepts the name of the index. """ self.__check_okay_to_chain() self.__set_hint(index) return self def comment(self, comment): """Adds a 'comment' to the cursor. http://docs.mongodb.org/manual/reference/operator/comment/ :Parameters: - `comment`: A string or document .. versionadded:: 2.7 """ self.__check_okay_to_chain() self.__comment = comment return self def where(self, code): """Adds a $where clause to this query. The `code` argument must be an instance of :class:`basestring` (:class:`str` in python 3) or :class:`~bson.code.Code` containing a JavaScript expression. This expression will be evaluated for each document scanned. Only those documents for which the expression evaluates to *true* will be returned as results. The keyword *this* refers to the object currently being scanned. Raises :class:`TypeError` if `code` is not an instance of :class:`basestring` (:class:`str` in python 3). Raises :class:`~pymongo.errors.InvalidOperation` if this :class:`Cursor` has already been used. Only the last call to :meth:`where` applied to a :class:`Cursor` has any effect. :Parameters: - `code`: JavaScript expression to use as a filter """ self.__check_okay_to_chain() if not isinstance(code, Code): code = Code(code) self.__spec["$where"] = code return self def collation(self, collation): """Adds a :class:`~pymongo.collation.Collation` to this query. This option is only supported on MongoDB 3.4 and above. Raises :exc:`TypeError` if `collation` is not an instance of :class:`~pymongo.collation.Collation` or a ``dict``. Raises :exc:`~pymongo.errors.InvalidOperation` if this :class:`Cursor` has already been used. Only the last collation applied to this cursor has any effect. :Parameters: - `collation`: An instance of :class:`~pymongo.collation.Collation`. """ self.__check_okay_to_chain() self.__collation = validate_collation_or_none(collation) return self def __send_message(self, operation): """Send a query or getmore operation and handles the response. If operation is ``None`` this is an exhaust cursor, which reads the next result batch off the exhaust socket instead of sending getMore messages to the server. Can raise ConnectionFailure. """ client = self.__collection.database.client listeners = client._event_listeners publish = listeners.enabled_for_commands from_command = False start = datetime.datetime.now() def duration(): return datetime.datetime.now() - start if operation: try: response = client._send_message_with_response( operation, exhaust=self.__exhaust, address=self.__address) self.__address = response.address if self.__exhaust: # 'response' is an ExhaustResponse. self.__exhaust_mgr = _SocketManager(response.socket_info, response.pool) cmd_name = operation.name reply = response.data rqst_id = response.request_id from_command = response.from_command except AutoReconnect: # Don't try to send kill cursors on another socket # or to another server. It can cause a _pinValue # assertion on some server releases if we get here # due to a socket timeout. self.__killed = True self.__die() raise else: # Exhaust cursor - no getMore message. rqst_id = 0 cmd_name = 'getMore' if publish: # Fake a getMore command. cmd = SON([('getMore', self.__id), ('collection', self.__collection.name)]) if self.__batch_size: cmd['batchSize'] = self.__batch_size if self.__max_time_ms: cmd['maxTimeMS'] = self.__max_time_ms listeners.publish_command_start( cmd, self.__collection.database.name, 0, self.__address) try: reply = self.__exhaust_mgr.sock.receive_message(None) except Exception as exc: if publish: listeners.publish_command_failure( duration(), _convert_exception(exc), cmd_name, rqst_id, self.__address) if isinstance(exc, ConnectionFailure): self.__die() raise try: docs = self._unpack_response(response=reply, cursor_id=self.__id, codec_options=self.__codec_options) if from_command: first = docs[0] client._receive_cluster_time(first, self.__session) helpers._check_command_response(first) except OperationFailure as exc: self.__killed = True # Make sure exhaust socket is returned immediately, if necessary. self.__die() if publish: listeners.publish_command_failure( duration(), exc.details, cmd_name, rqst_id, self.__address) # If this is a tailable cursor the error is likely # due to capped collection roll over. Setting # self.__killed to True ensures Cursor.alive will be # False. No need to re-raise. if self.__query_flags & _QUERY_OPTIONS["tailable_cursor"]: return raise except NotMasterError as exc: # Don't send kill cursors to another server after a "not master" # error. It's completely pointless. self.__killed = True # Make sure exhaust socket is returned immediately, if necessary. self.__die() if publish: listeners.publish_command_failure( duration(), exc.details, cmd_name, rqst_id, self.__address) client._reset_server_and_request_check(self.__address) raise except Exception as exc: if publish: listeners.publish_command_failure( duration(), _convert_exception(exc), cmd_name, rqst_id, self.__address) raise if publish: # Must publish in find / getMore / explain command response format. if from_command: res = docs[0] elif cmd_name == "explain": res = docs[0] if docs else {} else: res = {"cursor": {"id": reply.cursor_id, "ns": self.__collection.full_name}, "ok": 1} if cmd_name == "find": res["cursor"]["firstBatch"] = docs else: res["cursor"]["nextBatch"] = docs listeners.publish_command_success( duration(), res, cmd_name, rqst_id, self.__address) if from_command: if cmd_name != "explain": cursor = docs[0]['cursor'] self.__id = cursor['id'] if cmd_name == 'find': documents = cursor['firstBatch'] else: documents = cursor['nextBatch'] self.__data = deque(documents) self.__retrieved += len(documents) else: self.__id = 0 self.__data = deque(docs) self.__retrieved += len(docs) else: self.__id = reply.cursor_id self.__data = deque(docs) self.__retrieved += reply.number_returned if self.__id == 0: self.__killed = True # Don't wait for garbage collection to call __del__, return the # socket and the session to the pool now. self.__die() if self.__limit and self.__id and self.__limit <= self.__retrieved: self.__die() def _unpack_response(self, response, cursor_id, codec_options): return response.unpack_response(cursor_id, codec_options) def _read_preference(self): if self.__read_preference is None: # Save the read preference for getMore commands. self.__read_preference = self.__collection._read_preference_for( self.session) return self.__read_preference def _refresh(self): """Refreshes the cursor with more data from Mongo. Returns the length of self.__data after refresh. Will exit early if self.__data is already non-empty. Raises OperationFailure when the cursor cannot be refreshed due to an error on the query. """ if len(self.__data) or self.__killed: return len(self.__data) if not self.__session: self.__session = self.__collection.database.client._ensure_session() if self.__id is None: # Query q = self._query_class(self.__query_flags, self.__collection.database.name, self.__collection.name, self.__skip, self.__query_spec(), self.__projection, self.__codec_options, self._read_preference(), self.__limit, self.__batch_size, self.__read_concern, self.__collation, self.__session, self.__collection.database.client) self.__send_message(q) elif self.__id: # Get More if self.__limit: limit = self.__limit - self.__retrieved if self.__batch_size: limit = min(limit, self.__batch_size) else: limit = self.__batch_size # Exhaust cursors don't send getMore messages. if self.__exhaust: self.__send_message(None) else: g = self._getmore_class(self.__collection.database.name, self.__collection.name, limit, self.__id, self.__codec_options, self._read_preference(), self.__session, self.__collection.database.client, self.__max_await_time_ms) self.__send_message(g) return len(self.__data) @property def alive(self): """Does this cursor have the potential to return more data? This is mostly useful with `tailable cursors `_ since they will stop iterating even though they *may* return more results in the future. With regular cursors, simply use a for loop instead of :attr:`alive`:: for doc in collection.find(): print(doc) .. note:: Even if :attr:`alive` is True, :meth:`next` can raise :exc:`StopIteration`. :attr:`alive` can also be True while iterating a cursor from a failed server. In this case :attr:`alive` will return False after :meth:`next` fails to retrieve the next batch of results from the server. """ return bool(len(self.__data) or (not self.__killed)) @property def cursor_id(self): """Returns the id of the cursor Useful if you need to manage cursor ids and want to handle killing cursors manually using :meth:`~pymongo.mongo_client.MongoClient.kill_cursors` .. versionadded:: 2.2 """ return self.__id @property def address(self): """The (host, port) of the server used, or None. .. versionchanged:: 3.0 Renamed from "conn_id". """ return self.__address @property def session(self): """The cursor's :class:`~pymongo.client_session.ClientSession`, or None. .. versionadded:: 3.6 """ if self.__explicit_session: return self.__session def __iter__(self): return self def next(self): """Advance the cursor.""" if self.__empty: raise StopIteration if len(self.__data) or self._refresh(): if self.__manipulate: _db = self.__collection.database return _db._fix_outgoing(self.__data.popleft(), self.__collection) else: return self.__data.popleft() else: raise StopIteration __next__ = next def __enter__(self): return self def __exit__(self, exc_type, exc_val, exc_tb): self.close() def __copy__(self): """Support function for `copy.copy()`. .. versionadded:: 2.4 """ return self._clone(deepcopy=False) def __deepcopy__(self, memo): """Support function for `copy.deepcopy()`. .. versionadded:: 2.4 """ return self._clone(deepcopy=True) def _deepcopy(self, x, memo=None): """Deepcopy helper for the data dictionary or list. Regular expressions cannot be deep copied but as they are immutable we don't have to copy them when cloning. """ if not hasattr(x, 'items'): y, is_list, iterator = [], True, enumerate(x) else: y, is_list, iterator = {}, False, iteritems(x) if memo is None: memo = {} val_id = id(x) if val_id in memo: return memo.get(val_id) memo[val_id] = y for key, value in iterator: if isinstance(value, (dict, list)) and not isinstance(value, SON): value = self._deepcopy(value, memo) elif not isinstance(value, RE_TYPE): value = copy.deepcopy(value, memo) if is_list: y.append(value) else: if not isinstance(key, RE_TYPE): key = copy.deepcopy(key, memo) y[key] = value return y class RawBatchCursor(Cursor): """A cursor / iterator over raw batches of BSON data from a query result.""" _query_class = _RawBatchQuery _getmore_class = _RawBatchGetMore def __init__(self, *args, **kwargs): """Create a new cursor / iterator over raw batches of BSON data. Should not be called directly by application developers - see :meth:`~pymongo.collection.Collection.find_raw_batches` instead. .. mongodoc:: cursors """ manipulate = kwargs.get('manipulate') kwargs['manipulate'] = False super(RawBatchCursor, self).__init__(*args, **kwargs) # Throw only after cursor's initialized, to prevent errors in __del__. if manipulate: raise InvalidOperation( "Cannot use RawBatchCursor with manipulate=True") def _unpack_response(self, response, cursor_id, codec_options): return response.raw_response(cursor_id) def explain(self): """Returns an explain plan record for this cursor. .. mongodoc:: explain """ clone = self._clone(deepcopy=True, base=Cursor(self.collection)) return clone.explain() def __getitem__(self, index): raise InvalidOperation("Cannot call __getitem__ on RawBatchCursor")