909 lines
33 KiB
Python
909 lines
33 KiB
Python
# Copyright 2009-present MongoDB, 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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"""Tools for representing files stored in GridFS."""
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import datetime
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import io
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import math
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import os
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from typing import Any, Iterable, List, Mapping, NoReturn, Optional
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from bson.binary import Binary
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from bson.int64 import Int64
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from bson.objectid import ObjectId
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from bson.son import SON
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from gridfs.errors import CorruptGridFile, FileExists, NoFile
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from pymongo import ASCENDING
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from pymongo.client_session import ClientSession
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from pymongo.collection import Collection
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from pymongo.cursor import Cursor
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from pymongo.errors import (
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ConfigurationError,
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CursorNotFound,
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DuplicateKeyError,
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InvalidOperation,
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OperationFailure,
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)
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from pymongo.read_preferences import ReadPreference
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_SEEK_SET = os.SEEK_SET
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_SEEK_CUR = os.SEEK_CUR
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_SEEK_END = os.SEEK_END
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EMPTY = b""
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NEWLN = b"\n"
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"""Default chunk size, in bytes."""
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# Slightly under a power of 2, to work well with server's record allocations.
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DEFAULT_CHUNK_SIZE = 255 * 1024
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_C_INDEX: SON[str, Any] = SON([("files_id", ASCENDING), ("n", ASCENDING)])
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_F_INDEX: SON[str, Any] = SON([("filename", ASCENDING), ("uploadDate", ASCENDING)])
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def _grid_in_property(
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field_name: str,
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docstring: str,
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read_only: Optional[bool] = False,
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closed_only: Optional[bool] = False,
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) -> Any:
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"""Create a GridIn property."""
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def getter(self: Any) -> Any:
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if closed_only and not self._closed:
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raise AttributeError("can only get %r on a closed file" % field_name)
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# Protect against PHP-237
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if field_name == "length":
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return self._file.get(field_name, 0)
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return self._file.get(field_name, None)
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def setter(self: Any, value: Any) -> Any:
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if self._closed:
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self._coll.files.update_one({"_id": self._file["_id"]}, {"$set": {field_name: value}})
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self._file[field_name] = value
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if read_only:
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docstring += "\n\nThis attribute is read-only."
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elif closed_only:
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docstring = "{}\n\n{}".format(
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docstring,
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"This attribute is read-only and "
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"can only be read after :meth:`close` "
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"has been called.",
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)
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if not read_only and not closed_only:
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return property(getter, setter, doc=docstring)
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return property(getter, doc=docstring)
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def _grid_out_property(field_name: str, docstring: str) -> Any:
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"""Create a GridOut property."""
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def getter(self: Any) -> Any:
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self._ensure_file()
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# Protect against PHP-237
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if field_name == "length":
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return self._file.get(field_name, 0)
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return self._file.get(field_name, None)
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docstring += "\n\nThis attribute is read-only."
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return property(getter, doc=docstring)
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def _clear_entity_type_registry(entity: Any, **kwargs: Any) -> Any:
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"""Clear the given database/collection object's type registry."""
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codecopts = entity.codec_options.with_options(type_registry=None)
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return entity.with_options(codec_options=codecopts, **kwargs)
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def _disallow_transactions(session: Optional[ClientSession]) -> None:
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if session and session.in_transaction:
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raise InvalidOperation("GridFS does not support multi-document transactions")
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class GridIn:
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"""Class to write data to GridFS."""
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def __init__(
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self, root_collection: Collection, session: Optional[ClientSession] = None, **kwargs: Any
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) -> None:
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"""Write a file to GridFS
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Application developers should generally not need to
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instantiate this class directly - instead see the methods
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provided by :class:`~gridfs.GridFS`.
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Raises :class:`TypeError` if `root_collection` is not an
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instance of :class:`~pymongo.collection.Collection`.
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Any of the file level options specified in the `GridFS Spec
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<http://dochub.mongodb.org/core/gridfsspec>`_ may be passed as
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keyword arguments. Any additional keyword arguments will be
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set as additional fields on the file document. Valid keyword
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arguments include:
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- ``"_id"``: unique ID for this file (default:
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:class:`~bson.objectid.ObjectId`) - this ``"_id"`` must
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not have already been used for another file
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- ``"filename"``: human name for the file
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- ``"contentType"`` or ``"content_type"``: valid mime-type
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for the file
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- ``"chunkSize"`` or ``"chunk_size"``: size of each of the
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chunks, in bytes (default: 255 kb)
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- ``"encoding"``: encoding used for this file. Any :class:`str`
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that is written to the file will be converted to :class:`bytes`.
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:Parameters:
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- `root_collection`: root collection to write to
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- `session` (optional): a
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:class:`~pymongo.client_session.ClientSession` to use for all
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commands
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- `**kwargs: Any` (optional): file level options (see above)
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.. versionchanged:: 4.0
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Removed the `disable_md5` parameter. See
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:ref:`removed-gridfs-checksum` for details.
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.. versionchanged:: 3.7
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Added the `disable_md5` parameter.
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.. versionchanged:: 3.6
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Added ``session`` parameter.
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.. versionchanged:: 3.0
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`root_collection` must use an acknowledged
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:attr:`~pymongo.collection.Collection.write_concern`
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"""
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if not isinstance(root_collection, Collection):
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raise TypeError("root_collection must be an instance of Collection")
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if not root_collection.write_concern.acknowledged:
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raise ConfigurationError("root_collection must use acknowledged write_concern")
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_disallow_transactions(session)
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# Handle alternative naming
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if "content_type" in kwargs:
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kwargs["contentType"] = kwargs.pop("content_type")
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if "chunk_size" in kwargs:
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kwargs["chunkSize"] = kwargs.pop("chunk_size")
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coll = _clear_entity_type_registry(root_collection, read_preference=ReadPreference.PRIMARY)
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# Defaults
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kwargs["_id"] = kwargs.get("_id", ObjectId())
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kwargs["chunkSize"] = kwargs.get("chunkSize", DEFAULT_CHUNK_SIZE)
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object.__setattr__(self, "_session", session)
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object.__setattr__(self, "_coll", coll)
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object.__setattr__(self, "_chunks", coll.chunks)
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object.__setattr__(self, "_file", kwargs)
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object.__setattr__(self, "_buffer", io.BytesIO())
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object.__setattr__(self, "_position", 0)
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object.__setattr__(self, "_chunk_number", 0)
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object.__setattr__(self, "_closed", False)
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object.__setattr__(self, "_ensured_index", False)
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def __create_index(self, collection: Collection, index_key: Any, unique: bool) -> None:
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doc = collection.find_one(projection={"_id": 1}, session=self._session)
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if doc is None:
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try:
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index_keys = [
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index_spec["key"]
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for index_spec in collection.list_indexes(session=self._session)
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]
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except OperationFailure:
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index_keys = []
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if index_key not in index_keys:
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collection.create_index(index_key.items(), unique=unique, session=self._session)
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def __ensure_indexes(self) -> None:
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if not object.__getattribute__(self, "_ensured_index"):
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_disallow_transactions(self._session)
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self.__create_index(self._coll.files, _F_INDEX, False)
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self.__create_index(self._coll.chunks, _C_INDEX, True)
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object.__setattr__(self, "_ensured_index", True)
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def abort(self) -> None:
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"""Remove all chunks/files that may have been uploaded and close."""
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self._coll.chunks.delete_many({"files_id": self._file["_id"]}, session=self._session)
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self._coll.files.delete_one({"_id": self._file["_id"]}, session=self._session)
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object.__setattr__(self, "_closed", True)
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@property
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def closed(self) -> bool:
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"""Is this file closed?"""
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return self._closed
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_id: Any = _grid_in_property("_id", "The ``'_id'`` value for this file.", read_only=True)
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filename: Optional[str] = _grid_in_property("filename", "Name of this file.")
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name: Optional[str] = _grid_in_property("filename", "Alias for `filename`.")
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content_type: Optional[str] = _grid_in_property("contentType", "Mime-type for this file.")
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length: int = _grid_in_property("length", "Length (in bytes) of this file.", closed_only=True)
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chunk_size: int = _grid_in_property("chunkSize", "Chunk size for this file.", read_only=True)
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upload_date: datetime.datetime = _grid_in_property(
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"uploadDate", "Date that this file was uploaded.", closed_only=True
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)
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md5: Optional[str] = _grid_in_property(
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"md5", "MD5 of the contents of this file if an md5 sum was created.", closed_only=True
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)
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_buffer: io.BytesIO
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_closed: bool
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def __getattr__(self, name: str) -> Any:
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if name in self._file:
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return self._file[name]
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raise AttributeError("GridIn object has no attribute '%s'" % name)
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def __setattr__(self, name: str, value: Any) -> None:
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# For properties of this instance like _buffer, or descriptors set on
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# the class like filename, use regular __setattr__
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if name in self.__dict__ or name in self.__class__.__dict__:
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object.__setattr__(self, name, value)
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else:
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# All other attributes are part of the document in db.fs.files.
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# Store them to be sent to server on close() or if closed, send
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# them now.
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self._file[name] = value
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if self._closed:
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self._coll.files.update_one({"_id": self._file["_id"]}, {"$set": {name: value}})
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def __flush_data(self, data: Any) -> None:
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"""Flush `data` to a chunk."""
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self.__ensure_indexes()
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if not data:
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return
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assert len(data) <= self.chunk_size
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chunk = {"files_id": self._file["_id"], "n": self._chunk_number, "data": Binary(data)}
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try:
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self._chunks.insert_one(chunk, session=self._session)
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except DuplicateKeyError:
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self._raise_file_exists(self._file["_id"])
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self._chunk_number += 1
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self._position += len(data)
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def __flush_buffer(self) -> None:
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"""Flush the buffer contents out to a chunk."""
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self.__flush_data(self._buffer.getvalue())
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self._buffer.close()
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self._buffer = io.BytesIO()
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def __flush(self) -> Any:
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"""Flush the file to the database."""
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try:
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self.__flush_buffer()
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# The GridFS spec says length SHOULD be an Int64.
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self._file["length"] = Int64(self._position)
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self._file["uploadDate"] = datetime.datetime.now(tz=datetime.timezone.utc)
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return self._coll.files.insert_one(self._file, session=self._session)
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except DuplicateKeyError:
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self._raise_file_exists(self._id)
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def _raise_file_exists(self, file_id: Any) -> NoReturn:
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"""Raise a FileExists exception for the given file_id."""
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raise FileExists("file with _id %r already exists" % file_id)
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def close(self) -> None:
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"""Flush the file and close it.
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A closed file cannot be written any more. Calling
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:meth:`close` more than once is allowed.
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"""
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if not self._closed:
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self.__flush()
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object.__setattr__(self, "_closed", True)
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def read(self, size: int = -1) -> NoReturn:
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raise io.UnsupportedOperation("read")
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def readable(self) -> bool:
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return False
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def seekable(self) -> bool:
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return False
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def write(self, data: Any) -> None:
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"""Write data to the file. There is no return value.
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`data` can be either a string of bytes or a file-like object
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(implementing :meth:`read`). If the file has an
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:attr:`encoding` attribute, `data` can also be a
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:class:`str` instance, which will be encoded as
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:attr:`encoding` before being written.
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Due to buffering, the data may not actually be written to the
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database until the :meth:`close` method is called. Raises
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:class:`ValueError` if this file is already closed. Raises
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:class:`TypeError` if `data` is not an instance of
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:class:`bytes`, a file-like object, or an instance of :class:`str`.
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Unicode data is only allowed if the file has an :attr:`encoding`
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attribute.
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:Parameters:
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- `data`: string of bytes or file-like object to be written
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to the file
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"""
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if self._closed:
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raise ValueError("cannot write to a closed file")
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try:
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# file-like
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read = data.read
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except AttributeError:
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# string
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if not isinstance(data, (str, bytes)):
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raise TypeError("can only write strings or file-like objects")
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if isinstance(data, str):
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try:
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data = data.encode(self.encoding)
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except AttributeError:
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raise TypeError("must specify an encoding for file in order to write str")
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read = io.BytesIO(data).read
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if self._buffer.tell() > 0:
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# Make sure to flush only when _buffer is complete
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space = self.chunk_size - self._buffer.tell()
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if space:
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try:
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to_write = read(space)
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except BaseException:
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self.abort()
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raise
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self._buffer.write(to_write)
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if len(to_write) < space:
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return # EOF or incomplete
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self.__flush_buffer()
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to_write = read(self.chunk_size)
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while to_write and len(to_write) == self.chunk_size:
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self.__flush_data(to_write)
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to_write = read(self.chunk_size)
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self._buffer.write(to_write)
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def writelines(self, sequence: Iterable[Any]) -> None:
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"""Write a sequence of strings to the file.
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Does not add separators.
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"""
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for line in sequence:
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self.write(line)
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def writeable(self) -> bool:
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return True
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def __enter__(self) -> "GridIn":
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"""Support for the context manager protocol."""
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return self
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def __exit__(self, exc_type: Any, exc_val: Any, exc_tb: Any) -> Any:
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"""Support for the context manager protocol.
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Close the file if no exceptions occur and allow exceptions to propagate.
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"""
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if exc_type is None:
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# No exceptions happened.
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self.close()
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else:
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# Something happened, at minimum mark as closed.
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object.__setattr__(self, "_closed", True)
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# propagate exceptions
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return False
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class GridOut(io.IOBase):
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"""Class to read data out of GridFS."""
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def __init__(
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self,
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root_collection: Collection,
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file_id: Optional[int] = None,
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file_document: Optional[Any] = None,
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session: Optional[ClientSession] = None,
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) -> None:
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"""Read a file from GridFS
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Application developers should generally not need to
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instantiate this class directly - instead see the methods
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provided by :class:`~gridfs.GridFS`.
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Either `file_id` or `file_document` must be specified,
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`file_document` will be given priority if present. Raises
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:class:`TypeError` if `root_collection` is not an instance of
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:class:`~pymongo.collection.Collection`.
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:Parameters:
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- `root_collection`: root collection to read from
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- `file_id` (optional): value of ``"_id"`` for the file to read
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- `file_document` (optional): file document from
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`root_collection.files`
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- `session` (optional): a
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:class:`~pymongo.client_session.ClientSession` to use for all
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commands
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.. versionchanged:: 3.8
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For better performance and to better follow the GridFS spec,
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:class:`GridOut` now uses a single cursor to read all the chunks in
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the file.
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.. versionchanged:: 3.6
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Added ``session`` parameter.
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.. versionchanged:: 3.0
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Creating a GridOut does not immediately retrieve the file metadata
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from the server. Metadata is fetched when first needed.
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"""
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if not isinstance(root_collection, Collection):
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raise TypeError("root_collection must be an instance of Collection")
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_disallow_transactions(session)
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root_collection = _clear_entity_type_registry(root_collection)
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super().__init__()
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self.__chunks = root_collection.chunks
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self.__files = root_collection.files
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self.__file_id = file_id
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self.__buffer = EMPTY
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# Start position within the current buffered chunk.
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self.__buffer_pos = 0
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self.__chunk_iter = None
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# Position within the total file.
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self.__position = 0
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self._file = file_document
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self._session = session
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_id: Any = _grid_out_property("_id", "The ``'_id'`` value for this file.")
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filename: str = _grid_out_property("filename", "Name of this file.")
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name: str = _grid_out_property("filename", "Alias for `filename`.")
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content_type: Optional[str] = _grid_out_property("contentType", "Mime-type for this file.")
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length: int = _grid_out_property("length", "Length (in bytes) of this file.")
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chunk_size: int = _grid_out_property("chunkSize", "Chunk size for this file.")
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upload_date: datetime.datetime = _grid_out_property(
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"uploadDate", "Date that this file was first uploaded."
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)
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aliases: Optional[List[str]] = _grid_out_property("aliases", "List of aliases for this file.")
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metadata: Optional[Mapping[str, Any]] = _grid_out_property(
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"metadata", "Metadata attached to this file."
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)
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md5: Optional[str] = _grid_out_property(
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"md5", "MD5 of the contents of this file if an md5 sum was created."
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)
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_file: Any
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__chunk_iter: Any
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def _ensure_file(self) -> None:
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if not self._file:
|
|
_disallow_transactions(self._session)
|
|
self._file = self.__files.find_one({"_id": self.__file_id}, session=self._session)
|
|
if not self._file:
|
|
raise NoFile(
|
|
f"no file in gridfs collection {self.__files!r} with _id {self.__file_id!r}"
|
|
)
|
|
|
|
def __getattr__(self, name: str) -> Any:
|
|
self._ensure_file()
|
|
if name in self._file:
|
|
return self._file[name]
|
|
raise AttributeError("GridOut object has no attribute '%s'" % name)
|
|
|
|
def readable(self) -> bool:
|
|
return True
|
|
|
|
def readchunk(self) -> bytes:
|
|
"""Reads a chunk at a time. If the current position is within a
|
|
chunk the remainder of the chunk is returned.
|
|
"""
|
|
received = len(self.__buffer) - self.__buffer_pos
|
|
chunk_data = EMPTY
|
|
chunk_size = int(self.chunk_size)
|
|
|
|
if received > 0:
|
|
chunk_data = self.__buffer[self.__buffer_pos :]
|
|
elif self.__position < int(self.length):
|
|
chunk_number = int((received + self.__position) / chunk_size)
|
|
if self.__chunk_iter is None:
|
|
self.__chunk_iter = _GridOutChunkIterator(
|
|
self, self.__chunks, self._session, chunk_number
|
|
)
|
|
|
|
chunk = self.__chunk_iter.next()
|
|
chunk_data = chunk["data"][self.__position % chunk_size :]
|
|
|
|
if not chunk_data:
|
|
raise CorruptGridFile("truncated chunk")
|
|
|
|
self.__position += len(chunk_data)
|
|
self.__buffer = EMPTY
|
|
self.__buffer_pos = 0
|
|
return chunk_data
|
|
|
|
def _read_size_or_line(self, size: int = -1, line: bool = False) -> bytes:
|
|
"""Internal read() and readline() helper."""
|
|
self._ensure_file()
|
|
remainder = int(self.length) - self.__position
|
|
if size < 0 or size > remainder:
|
|
size = remainder
|
|
|
|
if size == 0:
|
|
return EMPTY
|
|
|
|
received = 0
|
|
data = []
|
|
while received < size:
|
|
needed = size - received
|
|
if self.__buffer:
|
|
# Optimization: Read the buffer with zero byte copies.
|
|
buf = self.__buffer
|
|
chunk_start = self.__buffer_pos
|
|
chunk_data = memoryview(buf)[self.__buffer_pos :]
|
|
self.__buffer = EMPTY
|
|
self.__buffer_pos = 0
|
|
self.__position += len(chunk_data)
|
|
else:
|
|
buf = self.readchunk()
|
|
chunk_start = 0
|
|
chunk_data = memoryview(buf)
|
|
if line:
|
|
pos = buf.find(NEWLN, chunk_start, chunk_start + needed) - chunk_start
|
|
if pos >= 0:
|
|
# Decrease size to exit the loop.
|
|
size = received + pos + 1
|
|
needed = pos + 1
|
|
if len(chunk_data) > needed:
|
|
data.append(chunk_data[:needed])
|
|
# Optimization: Save the buffer with zero byte copies.
|
|
self.__buffer = buf
|
|
self.__buffer_pos = chunk_start + needed
|
|
self.__position -= len(self.__buffer) - self.__buffer_pos
|
|
else:
|
|
data.append(chunk_data)
|
|
received += len(chunk_data)
|
|
|
|
# Detect extra chunks after reading the entire file.
|
|
if size == remainder and self.__chunk_iter:
|
|
try:
|
|
self.__chunk_iter.next()
|
|
except StopIteration:
|
|
pass
|
|
|
|
return b"".join(data)
|
|
|
|
def read(self, size: int = -1) -> bytes:
|
|
"""Read at most `size` bytes from the file (less if there
|
|
isn't enough data).
|
|
|
|
The bytes are returned as an instance of :class:`str` (:class:`bytes`
|
|
in python 3). If `size` is negative or omitted all data is read.
|
|
|
|
:Parameters:
|
|
- `size` (optional): the number of bytes to read
|
|
|
|
.. versionchanged:: 3.8
|
|
This method now only checks for extra chunks after reading the
|
|
entire file. Previously, this method would check for extra chunks
|
|
on every call.
|
|
"""
|
|
return self._read_size_or_line(size=size)
|
|
|
|
def readline(self, size: int = -1) -> bytes: # type: ignore[override]
|
|
"""Read one line or up to `size` bytes from the file.
|
|
|
|
:Parameters:
|
|
- `size` (optional): the maximum number of bytes to read
|
|
"""
|
|
return self._read_size_or_line(size=size, line=True)
|
|
|
|
def tell(self) -> int:
|
|
"""Return the current position of this file."""
|
|
return self.__position
|
|
|
|
def seek(self, pos: int, whence: int = _SEEK_SET) -> int:
|
|
"""Set the current position of this file.
|
|
|
|
:Parameters:
|
|
- `pos`: the position (or offset if using relative
|
|
positioning) to seek to
|
|
- `whence` (optional): where to seek
|
|
from. :attr:`os.SEEK_SET` (``0``) for absolute file
|
|
positioning, :attr:`os.SEEK_CUR` (``1``) to seek relative
|
|
to the current position, :attr:`os.SEEK_END` (``2``) to
|
|
seek relative to the file's end.
|
|
|
|
.. versionchanged:: 4.1
|
|
The method now returns the new position in the file, to
|
|
conform to the behavior of :meth:`io.IOBase.seek`.
|
|
"""
|
|
if whence == _SEEK_SET:
|
|
new_pos = pos
|
|
elif whence == _SEEK_CUR:
|
|
new_pos = self.__position + pos
|
|
elif whence == _SEEK_END:
|
|
new_pos = int(self.length) + pos
|
|
else:
|
|
raise OSError(22, "Invalid value for `whence`")
|
|
|
|
if new_pos < 0:
|
|
raise OSError(22, "Invalid value for `pos` - must be positive")
|
|
|
|
# Optimization, continue using the same buffer and chunk iterator.
|
|
if new_pos == self.__position:
|
|
return new_pos
|
|
|
|
self.__position = new_pos
|
|
self.__buffer = EMPTY
|
|
self.__buffer_pos = 0
|
|
if self.__chunk_iter:
|
|
self.__chunk_iter.close()
|
|
self.__chunk_iter = None
|
|
return new_pos
|
|
|
|
def seekable(self) -> bool:
|
|
return True
|
|
|
|
def __iter__(self) -> "GridOut":
|
|
"""Return an iterator over all of this file's data.
|
|
|
|
The iterator will return lines (delimited by ``b'\\n'``) of
|
|
:class:`bytes`. This can be useful when serving files
|
|
using a webserver that handles such an iterator efficiently.
|
|
|
|
.. versionchanged:: 3.8
|
|
The iterator now raises :class:`CorruptGridFile` when encountering
|
|
any truncated, missing, or extra chunk in a file. The previous
|
|
behavior was to only raise :class:`CorruptGridFile` on a missing
|
|
chunk.
|
|
|
|
.. versionchanged:: 4.0
|
|
The iterator now iterates over *lines* in the file, instead
|
|
of chunks, to conform to the base class :py:class:`io.IOBase`.
|
|
Use :meth:`GridOut.readchunk` to read chunk by chunk instead
|
|
of line by line.
|
|
"""
|
|
return self
|
|
|
|
def close(self) -> None:
|
|
"""Make GridOut more generically file-like."""
|
|
if self.__chunk_iter:
|
|
self.__chunk_iter.close()
|
|
self.__chunk_iter = None
|
|
super().close()
|
|
|
|
def write(self, value: Any) -> NoReturn:
|
|
raise io.UnsupportedOperation("write")
|
|
|
|
def writelines(self, lines: Any) -> NoReturn:
|
|
raise io.UnsupportedOperation("writelines")
|
|
|
|
def writable(self) -> bool:
|
|
return False
|
|
|
|
def __enter__(self) -> "GridOut":
|
|
"""Makes it possible to use :class:`GridOut` files
|
|
with the context manager protocol.
|
|
"""
|
|
return self
|
|
|
|
def __exit__(self, exc_type: Any, exc_val: Any, exc_tb: Any) -> Any:
|
|
"""Makes it possible to use :class:`GridOut` files
|
|
with the context manager protocol.
|
|
"""
|
|
self.close()
|
|
return False
|
|
|
|
def fileno(self) -> NoReturn:
|
|
raise io.UnsupportedOperation("fileno")
|
|
|
|
def flush(self) -> None:
|
|
# GridOut is read-only, so flush does nothing.
|
|
pass
|
|
|
|
def isatty(self) -> bool:
|
|
return False
|
|
|
|
def truncate(self, size: Optional[int] = None) -> NoReturn:
|
|
# See https://docs.python.org/3/library/io.html#io.IOBase.writable
|
|
# for why truncate has to raise.
|
|
raise io.UnsupportedOperation("truncate")
|
|
|
|
# Override IOBase.__del__ otherwise it will lead to __getattr__ on
|
|
# __IOBase_closed which calls _ensure_file and potentially performs I/O.
|
|
# We cannot do I/O in __del__ since it can lead to a deadlock.
|
|
def __del__(self) -> None:
|
|
pass
|
|
|
|
|
|
class _GridOutChunkIterator:
|
|
"""Iterates over a file's chunks using a single cursor.
|
|
|
|
Raises CorruptGridFile when encountering any truncated, missing, or extra
|
|
chunk in a file.
|
|
"""
|
|
|
|
def __init__(
|
|
self,
|
|
grid_out: GridOut,
|
|
chunks: Collection,
|
|
session: Optional[ClientSession],
|
|
next_chunk: Any,
|
|
) -> None:
|
|
self._id = grid_out._id
|
|
self._chunk_size = int(grid_out.chunk_size)
|
|
self._length = int(grid_out.length)
|
|
self._chunks = chunks
|
|
self._session = session
|
|
self._next_chunk = next_chunk
|
|
self._num_chunks = math.ceil(float(self._length) / self._chunk_size)
|
|
self._cursor = None
|
|
|
|
_cursor: Optional[Cursor]
|
|
|
|
def expected_chunk_length(self, chunk_n: int) -> int:
|
|
if chunk_n < self._num_chunks - 1:
|
|
return self._chunk_size
|
|
return self._length - (self._chunk_size * (self._num_chunks - 1))
|
|
|
|
def __iter__(self) -> "_GridOutChunkIterator":
|
|
return self
|
|
|
|
def _create_cursor(self) -> None:
|
|
filter = {"files_id": self._id}
|
|
if self._next_chunk > 0:
|
|
filter["n"] = {"$gte": self._next_chunk}
|
|
_disallow_transactions(self._session)
|
|
self._cursor = self._chunks.find(filter, sort=[("n", 1)], session=self._session)
|
|
|
|
def _next_with_retry(self) -> Mapping[str, Any]:
|
|
"""Return the next chunk and retry once on CursorNotFound.
|
|
|
|
We retry on CursorNotFound to maintain backwards compatibility in
|
|
cases where two calls to read occur more than 10 minutes apart (the
|
|
server's default cursor timeout).
|
|
"""
|
|
if self._cursor is None:
|
|
self._create_cursor()
|
|
assert self._cursor is not None
|
|
try:
|
|
return self._cursor.next()
|
|
except CursorNotFound:
|
|
self._cursor.close()
|
|
self._create_cursor()
|
|
return self._cursor.next()
|
|
|
|
def next(self) -> Mapping[str, Any]:
|
|
try:
|
|
chunk = self._next_with_retry()
|
|
except StopIteration:
|
|
if self._next_chunk >= self._num_chunks:
|
|
raise
|
|
raise CorruptGridFile("no chunk #%d" % self._next_chunk)
|
|
|
|
if chunk["n"] != self._next_chunk:
|
|
self.close()
|
|
raise CorruptGridFile(
|
|
"Missing chunk: expected chunk #%d but found "
|
|
"chunk with n=%d" % (self._next_chunk, chunk["n"])
|
|
)
|
|
|
|
if chunk["n"] >= self._num_chunks:
|
|
# According to spec, ignore extra chunks if they are empty.
|
|
if len(chunk["data"]):
|
|
self.close()
|
|
raise CorruptGridFile(
|
|
"Extra chunk found: expected %d chunks but found "
|
|
"chunk with n=%d" % (self._num_chunks, chunk["n"])
|
|
)
|
|
|
|
expected_length = self.expected_chunk_length(chunk["n"])
|
|
if len(chunk["data"]) != expected_length:
|
|
self.close()
|
|
raise CorruptGridFile(
|
|
"truncated chunk #%d: expected chunk length to be %d but "
|
|
"found chunk with length %d" % (chunk["n"], expected_length, len(chunk["data"]))
|
|
)
|
|
|
|
self._next_chunk += 1
|
|
return chunk
|
|
|
|
__next__ = next
|
|
|
|
def close(self) -> None:
|
|
if self._cursor:
|
|
self._cursor.close()
|
|
self._cursor = None
|
|
|
|
|
|
class GridOutIterator:
|
|
def __init__(self, grid_out: GridOut, chunks: Collection, session: ClientSession):
|
|
self.__chunk_iter = _GridOutChunkIterator(grid_out, chunks, session, 0)
|
|
|
|
def __iter__(self) -> "GridOutIterator":
|
|
return self
|
|
|
|
def next(self) -> bytes:
|
|
chunk = self.__chunk_iter.next()
|
|
return bytes(chunk["data"])
|
|
|
|
__next__ = next
|
|
|
|
|
|
class GridOutCursor(Cursor):
|
|
"""A cursor / iterator for returning GridOut objects as the result
|
|
of an arbitrary query against the GridFS files collection.
|
|
"""
|
|
|
|
def __init__(
|
|
self,
|
|
collection: Collection,
|
|
filter: Optional[Mapping[str, Any]] = None,
|
|
skip: int = 0,
|
|
limit: int = 0,
|
|
no_cursor_timeout: bool = False,
|
|
sort: Optional[Any] = None,
|
|
batch_size: int = 0,
|
|
session: Optional[ClientSession] = None,
|
|
) -> None:
|
|
"""Create a new cursor, similar to the normal
|
|
:class:`~pymongo.cursor.Cursor`.
|
|
|
|
Should not be called directly by application developers - see
|
|
the :class:`~gridfs.GridFS` method :meth:`~gridfs.GridFS.find` instead.
|
|
|
|
.. versionadded 2.7
|
|
|
|
.. seealso:: The MongoDB documentation on `cursors <https://dochub.mongodb.org/core/cursors>`_.
|
|
"""
|
|
_disallow_transactions(session)
|
|
collection = _clear_entity_type_registry(collection)
|
|
|
|
# Hold on to the base "fs" collection to create GridOut objects later.
|
|
self.__root_collection = collection
|
|
|
|
super().__init__(
|
|
collection.files,
|
|
filter,
|
|
skip=skip,
|
|
limit=limit,
|
|
no_cursor_timeout=no_cursor_timeout,
|
|
sort=sort,
|
|
batch_size=batch_size,
|
|
session=session,
|
|
)
|
|
|
|
def next(self) -> GridOut:
|
|
"""Get next GridOut object from cursor."""
|
|
_disallow_transactions(self.session)
|
|
next_file = super().next()
|
|
return GridOut(self.__root_collection, file_document=next_file, session=self.session)
|
|
|
|
__next__ = next
|
|
|
|
def add_option(self, *args: Any, **kwargs: Any) -> NoReturn:
|
|
raise NotImplementedError("Method does not exist for GridOutCursor")
|
|
|
|
def remove_option(self, *args: Any, **kwargs: Any) -> NoReturn:
|
|
raise NotImplementedError("Method does not exist for GridOutCursor")
|
|
|
|
def _clone_base(self, session: ClientSession) -> "GridOutCursor":
|
|
"""Creates an empty GridOutCursor for information to be copied into."""
|
|
return GridOutCursor(self.__root_collection, session=session)
|