458 lines
16 KiB
Python
458 lines
16 KiB
Python
# 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.
|
|
|
|
"""Tools for representing files stored in GridFS."""
|
|
|
|
import datetime
|
|
import math
|
|
import os
|
|
try:
|
|
from cStringIO import StringIO
|
|
except ImportError:
|
|
from StringIO import StringIO
|
|
|
|
from gridfs.errors import (CorruptGridFile,
|
|
FileExists,
|
|
NoFile,
|
|
UnsupportedAPI)
|
|
from pymongo import ASCENDING
|
|
from pymongo.binary import Binary
|
|
from pymongo.collection import Collection
|
|
from pymongo.errors import DuplicateKeyError
|
|
from pymongo.objectid import ObjectId
|
|
|
|
try:
|
|
_SEEK_SET = os.SEEK_SET
|
|
_SEEK_CUR = os.SEEK_CUR
|
|
_SEEK_END = os.SEEK_END
|
|
# before 2.5
|
|
except AttributeError:
|
|
_SEEK_SET = 0
|
|
_SEEK_CUR = 1
|
|
_SEEK_END = 2
|
|
|
|
|
|
"""Default chunk size, in bytes."""
|
|
DEFAULT_CHUNK_SIZE = 256 * 1024
|
|
|
|
|
|
def _create_property(field_name, docstring,
|
|
read_only=False, closed_only=False):
|
|
"""Helper for creating properties to read/write to files.
|
|
"""
|
|
def getter(self):
|
|
if closed_only and not self._closed:
|
|
raise AttributeError("can only get %r on a closed file" %
|
|
field_name)
|
|
return self._file.get(field_name, None)
|
|
|
|
def setter(self, value):
|
|
if self._closed:
|
|
raise AttributeError("cannot set %r on a closed file" %
|
|
field_name)
|
|
self._file[field_name] = value
|
|
|
|
if read_only:
|
|
docstring = docstring + "\n\nThis attribute is read-only."
|
|
elif not closed_only:
|
|
docstring = "%s\n\n%s" % (docstring, "This attribute can only be "
|
|
"set before :meth:`close` has been called.")
|
|
else:
|
|
docstring = "%s\n\n%s" % (docstring, "This attribute is read-only and "
|
|
"can only be read after :meth:`close` "
|
|
"has been called.")
|
|
|
|
if not read_only and not closed_only:
|
|
return property(getter, setter, doc=docstring)
|
|
return property(getter, doc=docstring)
|
|
|
|
|
|
class GridIn(object):
|
|
"""Class to write data to GridFS.
|
|
"""
|
|
def __init__(self, root_collection, **kwargs):
|
|
"""Write a file to GridFS
|
|
|
|
Application developers should generally not need to
|
|
instantiate this class directly - instead see the methods
|
|
provided by :class:`~gridfs.GridFS`.
|
|
|
|
Raises :class:`TypeError` if `root_collection` is not an
|
|
instance of :class:`~pymongo.collection.Collection`.
|
|
|
|
Any of the file level options specified in the `GridFS Spec
|
|
<http://dochub.mongodb.org/core/gridfsspec>`_ may be passed as
|
|
keyword arguments. Any additional keyword arguments will be
|
|
set as additional fields on the file document. Valid keyword
|
|
arguments include:
|
|
|
|
- ``"_id"``: unique ID for this file (default:
|
|
:class:`~pymongo.objectid.ObjectId`) - this ``"_id"`` must
|
|
not have already been used for another file
|
|
|
|
- ``"filename"``: human name for the file
|
|
|
|
- ``"contentType"`` or ``"content_type"``: valid mime-type
|
|
for the file
|
|
|
|
- ``"chunkSize"`` or ``"chunk_size"``: size of each of the
|
|
chunks, in bytes (default: 256 kb)
|
|
|
|
:Parameters:
|
|
- `root_collection`: root collection to write to
|
|
- `**kwargs` (optional): file level options (see above)
|
|
"""
|
|
if not isinstance(root_collection, Collection):
|
|
raise TypeError("root_collection must be an "
|
|
"instance of Collection")
|
|
|
|
# Handle alternative naming
|
|
if "content_type" in kwargs:
|
|
kwargs["contentType"] = kwargs.pop("content_type")
|
|
if "chunk_size" in kwargs:
|
|
kwargs["chunkSize"] = kwargs.pop("chunk_size")
|
|
|
|
# Defaults
|
|
kwargs["_id"] = kwargs.get("_id", ObjectId())
|
|
kwargs["chunkSize"] = kwargs.get("chunkSize", DEFAULT_CHUNK_SIZE)
|
|
|
|
root_collection.chunks.ensure_index([("files_id", ASCENDING),
|
|
("n", ASCENDING)],
|
|
unique=True)
|
|
object.__setattr__(self, "_coll", root_collection)
|
|
object.__setattr__(self, "_chunks", root_collection.chunks)
|
|
object.__setattr__(self, "_file", kwargs)
|
|
object.__setattr__(self, "_buffer", StringIO())
|
|
object.__setattr__(self, "_position", 0)
|
|
object.__setattr__(self, "_chunk_number", 0)
|
|
object.__setattr__(self, "_closed", False)
|
|
|
|
@property
|
|
def closed(self):
|
|
"""Is this file closed?
|
|
"""
|
|
return self._closed
|
|
|
|
_id = _create_property("_id", "The ``'_id'`` value for this file.",
|
|
read_only=True)
|
|
filename = _create_property("filename", "Name of this file.")
|
|
content_type = _create_property("contentType", "Mime-type for this file.")
|
|
length = _create_property("length", "Length (in bytes) of this file.",
|
|
closed_only=True)
|
|
chunk_size = _create_property("chunkSize", "Chunk size for this file.",
|
|
read_only=True)
|
|
upload_date = _create_property("uploadDate",
|
|
"Date that this file was uploaded.",
|
|
closed_only=True)
|
|
md5 = _create_property("md5", "MD5 of the contents of this file "
|
|
"(generated on the server).",
|
|
closed_only=True)
|
|
|
|
def __getattr__(self, name):
|
|
if name in self._file:
|
|
return self._file[name]
|
|
raise AttributeError("GridIn object has no attribute '%s'" % name)
|
|
|
|
def __setattr__(self, name, value):
|
|
if self._closed:
|
|
raise AttributeError("cannot set %r on a closed file" % name)
|
|
object.__setattr__(self, name, value)
|
|
|
|
def __flush_data(self, data):
|
|
"""Flush `data` to a chunk.
|
|
"""
|
|
if not data:
|
|
return
|
|
assert(len(data) <= self.chunk_size)
|
|
|
|
chunk = {"files_id": self._file["_id"],
|
|
"n": self._chunk_number,
|
|
"data": Binary(data)}
|
|
|
|
self._chunks.insert(chunk)
|
|
self._chunk_number += 1
|
|
self._position += len(data)
|
|
|
|
def __flush_buffer(self):
|
|
"""Flush the buffer contents out to a chunk.
|
|
"""
|
|
self.__flush_data(self._buffer.getvalue())
|
|
self._buffer.close()
|
|
self._buffer = StringIO()
|
|
|
|
def __flush(self):
|
|
"""Flush the file to the database.
|
|
"""
|
|
self.__flush_buffer()
|
|
|
|
md5 = self._coll.database.command("filemd5", self._id,
|
|
root=self._coll.name)["md5"]
|
|
|
|
self._file["md5"] = md5
|
|
self._file["length"] = self._position
|
|
self._file["uploadDate"] = datetime.datetime.utcnow()
|
|
|
|
try:
|
|
return self._coll.files.insert(self._file, safe=True)
|
|
except DuplicateKeyError:
|
|
raise FileExists("file with _id %r already exists" % self._id)
|
|
|
|
def close(self):
|
|
"""Flush the file and close it.
|
|
|
|
A closed file cannot be written any more. Calling
|
|
:meth:`close` more than once is allowed.
|
|
"""
|
|
if not self._closed:
|
|
self.__flush()
|
|
self._closed = True
|
|
|
|
# TODO should support writing unicode to a file. this means that files will
|
|
# need to have an encoding attribute.
|
|
def write(self, data):
|
|
"""Write data to the file. There is no return value.
|
|
|
|
`data` can be either a string of bytes or a file-like object
|
|
(implementing :meth:`read`).
|
|
|
|
Due to buffering, the data may not actually be written to the
|
|
database until the :meth:`close` method is called. Raises
|
|
:class:`ValueError` if this file is already closed. Raises
|
|
:class:`TypeError` if `data` is not an instance of
|
|
:class:`str` or a file-like object.
|
|
|
|
:Parameters:
|
|
- `data`: string of bytes or file-like object to be written
|
|
to the file
|
|
"""
|
|
if self._closed:
|
|
raise ValueError("cannot write to a closed file")
|
|
|
|
# file-like
|
|
try:
|
|
if self._buffer.tell() > 0:
|
|
space = self.chunk_size - self._buffer.tell()
|
|
self._buffer.write(data.read(space))
|
|
self.__flush_buffer()
|
|
to_write = data.read(self.chunk_size)
|
|
while to_write and len(to_write) == self.chunk_size:
|
|
self.__flush_data(to_write)
|
|
to_write = data.read(self.chunk_size)
|
|
self._buffer.write(to_write)
|
|
# string
|
|
except AttributeError:
|
|
if not isinstance(data, str):
|
|
raise TypeError("can only write strings or file-like objects")
|
|
|
|
while data:
|
|
space = self.chunk_size - self._buffer.tell()
|
|
|
|
if len(data) <= space:
|
|
self._buffer.write(data)
|
|
break
|
|
else:
|
|
self._buffer.write(data[:space])
|
|
self.__flush_buffer()
|
|
data = data[space:]
|
|
|
|
def writelines(self, sequence):
|
|
"""Write a sequence of strings to the file.
|
|
|
|
Does not add seperators.
|
|
"""
|
|
for line in sequence:
|
|
self.write(line)
|
|
|
|
def __enter__(self):
|
|
"""Support for the context manager protocol.
|
|
"""
|
|
return self
|
|
|
|
def __exit__(self, exc_type, exc_val, exc_tb):
|
|
"""Support for the context manager protocol.
|
|
|
|
Close the file and allow exceptions to propogate.
|
|
"""
|
|
self.close()
|
|
|
|
# propogate exceptions
|
|
return False
|
|
|
|
|
|
class GridOut(object):
|
|
"""Class to read data out of GridFS.
|
|
"""
|
|
def __init__(self, root_collection, file_id):
|
|
"""Read a file from GridFS
|
|
|
|
Application developers should generally not need to
|
|
instantiate this class directly - instead see the methods
|
|
provided by :class:`~gridfs.GridFS`.
|
|
|
|
Raises :class:`TypeError` if `root_collection` is not an instance of
|
|
:class:`~pymongo.collection.Collection`.
|
|
|
|
:Parameters:
|
|
- `root_collection`: root collection to read from
|
|
- `file_id`: value of ``"_id"`` for the file to read
|
|
"""
|
|
if not isinstance(root_collection, Collection):
|
|
raise TypeError("root_collection must be an "
|
|
"instance of Collection")
|
|
|
|
self.__chunks = root_collection.chunks
|
|
self._file = root_collection.files.find_one({"_id": file_id})
|
|
|
|
if not self._file:
|
|
raise NoFile("no file in gridfs collection %r with _id %r" %
|
|
(root_collection, file_id))
|
|
|
|
self.__buffer = ""
|
|
self.__position = 0
|
|
|
|
_id = _create_property("_id", "The ``'_id'`` value for this file.", True)
|
|
name = _create_property("filename", "Name of this file.", True)
|
|
content_type = _create_property("contentType", "Mime-type for this file.",
|
|
True)
|
|
length = _create_property("length", "Length (in bytes) of this file.",
|
|
True)
|
|
chunk_size = _create_property("chunkSize", "Chunk size for this file.",
|
|
True)
|
|
upload_date = _create_property("uploadDate",
|
|
"Date that this file was first uploaded.",
|
|
True)
|
|
aliases = _create_property("aliases", "List of aliases for this file.",
|
|
True)
|
|
metadata = _create_property("metadata", "Metadata attached to this file.",
|
|
True)
|
|
md5 = _create_property("md5", "MD5 of the contents of this file "
|
|
"(generated on the server).", True)
|
|
|
|
def __getattr__(self, name):
|
|
if name in self._file:
|
|
return self._file[name]
|
|
raise AttributeError("GridIn object has no attribute '%s'" % name)
|
|
|
|
def read(self, size=-1):
|
|
"""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`. If
|
|
`size` is negative or omitted all data is read.
|
|
|
|
:Parameters:
|
|
- `size` (optional): the number of bytes to read
|
|
"""
|
|
if size == 0:
|
|
return ""
|
|
|
|
remainder = int(self.length) - self.__position
|
|
if size < 0 or size > remainder:
|
|
size = remainder
|
|
|
|
data = self.__buffer
|
|
chunk_number = (len(data) + self.__position) / self.chunk_size
|
|
|
|
while len(data) < size:
|
|
chunk = self.__chunks.find_one({"files_id": self._id,
|
|
"n": chunk_number})
|
|
if not chunk:
|
|
raise CorruptGridFile("no chunk #%d" % chunk_number)
|
|
|
|
if not data:
|
|
data += chunk["data"][self.__position % self.chunk_size:]
|
|
else:
|
|
data += chunk["data"]
|
|
|
|
chunk_number += 1
|
|
|
|
self.__position += size
|
|
to_return = data[:size]
|
|
self.__buffer = data[size:]
|
|
return to_return
|
|
|
|
def tell(self):
|
|
"""Return the current position of this file.
|
|
"""
|
|
return self.__position
|
|
|
|
def seek(self, pos, whence=_SEEK_SET):
|
|
"""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.
|
|
"""
|
|
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 IOError(22, "Invalid value for `whence`")
|
|
|
|
if new_pos < 0:
|
|
raise IOError(22, "Invalid value for `pos` - must be positive")
|
|
|
|
self.__position = new_pos
|
|
self.__buffer = ""
|
|
|
|
def __iter__(self):
|
|
"""Return an iterator over all of this file's data.
|
|
|
|
The iterator will return chunk-sized instances of
|
|
:class:`str`. This can be useful when serving files using a
|
|
webserver that handles such an iterator efficiently.
|
|
"""
|
|
return GridOutIterator(self, self.__chunks)
|
|
|
|
|
|
class GridOutIterator(object):
|
|
def __init__(self, grid_out, chunks):
|
|
self.__id = grid_out._id
|
|
self.__chunks = chunks
|
|
self.__current_chunk = 0
|
|
self.__max_chunk = math.ceil(float(grid_out.length) /
|
|
grid_out.chunk_size)
|
|
|
|
def __iter__(self):
|
|
return self
|
|
|
|
def next(self):
|
|
if self.__current_chunk >= self.__max_chunk:
|
|
raise StopIteration
|
|
chunk = self.__chunks.find_one({"files_id": self.__id,
|
|
"n": self.__current_chunk})
|
|
if not chunk:
|
|
raise CorruptGridFile("no chunk #%d" % self.__current_chunk)
|
|
self.__current_chunk += 1
|
|
return str(chunk["data"])
|
|
|
|
|
|
class GridFile(object):
|
|
"""No longer supported.
|
|
|
|
.. versionchanged:: 1.6
|
|
The GridFile class is no longer supported.
|
|
"""
|
|
def __init__(self, *args, **kwargs):
|
|
raise UnsupportedAPI("The GridFile class is no longer supported. "
|
|
"Please use GridIn or GridOut instead.")
|