gridfs – Tools for working with GridFS

GridFS is a specification for storing large objects in Mongo.

The gridfs package is an implementation of GridFS on top of pymongo, exposing a file-like interface.

See also

See general MongoDB documentation

gridfs

class gridfs.GridFS(database, collection='fs')

Create a new instance of GridFS.

Raises TypeError if database is not an instance of Database.

Parameters:
  • database: database to use
  • collection (optional): root collection to use

Changed in version 3.0: database must use an acknowledged write_concern

See also

See general MongoDB documentation

gridfs

delete(file_id)

Delete a file from GridFS by "_id".

Deletes all data belonging to the file with "_id": file_id.

Warning

Any processes/threads reading from the file while this method is executing will likely see an invalid/corrupt file. Care should be taken to avoid concurrent reads to a file while it is being deleted.

Note

Deletes of non-existent files are considered successful since the end result is the same: no file with that _id remains.

Parameters:
  • file_id: "_id" of the file to delete
exists(document_or_id=None, **kwargs)

Check if a file exists in this instance of GridFS.

The file to check for can be specified by the value of its _id key, or by passing in a query document. A query document can be passed in as dictionary, or by using keyword arguments. Thus, the following three calls are equivalent:

>>> fs.exists(file_id)
>>> fs.exists({"_id": file_id})
>>> fs.exists(_id=file_id)

As are the following two calls:

>>> fs.exists({"filename": "mike.txt"})
>>> fs.exists(filename="mike.txt")

And the following two:

>>> fs.exists({"foo": {"$gt": 12}})
>>> fs.exists(foo={"$gt": 12})

Returns True if a matching file exists, False otherwise. Calls to exists() will not automatically create appropriate indexes; application developers should be sure to create indexes if needed and as appropriate.

Parameters:
  • document_or_id (optional): query document, or _id of the document to check for
  • **kwargs (optional): keyword arguments are used as a query document, if they’re present.
find(*args, **kwargs)

Query GridFS for files.

Returns a cursor that iterates across files matching arbitrary queries on the files collection. Can be combined with other modifiers for additional control. For example:

for grid_out in fs.find({"filename": "lisa.txt"},
                        no_cursor_timeout=True):
    data = grid_out.read()

would iterate through all versions of “lisa.txt” stored in GridFS. Note that setting no_cursor_timeout to True may be important to prevent the cursor from timing out during long multi-file processing work.

As another example, the call:

most_recent_three = fs.find().sort("uploadDate", -1).limit(3)

would return a cursor to the three most recently uploaded files in GridFS.

Follows a similar interface to find() in Collection.

Parameters:
  • filter (optional): a SON object specifying elements which must be present for a document to be included in the result set
  • skip (optional): the number of files to omit (from the start of the result set) when returning the results
  • limit (optional): the maximum number of results to return
  • no_cursor_timeout (optional): if False (the default), any returned cursor is closed by the server after 10 minutes of inactivity. If set to True, the returned cursor will never time out on the server. Care should be taken to ensure that cursors with no_cursor_timeout turned on are properly closed.
  • sort (optional): a list of (key, direction) pairs specifying the sort order for this query. See sort() for details.

Raises TypeError if any of the arguments are of improper type. Returns an instance of GridOutCursor corresponding to this query.

Changed in version 3.0: Removed the read_preference, tag_sets, and secondary_acceptable_latency_ms options.

New in version 2.7.

See also

See general MongoDB documentation

find

find_one(filter=None, *args, **kwargs)

Get a single file from gridfs.

All arguments to find() are also valid arguments for find_one(), although any limit argument will be ignored. Returns a single GridOut, or None if no matching file is found. For example:

file = fs.find_one({"filename": "lisa.txt"})
Parameters:
  • filter (optional): a dictionary specifying the query to be performing OR any other type to be used as the value for a query for "_id" in the file collection.
  • *args (optional): any additional positional arguments are the same as the arguments to find().
  • **kwargs (optional): any additional keyword arguments are the same as the arguments to find().
get(file_id)

Get a file from GridFS by "_id".

Returns an instance of GridOut, which provides a file-like interface for reading.

Parameters:
  • file_id: "_id" of the file to get
get_last_version(filename=None, **kwargs)

Get the most recent version of a file in GridFS by "filename" or metadata fields.

Equivalent to calling get_version() with the default version (-1).

Parameters:
  • filename: "filename" of the file to get, or None
  • **kwargs (optional): find files by custom metadata.
get_version(filename=None, version=-1, **kwargs)

Get a file from GridFS by "filename" or metadata fields.

Returns a version of the file in GridFS whose filename matches filename and whose metadata fields match the supplied keyword arguments, as an instance of GridOut.

Version numbering is a convenience atop the GridFS API provided by MongoDB. If more than one file matches the query (either by filename alone, by metadata fields, or by a combination of both), then version -1 will be the most recently uploaded matching file, -2 the second most recently uploaded, etc. Version 0 will be the first version uploaded, 1 the second version, etc. So if three versions have been uploaded, then version 0 is the same as version -3, version 1 is the same as version -2, and version 2 is the same as version -1.

Raises NoFile if no such version of that file exists.

An index on {filename: 1, uploadDate: -1} will automatically be created when this method is called the first time.

Parameters:
  • filename: "filename" of the file to get, or None
  • version (optional): version of the file to get (defaults to -1, the most recent version uploaded)
  • **kwargs (optional): find files by custom metadata.
list()

List the names of all files stored in this instance of GridFS.

An index on {filename: 1, uploadDate: -1} will automatically be created when this method is called the first time.

Changed in version 2.7: list ensures an index, the same as get_version.

new_file(**kwargs)

Create a new file in GridFS.

Returns a new GridIn instance to which data can be written. Any keyword arguments will be passed through to GridIn().

If the "_id" of the file is manually specified, it must not already exist in GridFS. Otherwise FileExists is raised.

Parameters:
  • **kwargs (optional): keyword arguments for file creation
put(data, **kwargs)

Put data in GridFS as a new file.

Equivalent to doing:

try:
    f = new_file(**kwargs)
    f.write(data)
finally:
    f.close()

data can be either an instance of str (bytes in python 3) or a file-like object providing a read() method. If an encoding keyword argument is passed, data can also be a unicode (str in python 3) instance, which will be encoded as encoding before being written. Any keyword arguments will be passed through to the created file - see GridIn() for possible arguments. Returns the "_id" of the created file.

If the "_id" of the file is manually specified, it must not already exist in GridFS. Otherwise FileExists is raised.

Parameters:
  • data: data to be written as a file.
  • **kwargs (optional): keyword arguments for file creation

Changed in version 3.0: w=0 writes to GridFS are now prohibited.

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