grid_file – Tools for representing files stored in GridFS

Tools for representing files stored in GridFS.

class gridfs.grid_file.GridIn(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 GridFS.

Raises TypeError if root_collection is not an instance of Collection.

Any of the file level options specified in the GridFS Spec 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: 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)
  • "encoding": encoding used for this file. In Python 2, any unicode that is written to the file will be converted to a str. In Python 3, any str that is written to the file will be converted to bytes.

If you turn off write-acknowledgment for performance reasons, it is critical to wrap calls to write() and close() within a single request:

>>> from pymongo import MongoClient
>>> from gridfs import GridFS
>>> client = MongoClient(w=0) # turn off write acknowledgment
>>> fs = GridFS(client.database)
>>> gridin = fs.new_file()
>>> request = client.start_request()
>>> try:
...     for i in range(10):
...         gridin.write('foo')
...     gridin.close()
... finally:
...     request.end()

In Python 2.5 and later this code can be simplified with a with-statement, see Requests for more information.

Parameters :
  • root_collection: root collection to write to
  • **kwargs (optional): file level options (see above)
_id

The '_id' value for this file.

This attribute is read-only.

chunk_size

Chunk size for this file.

This attribute is read-only.

close()

Flush the file and close it.

A closed file cannot be written any more. Calling close() more than once is allowed.

closed

Is this file closed?

content_type

Mime-type for this file.

filename

Name of this file.

length

Length (in bytes) of this file.

This attribute is read-only and can only be read after close() has been called.

md5

MD5 of the contents of this file (generated on the server).

This attribute is read-only and can only be read after close() has been called.

name

Alias for filename.

upload_date

Date that this file was uploaded.

This attribute is read-only and can only be read after close() has been called.

write(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 read()). If the file has an encoding attribute, data can also be a unicode (str in python 3) instance, which will be encoded as encoding before being written.

Due to buffering, the data may not actually be written to the database until the close() method is called. Raises ValueError if this file is already closed. Raises TypeError if data is not an instance of str (bytes in python 3), a file-like object, or an instance of unicode (str in python 3). Unicode data is only allowed if the file has an encoding attribute.

Parameters :
  • data: string of bytes or file-like object to be written to the file

New in version 1.9: The ability to write unicode, if the file has an encoding attribute.

writelines(sequence)

Write a sequence of strings to the file.

Does not add seperators.

class gridfs.grid_file.GridOut(root_collection, file_id=None, file_document=None, _connect=True)

Read a file from GridFS

Application developers should generally not need to instantiate this class directly - instead see the methods provided by GridFS.

Either file_id or file_document must be specified, file_document will be given priority if present. Raises TypeError if root_collection is not an instance of Collection.

Parameters :
  • root_collection: root collection to read from
  • file_id: value of "_id" for the file to read
  • file_document: file document from root_collection.files

New in version 1.9: The file_document parameter.

_id

The '_id' value for this file.

This attribute is read-only.

__iter__()

Return an iterator over all of this file’s data.

The iterator will return chunk-sized instances of str (bytes in python 3). This can be useful when serving files using a webserver that handles such an iterator efficiently.

aliases

List of aliases for this file.

This attribute is read-only.

chunk_size

Chunk size for this file.

This attribute is read-only.

close()

Make GridOut more generically file-like.

content_type

Mime-type for this file.

This attribute is read-only.

filename

Name of this file.

This attribute is read-only.

length

Length (in bytes) of this file.

This attribute is read-only.

md5

MD5 of the contents of this file (generated on the server).

This attribute is read-only.

metadata

Metadata attached to this file.

This attribute is read-only.

name

Alias for filename.

This attribute is read-only.

read(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 str (bytes in python 3). If size is negative or omitted all data is read.

Parameters :
  • size (optional): the number of bytes to read
readchunk()

Reads a chunk at a time. If the current position is within a chunk the remainder of the chunk is returned.

readline(size=-1)

Read one line or up to size bytes from the file.

Parameters :
  • size (optional): the maximum number of bytes to read

New in version 1.9.

seek(pos, whence=0)

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. os.SEEK_SET (0) for absolute file positioning, os.SEEK_CUR (1) to seek relative to the current position, os.SEEK_END (2) to seek relative to the file’s end.
tell()

Return the current position of this file.

upload_date

Date that this file was first uploaded.

This attribute is read-only.

class gridfs.grid_file.GridFile(*args, **kwargs)

No longer supported.

Changed in version 1.6: The GridFile class is no longer supported.

class gridfs.grid_file.GridOutCursor(collection, spec=None, skip=0, limit=0, timeout=True, sort=None, max_scan=None, read_preference=None, tag_sets=None, secondary_acceptable_latency_ms=None, compile_re=True)

Create a new cursor, similar to the normal Cursor.

Should not be called directly by application developers - see the GridFS method find() instead.

See general MongoDB documentation

cursors

next()

Get next GridOut object from cursor.

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