grid_file – Tools for representing files stored in GridFS

Tools for representing files stored in GridFS.

class gridfs.grid_file.GridIn(root_collection, session=None, disable_md5=False, \*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: 255 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.

Changed in version 3.6: Added session parameter.

Changed in version 3.0: root_collection must use an acknowledged write_concern

• _id

  The '_id' value for this file.

  This attribute is read-only.

• abort()

  Remove all chunks/files that may have been uploaded and close.

• 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 if an md5 sum was created.

  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

• 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, session=None)

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.

Changed in version 3.8: For better performance and to better follow the GridFS spec, GridOut now uses a single cursor to read all the chunks in the file.

Changed in version 3.6: Added session parameter.

Changed in version 3.0: Creating a GridOut does not immediately retrieve the file metadata from the server. Metadata is fetched when first needed.

• _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.

  Note

  This is different from io.IOBase which iterates over lines in the file. Use GridOut.readline() to read line by line instead of chunk by chunk.

  Changed in version 3.8: The iterator now raises CorruptGridFile when encountering any truncated, missing, or extra chunk in a file. The previous behavior was to only raise CorruptGridFile on a missing chunk.

• 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 if an md5 sum was created.

  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

  Changed in version 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.

• 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

• 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.GridOutCursor(collection, filter=None, skip=0, limit=0, no_cursor_timeout=False, sort=None, batch_size=0, session=None)

Create a new cursor, similar to the normal Cursor.

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

See also

The MongoDB documentation on

cursors

• add_option(\args, **kwargs*)

  Set arbitrary query flags using a bitmask.

  To set the tailable flag: cursor.add_option(2)

• next()

  Get next GridOut object from cursor.

• remove_option(\args, **kwargs*)

  Unset arbitrary query flags using a bitmask.

  To unset the tailable flag: cursor.remove_option(2)