How to get a file object from mongodb using pymongo?

Question

I am currently using:

some_fs = gridfs.GridFS(db, "some.col")
fs_file = some_fs.get(index)

to get a <class 'gridfs.grid_file.GridOut'> object.

How do I get a file object instead or how do I convert this to a python file object? Do I have to save as a temp file to do this?

Edit:

This is the full code I am using:

FFMPEG_BIN = "ffmpeg.exe"
some_fs = gridfs.GridFS(db, "some.col")
vid_id = ObjectId("5339e3b5b322631b544b2338")

vid_file = some_fs.get(vid_id)
raw =  vid_file.read()
print type(vid_file), type(raw)

with open(raw, "rb") as infile:
    pipe = sp.Popen([FFMPEG_BIN,
                 # "-v", "quiet",
                 "-y",
                 "-i", "-",
                 "-vcodec", "copy", "-acodec", "copy",
                 "-ss", "00:00:00", "-t", "00:00:10", "-sn",
                 "test.mp4" ]
                ,stdin=infile, stdout=sp.PIPE
)
pipe.wait()

Output:

[2014-03-31 19:03:00] Connected to DB.
<class 'gridfs.grid_file.GridOut'> <type 'str'>
Traceback (most recent call last):
  File "C:/dev/proj/src/lib/ffmpeg/win/test.py", line 19, in <module>
    with open(raw, "rb") as infile:
TypeError: file() argument 1 must be encoded string without NULL bytes, not str

Nick Rempel · Accepted Answer · 2014-03-31 23:40:58Z

2

Edit: Maybe the GridOut isn't a proper implementation of python file objects. My last suggestion is to try using a memory file with StringIO.

import StringIO

FFMPEG_BIN = "ffmpeg.exe"
some_fs = gridfs.GridFS(db, "some.col")
vid_id = ObjectId("5339e3b5b322631b544b2338")

vid_file = some_fs.get(vid_id)

# Should be a proper file-like object
infile =  StringIO.StringIO(vid_file.read())

pipe = sp.Popen([FFMPEG_BIN,
    # "-v", "quiet",
    "-y",
    "-i", "-",
    "-vcodec", "copy", "-acodec", "copy",
    "-ss", "00:00:00", "-t", "00:00:10", "-sn",
    "test.mp4" ]
    ,stdin=infile, stdout=sp.PIPE
)
pipe.wait()

...

infile.close()

edited Mar 31, 2014 at 23:40

answered Mar 31, 2014 at 23:16

Nick Rempel

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4 Comments

Jeff Over a year ago

infile is not set to anything... what should I use as input?

Jeff Over a year ago

That gives me: TypeError: must be convertible to a buffer, not GridOut

Nick Rempel Over a year ago

@Jeff, it looks like GridOut isn't a proper implementation of python file-like objects. Try creating a memory file to read from. I've updated my answer.

Jeff Over a year ago

That gives: File "C:\Python27\lib\subprocess.py", line 665, in init errread, errwrite) = self._get_handles(stdin, stdout, stderr) File "C:\Python27\lib\subprocess.py", line 772, in _get_handles p2cread = msvcrt.get_osfhandle(stdin.fileno()) AttributeError: StringIO instance has no attribute 'fileno'

Salvador Dali · Accepted Answer · 2014-03-31 22:56:10Z

0

Based on this documentation you need to use .read() method.

I think that some_fs.get(index).read() will give you what you need.

answered Mar 31, 2014 at 22:56

Salvador Dali

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2 Comments

Salvador Dali Over a year ago

@Jeff can you please tell what kind of string is there and what do you expect to be in a file? It sounds like your <class ...> is actually a fileobject and read() gives you what is inside of that file.

Jeff Over a year ago

I edited my question... I hope this doesn't change my question too much!

user7255148 · Accepted Answer · 2016-12-06 04:00:18Z

0

This worked for me

FFMPEG_BIN = "ffmpeg.exe"
some_fs = gridfs.GridFS(db, "some.col")
vid_id = ObjectId("5339e3b5b322631b544b2338")

vid_file = some_fs.get(vid_id)

pipe = sp.Popen([FFMPEG_BIN,
    # "-v", "quiet",
    "-y",
    "-i", "-",
    "-vcodec", "copy", "-acodec", "copy",
    "-ss", "00:00:00", "-t", "00:00:10", "-sn",
    "test.mp4" ]
    ,stdin=sp.PIPE, stdout=sp.PIPE
)
pipe.stdin=vid_file.read()

answered Dec 6, 2016 at 4:00

user7255148

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