4

I have a mongodb collection that looks something like this:

{
 u'_id': u'someid',
 u'files': {u'screenshot': Binary('\x89PNG\r\n\x1a\n\...', 0)}
}

The screenshot is in a binary format and I would like to display it. How would I do this in python?

I've setup a connection to the database with pymongo but I have no idea how I can decode the bytestream. Bear in mind that I did not create this database, I only have access to it.

Stanko
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2 Answers2

3

one might use for example Pillow 

import sys
from cStringIO import StringIO

from bson.binary import Binary
from pymongo import MongoClient
from PIL import Image

data = open(sys.argv[1], 'rb').read()

client = MongoClient()
db = client.so
db['images'].remove()
db['images'].insert({'id': 1, 'img': Binary(data)})

for rec in db['images'].find():
    im = Image.open(StringIO(rec['img']))
    im.show()

this script takes a PNG file as its first argument, inserts its binary representation into a Mongo collection, retrieves this binary representation and finally displays the figure

ewcz
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    for **python3** we have to `from io import BytesIO` and `im = Image.open(BytesIO(rec['img']))` – thanasisp Feb 26 '17 at 23:00
  • @thanasisp indeed, good point, from the OP's question, I assumed that he/she is using Python 2.X (judging by the output sample) – ewcz Feb 27 '17 at 08:56
0

Someone answered to the question and then deleted his answer, I don't know why he deleted it because it helped me. The following two lines were his contribution: 

with open('output.png', 'wb') as f:
    f.write(item[u'files'][u'screenshot'])

Then I used Tkinter to display the image:

from Tkinter import *
root = Tk()

topFrame = Frame(root)
topFrame.pack()

screenshot = PhotoImage(file="output.png")
label_screenshot = Label(topFrame, image=screenshot)
label_screenshot.pack()

root.mainloop()
Stanko
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    To the people downvoting, please expain what's wrong with this solution and why the other one is better. – Stanko Mar 06 '17 at 08:59
  • f.write(item[u'files'][u'screenshot']) is showing following error TypeError: argument 1 must be convertible to a buffer, not GridOut – Mammu yedukondalu Nov 12 '18 at 11:08