How to decode a QR-code image in (preferably pure) Python?
TL;DR : I need a way to decode a QR-code from an image file using (preferable pure) Python.
I've got a jpg file with a QR-code which I want to decode using Python. I've found a couple libraries which claim to do this:
PyQRCode (website here) which supposedly can decode qr codes from images by simply providing a path like this:
import sys, qrcode d = qrcode.Decoder() if d.decode('out.png'): print 'result: ' + d.result else: print 'error: ' + d.error
So I simply installed it using
sudo pip install pyqrcode. The thing I find strange about the example code above however, is that it only imports
qrcode (and not
pyqrcode though) Since I think
qrcode refers to this library which can only generate qr-code images it kind of confused me. So I tried the code above with both
qrcode, but both fail at the second line saying
AttributeError: 'module' object has no attribute 'Decoder'. Furthermore, the website refers to Ubuntu 8.10 (which came out more than 6 years ago) and I can't find a public (git or other) repository of it to check the latest commit. So I moved on to the next library:
ZBar (website here) claims to be
"an open source software suite for reading bar codes from various sources, such as image files." So I tried installing it on Mac OSX running
sudo pip install zbar. This fails with
error: command 'cc' failed with exit status 1. I tried to suggestions in the answers to this SO question, but I can't seem to solve it. So I decided to move on again:
QRTools , which according to this blogpost can decode images easily by using the following code:
from qrtools import QR myCode = QR(filename=u"/home/psutton/Documents/Python/qrcodes/qrcode.png") if myCode.decode(): print myCode.data print myCode.data_type print myCode.data_to_string()
So I tried installing it using
sudo pip install qrtools, which can't find anything. I also tried it with
python-qrtools and a couple more combinations, but unfortunately to no avail. I suppose it refers to this repo which says it is based on ZBar (see above). Although I want to run my code on Heroku (and thus prefer a pure Python solution) I successfully installed it on a Linux box (with
sudo apt-get install python-qrtools) and tried running it:
from qrtools import QR c = QR(filename='/home/kramer65/qrcode.jpg') c.data # prints u'NULL' c.data_type # prints u'text' c.data_to_string() # prints '\xef\xbb\xbfNULL' where I expect an int (being `1234567890`)
Although this seems to decode it, It doesn't seem to do it correctly. It furthermore needs ZBar and is thus not pure Python. So I decided to find yet another library.
For the rest I found a couple qr- en coders (not de coders) and some API endpoints which can decode for you. Since I don't like this service to be dependent on other API endpoints I would want to keep the decoding local though.
So to conclude; would anybody know how I can decode QR-codes from images in (preferable pure) Python? All tips are welcome!
You can try the following steps and code using
qrcodefile, if not already existing
- I used
pyqrcodefor doing this, which can be installed using
pip install pyqrcode
- And then use the code:
- I used
>>> import pyqrcode >>> qr = pyqrcode.create("HORN O.K. PLEASE.") >>> qr.png("horn.png", scale=6)
Decode an existing
sudo apt-get install python-qrtools
- Now use the following code within your python prompt
>>> import qrtools >>> qr = qrtools.QR() >>> qr.decode("horn.png") >>> print qr.data u'HORN O.K. PLEASE.'
Here is the complete code in a single run:
In : import pyqrcode In : qr = pyqrcode.create("HORN O.K. PLEASE.") In : qr.png("horn.png", scale=6) In : import qrtools In : qr = qrtools.QR() In : qr.decode("horn.png") Out: True In : print qr.data HORN O.K. PLEASE.
- You might need to install
pip install pypngfor using
- In case you have
PILinstalled, you might get
IOError: decoder zip not available. In that case, try uninstalling and reinstalling
pip uninstall PIL pip install PIL
- If that doesn't work, try using
pip uninstall PIL pip install pillow