Search code examples
pythonfile-iobarcodein-memory

Hold contents in memory before writing to file

I am trying to use viivakoodi libary here to generate barcode from a string. I want to read this data in memory and not write it to file. Is there a way to do so ?

import barcode
EAN = barcode.get_barcode_class('ean13')
ean = EAN(u'5901234123457', writer=ImageWriter())

After I run this in python, I am getting following in ean object after printing ean.writer.__dict__

{'_callbacks': {'finish': <bound method ImageWriter._finish of <barcode.writer.ImageWriter object at 0x7f0894072d90>>,
  'initialize': <bound method ImageWriter._init of <barcode.writer.ImageWriter object at 0x7f0894072d90>>,
  'paint_module': <bound method ImageWriter._paint_module of <barcode.writer.ImageWriter object at 0x7f0894072d90>>,
  'paint_text': <bound method ImageWriter._paint_text of <barcode.writer.ImageWriter object at 0x7f0894072d90>>},
 '_draw': None,
 '_image': None,
 'background': u'white',
 'center_text': True,
 'dpi': 300,
 'font_size': 10,
 'foreground': u'black',
 'format': u'PNG',
 'module_height': 10,
 'module_width': 10,
 'quiet_zone': 6.5,
 'text': u'',
 'text_distance': 5}

Not sure how I can read the bytes that will be written to file in a variable!

Following writes bytes to file but I want to read it in memory instead of writing:

ean.save('ean13_barcode')

Solution

  • The library's examples mention you can create a (file-like but in-memory) StringIO object, and write the ean into it.

    import barcode
from StringIO import StringIO  # Python 2
from io import StringIO  # Python 3

EAN = barcode.get_barcode_class('ean13')
ean = EAN(u'5901234123457', writer=ImageWriter())

fp = StringIO()
ean.write(fp)

    Then you can call ean.getvalue() to access the object's value.