How to parse data-uri in python?

Question

HTML image elements have this simplified format:

<img src='something'>

That something can be data-uri, for example:

data:image/png;base64,iVBORw0KGg...

Is there a standard way of parsing this with python, so that I get content_type and base64 data separated, or should I create my own parser for this?

Answer 1

Split the data URI on the comma to get the base64 encoded data without the header. Call base64.b64decode to decode that to bytes. Last, write the bytes to a file.

from base64 import b64decode

data_uri = "data:image/png;base64,iVBORw0KGg..."

# Python 2 and <Python 3.4
header, encoded = data_uri.split(",", 1)
data = b64decode(encoded)

# Python 3.4+
# from urllib import request
# with request.urlopen(data_uri) as response:
#     data = response.read()

with open("image.png", "wb") as f:
    f.write(data)

Answer 2

Python since 3.4 has support for data-uri, under the hood using urllib.request.DataHandler.

from urllib.request import urlopen

with urlopen(data_uri) as response:
    data = response.read()

Answer 3

w3lib (a library used by Scrapy) has a function to parse data uris:

>>> from w3lib.url import parse_data_uri
>>> parse_data_uri('data:image/png;base64,iVBORw0KGg==')
ParseDataURIResult(media_type='image/png', media_type_parameters={}, data=b'\x89PNG\r\n\x1a')