如何在 python 中解析数据 uri？

Question

HTML 图像元素具有this 简化格式：

<img src='something'>

表示某事可以是

data-uri

，例如：

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

是否有一种用 python 解析它的标准方法，以便我将

content_type

和 base64 数据分开，或者我应该为此创建自己的解析器吗？

Answer 1

在逗号上拆分数据URI，得到没有头部的base64编码数据。调用

base64.b64decode

将其解码为字节。最后，将字节写入文件。

from base64 import b64decode

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

# Python 2 and <Python 3.4
header, encoded = data_uri.split("base64,", 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 自 3.4 以来支持数据 uri，在引擎盖下使用

urllib.request.DataHandler

.

from urllib.request import urlopen

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

Answer 3

w3lib（Scrapy 使用的库）有一个function 来解析数据 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')

Answer 4

这可能有帮助：

import re
from lxml import html

BASE_NAME = "image_"

source_code = """<img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUA
AAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO
9TXL0Y4OHwAAAABJRU5ErkJggg==" alt="Red dot" />
<img src="data:image/gif;base64,R0lGODlhAQABAIAAAAUEBAAAACwAAAAAAQABAAACAkQBADs=" alt="Black dot" />"""

tree = html.fromstring(source_code)

for i,image in enumerate(tree.xpath('//img[contains(@src, "data:image")]/@src')):
    image_type, image_content = image.split(',', 1)
    image_type = re.findall('data:image\/(\w+);base64', image_type)[0]
    with open("{}{}.{}".format(BASE_NAME, i, image_type), "wb") as f:
        f.write(image_content.decode('base64'))
    print "[*] '{}' image found with content: {}\n".format(image_type, image_content)

输出：

[*] 'png' image found with content: iVBORw0KGgoAAAANSUhEUgAAAAUA
AAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO
9TXL0Y4OHwAAAABJRU5ErkJggg==

[*] 'gif' image found with content: R0lGODlhAQABAIAAAAUEBAAAACwAAAAAAQABAAACAkQBADs=

它将在

base64

标签中保存每个

<img>

图像，并带有各自的文件扩展名：

前缀为BASE_NAME + auto-increment digit(s) provided by

enumerate

+ image_extension

Answer 5

更正 JRodDynamite 的帖子：

from base64 import decodestring

png_arr= "data:image/png;base64,iVBORw0KGg..."
png_arr = png_arr.split(",")
png_arr = png_arr[1]

fh = open("imageToSave.png", "wb")
fh.write(decodestring(png_arr))
fh.close()

Answer 6

from urllib import request

def download(data_uri,name):

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

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

en="https://encrypted-tbn0.gstatic.com/images..."

src="data:image/png;base64,..."

download(en,"en")

download(src,"src")