破解字体加密，以58同城网站为例。
字体加密是爬取网页的过程中比较麻烦的问题。
字体加密一般是网页修改了默认的字符编码集，在网页上加载的他们自己定义的字体文件作为字体的样式，可以正确地显示数字，但是在源码上同样的二进制数由于未加载自定义的字体文件就由计算机默认编码成了乱码。
网站url:https://zz.58.com/pinpaigongyu/?utm_source=sem-baidu-pc&spm=105916146708.26420796287&PGTID=0d100000-0015-63fb-169b-74ddef51914e&ClickID=2
一般来说，通用的解决办法是找到字体文件，分析文件中的映射关系。一般来说，字体文件都是作为样式加在加密字体的部位。
在样式中，我基本上都看完了， 从名字上看只有这个fangchan-secret最可能是字体加密文件。
在源码中Ctrl+F搜索fangchan-secret 寻找字体加密文件
在58的源码中，字体文件是通过base64加密之后放在js里面了。把其中加密的部分取出，第一次是分析，在代码中可使用正则将其中的内容取出来。
58的字体加密文件每次网页刷新，其中的映射顺序会变，所以在不刷新的情况下，再复制一份
这里取第一条799 及其对应的乱码。
base64_str = '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'
price_code = '鸺齤齤'
首先进行base64解码，转化成为二进制形式，在方法中同时我也将字体文件写入了otf字体文件中。
def make_font_file(base64_string: str):
bin_data = base64.decodebytes(base64_string.encode())
with open('text.otf','wb') as f:
f.write(bin_data)
return bin_data
使用fontCreator打开字体文件可以直观的看到每一个数字对应的编码
将字节文件转化为xml格式
def convert_font_to_xml(bin_data):
# 由于TTFont接收一个文件类型
# BytesIO(bin_data) 把二进制数据当作文件来操作
font = TTFont(BytesIO(bin_data))
font.saveXML("text.xml")
bin_data = make_font_file(base64_str)
convert_font_to_xml(bin_data)
# 获取对应关系
font = TTFont(BytesIO(make_font_file(base64_str)))
uniList = font['cmap'].tables[0].ttFont.getGlyphOrder()
c = font['cmap'].tables[0].ttFont.tables['cmap'].tables[0].cmap
# c = font.getBestCmap()
print('cmap is:::::', c)
打印出来是这样子：cmap is::::: {38006: 'glyph00007', 38287: 'glyph00009', 39228: 'glyph00004', 39499: 'glyph00005', 40506: 'glyph00008', 40611: 'glyph00006', 40804: 'glyph00010', 40850: 'glyph00001', 40868: 'glyph00003', 40869: 'glyph00002'}
该字典的键就是网页上显示的乱码的unicode编码，值就是该乱码对应的真正数字。
其中glyph00007是资源，每一个glyph0000x对应一个数字
58的字体文件比较偷懒，根据其后缀就知道对应的数字是对少
又字体的xml文件中，下图部分开始可知（我没截取完），glyph00000没有意义，glyph00001对应0，glyph00001对应1以此类推。
那么，我们根据网页抓取的乱码的unicode编码，获取其对对应的字源，即可获取所对应的数字。
def get_num(string):
ret_list = []
for char in string:
decode_num = ord(char)
num = c[decode_num]
num = int(num[-2:])-1
ret_list.append(num)
return ret_list
如果通过浏览器看到的是类似鸺齤齤这样的乱码，使用爬虫获取的数据是类似 鸺龒龒 十六进制的数字，可直接截取后面四位转化为十进制数后在通过映射表查找。
至于还有其他类似的有字体加密的网站：起点中文网的书籍信息https://book.qidian.com/info/1013302908
这里的字体文件在style标签内可以直接通过src获取
获取字体文件之后，操作步骤和58的类似