您可以使用标准库中email模块中的email.message.Message类。
通过修改您链接的问题中的answer，下面是解析HTTP头的Python3示例。
假设你想创建一个包含所有头字段的字典：

import email
import pprint
from io import StringIO

request_string = 'GET / HTTP/1.1\r\nHost: localhost\r\nConnection: keep-alive\r\nCache-Control: max-age=0\r\nUpgrade-Insecure-Requests: 1\r\nUser-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36\r\nAccept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8\r\nAccept-Encoding: gzip, deflate, sdch\r\nAccept-Language: en-US,en;q=0.8'

# pop the first line so we only process headers
_, headers = request_string.split('\r\n', 1)

# construct a message from the request string
message = email.message_from_file(StringIO(headers))

# construct a dictionary containing the headers
headers = dict(message.items())

# pretty-print the dictionary of headers
pprint.pprint(headers, width=160)

如果你在python提示符下运行它，结果会是这样的：

{'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8',
 'Accept-Encoding': 'gzip, deflate, sdch',
 'Accept-Language': 'en-US,en;q=0.8',
 'Cache-Control': 'max-age=0',
 'Connection': 'keep-alive',
 'Host': 'localhost',
 'Upgrade-Insecure-Requests': '1',
 'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36'}

这些字段名中的每一个都应该由回车符分隔，然后是换行符，然后字段名和值由冒号分隔。所以假设你已经有了一个字符串形式的响应，它 * 应该 * 像下面这样简单：

fields = resp.split("\r\n")
fields = fields[1:] #ignore the GET / HTTP/1.1
output = {}
for field in fields:
    key,value = field.split(':', 1)#split each line by http field name and value
    output[key] = value

更新4/13
使用链接到post中的示例http resp：

resp = 'GET /search?sourceid=chrome&ie=UTF-8&q=ergterst HTTP/1.1\r\nHost: www.google.com\r\nConnection: keep-alive\r\nA
ccept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5\r\nUser-Agent: Mozill
a/5.0 (Macintosh; U; Intel Mac OS X 10_6_6; en-US) AppleWebKit/534.13 (KHTML, like Gecko) Chrome/9.0.597.45 Safari/534.
13\r\nAccept-Encoding: gzip,deflate,sdch\r\nAvail-Dictionary: GeNLY2f-\r\nAccept-Language: en-US,en;q=0.8\r\n'

fields = resp.split("\r\n")
fields = fields[1:] #ignore the GET / HTTP/1.1
output = {}
for field in fields:
    if not field:
        continue
    key,value = field.split(':', 1)
    output[key] = value    
print(output)

需要进行额外检查以确保field不为空。输出：

{'Host': ' www.google.com', 'Connection': ' keep-alive', 'Accept': ' application/xml,application/xhtml+xml,text/html;q=
0.9,text/plain;q=0.8,image/png,*/*;q=0.5', 'User-Agent': ' Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_6; en-US) App
leWebKit/534.13 (KHTML, like Gecko) Chrome/9.0.597.45 Safari/534.13', 'Accept-Encoding': ' gzip,deflate,sdch', 'Avail-D
ictionary': ' GeNLY2f-', 'Accept-Language': ' en-US,en;q=0.8'}

以下是一些Python包，旨在正确解析HTTP协议：

• www.example.com
• https://h11.readthedocs.io/en/latest/
• https://github.com/benoitc/http-parser/（C后端）
• https://github.com/MagicStack/httptools（基于NodeJS的C后端）
• https://github.com/silentsignal/netlib-offline（无耻插件）