gistfile1.txt

#!/usr/bin/env python3
# -*- coding:utf-8 -*-

__author__ = 'Nisests'

import requests
from bs4 import BeautifulSoup

login_url = 'https://www.packtpub.com/'
accout_url = 'https://www.packtpub.com/account'

headers = {
    'referer':'https://www.packtpub.com/',
    'user-agent':'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.87 Safari/537.36'
}

s = requests.session()
data = s.get(login_url,headers=headers)
# print(data.text)
soup = BeautifulSoup(data.text,'html.parser')
form_build_id = soup.find('input',attrs={'name':'form_build_id'})['value']
# print(form_build_id)

data = {
    'email':'251323229@qq.com',
    'password':'1qaz2wsx3edc',
    'op':'Login',
    'form_build_id':form_build_id,
    'form_id':'packt_user_login_form'
}

s.post(login_url,headers=headers,data=data)

# test
accout = s.get(accout_url,headers=headers)
print(accout.text)