bunpro_login.py

import requests
from bs4 import BeautifulSoup

LOGIN_URL = 'https://bunpro.jp/users/sign_in'

headers = {
    'accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7',
    'accept-encoding': 'gzip, deflate, br, zstd',
    'accept-language': 'en-US,en;q=0.9',
    'cache-control': 'max-age=0',
    'content-length': '248',
    'content-type': 'application/x-www-form-urlencoded',
    'origin': 'https://bunpro.jp',
    'priority': 'u=0, i',
    'referer': LOGIN_URL,
    'sec-ch-ua': '"Chromium";v="128", "Not;A=Brand";v="24", "Google Chrome";v="128"',
    'sec-ch-ua-mobile': '?1',
    'sec-ch-ua-platform': '"Android"',
    'sec-fetch-dest': 'document',
    'sec-fetch-mode': 'navigate',
    'sec-fetch-site': 'same-origin',
    'sec-fetch-user': '?1',
    'upgrade-insecure-requests': '1',
    'user-agent': 'Mozilla/5.0 (Linux; Android 6.0; Nexus 5 Build/MRA58N) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Mobile Safari/537.36'
}

payload = {
    'utf8': '✓',
    'user[email]': '...',
    'user[password]': '...',
    'user[remember_me]': '1',
    'commit': 'Log In'
}

with requests.Session() as session:
    response = session.get(LOGIN_URL)

    soup = BeautifulSoup(response.text, 'lxml')
    payload['authenticity_token'] = soup.select_one('meta[name="csrf-token"]')['content']

    headers['cookie'] = '; '.join([x.name + '=' + x.value for x in response.cookies])

    response = session.post(LOGIN_URL, data=payload, headers=headers, allow_redirects=False)

    assert response.status_code == 302
    print(response.cookies.get_dict())

    r = session.get('https://bunpro.jp/grammar_points/1', stream=True, cookies=response.cookies.get_dict())
    print(r.text)