Pixiv OAuth Flow

README.md

Retrieving Auth Token

1. Run the command:

   python pixiv_auth.py login

   This will open the browser with Pixiv login page.

2. Open dev console (F12) and switch to network tab.

3. Enable persistent logging ("Preserve log").

4. Type into the filter field: callback?

5. Proceed with Pixiv login.

6. After logging in you should see a blank page and request that looks like this: https://app-api.pixiv.net/web/v1/users/auth/pixiv/callback?state=...&code=.... Copy value of the code param into the pixiv_auth.py's prompt and hit the Enter key.

If you did everything right and Pixiv did not change their auth flow, pair of auth_token and refresh_token should be displayed.

⚠️ code's lifetime is extremely short, so make sure to minimize delay between step 5 and 6. Otherwise, repeat everything starting step 1.

Refresh Tokens

python pixiv_auth.py refresh OLD_REFRESH_TOKEN

pixiv_auth.py

#!/usr/bin/env python

from argparse import ArgumentParser
from base64 import urlsafe_b64encode
from hashlib import sha256
from pprint import pprint
from secrets import token_urlsafe
from sys import exit
from urllib.parse import urlencode
from webbrowser import open as open_url

import requests

# Latest app version can be found using GET /v1/application-info/android
USER_AGENT = "PixivAndroidApp/5.0.234 (Android 11; Pixel 5)"
REDIRECT_URI = "https://app-api.pixiv.net/web/v1/users/auth/pixiv/callback"
LOGIN_URL = "https://app-api.pixiv.net/web/v1/login"
AUTH_TOKEN_URL = "https://oauth.secure.pixiv.net/auth/token"
CLIENT_ID = "MOBrBDS8blbauoSck0ZfDbtuzpyT"
CLIENT_SECRET = "lsACyCD94FhDUtGTXi3QzcFE2uU1hqtDaKeqrdwj"


def s256(data):
    """S256 transformation method."""

    return urlsafe_b64encode(sha256(data).digest()).rstrip(b"=").decode("ascii")


def oauth_pkce(transform):
    """Proof Key for Code Exchange by OAuth Public Clients (RFC7636)."""

    code_verifier = token_urlsafe(32)
    code_challenge = transform(code_verifier.encode("ascii"))

    return code_verifier, code_challenge


def print_auth_token_response(response):
    data = response.json()

    try:
        access_token = data["access_token"]
        refresh_token = data["refresh_token"]
    except KeyError:
        print("error:")
        pprint(data)
        exit(1)

    print("access_token:", access_token)
    print("refresh_token:", refresh_token)
    print("expires_in:", data.get("expires_in", 0))


def login():
    code_verifier, code_challenge = oauth_pkce(s256)
    login_params = {
        "code_challenge": code_challenge,
        "code_challenge_method": "S256",
        "client": "pixiv-android",
    }

    open_url(f"{LOGIN_URL}?{urlencode(login_params)}")

    try:
        code = input("code: ").strip()
    except (EOFError, KeyboardInterrupt):
        return

    response = requests.post(
        AUTH_TOKEN_URL,
        data={
            "client_id": CLIENT_ID,
            "client_secret": CLIENT_SECRET,
            "code": code,
            "code_verifier": code_verifier,
            "grant_type": "authorization_code",
            "include_policy": "true",
            "redirect_uri": REDIRECT_URI,
        },
        headers={"User-Agent": USER_AGENT},
    )

    print_auth_token_response(response)


def refresh(refresh_token):
    response = requests.post(
        AUTH_TOKEN_URL,
        data={
            "client_id": CLIENT_ID,
            "client_secret": CLIENT_SECRET,
            "grant_type": "refresh_token",
            "include_policy": "true",
            "refresh_token": refresh_token,
        },
        headers={"User-Agent": USER_AGENT},
    )
    print_auth_token_response(response)


def main():
    parser = ArgumentParser()
    subparsers = parser.add_subparsers()
    parser.set_defaults(func=lambda _: parser.print_usage())
    login_parser = subparsers.add_parser("login")
    login_parser.set_defaults(func=lambda _: login())
    refresh_parser = subparsers.add_parser("refresh")
    refresh_parser.add_argument("refresh_token")
    refresh_parser.set_defaults(func=lambda ns: refresh(ns.refresh_token))
    args = parser.parse_args()
    args.func(args)


if __name__ == "__main__":
    main()

Yes this method is still usable. About the refresh token staying the same: this is how OAuth2 protocol works, what is returned is the new access_token (that expires in 1 hour). To make authenticated requests you need access_token, refresh_token is used to get that access_token every hour and it should not change (it's a long-term key). I suppose this instruction is slightly confusing python pixiv_auth.py refresh OLD_REFRESH_TOKEN, should be python pixiv_auth.py access_token REFRESH_TOKEN or something along these lines.