Reddit native auth / GQL example

reddit.py

import requests
import hashlib
import base64
import uuid
import time
import json
import hmac

# Android app api keys, posted here: https://news.ycombinator.com/item?id=36086240
REDDIT_ANDROID_OAUTH_CLIENT_ID = 'ohXpoqrZYub1kg'
REDDIT_ANDROID_HMAC_SECRET = '8c7abaa5f905f70400c81bf3a1a101e75f7210104b1991f0cd5240aa80c4d99d'

class Reddit:
    GQL_ENDPOINT = 'https://gql.reddit.com'
    AUTH_ENDPOINT = 'https://accounts.reddit.com'
    USER_AGENT = 'Reddit/Version 2023.21.0/Build 956283/Android 13'

    def __init__(self, client_id, hmac_secret):
        self.client_id = client_id
        self.hmac_secret = hmac_secret
        self.token = None

        self.s = requests.session()

        self.uuid = str(uuid.uuid4())
        self.s.headers.update({
            'Client-Vendor-Id': self.uuid,
            'X-Reddit-Device-Id': self.uuid,
            'User-Agent': self.USER_AGENT
        })

    def login_anonymous(self):
        return self._get_token()
    
    def login_user(self, username, password):
        epoch = str(int(time.time()))
        body = json.dumps({'username': username, 'password': password}, separators = (',', ':'))

        body_sig = f'1:android:2:{epoch}:{self._generate_body_sig(epoch, body)}'
        result_sig = f'1:android:2:{epoch}:{self._generate_result_sig(epoch)}'

        r = self.s.post(
            f'{self.AUTH_ENDPOINT}/api/login',
            data = body,
            headers = {
                'X-Hmac-Signed-Body': body_sig,
                'X-Hmac-Signed-Result': result_sig
            }
        )

        if r.json()['success']:
            print('reddit_session =', r.cookies['reddit_session'])
            print('modhash =', r.json()['modhash'])
            return self._get_token()
        else:
            raise Exception('Login error')


    def gql_get_posts(self, subreddit, sort='HOT', after=None):
        if not self.token:
            raise Exception('Not authorized')
        
        json_body = {
            'id': '3496a5858eb9',  # SubredditFeedElements
            'variables': {
                'subredditName': subreddit,
                'sort': sort,
                'adContext': {
                    'distance': None,
                    'layout': 'CARD',
                    'deviceAdId': '',
                    'clientSignalSessionData': {
                        'adsSeenCount': 123,
                        'totalPostsSeenCount': 456,
                        'sessionStartTime': '2023-06-05T12:34:56.000000+0000'
                    }
                },
                'forceAds': {},
                'feedFilters': {},
                'optedIn': True,
                'includeSubredditInPosts': False,
                'includeAwards': False,
                'feedContext': {
                    'experimentOverrides': []
                },
                'includePostStats': False
            }
        }

        if after:
            json_body['variables']['after'] = base64.b64encode(after.encode()).decode()

        r = self.s.post(
            self.GQL_ENDPOINT,
            json = json_body
        )

        return r.json()

    def _get_token(self):
        r = self.s.post(
            f'{self.AUTH_ENDPOINT}/api/access_token', 
            json = {
                'scopes': ['*','email','pii']
            },
            auth = requests.auth.HTTPBasicAuth(self.client_id, '')
        )

        if 'access_token' in r.json():
            self.token = r.json()['access_token']
            self.s.headers.update({'Authorization': f'Bearer {self.token}'})
            return True
        else:
            raise Exception('Login error')

    def _generate_body_sig(self, epoch, body):
        return self._hmac_sign_data(f'Epoch:{epoch}|Body:{body}')

    def _generate_result_sig(self, epoch):
        return self._hmac_sign_data(f'Epoch:{epoch}|User-Agent:{self.USER_AGENT}|Client-Vendor-ID:{self.uuid}')

    def _hmac_sign_data(self, data):
        return hmac.new(self.hmac_secret.encode(), msg = data.encode(), digestmod = hashlib.sha256).hexdigest()


if __name__ == '__main__':
    r = Reddit(REDDIT_ANDROID_OAUTH_CLIENT_ID, REDDIT_ANDROID_HMAC_SECRET)
    r.login_anonymous() # r.login_user('user', 'pass')
    print(r.gql_get_posts('technology', after='t3_13zvyn5'))

Thanks for this!

This is awesome, thank you. Is there a way to save the session cookies and load it to use it after?