How to Automate Reddit Comment Replies using the API

1import requests
2import time
3import os
4import logging
5from datetime import datetime, timedelta
6
7logging.basicConfig(level=logging.INFO)
8log = logging.getLogger('reddit_bot')
9
10CLIENT_ID = os.environ['REDDIT_CLIENT_ID']
11CLIENT_SECRET = os.environ['REDDIT_CLIENT_SECRET']
12USERNAME = os.environ['REDDIT_USERNAME']
13PASSWORD = os.environ['REDDIT_PASSWORD']
14USER_AGENT = f'python:com.example.replybot:v1.0 (by /u/{USERNAME})'
15
16SUBREDDITS = ['python', 'learnprogramming']
17KEYWORDS = ['how do I connect', 'supabase question', 'api help']
18REPLY_TEMPLATE = 'Great question! You might find this useful: [link]. Let me know if you need more details.'
19
20token = None
21token_expiry = datetime.now()
22processed_ids = set()
23
24def refresh_token_if_needed():
25    global token, token_expiry
26    if datetime.now() >= token_expiry - timedelta(minutes=5):
27        auth = requests.auth.HTTPBasicAuth(CLIENT_ID, CLIENT_SECRET)
28        r = requests.post(
29            'https://www.reddit.com/api/v1/access_token',
30            auth=auth,
31            data={'grant_type': 'password', 'username': USERNAME, 'password': PASSWORD},
32            headers={'User-Agent': USER_AGENT}
33        )
34        r.raise_for_status()
35        data = r.json()
36        token = data['access_token']
37        token_expiry = datetime.now() + timedelta(seconds=data['expires_in'])
38        log.info('Token refreshed')
39
40def api_get(path, params=None):
41    refresh_token_if_needed()
42    r = requests.get(
43        f'https://oauth.reddit.com{path}',
44        headers={'Authorization': f'Bearer {token}', 'User-Agent': USER_AGENT},
45        params=params
46    )
47    r.raise_for_status()
48    return r.json()
49
50def post_reply(thing_id, text):
51    refresh_token_if_needed()
52    r = requests.post(
53        'https://oauth.reddit.com/api/comment',
54        headers={'Authorization': f'Bearer {token}', 'User-Agent': USER_AGENT},
55        data={'thing_id': thing_id, 'text': text}
56    )
57    r.raise_for_status()
58    result = r.json()
59    errors = result.get('json', {}).get('errors', [])
60    if errors:
61        if errors[0][0] == 'RATELIMIT':
62            log.warning(f'Rate limited by subreddit: {errors[0][1]}')
63            time.sleep(600)
64            return None
65        raise Exception(f'Reply error: {errors}')
66    return result['json']['data']['things'][0]['data']['id']
67
68def run_bot():
69    log.info('Starting comment reply bot')
70    while True:
71        for subreddit in SUBREDDITS:
72            try:
73                data = api_get(f'/r/{subreddit}/comments', {'limit': 100, 'sort': 'new'})
74                comments = data['data']['children']
75                for item in comments:
76                    c = item['data']
77                    if c['id'] in processed_ids:
78                        continue
79                    processed_ids.add(c['id'])
80                    body = c.get('body', '').lower()
81                    if c['author'] == USERNAME:
82                        continue
83                    if any(kw.lower() in body for kw in KEYWORDS):
84                        log.info(f'Replying to {c["name"]} in r/{subreddit}')
85                        reply_id = post_reply(c['name'], REPLY_TEMPLATE)
86                        if reply_id:
87                            log.info(f'Reply posted: t1_{reply_id}')
88                        time.sleep(3)
89            except Exception as e:
90                log.error(f'Error in r/{subreddit}: {e}')
91        time.sleep(30)
92
93if __name__ == '__main__':
94    run_bot()