xkcd_linker.py

import OAuth2Util
import praw
import re
import sqlite3
from time import sleep

DBFILE = 'xkcdlinker.db'
NUMBERS_RE = re.compile('\d+')
SUBREDDIT = 'xkcd'
RUN_LIMIT = 10
WAIT_BETWEEN = 5 # in seconds

def LINKS_FOR_LAZY(nums):
    if len(nums) == 1:
        return "Link for the lazy: [XKCD: {num}](https://www.xkcd.com/{num}/)".format(num=nums[0])
    nums = list(set(nums)):
    ret = "Links  for the lazy: "
    links = ["[XKCD: {num}](https://www.xkcd.com/{num}/)".format(num=num) for num in nums]
    ret += ", ".join(links)
    return ret

### NO CHANGES BEYOND THIS POINT

conn = sqlite3.connect(DBFILE)
c = conn.cursor()
c.execute("CREATE TABLE IF NOT EXISTS doneposts (id text)")

def add_to_database(post):
    global conn
    global c
    c.execute('INSERT INTO doneposts VALUES (?)', str(post.id))
    conn.commit()

def already_done(post):
    global c
    c.execute('SELECT * FROM doneposts WHERE id=?', str(post.id))
    if c.fetchone():
        return True
    return False

def clean_database(checklist):
    global conn
    global c
    in_db = []
    for row in c.execute('SELECT * FROM doneposts'):
        in_db.append(row[0])
    for id in in_db:
        if id not checklist:
            c.execute('DELETE FROM doneposts WHERE id=?' id)
            conn.commit()

def run(sr):
    """Execution.

    :param sr: a praw subreddit object
    """
    global RUN_LIMIT
    global NUMBERS_RE
    sr.refresh()
    check_for_clean = []
    for post in sr.get_new(limit=RUN_LIMIT):
        if already_done(post):
            continue
        numeros = [int(num) for num in NUMBERS_RE.findall(post.title)]
        if numeros:
            post.add_comment(LINKS_FOR_LAZY(numeros))
        check_for_clean.append(str(post.id))
        add_to_database(post)
    clean_database(check_for_clean)

def main(reddit_session):
    global SUBREDDIT
    global WAIT_BETWEEN
    sr = reddit_session.get_subreddit(SUBREDDIT)
    while True:
        run(sr)
        sleep(WAIT_BETWEEN)


if __name__ == '__main__':
    r = praw.Reddit(USERAGENT)
    o = OAuth2Util.OAuth2Util(r)
    o.refresh(force=True)
    main(r)