Post new posts from a subreddit to Slack

from clickruntime import on_trigger, credentials, http, state, notify

SUBREDDITS = ["selfhosted", "homelab"]
KEYWORDS = []          # e.g. ["backup", "sync"]; empty means every post
CHANNEL = "#reddit"

UA = "clickruntime-automation/1.0"

def reddit(path, **params):
    resp = http.get(f"https://oauth.reddit.com{path}", params=params, headers={
        "Authorization": f"Bearer {credentials.connection('reddit', 'work')}", "User-Agent": UA})
    resp.raise_for_status()
    return resp.json()

@on_trigger
def run(event):
    seen = state.get("seen")
    first = seen is None
    seen = set(seen or [])
    posted = 0
    for sub in SUBREDDITS:
        for child in reversed(reddit(f"/r/{sub}/new", limit=25)["data"]["children"]):
            p = child["data"]
            if p["name"] in seen:
                continue
            seen.add(p["name"])
            if first or p.get("over_18") or p.get("removed_by_category"):
                continue
            text = f"{p['title']} {p.get('selftext', '')}".lower()
            if KEYWORDS and not any(k.lower() in text for k in KEYWORDS):
                continue
            flair = f"[{p['link_flair_text']}] " if p.get("link_flair_text") else ""
            notify.slack(f"r/{sub} · {flair}*{p['title']}*\nby u/{p['author']} · {p['num_comments']} comments\nhttps://reddit.com{p['permalink']}", channel=CHANNEL)
            posted += 1
    state.set("seen", list(seen)[-2000:])
    return {"posted": posted, "baseline": first}