Files

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Python

"""Low-level authed Reddit transport.
Talks to Reddit as the user's own logged-in browser: borrow the session cookies and
call the classic www.reddit.com JSON API (reads take a .json suffix, writes carry the
account's modhash), no OAuth app and no API key. Modern Reddit ("shreddit") stopped
embedding a bearer token in its page HTML, so the cookie + modhash path is the durable
one. Rate-limited and self-healing on a 401/403 by re-borrowing the session. stdlib-only.
"""
import json
import time
import urllib.error
import urllib.parse
import urllib.request
from typing import Any, Dict, Optional
from backend.apps.reddit_mcp_shim import rate_limit
from backend.apps.social_shims.session_source import get_session, invalidate
DOMAIN = "reddit.com"
WWW = "https://www.reddit.com"
MODHASH_TTL_S = 300.0
p_modhash = ""
p_modhash_exp = 0.0
class RedditError(Exception):
"""A Reddit request failed in a way worth surfacing to the agent."""
def modhash(force: bool = False) -> str:
"""Return the logged-in account's modhash (Reddit's per-session write token), cached briefly."""
global p_modhash, p_modhash_exp
now = time.time()
if not force and p_modhash and now < p_modhash_exp:
return p_modhash
me = p_send("GET", "/api/me.json", params=None, form=None, action="read", retried=False)
mh = (me or {}).get("data", {}).get("modhash") or ""
if not mh:
invalidate(DOMAIN)
raise RedditError(
"Not logged in to Reddit. Open reddit.com in the OpenSwarm browser, sign in, then retry."
)
p_modhash, p_modhash_exp = mh, now + MODHASH_TTL_S
return mh
def api(method: str, path: str, *, params: Optional[Dict[str, Any]] = None,
form: Optional[Dict[str, Any]] = None, action: str = "read") -> Any:
"""Authenticated www.reddit.com call: reads get a .json suffix, writes carry the modhash."""
return p_send(method, path, params=params, form=form, action=action, retried=False)
def p_send(method: str, path: str, *, params: Optional[Dict[str, Any]],
form: Optional[Dict[str, Any]], action: str, retried: bool) -> Any:
rate_limit.acquire(action)
cookie, ua = get_session(DOMAIN)
headers = {"Cookie": cookie, "User-Agent": ua, "Accept": "application/json"}
data = None
if method == "GET":
p = path if path.endswith(".json") else path + ".json"
qs = dict(params or {})
qs.setdefault("raw_json", 1)
url = f"{WWW}{p}?" + urllib.parse.urlencode({k: v for k, v in qs.items() if v is not None})
else:
url = f"{WWW}{path}"
if params:
url += "?" + urllib.parse.urlencode({k: v for k, v in params.items() if v is not None})
body = dict(form or {})
body.setdefault("api_type", "json")
body["uh"] = modhash()
data = urllib.parse.urlencode({k: v for k, v in body.items() if v is not None}).encode()
headers["Content-Type"] = "application/x-www-form-urlencoded"
req = urllib.request.Request(url, data=data, headers=headers, method=method)
try:
with urllib.request.urlopen(req, timeout=30.0) as resp:
status, raw, rhdr = resp.status, resp.read(), dict(resp.headers)
except urllib.error.HTTPError as e:
status, raw, rhdr = e.code, (e.read() if e.fp else b""), dict(e.headers or {})
except urllib.error.URLError as e:
raise RedditError(f"Reddit unreachable: {getattr(e, 'reason', e)}")
rate_limit.note_response(status, {k.lower(): v for k, v in rhdr.items()})
if status in (401, 403) and not retried:
invalidate(DOMAIN)
p_reset_modhash()
return p_send(method, path, params=params, form=form, action=action, retried=True)
if status == 429:
raise RedditError("Reddit is rate-limiting this account; slow down and retry shortly.")
if status >= 400:
raise RedditError(f"Reddit HTTP {status}: {raw[:300].decode('utf-8', 'replace')}")
try:
return json.loads(raw.decode("utf-8", errors="replace") or "{}")
except json.JSONDecodeError:
return {"raw": raw.decode("utf-8", errors="replace")}
def p_reset_modhash() -> None:
global p_modhash_exp
p_modhash_exp = 0.0