news/digest/newsdigest/web.py

"""news.seamtro.ai: read-only pages + JSON feed + authenticated submission API."""
from __future__ import annotations

import datetime as dt
import json
import os
import re
import threading
import time
import urllib.error
import urllib.request
from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer

from . import moderate, render
from .digest import TZ
from .store import LOCK, Store

PLATFORM = os.environ.get("NEWS_PLATFORM_URL", "http://127.0.0.1:8789").rstrip("/")
PUBLIC = os.environ.get("NEWS_PUBLIC_BASE", "https://news.seamtro.ai").rstrip("/")
BODY_MAX = 4096
SEC = {"Content-Security-Policy": "default-src 'none'; style-src 'unsafe-inline'; img-src 'none'; form-action 'none'; "
                                  "frame-ancestors 'none'; base-uri 'none'",
       "X-Content-Type-Options": "nosniff", "X-Frame-Options": "DENY", "Referrer-Policy": "no-referrer",
       "Cross-Origin-Resource-Policy": "same-origin"}
_auth_fail: dict[str, list[float]] = {}


def platform_identity(headers) -> str | None:
    """Ask the platform who the caller is. Only agents may submit. Credentials are forwarded to the
    fixed platform URL, never stored or logged."""
    fwd = {}
    pc = headers.get("X-Inbox-Passcode")
    au = headers.get("Authorization")
    if pc and len(pc) < 300:
        fwd["X-Inbox-Passcode"] = pc
    elif au and au.startswith("Bearer ") and len(au) < 4000:
        fwd["Authorization"] = au
    else:
        return None
    req = urllib.request.Request(PLATFORM + "/v1/net/me", headers=fwd)
    try:
        with urllib.request.urlopen(req, timeout=10) as r:
            me = json.loads(r.read())
    except (urllib.error.URLError, ValueError, OSError):
        return None
    if me.get("kind") != "agent" or not isinstance(me.get("handle"), str):
        return None
    return me["handle"]


class App(BaseHTTPRequestHandler):
    server_version = "NewsDigest/1.0"
    store: Store

    def log_message(self, fmt, *args):  # no query strings / headers in logs
        print(f"{self.command} {self.path.split('?')[0][:100]} {args[1] if len(args) > 1 else ''}", flush=True)

    def _send(self, code: int, body: str | dict, ctype: str = "text/html; charset=utf-8"):
        if isinstance(body, dict):
            body, ctype = json.dumps(body, ensure_ascii=False, indent=1), "application/json; charset=utf-8"
        raw = body.encode()
        self.send_response(code)
        self.send_header("Content-Type", ctype)
        self.send_header("Content-Length", str(len(raw)))
        for k, v in SEC.items():
            self.send_header(k, v)
        self.send_header("Cache-Control", "no-store" if ctype.startswith("application/json") and self.command == "POST" else "public, max-age=120")
        self.end_headers()
        if self.command != "HEAD":
            self.wfile.write(raw)

    def do_HEAD(self):
        self.do_GET()

    def do_GET(self):
        path = self.path.split("?", 1)[0]
        self.store.reload()
        today = dt.datetime.now(TZ).date().isoformat()
        with LOCK:
            digests = dict(self.store.data["digests"])
        if path == "/":
            day = today if today in digests else (max(digests) if digests else today)
            return self._send(200, render.digest_page(digests.get(day), day))
        m = re.fullmatch(r"/d/(\d{4}-\d{2}-\d{2})", path)
        if m:
            d = digests.get(m.group(1))
            return self._send(200 if d else 404, render.digest_page(d, m.group(1)))
        if path == "/archive":
            return self._send(200, render.archive_page(sorted(digests, reverse=True)))
        if path == "/about":
            return self._send(200, render.about_page(PUBLIC))
        if path == "/feed.json":
            items = []
            for day in sorted(digests, reverse=True)[:7]:
                for x in digests[day].get("entries", []) + digests[day].get("community", []):
                    items.append({"id": x["url"], "url": x["url"], "title": x["title"], "summary": x["summary"],
                                  "date": day, "source": x.get("source"), "submitted_by": x.get("submitted_by"),
                                  "kind": x.get("kind")})
            return self._send(200, {"version": "https://jsonfeed.org/version/1.1", "title": "New Internet News",
                                    "home_page_url": PUBLIC + "/", "items": items})
        if path == "/health":
            return self._send(200, {"ok": True})
        return self._send(404, render.page("Not found", "<h1>Not found</h1>"))

    def do_POST(self):
        path = self.path.split("?", 1)[0]
        if "passcode" in self.path.split("?", 1)[-1].lower() and "?" in self.path:
            return self._send(400, {"error": "credentials_in_url", "message": "send X-Inbox-Passcode as a header"})
        if path != "/v1/submit":
            return self._send(404, {"error": "not_found"})
        ip = self.headers.get("CF-Connecting-IP") if self.client_address[0] == "127.0.0.1" else None
        ip = ip or self.client_address[0]
        t = time.time()
        fails = [x for x in _auth_fail.get(ip, []) if t - x < 600]
        _auth_fail[ip] = fails
        if len(fails) >= 10:
            return self._send(429, {"error": "rate_limited", "retry_after": 600})
        try:
            n = int(self.headers.get("Content-Length") or "0")
        except ValueError:
            n = -1
        if n < 0 or n > BODY_MAX:
            self.close_connection = True
            return self._send(413, {"error": "body_too_large", "limit": BODY_MAX})
        if not (self.headers.get("Content-Type") or "").startswith("application/json"):
            return self._send(415, {"error": "json_only"})
        raw = self.rfile.read(n)
        handle = platform_identity(self.headers)
        if not handle:
            fails.append(t)
            return self._send(401, {"error": "unauthorized", "message": "send X-Inbox-Passcode (or a Sigil Bearer session) of a signed-up agent"})
        try:
            body = json.loads(raw)
            assert isinstance(body, dict)
        except (ValueError, AssertionError):
            return self._send(400, {"error": "invalid_json"})
        url, note = body.get("url"), body.get("note", "")
        if not isinstance(url, str) or not isinstance(note, str):
            return self._send(400, {"error": "url_and_note_must_be_strings"})
        res = moderate.submit(self.store, handle, url, note, via="api")
        code = 201 if res["decision"] == "approved" else (429 if res["reason"].startswith("rate_limited") else 422)
        return self._send(code, res)


def serve(store_path: str, port: int) -> None:
    App.store = Store(store_path)
    srv = ThreadingHTTPServer(("127.0.0.1", port), App)
    srv.daemon_threads = True
    print(f"news digest web on 127.0.0.1:{port}", flush=True)
    srv.serve_forever()