calcurse: one-click Google login renewal

On expiry calcurse-sync starts calcurse-relogin, a notification that opens the consent page when clicked and catches the OAuth code on 127.0.0.1:8749. dunst's left-click now runs a notification's action before closing it.

.local/bin/calcurse-relogin

@@ -0,0 +1,101 @@
+#!/usr/bin/env python3
+"""Renew calcurse-caldav's Google login: catch the OAuth redirect on 127.0.0.1 and hand the code to calcurse-sync.
+
+--prompt shows a notification first and logs in when it is clicked.
+"""
+
+import argparse
+import configparser
+import os
+import subprocess
+import sys
+import time
+import urllib.parse
+from http.server import BaseHTTPRequestHandler, HTTPServer
+from pathlib import Path
+
+CONFIG = Path(os.environ.get("XDG_CONFIG_HOME", Path.home() / ".config")) / "calcurse" / "caldav" / "config"
+WAIT_SECONDS = 300
+
+
+def notify(summary: str, body: str = "", *extra: str) -> str:
+    """Send a calcurse notification; with actions in extra, wait and return the chosen action's name."""
+    cmd = ["notify-send", "-a", "calcurse", "-i", "x-office-calendar", *extra, summary, body]
+    return subprocess.run(cmd, capture_output=True, text=True).stdout.strip()
+
+
+def redirect_port() -> int:
+    parser = configparser.RawConfigParser()
+    parser.read(CONFIG)
+    uri = urllib.parse.urlparse(parser.get("OAuth2", "RedirectURI", fallback=""))
+    if uri.hostname != "127.0.0.1" or uri.port is None:
+        sys.exit(f"RedirectURI in {CONFIG} must be http://127.0.0.1:<port>")
+    return uri.port
+
+
+def ui_running() -> bool:
+    ttys = subprocess.run(["ps", "-C", "calcurse", "-o", "tty="], capture_output=True, text=True).stdout.split()
+    return any(tty != "?" for tty in ttys)
+
+
+class RedirectHandler(BaseHTTPRequestHandler):
+    result: dict[str, str] = {}
+
+    def do_GET(self) -> None:
+        query = urllib.parse.parse_qs(urllib.parse.urlparse(self.path).query)
+        for key in ("code", "error"):
+            if key in query:
+                RedirectHandler.result[key] = query[key][0]
+        done = bool(RedirectHandler.result)
+        self.send_response(200 if done else 404)
+        self.send_header("Content-Type", "text/plain; charset=utf-8")
+        self.end_headers()
+        if done:
+            self.wfile.write(b"calcurse: login received, you can close this tab.\n")
+
+    def log_message(self, format: str, *args: object) -> None:
+        pass
+
+
+def login() -> int:
+    if ui_running():
+        notify("Google Calendar login", "Close calcurse first, then log in again.", "-u", "critical")
+        return 1
+    server = HTTPServer(("127.0.0.1", redirect_port()), RedirectHandler)
+    # With an expired login calcurse-caldav opens the consent page and exits; with a valid one it just syncs.
+    if subprocess.run(["calcurse-caldav"], capture_output=True).returncode == 0:
+        notify("Google Calendar login", "Already logged in.")
+        return 0
+    deadline = time.monotonic() + WAIT_SECONDS
+    while not RedirectHandler.result and (left := deadline - time.monotonic()) > 0:
+        server.timeout = left
+        server.handle_request()
+    server.server_close()
+    code = RedirectHandler.result.get("code")
+    if not code:
+        reason = RedirectHandler.result.get("error", "no answer from the browser")
+        notify("Google Calendar login failed", reason, "-u", "critical")
+        return 1
+    # The user manager's PATH lacks ~/.local/bin: call calcurse-sync from this script's folder.
+    calcurse_sync = Path(__file__).resolve().with_name("calcurse-sync")
+    sync = subprocess.run([calcurse_sync, "--authcode", code], capture_output=True, text=True)
+    if sync.returncode != 0:
+        last_line = (sync.stdout.strip().splitlines() or [""])[-1]
+        notify("Google Calendar login failed", last_line, "-u", "critical")
+        return 1
+    notify("Google Calendar login renewed", "Synced again.")
+    return 0
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description=__doc__.splitlines()[0])
+    parser.add_argument("--prompt", action="store_true", help="ask with a notification before logging in")
+    if parser.parse_args().prompt:
+        body = "Click to log in again, then click Allow in the browser."
+        if notify("Google Calendar login expired", body, "-u", "critical", "-A", "default=Log in") != "default":
+            return 0
+    return login()
+
+
+if __name__ == "__main__":
+    sys.exit(main())