feat: Add tool to generate endpoints (#307)

* feat: Add tool to generate endpoints

scripts/gendpoint.py

@@ -0,0 +1,56 @@
+#! env python3
+
+import argparse
+import os
+
+from cryptography.fernet import Fernet
+
+
+def config(env_args: os._Environ) -> argparse.Namespace:
+    """Read the configuration from the args and environment."""
+    parser = argparse.ArgumentParser(
+        description="Generate Endpoint from environment and known UAID + CHID")
+    parser.add_argument(
+        '--key', '-k',
+        help="Endpoint cryptographic keys. Can be either a single key "
+             "string or a list of strings. Will only use the first key"
+             " found.",
+        default=env_args.get("AUTOEND_CRYPTO_KEYS"))
+    parser.add_argument(
+        '--uaid', '-u', required=True,
+        help="User Agent ID")
+    parser.add_argument(
+        '--chid', '-c', required=True,
+        help="Channel ID")
+    parser.add_argument(
+        '--root', '-r',
+        default=env_args.get("AUTOEND_ENDPOINT_URL"),
+        help="Server root (e.g. 'example.com')")
+    args = parser.parse_args()
+    if not args.key:
+        raise Exception("Missing key")
+    if not args.root:
+        raise Exception("Missing root")
+    return args
+
+
+def main():
+    args = config(os.environ)
+    if isinstance(args.key, list):
+        key = args.key[0]
+    else:
+        key = args.key
+    print(gendpoint(key, args))
+
+
+def gendpoint(key: bytes, args: argparse.Namespace) -> str:
+    """Generate the endpoint"""
+    fernet = Fernet(key)
+    base = bytes(
+        list((bytes.fromhex(args.uaid.replace('-', '')) +
+              bytes.fromhex(args.chid.replace('-', '')))))
+    ekey = fernet.encrypt(base).strip(b'=').decode('utf-8')
+    return f"https://{args.root}/wpush/v1/{ekey}"
+
+
+main()