Add method to automatically determine EncryptionMethod to use (#50)

Author: iMicknl

README.md

@@ -112,7 +112,11 @@ asyncio.run(main())
 
 ### Determine the EncryptionMethod
 
-(not supported yet)
+If you are not sure which encryption method to use, you can leave it empty or pass `None` and use `get_encryption_method` to determine the encryption method.
+
+`get_encryption_method` will return an `EncryptionMethod` when a match is found. Best would be to use this function only during your initial investigation.
+
+This function will throw a `LoginTimeoutException` when no match is found, since this is still a HTTP Time Out. This could caused by the wrong encryption method, but also by trying to connect to an inaccessible host.
 
 ### Handle exceptions
 

sagemcom_api/client.py

@@ -27,6 +27,7 @@
     DEFAULT_USER_AGENT,
     XMO_ACCESS_RESTRICTION_ERR,
     XMO_AUTHENTICATION_ERR,
+    XMO_LOGIN_RETRY_ERR,
     XMO_MAX_SESSION_COUNT_ERR,
     XMO_NO_ERR,
     XMO_NON_WRITABLE_PARAMETER_ERR,
@@ -39,6 +40,7 @@
     AccessRestrictionException,
     AuthenticationException,
     BadRequestException,
+    LoginRetryErrorException,
     LoginTimeoutException,
     MaximumSessionCountException,
     NonWritableParameterException,
@@ -61,7 +63,7 @@ def __init__(
         host: str,
         username: str,
         password: str,
-        authentication_method: EncryptionMethod,
+        authentication_method: EncryptionMethod | None = None,
         session: ClientSession | None = None,
         ssl: bool | None = False,
         verify_ssl: bool | None = True,
@@ -78,8 +80,8 @@ def __init__(
         self.host = host
         self.username = username
         self.authentication_method = authentication_method
+        self.password = password
         self._password_hash = self.__generate_hash(password)
-
         self.protocol = "https" if ssl else "http"
 
         self._current_nonce = None
@@ -232,6 +234,9 @@ async def __post(self, url, data):
                     if action_error_desc == XMO_MAX_SESSION_COUNT_ERR:
                         raise MaximumSessionCountException(action_error)
 
+                    if action_error_desc == XMO_LOGIN_RETRY_ERR:
+                        raise LoginRetryErrorException(action_error)
+
                     raise UnknownException(action_error)
 
             return result
@@ -267,7 +272,8 @@ async def __api_request_async(self, actions, priority=False):
             raise ConnectionError(str(exception)) from exception
 
     async def login(self):
-        """TODO."""
+        """Login to the SagemCom F@st router using a username and password."""
+
         actions = {
             "id": 0,
             "method": "logIn",
@@ -296,7 +302,7 @@ async def login(self):
             response = await self.__api_request_async([actions], True)
         except asyncio.TimeoutError as exception:
             raise LoginTimeoutException(
-                "Request timed-out. This is mainly due to using the wrong encryption method."
+                "Login request timed-out. This could be caused by using the wrong encryption method, or using a (non) SSL connection."
             ) from exception
 
         data = self.__get_response(response)
@@ -318,6 +324,31 @@ async def logout(self):
         self._server_nonce = ""
         self._request_id = -1
 
+    async def get_encryption_method(self):
+        """Determine which encryption method to use for authentication and set it directly."""
+        for encryption_method in EncryptionMethod:
+            try:
+                self.authentication_method = encryption_method
+                self._password_hash = self.__generate_hash(
+                    self.password, encryption_method
+                )
+
+                await self.login()
+
+                self._server_nonce = ""
+                self._session_id = 0
+                self._request_id = -1
+
+                return encryption_method
+            except (
+                LoginTimeoutException,
+                AuthenticationException,
+                LoginRetryErrorException,
+            ):
+                pass
+
+        return None
+
     async def get_value_by_xpath(self, xpath: str, options: dict | None = None) -> dict:
         """
         Retrieve raw value from router using XPath.

sagemcom_api/const.py

@@ -13,3 +13,4 @@
 XMO_REQUEST_NO_ERR = "XMO_REQUEST_NO_ERR"
 XMO_UNKNOWN_PATH_ERR = "XMO_UNKNOWN_PATH_ERR"
 XMO_MAX_SESSION_COUNT_ERR = "XMO_MAX_SESSION_COUNT_ERR"
+XMO_LOGIN_RETRY_ERR = "XMO_LOGIN_RETRY_ERR"

sagemcom_api/exceptions.py

@@ -10,6 +10,10 @@ class AuthenticationException(Exception):
     """Raised when authentication is not correct."""
 
 
+class LoginRetryErrorException(Exception):
+    """Raised when too many login retries are attempted."""
+
+
 class LoginTimeoutException(Exception):
     """Raised when a timeout is encountered during login."""