Completely overhaul errors to be generated dynamically

telethon/errors/_custom.py

@@ -0,0 +1,152 @@
+"""Errors not related to the Telegram API itself"""
+import struct
+
+from .. import _tl
+
+
+class ReadCancelledError(Exception):
+    """Occurs when a read operation was cancelled."""
+    def __init__(self):
+        super().__init__('The read operation was cancelled.')
+
+
+class TypeNotFoundError(Exception):
+    """
+    Occurs when a type is not found, for example,
+    when trying to read a TLObject with an invalid constructor code.
+    """
+    def __init__(self, invalid_constructor_id, remaining):
+        super().__init__(
+            'Could not find a matching Constructor ID for the TLObject '
+            'that was supposed to be read with ID {:08x}. Most likely, '
+            'a TLObject was trying to be read when it should not be read. '
+            'Remaining bytes: {!r}'.format(invalid_constructor_id, remaining))
+
+        self.invalid_constructor_id = invalid_constructor_id
+        self.remaining = remaining
+
+
+class InvalidChecksumError(Exception):
+    """
+    Occurs when using the TCP full mode and the checksum of a received
+    packet doesn't match the expected checksum.
+    """
+    def __init__(self, checksum, valid_checksum):
+        super().__init__(
+            'Invalid checksum ({} when {} was expected). '
+            'This packet should be skipped.'
+            .format(checksum, valid_checksum))
+
+        self.checksum = checksum
+        self.valid_checksum = valid_checksum
+
+
+class InvalidBufferError(BufferError):
+    """
+    Occurs when the buffer is invalid, and may contain an HTTP error code.
+    For instance, 404 means "forgotten/broken authorization key", while
+    """
+    def __init__(self, payload):
+        self.payload = payload
+        if len(payload) == 4:
+            self.code = -struct.unpack('<i', payload)[0]
+            super().__init__(
+                'Invalid response buffer (HTTP code {})'.format(self.code))
+        else:
+            self.code = None
+            super().__init__(
+                'Invalid response buffer (too short {})'.format(self.payload))
+
+
+class SecurityError(Exception):
+    """
+    Generic security error, mostly used when generating a new AuthKey.
+    """
+    def __init__(self, *args):
+        if not args:
+            args = ['A security check failed.']
+        super().__init__(*args)
+
+
+class CdnFileTamperedError(SecurityError):
+    """
+    Occurs when there's a hash mismatch between the decrypted CDN file
+    and its expected hash.
+    """
+    def __init__(self):
+        super().__init__(
+            'The CDN file has been altered and its download cancelled.'
+        )
+
+
+class BadMessageError(Exception):
+    """Occurs when handling a bad_message_notification."""
+    ErrorMessages = {
+        16:
+        'msg_id too low (most likely, client time is wrong it would be '
+        'worthwhile to synchronize it using msg_id notifications and re-send '
+        'the original message with the "correct" msg_id or wrap it in a '
+        'container with a new msg_id if the original message had waited too '
+        'long on the client to be transmitted).',
+        17:
+        'msg_id too high (similar to the previous case, the client time has '
+        'to be synchronized, and the message re-sent with the correct msg_id).',
+        18:
+        'Incorrect two lower order msg_id bits (the server expects client '
+        'message msg_id to be divisible by 4).',
+        19:
+        'Container msg_id is the same as msg_id of a previously received '
+        'message (this must never happen).',
+        20:
+        'Message too old, and it cannot be verified whether the server has '
+        'received a message with this msg_id or not.',
+        32:
+        'msg_seqno too low (the server has already received a message with a '
+        'lower msg_id but with either a higher or an equal and odd seqno).',
+        33:
+        'msg_seqno too high (similarly, there is a message with a higher '
+        'msg_id but with either a lower or an equal and odd seqno).',
+        34:
+        'An even msg_seqno expected (irrelevant message), but odd received.',
+        35:
+        'Odd msg_seqno expected (relevant message), but even received.',
+        48:
+        'Incorrect server salt (in this case, the bad_server_salt response '
+        'is received with the correct salt, and the message is to be re-sent '
+        'with it).',
+        64:
+        'Invalid container.'
+    }
+
+    def __init__(self, request, code):
+        super().__init__(request, self.ErrorMessages.get(
+            code,
+            'Unknown error code (this should not happen): {}.'.format(code)))
+
+        self.code = code
+
+
+class MultiError(Exception):
+    """Exception container for multiple `TLRequest`'s."""
+
+    def __new__(cls, exceptions, result, requests):
+        if len(result) != len(exceptions) != len(requests):
+            raise ValueError(
+                'Need result, exception and request for each error')
+        for e, req in zip(exceptions, requests):
+            if not isinstance(e, BaseException) and e is not None:
+                raise TypeError(
+                    "Expected an exception object, not '%r'" % e
+                )
+            if not isinstance(req, _tl.TLRequest):
+                raise TypeError(
+                    "Expected TLRequest object, not '%r'" % req
+                )
+
+        if len(exceptions) == 1:
+            return exceptions[0]
+        self = BaseException.__new__(cls)
+        self.exceptions = list(exceptions)
+        self.results = list(result)
+        self.requests = list(requests)
+        return self