empty stream name error for user input

lbry/error/README.md

@@ -25,6 +25,7 @@ Message | User friendly error message explaining the exceptional event. Supports
 Code | Name | Message
 ---:|---|---
 **1xx** | UserInput | User input errors.
+111 | EmptyStreamName | Stream name cannot be blank.
 **10x** | Command | Errors preparing to execute commands.
 101 | CommandDoesNotExist | Command '{command}' does not exist.
 102 | CommandDeprecated | Command '{command}' is deprecated.

lbry/error/__init__.py

@@ -7,6 +7,12 @@ class UserInputError(BaseError):
     """
 
 
+class EmptyStreamNameError(UserInputError):
+
+    def __init__(self):
+        super().__init__("Stream name cannot be blank.")
+
+
 class CommandError(UserInputError):
     """
     Errors preparing to execute commands.

lbry/extras/daemon/daemon.py

@@ -38,7 +38,7 @@ from lbry.dht.peer import make_kademlia_peer
 from lbry.error import (
     DownloadSDTimeoutError, ComponentsNotStartedError, ComponentStartConditionNotMetError,
     CommandDoesNotExistError, BaseError, WalletNotFoundError, WalletAlreadyLoadedError, WalletAlreadyExistsError,
-    ConflictingInputValueError, AlreadyPurchasedError, PrivateKeyNotFoundError
+    ConflictingInputValueError, AlreadyPurchasedError, PrivateKeyNotFoundError, EmptyStreamNameError
 )
 from lbry.extras import system_info
 from lbry.extras.daemon import analytics
@@ -5242,8 +5242,7 @@ class Daemon(metaclass=JSONRPCServerType):
     def valid_stream_name_or_error(name: str):
         try:
             if not name:
-                # TODO: use error from lbry.error
-                raise Exception('Stream name cannot be blank.')
+                raise EmptyStreamNameError()
             parsed = URL.parse(name)
             if parsed.has_channel:
                 # TODO: use error from lbry.error