token symbol/name decoding fix

src/dexorder/tokens.py

@@ -11,6 +11,7 @@ from dexorder.contract import ERC20, ContractProxy, CONTRACT_ERRORS
 from dexorder.database.model import Token
 from dexorder.database.model.token import OldTokenDict
 from dexorder.metadata import get_metadata
+from dexorder.util import hexstr
 
 log = logging.getLogger(__name__)
 
@@ -35,21 +36,25 @@ async def load_token(address: str) -> Optional[OldTokenDict]:
             return OldTokenDict(type='Token', chain=chain_id, address=address,
                                 name=token.name, symbol=token.symbol, decimals=token.decimals,
                                 approved=token.approved)
+
     async def get_string_or_bytes32(func_name):
         try:
-            result = await getattr(contract, func_name)()
+            return await getattr(contract, func_name)()
         except (InsufficientDataBytes, BadFunctionCallOutput, OverflowError):
             # this happens when the token returns bytes32 instead of a string
             try:
                 rb: bytes = await ContractProxy(address, 'ERC20.sb').symbol()
-                end = rb.find(b'\x00')
-                if end == -1:
-                    end = 32
-                result = rb[:end].decode('utf8')
             except CONTRACT_ERRORS:
                 log.warning(f'token {address} has broken {func_name}()')
                 return None
-        return result
+            end = rb.find(b'\x00')
+            if end == -1:
+                end = 32
+            try:
+                return rb[:end].decode('utf8')
+            except UnicodeDecodeError:
+                log.warning(f'token {address} has an invalid {func_name}() {rb}')
+                return None
 
     dec_prom = contract.decimals()
     symbol_prom = get_string_or_bytes32('symbol')