Changes since PR ethereum#3048 was put up for review

- Add web3.providers.websocket.rst to .gitignore
- Put back formatters for eth_getCode / remove unnecessary ``compose()``
- Add read-friendly comment splitting Web3 from AsyncWeb3 in main.py
- Use correct class name in docstring
- Friendlier message when exception is raised connecting to websocket endpoint
- Friendlier message for websocket restricted_kwargs; use a merge of default + provided websocket_kwargs with the provided values taking precedence
- Validate "ws://" / "wss://" in websocket endpoint
- Use Dict[str, Any] for websocket_kwargs type

.gitignore

@@ -49,6 +49,7 @@ docs/web3.gas_strategies.rst
 docs/web3.middleware.rst
 docs/web3.providers.eth_tester.rst
 docs/web3.providers.rst
+docs/web3.providers.websocket.rst
 docs/web3.rst
 docs/web3.scripts.release.rst
 docs/web3.scripts.rst

web3/_utils/method_formatters.py

@@ -484,7 +484,7 @@ def apply_list_to_array_formatter(formatter: Any) -> Callable[..., Any]:
         to_hex_if_integer,
         0,
     ),
-    RPC.eth_getCode: compose(apply_formatter_at_index(to_hex_if_integer, 1)),
+    RPC.eth_getCode: apply_formatter_at_index(to_hex_if_integer, 1),
     RPC.eth_getStorageAt: apply_formatter_at_index(to_hex_if_integer, 2),
     RPC.eth_getTransactionByBlockNumberAndIndex: compose(
         apply_formatter_at_index(to_hex_if_integer, 0),

web3/main.py

@@ -430,6 +430,9 @@ def ens(self, new_ens: Union[ENS, "Empty"]) -> None:
         self._ens = new_ens
 
 
+# -- async -- #
+
+
 class AsyncWeb3(BaseWeb3):
     # mypy Types
     eth: AsyncEth
@@ -505,7 +508,7 @@ def persistent_websocket(
     ) -> "_PersistentConnectionWeb3":
         """
         Establish a persistent connection via websockets to a websocket provider using
-        a WebsocketProviderV2 instance.
+        a ``PersistentConnectionProvider`` instance.
         """
         return _PersistentConnectionWeb3(
             provider,

web3/providers/websocket/websocket_v2.py

@@ -3,13 +3,17 @@
 import os
 from typing import (
     Any,
+    Dict,
     Optional,
     Union,
 )
 
 from eth_typing import (
     URI,
 )
+from toolz import (
+    merge,
+)
 from websockets.client import (
     connect,
 )
@@ -31,6 +35,7 @@
 DEFAULT_PING_INTERVAL = 30  # 30 seconds
 DEFAULT_PING_TIMEOUT = 300  # 5 minutes
 
+VALID_WEBSOCKET_URI_PREFIXES = {"ws://", "wss://"}
 RESTRICTED_WEBSOCKET_KWARGS = {"uri", "loop"}
 DEFAULT_WEBSOCKET_KWARGS = {
     # set how long to wait between pings from the server
@@ -51,26 +56,34 @@ class WebsocketProviderV2(PersistentConnectionProvider):
     def __init__(
         self,
         endpoint_uri: Optional[Union[URI, str]] = None,
-        websocket_kwargs: Optional[Any] = None,
+        websocket_kwargs: Optional[Dict[str, Any]] = None,
         call_timeout: Optional[int] = None,
     ) -> None:
         self.endpoint_uri = URI(endpoint_uri)
         if self.endpoint_uri is None:
             self.endpoint_uri = get_default_endpoint()
 
-        if websocket_kwargs is None:
-            websocket_kwargs = DEFAULT_WEBSOCKET_KWARGS
-        else:
+        if not any(
+            self.endpoint_uri.startswith(prefix)
+            for prefix in VALID_WEBSOCKET_URI_PREFIXES
+        ):
+            raise Web3ValidationError(
+                f"Websocket endpoint uri must begin with 'ws://' or 'wss://': "
+                f"{self.endpoint_uri}"
+            )
+
+        if websocket_kwargs is not None:
             found_restricted_keys = set(websocket_kwargs).intersection(
                 RESTRICTED_WEBSOCKET_KWARGS
             )
             if found_restricted_keys:
                 raise Web3ValidationError(
-                    f"{RESTRICTED_WEBSOCKET_KWARGS} are not allowed "
-                    f"in websocket_kwargs, found: {found_restricted_keys}"
+                    f"Found restricted keys for websocket_kwargs: "
+                    f"{found_restricted_keys}."
                 )
 
-        self.websocket_kwargs = websocket_kwargs
+        self.websocket_kwargs = merge(DEFAULT_WEBSOCKET_KWARGS, websocket_kwargs or {})
+
         super().__init__(endpoint_uri, call_timeout=call_timeout)
 
     def __str__(self) -> str:
@@ -93,7 +106,12 @@ async def is_connected(self, show_traceback: bool = False) -> bool:
             return False
 
     async def connect(self) -> None:
-        self.ws = await connect(self.endpoint_uri, **self.websocket_kwargs)
+        try:
+            self.ws = await connect(self.endpoint_uri, **self.websocket_kwargs)
+        except Exception as e:
+            raise ProviderConnectionError(
+                f"Could not connect to endpoint: {self.endpoint_uri}"
+            ) from e
 
     async def disconnect(self) -> None:
         await self.ws.close()