Handle response of type None (#4)

Author: namikmesic

CHANGELOG.md

@@ -2,4 +2,12 @@
 
 ## v1.0.0
 
-Initial release
+Initial release
+
+## v1.0.1
+
+Reworked logic for totalDifficulty to support chains that don't use it
+
+## v1.0.2
+
+Handling response of type `None` in JSON RPC response.

src/probe.py

@@ -103,21 +103,23 @@ async def _fetch_total_difficulty(self, ws, block_height):
                                timeout=self.timeout)
         response = await asyncio.wait_for(ws.recv(), timeout=self.timeout)
         response_json = json.loads(response)
+        if response_json['result'] == None:
+            error = "RPC returned response of type `None`"
+        else:
+            try:
+                result = response_json['result']
+            except KeyError:
+                logging.debug(response_json)
+                error = "Key `result` was not found in response while requesting eth_getBlockByNumber"
 
-        try:
-            result = response_json['result']
-        except KeyError:
-            logging.debug(response_json)
-            error = "Key `result` was not found in response while requesting eth_getBlockByNumber"
-
-        if "totalDifficulty" in response_json['result']:
-            total_difficulty = int(result['totalDifficulty'], 16)
+            if "totalDifficulty" in response_json['result']:
+                total_difficulty = int(result['totalDifficulty'], 16)
 
-        elif "error" in response_json:
-            error = response_json['error']['message']
-        else:
-            # Set totalDifficulty to 0 if blockchain does not use it.
-            total_difficulty = 0
+            elif "error" in response_json:
+                error = response_json['error']['message']
+            else:
+                # Set totalDifficulty to 0 if blockchain does not use it.
+                total_difficulty = 0
 
         return total_difficulty, error
 
@@ -134,16 +136,19 @@ async def _fetch_block_height(self, ws):
                                timeout=self.timeout)
         # TODO: Implement error handling for JSON-RPC 2.0 Specification https://www.jsonrpc.org/specification#error_object
         response = await asyncio.wait_for(ws.recv(), timeout=self.timeout)
-
-        result = json.loads(response)
-        if "error" in result:
-            error = result['error']['message']
+        response_json = json.loads(response)
+        if response_json['result'] == None:
+            error = "RPC returned response of type `None`"
         else:
-            try:
-                block_height = int(result['result'], 16)
-            except KeyError:
-                logging.debug(response)
-                error = "Key `result` was not found in response while requesting eth_blockNumber"
+            result = json.loads(response)
+            if "error" in result:
+                error = result['error']['message']
+            else:
+                try:
+                    block_height = int(result['result'], 16)
+                except KeyError:
+                    logging.debug(response)
+                    error = "Key `result` was not found in response while requesting eth_blockNumber"
         return block_height, error
 
     async def _collect(self, uri, provider):