Complain if API response is not JSON (#40966)

lib/ansible/plugins/httpapi/eos.py

@@ -34,7 +34,11 @@ class HttpApi:
         headers = {'Content-Type': 'application/json-rpc'}
 
         response = self.connection.send('/command-api', request, headers=headers, method='POST')
-        response = json.loads(to_text(response.read()))
+        response_text = to_text(response.read())
+        try:
+            response = json.loads(response_text)
+        except ValueError:
+            raise ConnectionError('Response was not valid JSON, got {0}'.format(response_text))
         results = handle_response(response)
 
         if self._become:

lib/ansible/plugins/httpapi/nxos.py

@@ -29,7 +29,12 @@ class HttpApi:
         headers = {'Content-Type': 'application/json'}
 
         response = self.connection.send('/ins', request, headers=headers, method='POST')
-        response = json.loads(to_text(response.read()))
+        response_text = to_text(response.read())
+        try:
+            response = json.loads(response_text)
+        except ValueError:
+            raise ConnectionError('Response was not valid JSON, got {0}'.format(response_text))
+
         results = handle_response(response)
 
         if self._become: