Avoid parsing the response body when we've already decided not to

cache the result

jussi/middlewares/caching.py

@@ -67,6 +67,8 @@ async def cache_response(request: HTTPRequest, response: HTTPResponse) -> None:
             return
         if 'x-jussi-error-id' in response.headers:
             return
+        if request.jsonrpc.upstream.ttl == -1: #don't waste time parsing response if not cacheable
+            return
         jsonrpc_response = loads(response.body)
         if not jsonrpc_response:
             return

jussi/middlewares/update_block_num.py

@@ -19,8 +19,8 @@ async def update_last_irreversible_block_num(request: HTTPRequest, response: HTT
         return
     request.timings.append((perf_counter(), 'update_last_irreversible_block_num.enter'))
     try:
-        jsonrpc_response = ujson.loads(response.body)
         if is_get_dynamic_global_properties_request(request.jsonrpc):
+            jsonrpc_response = ujson.loads(response.body)
             last_irreversible_block_num = jsonrpc_response['result']['last_irreversible_block_num']
             cache_group = request.app.config.cache_group
             request.app.config.last_irreversible_block_num = last_irreversible_block_num