feat: MsgPack RpcError type (cannot deserialize)

Author: eigen-value

examples/rpc_lite_client/rpc_lite_client.ino

@@ -28,7 +28,8 @@ void blink_before(){
 void loop() {
     float result;
     blink_before();
-    bool ok = client.call("mult", result, 2.0, 3.0);
+    //bool ok = client.call("mult", result, 2.0, 3.0);
+    bool ok = client.call("divi", result, 2.0, 0.0);
 
     if (ok) {
         Serial.print("Result: ");

extras/examples/serial_server_example.py

@@ -9,11 +9,15 @@ def greet(name):
 def multiply(a, b):
     return a*b
 
+def divide(a, b):
+    return a/b
+
 PORT = '/dev/ttySTM0'
 
 server = SerialServer(port=PORT, baudrate=115200)
 server.register_callback('add', add)
 server.register_callback('mult', multiply)
+server.register_callback('divi', divide)
 server.register_callback('greet', greet)
 server.start()
 

extras/serial_server.py

@@ -7,6 +7,7 @@
 RESPONSE = 1
 NOTIFY = 2
 
+GENERIC_EXCEPTION = 0xff
 
 class SerialServer:
     def __init__(self, port, baudrate=115200):
@@ -24,7 +25,7 @@ def on_request(self, msg_id, command, args):
             result = self.callbacks[command](*args)
             return [RESPONSE, msg_id, None, result]
         except Exception as e:
-            print("Not handling exceptions yet")
+            return [RESPONSE, msg_id, [GENERIC_EXCEPTION, str(e)] ,None]
 
     def handle_message(self, message) -> bytes:
         """Process incoming messages"""

src/client.h

@@ -5,6 +5,7 @@
 #ifndef RPCLITE_CLIENT_H
 #define RPCLITE_CLIENT_H
 #include "rpc.h"
+#include "error.h"
 
 class RPCClient {
     ITransport& transport;
@@ -37,19 +38,33 @@ class RPCClient {
 
         int r_msg_type;
         int r_msg_id;
-        MsgPack::object::nil_t error;
+        MsgPack::object::nil_t nil;
+        RpcError rpc_error;
 
         MsgPack::arr_size_t resp_size(4);
 
-        bool ok = unpacker.deserialize(resp_size, r_msg_type, r_msg_id, error, result);
+        if (!unpacker.deserialize(resp_size, r_msg_type, r_msg_id, nil, result)){
+            //Try to deserialize for a RpcError
+            if (!unpacker.deserialize(resp_size, r_msg_type, r_msg_id, rpc_error, nil)){
+                Serial.println("Unable to deserialize");
+                Serial.print(raw_buffer_fill);
+                for (size_t i = 0; i<raw_buffer_fill; i++){
+                    Serial.print(raw_buffer[i], HEX);
+                    Serial.print("-");
+                }
+                flush_buffer();
+                return false;
+            } else {
+                Serial.print("RPC produced an error: ");
+                Serial.println(rpc_error.code);
+                Serial.println(rpc_error.traceback);
+            }
 
-        if (!ok){
-            //Serial.println("could not serialize resp");
-            return false;
         }
 
         if (r_msg_id != msg_id){
             //Serial.println("msg_id mismatch");
+            flush_buffer();
             return false;
         }
 
@@ -58,8 +73,6 @@ class RPCClient {
         flush_buffer();
         return true;
 
-
-        return false;
     }
 };
 

src/error.h

@@ -0,0 +1,15 @@
+// Created by lucio on 4/25/25.
+//
+
+#ifndef ERROR_RPC_H
+#define ERROR_RPC_H
+
+#include "MsgPack.h"
+
+struct RpcError {
+    int code;
+    MsgPack::str_t traceback;
+    MSGPACK_DEFINE(code, traceback); // -> [code, traceback]
+};
+
+#endif