RPC layer specifications

Contents

• RPC layer specifications

  • Payload bytes

    • Requests

    • Responses

    • Error codes

A client can send and receive notifications, incoming calls and replies.

The layer completely replaces one-to-one messaging, all notifications must be prefixed with 0x00 to tell the client that the frame is notification-only event.

RPC calls can be also used as notifications. If call ID is set to zero, no response is required from the other side.

The RPC layer is similar to JSON RPC 2.0, but optimized for the byte protocol.

Payload bytes

0 - event type (0x0 - notification, 0x1 - request, 0x11 - reply, 0x12 - error reply)

for event: 1 - payload

Requests

1-4 call ID 5- - method (str) 00 PARAMS

The parameters can be serialized in any way, msgpack is preferred. If call ID is zero - no response is required.

Responses

1-4 call ID 5- - response payload

for error response 1-4 call ID 5-6 - error code 7 - error payload

A response payload and error can be serialized in any way, for the payload msgpack is preferred. for the error - str

When RPC layer is on, all messages are processed as RPC or event calls, broadcasts and topics are processed as-is.

Error codes

The standard codes are sent as i16, in the format “-32000 - BUS_ERROR_CODE”.