The problem is that every serializer that i've tried (except json), cannot
downcast a serialized message to its base type.
json, the only serializer that does the job (but only on non ref types):
import json
type
MsgBase* = object of RootObj
version*: byte
messageId*: string
timestamp*: string
senderName*: string
senderPublicKey*: string
MsgControlReq* = object of MsgBase
command*: string
param*: string
var conreq = MsgControlReq()
conreq.version = 1.byte
conreq.messageId = "messageId"
conreq.timestamp = "timestamp"
conreq.senderName = "senderNameVal"
conreq.senderPublicKey = "senderPublicKeyVal"
conreq.command = "CMD" # <- first not in base
var conreqj = (%* conreq)
var base = conreqj.to(MsgBase)
echo base
Run
works:
(version: 1, messageId: "messageId", timestamp: "timestamp", senderName:
"senderNameVal", senderPublicKey: "senderPublicKeyVal")
Run
not working marshal:
import marshal
type
MsgBase* = object of RootObj
version*: byte
messageId*: string
timestamp*: string
senderName*: string
senderPublicKey*: string
MsgControlReq* = object of MsgBase
command*: string
param*: string
var conreq = MsgControlReq()
conreq.version = 1.byte
conreq.messageId = "messageId"
conreq.timestamp = "timestamp"
conreq.senderName = "senderNameVal"
conreq.senderPublicKey = "senderPublicKeyVal"
conreq.command = "CMD" # <- first not in base
var conreqj = $$conreq
var base = to[MsgBase](conreqj)
echo base
Run
error:
/home/david/nimPepper/deleteme/mt.nim(22) mt
/home/david/Nim/lib/pure/marshal.nim(333) to
/home/david/Nim/lib/pure/marshal.nim(266) loadAny
/home/david/Nim/lib/pure/marshal.nim(186) loadAny
/home/david/Nim/lib/core/typeinfo.nim(370) []
/home/david/Nim/lib/core/typeinfo.nim(372) []
Error: unhandled exception: invalid field name: command [ValueError]
Error: execution of an external program failed:
'/home/david/nimPepper/deleteme/mt '
Run
not working msgpack4nim
import msgpack4nim
type
MsgBase* = object of RootObj
version*: byte
messageId*: string
timestamp*: string
senderName*: string
senderPublicKey*: string
MsgControlReq* = object of MsgBase
command*: string
param*: string
var conreq = MsgControlReq()
conreq.version = 1.byte
conreq.messageId = "messageId"
conreq.timestamp = "timestamp"
conreq.senderName = "senderNameVal"
conreq.senderPublicKey = "senderPublicKeyVal"
conreq.command = "CMD" # <- first not in base
var conreqj = pack(conreq)
var base: MsgBase
unpack(conreqj, base)
echo base
Run
error:
/home/david/.nimble/pkgs/msgpack4nim-0.2.9/msgpack4nim.nim(1103) unpack
/home/david/.nimble/pkgs/msgpack4nim-0.2.9/msgpack4nim.nim(1093) unpack
/home/david/.nimble/pkgs/msgpack4nim-0.2.9/msgpack4nim.nim(987) unpack_type
/home/david/.nimble/pkgs/msgpack4nim-0.2.9/msgpack4nim.nim(1093) unpack
/home/david/.nimble/pkgs/msgpack4nim-0.2.9/msgpack4nim.nim(811) unpack_type
/home/david/.nimble/pkgs/msgpack4nim-0.2.9/msgpack4nim.nim(245)
unpack_imp_uint8
Error: unhandled exception: uint8 [ObjectConversionError]
Error: execution of an external program failed:
'/home/david/nimPepper/deleteme/mpt '
Run
i think the reason is that the fields of the derived message are before the
base type fields. This is at least what i've noticed, i don't know the
technical reason.
import msgpack4nim
import msgpack2any
type
MsgBase* = object of RootObj
version*: byte
messageId*: string
timestamp*: string
senderName*: string
senderPublicKey*: string
MsgControlReq* = object of MsgBase
command*: string
param*: string
var conreq = MsgControlReq()
conreq.version = 1.byte
conreq.messageId = "messageId"
conreq.timestamp = "timestamp"
conreq.senderName = "senderNameVal"
conreq.senderPublicKey = "senderPublicKeyVal"
conreq.command = "CMD" # <- first not in base
var conreqj = pack(conreq)
echo conreqj.toAny
Run
output:
[ "CMD", "", 1, "messageId", "timestamp", "senderNameVal",
"senderPublicKeyVal" ]
Run
you see that the derived object fields are on first position.
PS: If you know a _binary_ serializer that can do proper object downcasting
please let me know! :)
