fix(store): waku store rpc codec support optional fields

tests/v2/test_waku_store_rpc_codec.nim

@@ -1,7 +1,7 @@
 {.used.}
 
 import
-  std/[options, times],
+  std/options,
   testutils/unittests,
   chronos
 import
@@ -50,7 +50,7 @@ procSuite "Waku Store - RPC codec":
     ## Given
     let
       index = PagingIndexRPC.compute(fakeWakuMessage(), receivedTime=ts(), pubsubTopic=DefaultPubsubTopic)
-      pagingInfo = PagingInfoRPC(pageSize: 1, cursor: index, direction: PagingDirectionRPC.FORWARD)
+      pagingInfo = PagingInfoRPC(pageSize: some(1'u64), cursor: some(index), direction: some(PagingDirectionRPC.FORWARD))
       
     ## When
     let pb = pagingInfo.encode()
@@ -61,7 +61,7 @@ procSuite "Waku Store - RPC codec":
       decodedPagingInfo.isOk()
 
     check:
-      # the fields of decodedPagingInfo must be the same as the original pagingInfo
+      # The fields of decodedPagingInfo must be the same as the original pagingInfo
       decodedPagingInfo.value == pagingInfo
       decodedPagingInfo.value.direction == pagingInfo.direction
   
@@ -85,8 +85,13 @@ procSuite "Waku Store - RPC codec":
     ## Given
     let
       index = PagingIndexRPC.compute(fakeWakuMessage(), receivedTime=ts(), pubsubTopic=DefaultPubsubTopic)
-      pagingInfo = PagingInfoRPC(pageSize: 1, cursor: index, direction: PagingDirectionRPC.BACKWARD)
+      pagingInfo = PagingInfoRPC(pageSize: some(1'u64), cursor: some(index), direction: some(PagingDirectionRPC.BACKWARD))
-      query = HistoryQueryRPC(contentFilters: @[HistoryContentFilterRPC(contentTopic: DefaultContentTopic), HistoryContentFilterRPC(contentTopic: DefaultContentTopic)], pagingInfo: pagingInfo, startTime: Timestamp(10), endTime: Timestamp(11))
+      query = HistoryQueryRPC(
+        contentFilters: @[HistoryContentFilterRPC(contentTopic: DefaultContentTopic), HistoryContentFilterRPC(contentTopic: DefaultContentTopic)],
+        pagingInfo: some(pagingInfo), 
+        startTime: some(Timestamp(10)), 
+        endTime: some(Timestamp(11))
+      )
     
     ## When
     let pb = query.encode()
@@ -121,8 +126,8 @@ procSuite "Waku Store - RPC codec":
     let
       message = fakeWakuMessage()
       index = PagingIndexRPC.compute(message, receivedTime=ts(), pubsubTopic=DefaultPubsubTopic)
-      pagingInfo = PagingInfoRPC(pageSize: 1, cursor: index, direction: PagingDirectionRPC.BACKWARD)
+      pagingInfo = PagingInfoRPC(pageSize: some(1'u64), cursor: some(index), direction: some(PagingDirectionRPC.BACKWARD))
-      res = HistoryResponseRPC(messages: @[message], pagingInfo:pagingInfo, error: HistoryResponseErrorRPC.INVALID_CURSOR)
+      res = HistoryResponseRPC(messages: @[message], pagingInfo: some(pagingInfo), error: HistoryResponseErrorRPC.INVALID_CURSOR)
     
     ## When
     let pb = res.encode()
@@ -150,4 +155,4 @@ procSuite "Waku Store - RPC codec":
 
     check:
       # check the correctness of init and encode for an empty HistoryResponseRPC
-      decodedEmptyRes.value == emptyRes
+      decodedEmptyRes.value == emptyRes

waku/common/protobuf.nim

@@ -6,6 +6,7 @@ else:
   {.push raises: [].}
 
 import
+  std/options,
   libp2p/protobuf/minprotobuf,
   libp2p/varint
  
@@ -15,7 +16,10 @@ export
 
 
 proc write3*(proto: var ProtoBuffer, field: int, value: auto) =
-  if default(type(value)) != value:
+  when value is Option:
+    if value.isSome():
+      proto.write(field, value.get())
+  else:
     proto.write(field, value)
 
 proc finish3*(proto: var ProtoBuffer) =

waku/v2/node/jsonrpc/jsonrpc_utils.nim

@@ -31,14 +31,20 @@ proc `%`*(value: WakuMessage): JsonNode =
 ## we need to convert between these and the types for the Nim API
 
 proc toPagingInfo*(pagingOptions: StorePagingOptions): PagingInfoRPC =
-  PagingInfoRPC(pageSize: pagingOptions.pageSize,
+  PagingInfoRPC(
-             cursor: if pagingOptions.cursor.isSome: pagingOptions.cursor.get else: PagingIndexRPC(),
+    pageSize: some(pagingOptions.pageSize),
-             direction: if pagingOptions.forward: PagingDirectionRPC.FORWARD else: PagingDirectionRPC.BACKWARD)
+    cursor: pagingOptions.cursor,
+    direction: if pagingOptions.forward: some(PagingDirectionRPC.FORWARD)
+               else: some(PagingDirectionRPC.BACKWARD)
+  )
 
 proc toPagingOptions*(pagingInfo: PagingInfoRPC): StorePagingOptions =
-  StorePagingOptions(pageSize: pagingInfo.pageSize,
+  StorePagingOptions(
-                     cursor: some(pagingInfo.cursor),
+    pageSize: pagingInfo.pageSize.get(0'u64),
-                     forward: if pagingInfo.direction == PagingDirectionRPC.FORWARD: true else: false)
+    cursor: pagingInfo.cursor,
+    forward: if pagingInfo.direction.isNone(): true
+             else: pagingInfo.direction.get() == PagingDirectionRPC.FORWARD
+  )
 
 proc toJsonRPCStoreResponse*(response: HistoryResponse): StoreResponse =
   StoreResponse(

waku/v2/protocol/waku_store/client.nim

@@ -53,7 +53,7 @@ proc sendHistoryQueryRPC(w: WakuStoreClient, req: HistoryQuery, peer: RemotePeer
   let connection = connOpt.get()
 
 
-  let reqRpc = HistoryRPC(requestId: generateRequestId(w.rng), query: req.toRPC())
+  let reqRpc = HistoryRPC(requestId: generateRequestId(w.rng), query: some(req.toRPC()))
   await connection.writeLP(reqRpc.encode().buffer)
 
 
@@ -69,11 +69,11 @@ proc sendHistoryQueryRPC(w: WakuStoreClient, req: HistoryQuery, peer: RemotePeer
   # Disabled ,for now, since the default response is a possible case (no messages, pagesize = 0, error = NONE(0))
   # TODO: Rework the RPC protocol to differentiate the default value from an empty value (e.g., status = 200 (OK))
   #        and rework the protobuf parsing to return Option[T] when empty values are received
-  # if respRpc.response == default(HistoryResponseRPC):
+  if respRpc.response.isNone():
-  #   waku_store_errors.inc(labelValues = [emptyRpcResponseFailure])
+    waku_store_errors.inc(labelValues = [emptyRpcResponseFailure])
-  #   return err(HistoryError(kind: HistoryErrorKind.BAD_RESPONSE, cause: emptyRpcResponseFailure))
+    return err(HistoryError(kind: HistoryErrorKind.BAD_RESPONSE, cause: emptyRpcResponseFailure))
 
-  let resp = respRpc.response
+  let resp = respRpc.response.get()
 
   return resp.toAPI()
 

waku/v2/protocol/waku_store/protocol.nim

@@ -222,7 +222,7 @@ proc initProtocolHandler*(ws: WakuStore) =
 
     let reqRpc = decodeRes.value
 
-    if reqRpc.query == default(HistoryQueryRPC):
+    if reqRpc.query.isNone():
       error "empty query rpc", peerId=conn.peerId, requestId=reqRpc.requestId
       waku_store_errors.inc(labelValues = [emptyRpcQueryFailure])
       # TODO: Return (BAD_REQUEST, cause: "empty query")
@@ -239,19 +239,20 @@ proc initProtocolHandler*(ws: WakuStore) =
       error "history query failed", peerId=conn.peerId, requestId=reqRpc.requestId, error= $respErr
 
       let resp = HistoryResponseRPC(error: respErr.toRPC())
-      let rpc = HistoryRPC(requestId: reqRpc.requestId, response: resp)
+      let rpc = HistoryRPC(requestId: reqRpc.requestId, response: some(resp))
       await conn.writeLp(rpc.encode().buffer)
       return
 
 
-    let query = reqRpc.query.toApi()
+    let query = reqRpc.query.get().toAPI()
+    
     let respRes = ws.findMessages(query)
 
     if respRes.isErr():
       error "history query failed", peerId=conn.peerId, requestId=reqRpc.requestId, error=respRes.error
 
       let resp = respRes.toRPC()
-      let rpc = HistoryRPC(requestId: reqRpc.requestId, response: resp)
+      let rpc = HistoryRPC(requestId: reqRpc.requestId, response: some(resp))
       await conn.writeLp(rpc.encode().buffer)
       return
 
@@ -270,7 +271,7 @@ proc initProtocolHandler*(ws: WakuStore) =
 
     info "sending history response", peerId=conn.peerId, requestId=reqRpc.requestId, messages=resp.messages.len
 
-    let rpc = HistoryRPC(requestId: reqRpc.requestId, response: resp)
+    let rpc = HistoryRPC(requestId: reqRpc.requestId, response: some(resp))
     await conn.writeLp(rpc.encode().buffer)
 
   ws.handler = handler

waku/v2/protocol/waku_store/rpc.nim

@@ -49,9 +49,9 @@ type
 
   PagingInfoRPC* = object
     ## This type holds the information needed for the pagination
-    pageSize*: uint64
+    pageSize*: Option[uint64]
-    cursor*: PagingIndexRPC
+    cursor*: Option[PagingIndexRPC]
-    direction*: PagingDirectionRPC
+    direction*: Option[PagingDirectionRPC]
 
 
 type
@@ -60,10 +60,10 @@ type
 
   HistoryQueryRPC* = object
     contentFilters*: seq[HistoryContentFilterRPC]
-    pubsubTopic*: PubsubTopic
+    pubsubTopic*: Option[PubsubTopic]
-    pagingInfo*: PagingInfoRPC # used for pagination
+    pagingInfo*: Option[PagingInfoRPC]
-    startTime*: Timestamp # used for time-window query
+    startTime*: Option[int64]
-    endTime*: Timestamp # used for time-window query
+    endTime*: Option[int64]
 
   HistoryResponseErrorRPC* {.pure.} = enum
     ## HistoryResponseErrorRPC contains error message to inform  the querying node about 
@@ -74,13 +74,13 @@ type
 
   HistoryResponseRPC* = object
     messages*: seq[WakuMessage]
-    pagingInfo*: PagingInfoRPC # used for pagination
+    pagingInfo*: Option[PagingInfoRPC]
     error*: HistoryResponseErrorRPC
 
   HistoryRPC* = object
     requestId*: string
-    query*: HistoryQueryRPC
+    query*: Option[HistoryQueryRPC]
-    response*: HistoryResponseRPC
+    response*: Option[HistoryResponseRPC]
 
 
 proc parse*(T: type HistoryResponseErrorRPC, kind: uint32): T =
@@ -112,55 +112,53 @@ proc toAPI*(rpc: PagingIndexRPC): HistoryCursor =
 
 
 proc toRPC*(query: HistoryQuery): HistoryQueryRPC =
-  let 
+  var rpc = HistoryQueryRPC()
-    contentFilters = query.contentTopics.mapIt(HistoryContentFilterRPC(contentTopic: it))
 
-    pubsubTopic = query.pubsubTopic.get(default(string))
+  rpc.contentFilters = query.contentTopics.mapIt(HistoryContentFilterRPC(contentTopic: it))
-  
-    pageSize = query.pageSize
 
-    cursor = query.cursor.get(default(HistoryCursor)).toRPC()
+  rpc.pubsubTopic = query.pubsubTopic
 
-    direction = if query.ascending: PagingDirectionRPC.FORWARD
+  rpc.pagingInfo = block:
-                else: PagingDirectionRPC.BACKWARD
+      if query.cursor.isNone() and 
+         query.pageSize == default(type query.pageSize) and 
+         query.ascending == default(type query.ascending): 
+        none(PagingInfoRPC)
+      else:
+        let
+          pageSize = some(query.pageSize)
+          cursor = query.cursor.map(toRPC)
+          direction = if query.ascending: some(PagingDirectionRPC.FORWARD)
+                      else: some(PagingDirectionRPC.BACKWARD)
+        some(PagingInfoRPC(
+          pageSize: pageSize,
+          cursor: cursor,
+          direction: direction
+        ))
+      
+  rpc.startTime = query.startTime
+  rpc.endTime = query.endTime
 
-    startTime = query.startTime.get(default(Timestamp))
+  rpc
-    
-    endTime = query.endTime.get(default(Timestamp))
 
-  HistoryQueryRPC(
-    contentFilters: contentFilters,
-    pubsubTopic: pubsubTopic,
-    pagingInfo: PagingInfoRPC(
-      pageSize: pageSize,
-      cursor: cursor,
-      direction: direction
-    ),
-    startTime: startTime,
-    endTime: endTime
-  )
 
 proc toAPI*(rpc: HistoryQueryRPC): HistoryQuery =
   let 
-    pubsubTopic = if rpc.pubsubTopic == default(string): none(PubsubTopic)
+    pubsubTopic = rpc.pubsubTopic
-                  else: some(rpc.pubsubTopic)
     
     contentTopics = rpc.contentFilters.mapIt(it.contentTopic)
 
-    cursor = if rpc.pagingInfo == default(PagingInfoRPC) or rpc.pagingInfo.cursor == default(PagingIndexRPC): none(HistoryCursor)
+    cursor = if rpc.pagingInfo.isNone() or rpc.pagingInfo.get().cursor.isNone(): none(HistoryCursor)
-             else: some(rpc.pagingInfo.cursor.toAPI())
+             else: rpc.pagingInfo.get().cursor.map(toAPI)
 
-    startTime = if rpc.startTime == default(Timestamp): none(Timestamp)
+    startTime = rpc.startTime
-                else: some(rpc.startTime)
 
-    endTime = if rpc.endTime == default(Timestamp): none(Timestamp)
+    endTime = rpc.endTime
-              else: some(rpc.endTime)
     
-    pageSize = if rpc.pagingInfo == default(PagingInfoRPC): 0.uint64
+    pageSize = if rpc.pagingInfo.isNone() or rpc.pagingInfo.get().pageSize.isNone(): 0'u64
-               else: rpc.pagingInfo.pageSize
+               else: rpc.pagingInfo.get().pageSize.get()
 
-    ascending = if rpc.pagingInfo == default(PagingInfoRPC): true
+    ascending = if rpc.pagingInfo.isNone() or rpc.pagingInfo.get().direction.isNone(): true
-                else: rpc.pagingInfo.direction == PagingDirectionRPC.FORWARD
+                else: rpc.pagingInfo.get().direction.get() == PagingDirectionRPC.FORWARD
     
   HistoryQuery(
     pubsubTopic: pubsubTopic,
@@ -182,7 +180,7 @@ proc toRPC*(err: HistoryError): HistoryResponseErrorRPC =
   of HistoryErrorKind.SERVICE_UNAVAILABLE:
     HistoryResponseErrorRPC.SERVICE_UNAVAILABLE
   else:
-    HistoryResponseErrorRPC.INVALID_CURSOR    
+    HistoryResponseErrorRPC.INVALID_CURSOR
 
 proc toAPI*(err: HistoryResponseErrorRPC): HistoryError =
   # TODO: Better error mappings/move to error codes
@@ -208,18 +206,18 @@ proc toRPC*(res: HistoryResult): HistoryResponseRPC =
 
       pagingInfo = block:
         if resp.cursor.isNone():
-          default(PagingInfoRPC)
+          none(PagingInfoRPC)
         else: 
           let
-            pageSize = resp.pageSize
+            pageSize = some(resp.pageSize)
-            cursor = resp.cursor.get(default(HistoryCursor)).toRPC()
+            cursor = resp.cursor.map(toRPC)
-            direction = if resp.ascending: PagingDirectionRPC.FORWARD
+            direction = if resp.ascending: some(PagingDirectionRPC.FORWARD)
-                        else: PagingDirectionRPC.BACKWARD
+                        else: some(PagingDirectionRPC.BACKWARD)
-          PagingInfoRPC(
+          some(PagingInfoRPC(
             pageSize: pageSize,
             cursor: cursor,
             direction: direction
-          )
+          ))
 
       error = HistoryResponseErrorRPC.NONE
 
@@ -236,12 +234,14 @@ proc toAPI*(rpc: HistoryResponseRPC): HistoryResult =
     let
       messages = rpc.messages
 
-      pageSize = rpc.pagingInfo.pageSize
+      pageSize = if rpc.pagingInfo.isNone(): 0'u64
+                 else: rpc.pagingInfo.get().pageSize.get(0'u64)
 
-      ascending = rpc.pagingInfo == default(PagingInfoRPC) or rpc.pagingInfo.direction == PagingDirectionRPC.FORWARD
+      ascending = if rpc.pagingInfo.isNone(): true
+                  else: rpc.pagingInfo.get().direction.get(PagingDirectionRPC.FORWARD) == PagingDirectionRPC.FORWARD
 
-      cursor = if rpc.pagingInfo == default(PagingInfoRPC) or rpc.pagingInfo.cursor == default(PagingIndexRPC): none(HistoryCursor)
+      cursor = if rpc.pagingInfo.isNone(): none(HistoryCursor)
-               else: some(rpc.pagingInfo.cursor.toAPI())
+               else: rpc.pagingInfo.get().cursor.map(toAPI)
 
     ok(HistoryResponse(
       messages: messages,

waku/v2/protocol/waku_store/rpc_codec.nim

@@ -4,10 +4,10 @@ else:
   {.push raises: [].}
 
 import
+  std/options,
   nimcrypto/hash
 import
   ../../../common/protobuf,
-  ../../utils/time,
   ../waku_message,
   ./common,
   ./rpc
@@ -33,165 +33,199 @@ proc encode*(index: PagingIndexRPC): ProtoBuffer =
 
 proc decode*(T: type PagingIndexRPC, buffer: seq[byte]): ProtoResult[T] =
   ## creates and returns an Index object out of buffer
-  var index = PagingIndexRPC()
+  var rpc = PagingIndexRPC()
   let pb = initProtoBuffer(buffer)
 
   var data: seq[byte]
-  discard ?pb.getField(1, data)
+  if not ?pb.getField(1, data):
+    return err(ProtoError.RequiredFieldMissing)
+  else:
+    var digest = MessageDigest()
+    for count, b in data:
+      digest.data[count] = b
 
-  # create digest from data
+    rpc.digest = digest
-  index.digest = MessageDigest()
-  for count, b in data:
-    index.digest.data[count] = b
 
-  # read the timestamp
   var receiverTime: zint64
-  discard ?pb.getField(2, receiverTime)
+  if not ?pb.getField(2, receiverTime):
-  index.receiverTime = Timestamp(receiverTime)
+    return err(ProtoError.RequiredFieldMissing)
+  else:
+    rpc.receiverTime = int64(receiverTime)
 
-  # read the timestamp
   var senderTime: zint64
-  discard ?pb.getField(3, senderTime)
+  if not ?pb.getField(3, senderTime):
-  index.senderTime = Timestamp(senderTime)
+    return err(ProtoError.RequiredFieldMissing)
+  else:
+    rpc.senderTime = int64(senderTime)
 
-  # read the pubsubTopic
+  var pubsubTopic: string
-  discard ?pb.getField(4, index.pubsubTopic)
+  if not ?pb.getField(4, pubsubTopic):
+    return err(ProtoError.RequiredFieldMissing)
+  else:
+    rpc.pubsubTopic = pubsubTopic
 
-  ok(index) 
+  ok(rpc) 
 
 
-proc encode*(pinfo: PagingInfoRPC): ProtoBuffer =
+proc encode*(rpc: PagingInfoRPC): ProtoBuffer =
   ## Encodes a PagingInfo object into a ProtoBuffer
   ## returns the resultant ProtoBuffer
   var pb = initProtoBuffer()
 
-  pb.write3(1, pinfo.pageSize)
+  pb.write3(1, rpc.pageSize.map(proc(size: uint64): zint64 = zint64(size)))
-  pb.write3(2, pinfo.cursor.encode())
+  pb.write3(2, rpc.cursor.map(encode))
-  pb.write3(3, uint32(ord(pinfo.direction)))
+  pb.write3(3, rpc.direction.map(proc(d: PagingDirectionRPC): uint32 = uint32(ord(d))))
   pb.finish3()
 
   pb
 
 proc decode*(T: type PagingInfoRPC, buffer: seq[byte]): ProtoResult[T] =
   ## creates and returns a PagingInfo object out of buffer
-  var pagingInfo = PagingInfoRPC()
+  var rpc = PagingInfoRPC()
   let pb = initProtoBuffer(buffer)
 
-  var pageSize: uint64
+  var pageSize: zint64
-  discard ?pb.getField(1, pageSize)
+  if not ?pb.getField(1, pageSize):
-  pagingInfo.pageSize = pageSize
+    rpc.pageSize = none(uint64)
+  else:
+    rpc.pageSize = some(uint64(pageSize))
 
   var cursorBuffer: seq[byte]
-  discard ?pb.getField(2, cursorBuffer)
+  if not ?pb.getField(2, cursorBuffer):
-  pagingInfo.cursor = ?PagingIndexRPC.decode(cursorBuffer)
+    rpc.cursor = none(PagingIndexRPC)
+  else:
+    let cursor = ?PagingIndexRPC.decode(cursorBuffer)
+    rpc.cursor = some(cursor)
 
   var direction: uint32
-  discard ?pb.getField(3, direction)
+  if not ?pb.getField(3, direction):
-  pagingInfo.direction = PagingDirectionRPC(direction)
+    rpc.direction = none(PagingDirectionRPC)
+  else:
+    rpc.direction = some(PagingDirectionRPC(direction))
 
-  ok(pagingInfo) 
+  ok(rpc) 
 
 
 ## Wire protocol
 
-proc encode*(filter: HistoryContentFilterRPC): ProtoBuffer =
+proc encode*(rpc: HistoryContentFilterRPC): ProtoBuffer =
   var pb = initProtoBuffer()
 
-  pb.write3(1, filter.contentTopic)
+  pb.write3(1, rpc.contentTopic)
   pb.finish3()
 
   pb
 
 proc decode*(T: type HistoryContentFilterRPC, buffer: seq[byte]): ProtoResult[T] =
   let pb = initProtoBuffer(buffer)
+
   var contentTopic: ContentTopic
-  discard ?pb.getField(1, contentTopic)
+  if not ?pb.getField(1, contentTopic):
+    return err(ProtoError.RequiredFieldMissing)
 
   ok(HistoryContentFilterRPC(contentTopic: contentTopic))
 
 
-proc encode*(query: HistoryQueryRPC): ProtoBuffer =
+proc encode*(rpc: HistoryQueryRPC): ProtoBuffer =
   var pb = initProtoBuffer()
-  pb.write3(2, query.pubsubTopic)
+  pb.write3(2, rpc.pubsubTopic)
   
-  for filter in query.contentFilters:
+  for filter in rpc.contentFilters:
     pb.write3(3, filter.encode())
 
-  pb.write3(4, query.pagingInfo.encode())
+  pb.write3(4, rpc.pagingInfo.map(encode))
-  pb.write3(5, zint64(query.startTime))
+  pb.write3(5, rpc.startTime.map(proc (time: int64): zint64 = zint64(time)))
-  pb.write3(6, zint64(query.endTime))
+  pb.write3(6, rpc.endTime.map(proc (time: int64): zint64 = zint64(time)))
   pb.finish3()
 
   pb
 
 proc decode*(T: type HistoryQueryRPC, buffer: seq[byte]): ProtoResult[T] =
-  var msg = HistoryQueryRPC()
+  var rpc = HistoryQueryRPC()
   let pb = initProtoBuffer(buffer)
 
-  discard ?pb.getField(2, msg.pubsubTopic)
+  var pubsubTopic: string
+  if not ?pb.getField(2, pubsubTopic):
+    rpc.pubsubTopic = none(string)
+  else:
+    rpc.pubsubTopic = some(pubsubTopic)
 
   var buffs: seq[seq[byte]]
-  discard ?pb.getRepeatedField(3, buffs)
+  if not ?pb.getRepeatedField(3, buffs):
-  
+    rpc.contentFilters = @[]
-  for pb in buffs:
+  else:
-    msg.contentFilters.add(? HistoryContentFilterRPC.decode(pb))
+    for pb in buffs:
+      let filter = ?HistoryContentFilterRPC.decode(pb)
+      rpc.contentFilters.add(filter)
 
   var pagingInfoBuffer: seq[byte]
-  discard ?pb.getField(4, pagingInfoBuffer)
+  if not ?pb.getField(4, pagingInfoBuffer):
-
+    rpc.pagingInfo = none(PagingInfoRPC)
-  msg.pagingInfo = ?PagingInfoRPC.decode(pagingInfoBuffer)
+  else:
+    let pagingInfo = ?PagingInfoRPC.decode(pagingInfoBuffer)
+    rpc.pagingInfo = some(pagingInfo)
 
   var startTime: zint64
-  discard ?pb.getField(5, startTime)
+  if not ?pb.getField(5, startTime):
-  msg.startTime = Timestamp(startTime)
+    rpc.startTime = none(int64)
+  else:
+    rpc.startTime = some(int64(startTime))
 
   var endTime: zint64
-  discard ?pb.getField(6, endTime)
+  if not ?pb.getField(6, endTime):
-  msg.endTime = Timestamp(endTime)
+    rpc.endTime = none(int64)
+  else:
+    rpc.endTime = some(int64(endTime))
 
-  ok(msg)
+  ok(rpc)
 
 
 proc encode*(response: HistoryResponseRPC): ProtoBuffer =
   var pb = initProtoBuffer()
 
-  for msg in response.messages:
+  for rpc in response.messages:
-    pb.write3(2, msg.encode())
+    pb.write3(2, rpc.encode())
 
-  pb.write3(3, response.pagingInfo.encode())
+  pb.write3(3, response.pagingInfo.map(encode))
   pb.write3(4, uint32(ord(response.error)))
   pb.finish3()
 
   pb
 
 proc decode*(T: type HistoryResponseRPC, buffer: seq[byte]): ProtoResult[T] =
-  var msg = HistoryResponseRPC()
+  var rpc = HistoryResponseRPC()
   let pb = initProtoBuffer(buffer)
 
   var messages: seq[seq[byte]]
-  discard ?pb.getRepeatedField(2, messages)
+  if ?pb.getRepeatedField(2, messages):
-
+    for pb in messages:
-  for pb in messages:
+      let message = ?WakuMessage.decode(pb)
-    let message = ?WakuMessage.decode(pb)
+      rpc.messages.add(message)
-    msg.messages.add(message)
+  else:
+    rpc.messages = @[]
 
   var pagingInfoBuffer: seq[byte]
-  discard ?pb.getField(3, pagingInfoBuffer)
+  if ?pb.getField(3, pagingInfoBuffer):
-  msg.pagingInfo = ?PagingInfoRPC.decode(pagingInfoBuffer)
+    let pagingInfo = ?PagingInfoRPC.decode(pagingInfoBuffer)
+    rpc.pagingInfo = some(pagingInfo)
+  else:
+    rpc.pagingInfo = none(PagingInfoRPC)
 
   var error: uint32
-  discard ?pb.getField(4, error)
+  if not ?pb.getField(4, error):
-  msg.error = HistoryResponseErrorRPC.parse(error)
+    return err(ProtoError.RequiredFieldMissing)
+  else:
+    rpc.error = HistoryResponseErrorRPC.parse(error)
 
-  ok(msg)
+  ok(rpc)
 
 
 proc encode*(rpc: HistoryRPC): ProtoBuffer =
   var pb = initProtoBuffer()
 
   pb.write3(1, rpc.requestId)
-  pb.write3(2, rpc.query.encode())
+  pb.write3(2, rpc.query.map(encode))
-  pb.write3(3, rpc.response.encode())
+  pb.write3(3, rpc.response.map(encode))
   pb.finish3()
 
   pb
@@ -199,14 +233,22 @@ proc encode*(rpc: HistoryRPC): ProtoBuffer =
 proc decode*(T: type HistoryRPC, buffer: seq[byte]): ProtoResult[T] =
   var rpc = HistoryRPC()
   let pb = initProtoBuffer(buffer)
-  discard ?pb.getField(1, rpc.requestId)
+
+  if not ?pb.getField(1, rpc.requestId):
+    return err(ProtoError.RequiredFieldMissing)
 
   var queryBuffer: seq[byte]
-  discard ?pb.getField(2, queryBuffer)
+  if not ?pb.getField(2, queryBuffer):
-  rpc.query = ?HistoryQueryRPC.decode(queryBuffer)
+    rpc.query = none(HistoryQueryRPC)
+  else:
+    let query = ?HistoryQueryRPC.decode(queryBuffer)
+    rpc.query = some(query)
 
   var responseBuffer: seq[byte]
-  discard ?pb.getField(3, responseBuffer)
+  if not ?pb.getField(3, responseBuffer):
-  rpc.response = ?HistoryResponseRPC.decode(responseBuffer)
+    rpc.response = none(HistoryResponseRPC)
+  else:
+    let response = ?HistoryResponseRPC.decode(responseBuffer)
+    rpc.response = some(response)
 
   ok(rpc)