fix: return message id on `waku_relay_publish` (#2485)

* fix: return message id on `waku_relay_publish`
* fix: remove unneeded cast and handle 0 len seqs
* chore: rename messageId to messageHash

library/alloc.nim

@@ -19,8 +19,9 @@ proc alloc*(str: string): cstring =
   return ret
 
 proc allocSharedSeq*[T](s: seq[T]): SharedSeq[T] =
-  let data = cast[ptr T](allocShared(s.len))
-  copyMem(data, unsafeAddr s, s.len)
+  let data = allocShared(sizeof(T) * s.len)
+  if s.len != 0:
+    copyMem(data, unsafeAddr s[0], s.len)
   return (cast[ptr UncheckedArray[T]](data), s.len)
 
 proc deallocSharedSeq*[T](s: var SharedSeq[T]) =

library/events/json_message_event.nim

@@ -61,7 +61,7 @@ proc `%`*(value: WakuMessageHash): JsonNode =
 
 type JsonMessageEvent* = ref object of JsonEvent
     pubsubTopic*: string
-    messageId*: string
+    messageHash*: WakuMessageHash
     wakuMessage*: JsonMessage
 
 proc new*(T: type JsonMessageEvent,
@@ -83,12 +83,11 @@ proc new*(T: type JsonMessageEvent,
     copyMem(addr proof[0], unsafeAddr msg.proof[0], len(msg.proof))
 
   let msgHash = computeMessageHash(pubSubTopic, msg)
-  let msgHashHex = to0xHex(msgHash)
 
   return JsonMessageEvent(
     eventType: "message",
     pubSubTopic: pubSubTopic,
-    messageId: msgHashHex,
+    messageHash: msgHash,
     wakuMessage: JsonMessage(
         payload: base64.encode(payload),
         contentTopic: msg.contentTopic,

library/libwaku.nim

@@ -235,6 +235,8 @@ proc waku_relay_publish(ctx: ptr Context,
     callback(RET_ERR, unsafeAddr msg[0], cast[csize_t](len(msg)), userData)
     return RET_ERR
 
+  let msgHash = $sendReqRes.value
+  callback(RET_OK, unsafeAddr msgHash[0], cast[csize_t](len(msgHash)), userData)
   return RET_OK
 
 proc waku_start(ctx: ptr Context,

library/waku_thread/inter_thread_communication/requests/protocols/relay_request.nim

@@ -4,11 +4,13 @@ import
 import
   chronicles,
   chronos,
+  stew/byteutils,
   stew/results,
   stew/shims/net
 import
   ../../../../../waku/waku_core/message/message,
   ../../../../../waku/node/waku_node,
+  ../../../../../waku/waku_core/message,
   ../../../../../waku/waku_core/time, # Timestamp
   ../../../../../waku/waku_core/topics/pubsub_topic,
   ../../../../../waku/waku_relay/protocol,
@@ -104,13 +106,16 @@ proc process*(self: ptr RelayRequest,
       node.wakuRelay.unsubscribeAll($self.pubsubTopic)
 
     of PUBLISH:
-      let numPeers = await node.wakuRelay.publish($self.pubsubTopic,
-                                                  self.message.toWakuMessage())
+      let msg = self.message.toWakuMessage()
+      let pubsubTopic = $self.pubsubTopic
+
+      let numPeers = await node.wakuRelay.publish(pubsubTopic,
+                                                  msg)
       if numPeers == 0:
         return err("Message not sent because no peers found.")
 
       elif numPeers > 0:
-        # TODO: pending to return a valid message Id
-        return ok("hard-coded-message-id")
+        let msgHash = computeMessageHash(pubSubTopic, msg).to0xHex
+        return ok(msgHash)
 
   return ok("")