Single level '+' wildcard support

nmqtt.nim

@@ -847,6 +847,15 @@ proc onPublish(ctx: MqttCtx, pkt: Pkt) {.async.} =
         topicw.removeSuffix("#")
         if topic.contains(topicw):
           cb.cb(topic, message)
+      if top.contains("+"):
+        var topelem = split(top, '/')
+        if len(topelem) == count(topic, '/') + 1:
+          var i = 0
+          for e in split(topic, '/'):
+            if topelem[i] != "+" and e != topelem[i]: break
+            i = i+1
+          if i == len(topelem):
+            cb.cb(topic, message)
 
   if qos == 1:
     ctx.workQueue[msgId] = Work(wk: PubWork, msgId: msgId, state: WorkNew, qos: 1, typ: PubAck)

tests/subscribe.nim

@@ -210,6 +210,49 @@ suite "test suite for subscribe":
 
     waitFor conn()
 
+  test "subscribe to test/+":
+    let (_, msg) = tdata("subscribe to test/+")
+
+    proc conn() {.async.} =
+      var msgCount: int
+      proc on_data_sub_wild(topic: string, message: string) =
+        msgCount += 1
+
+      await ctxListen.subscribe("test/+", 0, on_data_sub_wild)
+      await sleepAsync 500
+      await ctxMain.publish("test/random1", msg, 0)
+      await ctxMain.publish("second/random2", msg, 0)
+      await ctxMain.publish("test", msg, 0)
+      await ctxMain.publish("test/random3", msg, 0)
+      await sleepAsync 500
+      await ctxListen.unsubscribe("test/+")
+      await sleepAsync 500
+      check(msgCount == 2)
+
+    waitFor conn()
+
+  test "subscribe to test/+/test":
+    let (_, msg) = tdata("subscribe to test/+/test")
+
+    proc conn() {.async.} =
+      var msgCount: int
+      proc on_data_sub_wild(topic: string, message: string) =
+        msgCount += 1
+
+      await ctxListen.subscribe("test/+/data", 0, on_data_sub_wild)
+      await sleepAsync 500
+      await ctxMain.publish("test/random1/data", msg, 0)
+      await ctxMain.publish("second/random2/data", msg, 0)
+      await ctxMain.publish("test/random3", msg, 0)
+      await ctxMain.publish("test/random4/data", msg, 0)
+      await ctxMain.publish("test/random5/data/random6", msg, 0)
+      await sleepAsync 500
+      await ctxListen.unsubscribe("test/+/data")
+      await sleepAsync 500
+      check(msgCount == 2)
+
+    waitFor conn()
+
   test "stay subscribed after disconnect with reconnect":
     let (tpc, msg) = tdata("stay subscribed after disconnect with reconnect")