Typed pubsub (#3)

examples/simple_tcp_ping/main.nim

@@ -1,4 +1,9 @@
-import std/strutils, testground_sdk, chronos, stew/byteutils
+import std/strutils, std/random
+import testground_sdk, chronos, stew/byteutils
+
+type
+  AwesomeStruct = object
+    rand: int
 
 testground(client):
   let
@@ -18,6 +23,12 @@ testground(client):
 
   await client.waitForBarrier("network_setup", client.testInstanceCount)
 
+  randomize()
+  await client.publish("rands", AwesomeStruct(rand: rand(100)))
+  let randomValues = client.subscribe("rands", AwesomeStruct)
+  for _ in 0 ..< 2:
+    echo await randomValues.popFirst()
+
   let
     payload = client.param(string, "payload")
     count = client.param(int, "count")

testground_sdk.nim

@@ -1,5 +1,5 @@
 import
-  std/[tables, parseutils, strutils, os, sequtils],
+  std/[tables, parseutils, strutils, os, sequtils, json],
   chronos, websock/websock, chronicles, stew/byteutils
 
 # workaround https://github.com/status-im/nim-serialization/issues/43
@@ -9,6 +9,7 @@ import json_serialization/std/options
 
 export sequtils, strutils, os, tables
 export chronos, options, chronicles, websock
+export json_serialization
 
 type
   Client* = ref object
@@ -197,7 +198,22 @@ proc subscribe*(c: Client, topic: string): AsyncQueue[string] =
     )
   ).toJson())
 
-proc publish*(c: Client, topic, content: string) {.async.} =
+proc subscribe*[T](c: Client, topic: string, _: type[T]): AsyncQueue[T] =
+  var
+    theQueue = c.subscribe(topic)
+    resQueue = newAsyncQueue[T](1000)
+  proc getter {.async.} =
+    mixin decode
+    while true:
+      let elem = await theQueue.popFirst()
+
+      let decoded = json_serialization.decode(Json, unescape(elem), T, allowUnknownFields = true)
+      resQueue.addLastNoWait(decoded)
+
+  asyncSpawn getter()
+  resQueue
+
+proc publish*(c: Client, topic: string, content: string) {.async.} =
   ## Publish `content` to `topic`
   let r = await c.request(Request(
     publish: some PublishRequest(
@@ -206,6 +222,10 @@ proc publish*(c: Client, topic, content: string) {.async.} =
     )
   ))
 
+proc publish*[T](c: Client, topic: string, content: T) {.async.} =
+  mixin toJson
+  await c.publish(topic, content.toJson())
+
 proc param*[T](c: Client, _: type[T], name: string): T =
   let params = getEnv("TEST_INSTANCE_PARAMS").split("|").mapIt(it.split("=", 2)).mapIt((it[0], it[1])).toTable()
 
@@ -250,7 +270,7 @@ proc runner(todo: proc(c: Client): Future[void] {.gcsafe.}) {.async.} =
       if parsed.id in c.requests:
         c.requests[parsed.id].complete(parsed)
       elif parsed.id in c.subbed:
-        c.subbed[parsed.id].addLastNoWait(parsed.subscribe.get().strip(chars = {'"'}))
+        c.subbed[parsed.id].addLastNoWait(parsed.subscribe.get())
       else:
         echo "Unknown response id!!!", parsed.id