Add ethers implementation for setMethodHandler

Was removed in json-rpc

ethers/providers/jsonrpc/subscriptions.nim

@@ -7,13 +7,71 @@ import ../../provider
 import ./rpccalls
 import ./conversions
 import ./looping
+import ./json
 
 type
   JsonRpcSubscriptions* = ref object of RootObj
     client: RpcClient
     callbacks: Table[JsonNode, SubscriptionCallback]
+    methodHandlers: Table[string, MethodHandler]
+  MethodHandler* = proc (j: JsonNode) {.gcsafe, raises: [].}
   SubscriptionCallback = proc(id, arguments: JsonNode) {.gcsafe, raises:[].}
 
+{.push raises:[].}
+
+template `or`(a: JsonNode, b: typed): JsonNode =
+  if a.isNil: b else: a
+
+func init*(subscriptions: JsonRpcSubscriptions) =
+  subscriptions.client.onProcessMessage =
+    proc(client: RpcClient,
+         line: string): Result[bool, string] {.gcsafe, raises: [].} =
+      # if json =? JrpcConv.decode(line, JsonNode).catch:
+      if json =? JsonNode.fromJson(line):
+        if "method" in json:
+          let methodName = json{"method"}.getStr()
+          if methodName in subscriptions.methodHandlers:
+            let handler = subscriptions.methodHandlers.getOrDefault(methodName)
+            if not handler.isNil:
+              echo "[subscriptions] processing method handler with params ", json{"params"}
+              handler(json{"params"} or newJArray())
+              return ok false # false = do not continue processing message using json_rpc's default processing handler
+
+      return ok true # true = continue processing message using json_rpc's default message handler
+
+
+proc setMethodHandler(
+  subscriptions: JsonRpcSubscriptions,
+  `method`: string,
+  handler: MethodHandler
+) =
+  subscriptions.methodHandlers[`method`] = handler
+
+func hash*(n: OrderedTable[string, JsonNode]): Hash {.raises: [].}
+
+proc hash*(n: JsonNode): Hash {.noSideEffect, raises: [].} =
+  ## Compute the hash for a JSON node
+  case n.kind
+  of JArray:
+    result = hash(n.elems)
+  of JObject:
+    result = hash(n.fields)
+  of JInt:
+    result = hash(n.num)
+  of JFloat:
+    result = hash(n.fnum)
+  of JBool:
+    result = hash(n.bval.int)
+  of JString:
+    result = hash(n.str)
+  of JNull:
+    result = Hash(0)
+
+func hash*(n: OrderedTable[string, JsonNode]): Hash {.raises: [].} =
+  for key, val in n:
+    result = result xor (hash(key) !& hash(val))
+  result = !$result
+
 method subscribeBlocks*(subscriptions: JsonRpcSubscriptions,
                         onBlock: BlockHandler):
                        Future[JsonNode]
@@ -56,18 +114,20 @@ proc new*(_: type JsonRpcSubscriptions,
           client: RpcWebSocketClient): JsonRpcSubscriptions =
   let subscriptions = WebSocketSubscriptions(client: client)
   proc subscriptionHandler(arguments: JsonNode) {.raises:[].} =
-    if id =? arguments["subscription"].catch and
+    if id =? arguments{"subscription"}.catch and
        callback =? subscriptions.getCallback(id):
+      echo "[subscription handler] calling callback for id ", id
       callback(id, arguments)
-  client.setMethodHandler("eth_subscription", subscriptionHandler)
+  subscriptions.setMethodHandler("eth_subscription", subscriptionHandler)
   subscriptions
 
 method subscribeBlocks(subscriptions: WebSocketSubscriptions,
                        onBlock: BlockHandler):
                       Future[JsonNode]
                       {.async.} =
-  proc callback(id, arguments: JsonNode) =
-    if blck =? Block.fromJson(arguments["result"]).catch:
+  proc callback(id, arguments: JsonNode) {.raises: [].} =
+    if blck =? Block.fromJson(arguments{"result"}):
+      echo "[subscription.subscribeBlocks callback] calling onBlock callback with Block"
       onBlock(blck)
   let id = await subscriptions.client.eth_subscribe("newHeads")
   subscriptions.callbacks[id] = callback
@@ -79,13 +139,13 @@ method subscribeLogs(subscriptions: WebSocketSubscriptions,
                     Future[JsonNode]
                     {.async.} =
   proc callback(id, arguments: JsonNode) =
-    if log =? Log.fromJson(arguments["result"]).catch:
+    if log =? Log.fromJson(arguments{"result"}):
       onLog(log)
   let id = await subscriptions.client.eth_subscribe("logs", filter)
   subscriptions.callbacks[id] = callback
   return id
 
-method unsubscribe(subscriptions: WebSocketSubscriptions,
+method unsubscribe*(subscriptions: WebSocketSubscriptions,
                    id: JsonNode)
                   {.async.} =
   subscriptions.callbacks.del(id)
@@ -161,7 +221,7 @@ method subscribeLogs(subscriptions: PollingSubscriptions,
   subscriptions.callbacks[id] = callback
   return id
 
-method unsubscribe(subscriptions: PollingSubscriptions,
+method unsubscribe*(subscriptions: PollingSubscriptions,
                    id: JsonNode)
                   {.async.} =
   subscriptions.callbacks.del(id)