Subscribe to logs with polling

ethers/providers/jsonrpc/signatures.nim

@@ -16,5 +16,6 @@ proc eth_subscribe(name: string, filter: Filter): JsonNode
 proc eth_subscribe(name: string): JsonNode
 proc eth_unsubscribe(id: JsonNode): bool
 proc eth_newBlockFilter(): JsonNode
+proc eth_newFilter(filter: Filter): JsonNode
 proc eth_getFilterChanges(id: JsonNode): JsonNode
 proc eth_uninstallFilter(id: JsonNode): bool

ethers/providers/jsonrpc/subscriptions.nim

@@ -146,6 +146,20 @@ method subscribeBlocks(subscriptions: PollingSubscriptions,
   subscriptions.callbacks[id] = callback
   return JsonRpcSubscription(subscriptions: subscriptions, id: id)
 
+method subscribeLogs(subscriptions: PollingSubscriptions,
+                     filter: Filter,
+                     onLog: LogHandler):
+                    Future[JsonRpcSubscription]
+                    {.async.} =
+
+  proc callback(id, change: JsonNode) =
+    if log =? Log.fromJson(change).catch:
+      onLog(log)
+
+  let id = await subscriptions.client.eth_newFilter(filter)
+  subscriptions.callbacks[id] = callback
+  return JsonRpcSubscription(subscriptions: subscriptions, id: id)
+
 method unsubscribe(subscriptions: PollingSubscriptions,
                    id: JsonNode)
                   {.async.} =