Fix block subscription

ethers/providers/jsonrpc.nim

@@ -164,6 +164,18 @@ proc subscribe(provider: JsonRpcProvider,
 
     return JsonRpcSubscription(id: id, provider: provider)
 
+proc subscribe(provider: JsonRpcProvider,
+               name: string,
+               handler: SubscriptionHandler): Future[Subscription] {.async.} =
+  convertError:
+    let client = await provider.client
+    doAssert client of RpcWebSocketClient, "subscriptions require websockets"
+
+    let id = await client.eth_subscribe(name)
+    provider.subscriptions[id] = handler
+
+    return JsonRpcSubscription(id: id, provider: provider)
+
 method subscribe*(provider: JsonRpcProvider,
                   filter: Filter,
                   callback: LogHandler):
@@ -179,7 +191,7 @@ method subscribe*(provider: JsonRpcProvider,
   proc handler(id, arguments: JsonNode) {.async.} =
     if blck =? Block.fromJson(arguments["result"]).catch:
       await callback(blck)
-  return await provider.subscribe("newHeads", Filter.none, handler)
+  return await provider.subscribe("newHeads", handler)
 
 method unsubscribe*(subscription: JsonRpcSubscription) {.async.} =
   convertError:

ethers/providers/jsonrpc/signatures.nim

@@ -10,5 +10,6 @@ proc eth_chainId(): UInt256
 proc eth_sendTransaction(transaction: Transaction): TransactionHash
 proc eth_getTransactionReceipt(hash: TransactionHash): ?TransactionReceipt
 proc eth_sign(account: Address, message: seq[byte]): seq[byte]
-proc eth_subscribe(name: string, filter = Filter.none): JsonNode
+proc eth_subscribe(name: string, filter: ?Filter): JsonNode
+proc eth_subscribe(name: string): JsonNode
 proc eth_unsubscribe(id: JsonNode): bool