RPC: Add new getzmqnotifications method.

This adds a new RPC method "getzmqnotifications", which returns
information about all active ZMQ notification endpoints.  This is useful
for software that layers on top of bitcoind, so it can verify that
ZeroMQ is enabled and also figure out where it should listen.

See https://github.com/bitcoin/bitcoin/issues/13526.

1 files changed, 10 insertions, 1 deletions

diff --git a/src/zmq/zmqnotificationinterface.cpp b/src/zmq/zmqnotificationinterface.cpp
index 89ae62f4c..8cbc96997 100644
--- a/src/zmq/zmqnotificationinterface.cpp
+++ b/src/zmq/zmqnotificationinterface.cpp
@@ -1,4 +1,4 @@
-// Copyright (c) 2015-2017 The Bitcoin Core developers
+// Copyright (c) 2015-2018 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -29,6 +29,15 @@ CZMQNotificationInterface::~CZMQNotificationInterface()
     }
 }
 
+std::list<const CZMQAbstractNotifier*> CZMQNotificationInterface::GetActiveNotifiers() const
+{
+    std::list<const CZMQAbstractNotifier*> result;
+    for (const auto* n : notifiers) {
+        result.push_back(n);
+    }
+    return result;
+}
+
 CZMQNotificationInterface* CZMQNotificationInterface::Create()
 {
     CZMQNotificationInterface* notificationInterface = nullptr;