RPC: Add new "getzmqnotifications" method.

Cherry-picked from Bitcoin Core.

src/Makefile.am

@@ -179,7 +179,8 @@ BITCOIN_CORE_H = \
   zmq/zmqabstractnotifier.h \
   zmq/zmqconfig.h\
   zmq/zmqnotificationinterface.h \
-  zmq/zmqpublishnotifier.h
+  zmq/zmqpublishnotifier.h \
+  zmq/zmqrpc.h
 
 BITCOIN_CORE_H += \
   keva/main.h \
@@ -243,7 +244,8 @@ libbitcoin_zmq_a_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 libbitcoin_zmq_a_SOURCES = \
   zmq/zmqabstractnotifier.cpp \
   zmq/zmqnotificationinterface.cpp \
-  zmq/zmqpublishnotifier.cpp
+  zmq/zmqpublishnotifier.cpp \
+  zmq/zmqrpc.cpp
 endif
 
 

src/init.cpp

@@ -65,6 +65,7 @@
 
 #if ENABLE_ZMQ
 #include <zmq/zmqnotificationinterface.h>
+#include <zmq/zmqrpc.h>
 #endif
 
 #ifdef USE_SSE2
@@ -79,9 +80,6 @@ static const bool DEFAULT_STOPAFTERBLOCKIMPORT = false;
 std::unique_ptr<CConnman> g_connman;
 std::unique_ptr<PeerLogicValidation> peerLogic;
 
-#if ENABLE_ZMQ
-static CZMQNotificationInterface* pzmqNotificationInterface = nullptr;
-#endif
 
 #ifdef WIN32
 // Win32 LevelDB doesn't use filedescriptors, and the ones used for
@@ -257,10 +255,10 @@ void Shutdown()
 #endif
 
 #if ENABLE_ZMQ
-    if (pzmqNotificationInterface) {
-        UnregisterValidationInterface(pzmqNotificationInterface);
-        delete pzmqNotificationInterface;
-        pzmqNotificationInterface = nullptr;
+    if (g_zmq_notification_interface) {
+        UnregisterValidationInterface(g_zmq_notification_interface);
+        delete g_zmq_notification_interface;
+        g_zmq_notification_interface = nullptr;
     }
 #endif
 
@@ -1260,6 +1258,9 @@ bool AppInitMain()
      * available in the GUI RPC console even if external calls are disabled.
      */
     RegisterAllCoreRPCCommands(tableRPC);
+#if ENABLE_ZMQ
+    RegisterZMQRPCCommands(tableRPC);
+#endif
 #ifdef ENABLE_WALLET
     RegisterWalletRPC(tableRPC);
 #endif
@@ -1388,10 +1389,10 @@ bool AppInitMain()
     }
 
 #if ENABLE_ZMQ
-    pzmqNotificationInterface = CZMQNotificationInterface::Create();
+    g_zmq_notification_interface = CZMQNotificationInterface::Create();
 
-    if (pzmqNotificationInterface) {
-        RegisterValidationInterface(pzmqNotificationInterface);
+    if (g_zmq_notification_interface) {
+        RegisterValidationInterface(g_zmq_notification_interface);
     }
 #endif
     uint64_t nMaxOutboundLimit = 0; //unlimited unless -maxuploadtarget is set

src/zmq/zmqnotificationinterface.cpp

@@ -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;
@@ -180,3 +189,5 @@ void CZMQNotificationInterface::BlockDisconnected(const std::shared_ptr<const CB
         TransactionAddedToMempool(ptx);
     }
 }
+
+CZMQNotificationInterface* g_zmq_notification_interface = nullptr;

src/zmq/zmqnotificationinterface.h

@@ -18,6 +18,8 @@ class CZMQNotificationInterface final : public CValidationInterface
 public:
     virtual ~CZMQNotificationInterface();
 
+    std::list<const CZMQAbstractNotifier*> GetActiveNotifiers() const;
+
     static CZMQNotificationInterface* Create();
 
 protected:
@@ -37,4 +39,6 @@ private:
     std::list<CZMQAbstractNotifier*> notifiers;
 };
 
+extern CZMQNotificationInterface* g_zmq_notification_interface;
+
 #endif // BITCOIN_ZMQ_ZMQNOTIFICATIONINTERFACE_H

src/zmq/zmqrpc.cpp

@@ -0,0 +1,61 @@
+// Copyright (c) 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.
+
+#include <zmq/zmqrpc.h>
+
+#include <rpc/server.h>
+#include <zmq/zmqabstractnotifier.h>
+#include <zmq/zmqnotificationinterface.h>
+
+#include <univalue.h>
+
+namespace {
+
+UniValue getzmqnotifications(const JSONRPCRequest& request)
+{
+    if (request.fHelp || request.params.size() != 0) {
+        throw std::runtime_error(
+            "getzmqnotifications\n"
+            "\nReturns information about the active ZeroMQ notifications.\n"
+            "\nResult:\n"
+            "[\n"
+            "  {                        (json object)\n"
+            "    \"type\": \"pubhashtx\",   (string) Type of notification\n"
+            "    \"address\": \"...\"       (string) Address of the publisher\n"
+            "  },\n"
+            "  ...\n"
+            "]\n"
+            "\nExamples:\n"
+            + HelpExampleCli("getzmqnotifications", "")
+            + HelpExampleRpc("getzmqnotifications", "")
+        );
+    }
+
+    UniValue result(UniValue::VARR);
+    if (g_zmq_notification_interface != nullptr) {
+        for (const auto* n : g_zmq_notification_interface->GetActiveNotifiers()) {
+            UniValue obj(UniValue::VOBJ);
+            obj.pushKV("type", n->GetType());
+            obj.pushKV("address", n->GetAddress());
+            result.push_back(obj);
+        }
+    }
+
+    return result;
+}
+
+const CRPCCommand commands[] =
+{ //  category              name                                actor (function)                argNames
+  //  -----------------     ------------------------            -----------------------         ----------
+    { "zmq",                "getzmqnotifications",              &getzmqnotifications,           {} },
+};
+
+} // anonymous namespace
+
+void RegisterZMQRPCCommands(CRPCTable& t)
+{
+    for (const auto& c : commands) {
+        t.appendCommand(c.name, &c);
+    }
+}

src/zmq/zmqrpc.h

@@ -0,0 +1,12 @@
+// Copyright (c) 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.
+
+#ifndef BITCOIN_ZMQ_ZMQRPC_H
+#define BITCOIN_ZMQ_ZMQRPC_H
+
+class CRPCTable;
+
+void RegisterZMQRPCCommands(CRPCTable& t);
+
+#endif // BITCOIN_ZMQ_ZMRRPC_H

test/functional/rpc_zmq.py

@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+# Copyright (c) 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.
+"""Test for the ZMQ RPC methods."""
+
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import assert_equal
+
+
+class RPCZMQTest(BitcoinTestFramework):
+
+    address = "tcp://127.0.0.1:28332"
+
+    def set_test_params(self):
+        self.num_nodes = 1
+        self.setup_clean_chain = True
+
+    def run_test(self):
+        self._test_getzmqnotifications()
+
+    def _test_getzmqnotifications(self):
+        self.restart_node(0, extra_args=[])
+        assert_equal(self.nodes[0].getzmqnotifications(), [])
+
+        self.restart_node(0, extra_args=["-zmqpubhashtx=%s" % self.address])
+        assert_equal(self.nodes[0].getzmqnotifications(), [
+            {"type": "pubhashtx", "address": self.address},
+        ])
+
+
+if __name__ == '__main__':
+    RPCZMQTest().main()
+

test/functional/test_runner.py

@@ -115,6 +115,7 @@ BASE_SCRIPTS= [
     'feature_versionbits_warning.py',
     'rpc_preciousblock.py',
     'wallet_importprunedfunds.py',
+    'rpc_zmq.py',
     'rpc_signmessage.py',
     'feature_nulldummy.py',
     'wallet_import_rescan.py',