PVA: Open server info API

core/pva/src/main/java/org/epics/pva/client/PVAClientMain.java

@@ -8,6 +8,7 @@
 package org.epics.pva.client;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
@@ -17,9 +18,11 @@
 import java.util.logging.Level;
 import java.util.logging.LogManager;
 import java.util.logging.Logger;
+import java.util.stream.Collectors;
 
 import org.epics.pva.PVASettings;
 import org.epics.pva.data.PVAData;
+import org.epics.pva.data.PVAStructure;
 
 /** Command line tool for PVA client
  *
@@ -37,9 +40,17 @@ public class PVAClientMain
     private static boolean completion = false;
     private static String request = "";
 
+    /** Commands */
+    private static enum Cmd
+    {
+        info, get, monitor, put, call, beacons
+    }
+
     private static void help()
     {
-        System.out.println("USAGE: pvaclient info|get|monitor|put|beacons [options] <PV name>...");
+        System.out.println("USAGE: pvaclient " +
+            Arrays.stream(Cmd.values()).map(Object::toString).collect(Collectors.joining("|")) +
+            " [options] <PV name>...");
         System.out.println();
         System.out.println("Options:");
         System.out.println("  -h             Help");
@@ -54,6 +65,7 @@ private static void help()
         System.out.println("get     <PV name>          Read PV's value");
         System.out.println("monitor <PV name>          Subscribe to PV's value changes");
         System.out.println("put     <PV name> <value>  Write value to PV");
+        System.out.println("call    <PV name>          Call RPC PV (no request params)");
         System.out.println("beacons                    Display received beacons");
     }
 
@@ -240,6 +252,36 @@ private static void put(final String name, final String value) throws Exception
         }
     }
 
+    private static void call(final String name, final PVAStructure request) throws Exception
+    {
+        try (final PVAClient pva = new PVAClient())
+        {
+            final CountDownLatch connected = new CountDownLatch(1);
+            final PVAChannel pv = pva.getChannel(name, (ch, state) ->
+            {
+                if (state == ClientChannelState.CONNECTED)
+                    connected.countDown();
+            });
+            final long timeout_ms = Math.round(seconds*1000);
+            if (! connected.await(timeout_ms, TimeUnit.MILLISECONDS))
+            {
+                System.err.println("Timeout waiting for " + name);
+                return;
+            }
+
+            try
+            {
+                PVAStructure result = pv.invoke(request).get(timeout_ms, TimeUnit.MILLISECONDS);
+                System.out.println(result);
+            }
+            catch (TimeoutException ex)
+            {
+                System.err.println("Call timed out");
+            }
+            pv.close();
+        }
+    }
+
     /** Watch received beacons
      *  @throws Exception on error
      */
@@ -336,21 +378,27 @@ else if (arg.startsWith("-"))
 
         final String command = names.remove(0);
 
-        if (command.equals("beacons") && names.size() == 0)
+        if (command.equals(Cmd.beacons.name()) && names.size() == 0)
             beacons();
-        else if (command.equals("info") && names.size() > 0)
+        else if (command.equals(Cmd.info.name()) && names.size() > 0)
             info(names);
-        else if (command.equals("get") && names.size() > 0)
+        else if (command.equals(Cmd.get.name()) && names.size() > 0)
             get(names);
-        else if (command.equals("monitor") && names.size() > 0)
+        else if (command.equals(Cmd.monitor.name()) && names.size() > 0)
             monitor(names);
-        else if (command.equals("put") && names.size() == 2)
+        else if (command.equals(Cmd.put.name()) && names.size() == 2)
         {
             // By default, write to the 'value' element data structure
             if (request.isEmpty())
                 request = "value";
             put(names.get(0), names.get(1));
         }
+        else if (command.equals(Cmd.call.name()) && names.size() > 0)
+        {
+            // For now not supporting any request detail from cmdline
+            PVAStructure request = new PVAStructure("", "");
+            call(names.get(0), request);
+        }
         else
             help();
     }

core/pva/src/main/java/org/epics/pva/data/nt/PVATable.java

@@ -48,9 +48,9 @@
  */
 public class PVATable extends PVAStructure {
     public static final String STRUCT_NAME = "epics:nt/NTTable:1.0";
-    private static final String LABELS_NAME = "labels";
-    private static final String VALUE_NAME = "value";
-    private static final String DESCRIPTOR_NAME = "descriptor";
+    public static final String LABELS_NAME = "labels";
+    public static final String VALUE_NAME = "value";
+    public static final String DESCRIPTOR_NAME = "descriptor";
 
     private final PVAStringArray labels;
     private final PVAStructure value;

core/pva/src/main/java/org/epics/pva/server/PVAServer.java

@@ -10,6 +10,7 @@
 import static org.epics.pva.PVASettings.logger;
 
 import java.net.InetSocketAddress;
+import java.util.Collection;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentHashMap.KeySetView;
 import java.util.concurrent.ForkJoinPool;
@@ -161,6 +162,26 @@ ServerPV getPV(final int sid)
         return pv_by_sid.get(sid);
     }
 
+
+    /** Info about a client to the PVA server:
+     *  Network address and authentication info
+     */
+    public static record ClientInfo(InetSocketAddress address,
+                                    ServerAuth authentication)
+    {
+    }
+
+    /** Get information about clients to this PVA server
+     *  @return {@link ClientInfo}s
+     */
+    public Collection<ClientInfo> getClientInfos()
+    {
+        return tcp_handlers.stream()
+                           .map(tcp -> new ClientInfo(tcp.getRemoteAddress(),
+                                                      tcp.getAuth()))
+                           .toList();
+    }
+
     /** Special address used in TCP search reply to indicate "Use this TCP connection" */
     private static final InetSocketAddress USE_THIS_TCP_CONNECTION = new InetSocketAddress(0);
 

core/pva/src/main/java/org/epics/pva/server/ServerAuth.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2019-2023 Oak Ridge National Laboratory.
+ * Copyright (c) 2019-2025 Oak Ridge National Laboratory.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -20,7 +20,7 @@
  *  @author Kay Kasemir
  */
 @SuppressWarnings("nls")
-abstract class ServerAuth
+public abstract class ServerAuth
 {
     /** @param channel Channel for which to check write access
      *  @return Does client have write access?
@@ -62,7 +62,7 @@ public static ServerAuth decode(final ServerTCPHandler tcp, final ByteBuffer buf
 
         if (PVAAuth.X509.equals(auth))
             return new X509ServerAuth(tls_info);
-        
+
         return Anonymous;
     }