Implemented client datasource

Source/Applications/StreamHub/StreamHub.cpp

@@ -255,13 +255,27 @@ bool StreamHub::Run() {
             PushStats();
         }
 
-        /* History: flush headers periodically */
+        /* History: flush headers at the configured interval, then re-broadcast
+         * historyInfo so new clients (or clients that saw empty signal lists
+         * before the first data was written) pick up the current state. */
         if (history_.IsEnabled()) {
-            uint32 histFlushDiv = history_.Decimation() > 0u
-                ? pushRateHz_ * 5u : pushRateHz_ * 5u; /* every 5s */
-            if (histFlushDiv == 0u) { histFlushDiv = 1u; }
-            if ((tickCount_ % histFlushDiv) == 0u) {
+            uint32 flushIntervalTicks = pushRateHz_ * 5u; /* default 5 s */
+            if (pushRateHz_ > 0u) {
+                flushIntervalTicks = pushRateHz_ * 5u;
+            }
+            if (flushIntervalTicks == 0u) { flushIntervalTicks = 1u; }
+            if ((tickCount_ % flushIntervalTicks) == 0u) {
                 history_.FlushHeaders();
+                /* Re-broadcast so clients see updated signal counts and
+                 * time ranges after the first batch of data is written. */
+                uint32 cap2 = 8192u;
+                char  *hbuf = new char[cap2];
+                uint32 hoff = 0u;
+                JsonAppendf(hbuf, hoff, cap2, "{\"type\":\"historyInfo\",");
+                history_.AppendInfoJSON(hbuf, hoff, cap2);
+                JsonAppendf(hbuf, hoff, cap2, "}");
+                wsServer_.BroadcastText(hbuf, hoff);
+                delete[] hbuf;
             }
         }
 
@@ -648,6 +662,14 @@ void StreamHub::OnWSClientConnected() {
         wsServer_.BroadcastText(hbuf, hoff);
         delete[] hbuf;
     }
+
+    /* Inform the new client about the current MaxPoints setting. */
+    {
+        char mp[64];
+        int n = snprintf(mp, sizeof(mp),
+            "{\"type\":\"maxPointsUpdated\",\"maxPoints\":%u}", maxPoints_);
+        if (n > 0) { wsServer_.BroadcastText(mp, static_cast<uint32>(n)); }
+    }
 }
 
 void StreamHub::OnWSClientDisconnected() {