Add display history REST API

include/Display_Graphic_Diagram.h

@@ -16,12 +16,14 @@ class DisplayGraphicDiagramClass {
 
     void updatePeriod();
 
+    const std::array<float, MAX_DATAPOINTS>& getGraphValues() const;
+    uint8_t getGraphValuesCount() const;
+    uint32_t getSecondsPerDot() const;
+
 private:
     void averageLoop();
     void dataPointLoop();
 
-    uint32_t getSecondsPerDot();
-
     Task _averageTask;
     Task _dataPointTask;
 

include/WebApi.h

@@ -3,6 +3,7 @@
 
 #include "WebApi_device.h"
 #include "WebApi_devinfo.h"
+#include "WebApi_display.h"
 #include "WebApi_dtu.h"
 #include "WebApi_errors.h"
 #include "WebApi_eventlog.h"
@@ -50,6 +51,7 @@ class WebApiClass {
 
     WebApiDeviceClass _webApiDevice;
     WebApiDevInfoClass _webApiDevInfo;
+    WebApiDisplayClass _webApiDisplay;
     WebApiDtuClass _webApiDtu;
     WebApiEventlogClass _webApiEventlog;
     WebApiFileClass _webApiFile;

include/WebApi_display.h

@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#pragma once
+
+#include <ESPAsyncWebServer.h>
+#include <TaskSchedulerDeclarations.h>
+
+class WebApiDisplayClass {
+public:
+    void init(AsyncWebServer& server, Scheduler& scheduler);
+
+private:
+    void onDisplayHistory(AsyncWebServerRequest* request);
+};

src/Display_Graphic_Diagram.cpp

@@ -47,7 +47,17 @@ void DisplayGraphicDiagramClass::dataPointLoop()
     }
 }
 
-uint32_t DisplayGraphicDiagramClass::getSecondsPerDot()
+const std::array<float, MAX_DATAPOINTS>& DisplayGraphicDiagramClass::getGraphValues() const
+{
+    return _graphValues;
+}
+
+uint8_t DisplayGraphicDiagramClass::getGraphValuesCount() const
+{
+    return _graphValuesCount;
+}
+
+uint32_t DisplayGraphicDiagramClass::getSecondsPerDot() const
 {
     return Configuration.get().Display.Diagram.Duration / _chartWidth;
 }

src/WebApi.cpp

@@ -19,6 +19,7 @@ void WebApiClass::init(Scheduler& scheduler)
 {
     _webApiDevice.init(_server, scheduler);
     _webApiDevInfo.init(_server, scheduler);
+    _webApiDisplay.init(_server, scheduler);
     _webApiDtu.init(_server, scheduler);
     _webApiEventlog.init(_server, scheduler);
     _webApiFile.init(_server, scheduler);

src/WebApi_display.cpp

@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2022-2026 Thomas Basler and others
+ */
+#include "WebApi_display.h"
+#include "Display_Graphic.h"
+#include "WebApi.h"
+#include <AsyncJson.h>
+
+void WebApiDisplayClass::init(AsyncWebServer& server, Scheduler& scheduler)
+{
+    using std::placeholders::_1;
+
+    server.on("/api/display/history", HTTP_GET, static_cast<ArRequestHandlerFunction>(std::bind(&WebApiDisplayClass::onDisplayHistory, this, _1)));
+}
+
+void WebApiDisplayClass::onDisplayHistory(AsyncWebServerRequest* request)
+{
+    if (!WebApi.checkCredentialsReadonly(request)) {
+        return;
+    }
+
+    AsyncJsonResponse* response = new AsyncJsonResponse();
+    auto& root = response->getRoot();
+
+    JsonArray values = root["values"].to<JsonArray>();
+    const auto& graphValues = Display.Diagram().getGraphValues();
+    const uint8_t graphValuesCount = Display.Diagram().getGraphValuesCount();
+    for (uint8_t i = 0; i < graphValuesCount; i++) {
+        values.add(graphValues[i]);
+    }
+
+    root["values_count"] = graphValuesCount;
+    root["seconds_per_dot"] = Display.Diagram().getSecondsPerDot();
+
+    WebApi.sendJsonResponse(request, response, __FUNCTION__, __LINE__);
+}