Add web page that allows configuration of the latitude, longitude and…

… RGB LED type.

config.cpp

@@ -0,0 +1,108 @@
+#include <Arduino.h>
+#include <ArduinoJson.h>
+
+#include "config.h"
+
+static FS *_fs;
+static StaticJsonDocument < 1024 > _jsonDoc;
+static String _config_name;
+static String _config_path;
+static String _config_page;
+static int _version = 0;
+
+static String template_processor(const String & string)
+{
+    // replace according to pattern "propName:propValue?replacement"
+    int i = string.indexOf("?");
+    if (i >= 0) {
+        String property = string.substring(0, i);
+        String replacement = string.substring(i + 1);
+        i = property.indexOf(":");
+        if (i >= 0) {
+            // split property in name and matching value
+            String propName = property.substring(0, i);
+            String propValue = property.substring(i + 1);
+            String actual = _jsonDoc[propName] | "";
+            if (actual == propValue) {
+                return replacement;
+            }
+        }
+    }
+    // try regular match
+    return _jsonDoc[string] | "";
+}
+
+static void handleGetConfig(AsyncWebServerRequest *request)
+{
+    // read the config file in preparation of presentation in the web UI
+    config_load();
+
+    // serve the config page from flash
+    request->send(*_fs, _config_page, "text/html", false, template_processor);
+}
+
+static void handlePostConfig(AsyncWebServerRequest *request)
+{
+    // put all parameters in the JSON document
+    for (size_t i = 0; i < request->params(); i++) {
+        const AsyncWebParameter *param = request->getParam(i);
+        String name = param->name();
+        String value = param->value();
+        _jsonDoc[name] = value;
+    }
+
+    // write the config file
+    config_save();
+
+    // redirect to page with values
+    request->redirect(_config_path);
+}
+
+void config_begin(FS & fs, String config_name)
+{
+    _fs = &fs;
+    _config_name = config_name; // e.g. "config.json"
+}
+
+void config_serve(AsyncWebServer & server, const char *config_path, const char *config_page)
+{
+    _config_path = config_path; // e.g. "/config"
+    _config_page = config_page; // e.g "/config.html"
+
+    // register ourselves with the server
+    server.on(config_path, HTTP_GET, handleGetConfig);
+    server.on(config_path, HTTP_POST, handlePostConfig);
+}
+
+bool config_load(void)
+{
+    File file = _fs->open(_config_name, "r");
+    DeserializationError error = deserializeJson(_jsonDoc, file);
+    file.close();
+    return error == DeserializationError::Ok;
+}
+
+bool config_save(void)
+{
+    File file = _fs->open(_config_name, "w");
+    size_t size = serializeJson(_jsonDoc, file);
+    file.close();
+    _version++;
+    return size > 0;
+}
+
+void config_set_value(String propName, String propValue)
+{
+    _jsonDoc[propName] = propValue;
+}
+
+String config_get_value(String propName)
+{
+    return _jsonDoc[propName] | "";
+}
+
+int config_get_version(void)
+{
+    return _version;
+}
+

config.h

@@ -0,0 +1,16 @@
+#include <stdbool.h>
+
+#include <FS.h>
+#include <ESPAsyncWebServer.h>
+
+void config_begin(FS &fs, String config_name);
+
+bool config_load(void);
+bool config_save(void);
+
+void config_serve(AsyncWebServer &server, const char *config_path, const char *config_page);
+
+void config_set_value(String propName, String propValue);
+String config_get_value(String propName);
+
+int config_get_version(void);