Remove refrence to SPIFFS global from persistence code, factor out persistence code so it can be re-used.

Author: rjwats

src/SettingsPersistence.h

@@ -0,0 +1,98 @@
+#ifndef SettingsPersistence_h
+#define SettingsPersistence_h
+
+#include <ESPAsyncWebServer.h>
+#include <FS.h>
+#include <AsyncJson.h>
+#include <ArduinoJson.h>
+#include <AsyncJsonRequestWebHandler.h>
+#include <AsyncJsonCallbackResponse.h>
+
+/**
+* At the moment, not expecting settings service to have to deal with large JSON
+* files this could be made configurable fairly simply, it's exposed on
+* AsyncJsonRequestWebHandler with a setter.
+*/
+#define MAX_SETTINGS_SIZE 1024
+
+/*
+* Mixin for classes which need to save settings to/from a file on the the file system as JSON.
+*/
+class SettingsPersistence {
+
+protected:
+
+  // will store and retrieve config from the file system
+  FS* _fs;
+
+  // the file path our settings will be saved to
+  char const* _filePath;
+
+  bool writeToFS() {
+    // create and populate a new json object
+    DynamicJsonBuffer jsonBuffer;
+    JsonObject& root = jsonBuffer.createObject();
+    writeToJsonObject(root);
+
+    // serialize it to filesystem
+    File configFile = _fs->open(_filePath, "w");
+
+    // failed to open file, return false
+    if (!configFile) {
+      return false;
+    }
+
+    root.printTo(configFile);
+    configFile.close();
+
+    return true;
+  }
+
+  void readFromFS(){
+    File configFile = _fs->open(_filePath, "r");
+
+    // use defaults if no config found
+    if (configFile) {
+      // Protect against bad data uploaded to file system
+      // We never expect the config file to get very large, so cap it.
+      size_t size = configFile.size();
+      if (size <= MAX_SETTINGS_SIZE) {
+        DynamicJsonBuffer jsonBuffer;
+        JsonObject& root = jsonBuffer.parseObject(configFile);
+        if (root.success()) {
+          readFromJsonObject(root);
+          configFile.close();
+          return;
+        }
+      }
+      configFile.close();
+    }
+
+    // If we reach here we have not been successful in loading the config,
+    // hard-coded emergency defaults are now applied.
+    applyDefaultConfig();
+  }
+
+
+    // serialization routene, from local config to JsonObject
+    virtual void readFromJsonObject(JsonObject& root){}
+    virtual void writeToJsonObject(JsonObject& root){}
+
+    // We assume the readFromJsonObject supplies sensible defaults if an empty object
+    // is supplied, this virtual function allows that to be changed.
+    virtual void applyDefaultConfig(){
+      DynamicJsonBuffer jsonBuffer;
+      JsonObject& root = jsonBuffer.createObject();
+      readFromJsonObject(root);
+    }
+
+  public:
+
+    SettingsPersistence(FS* fs, char const* servicePath, char const* filePath):
+      _fs(fs), _filePath(filePath) {}
+
+    virtual ~SettingsPersistence() {}
+
+};
+
+#endif // end SettingsPersistence

src/SettingsService.h

@@ -7,79 +7,24 @@
 #elif defined(ESP_PLATFORM)
   #include <WiFi.h>
   #include <AsyncTCP.h>
-  #include <SPIFFS.h>
 #endif
 
+#include <SettingsPersistence.h>
 #include <ESPAsyncWebServer.h>
-#include <FS.h>
 #include <AsyncJson.h>
 #include <ArduinoJson.h>
 #include <AsyncJsonRequestWebHandler.h>
 #include <AsyncJsonCallbackResponse.h>
 
-/**
-* At the moment, not expecting settings service to have to deal with large JSON
-* files this could be made configurable fairly simply, it's exposed on
-* AsyncJsonRequestWebHandler with a setter.
-*/
-#define MAX_SETTINGS_SIZE 1024
-
 /*
-* Abstraction of a service which stores it's settings as JSON in SPIFFS.
+* Abstraction of a service which stores it's settings as JSON in a file system.
 */
-class SettingsService {
+class SettingsService : public SettingsPersistence {
 
 private:
 
-  char const* _filePath;
-
   AsyncJsonRequestWebHandler _updateHandler;
 
-  bool writeToSPIFFS() {
-    // create and populate a new json object
-    DynamicJsonBuffer jsonBuffer;
-    JsonObject& root = jsonBuffer.createObject();
-    writeToJsonObject(root);
-
-    // serialize it to SPIFFS
-    File configFile = SPIFFS.open(_filePath, "w");
-
-    // failed to open file, return false
-    if (!configFile) {
-      return false;
-    }
-
-    root.printTo(configFile);
-    configFile.close();
-
-    return true;
-  }
-
-  void readFromSPIFFS(){
-    File configFile = SPIFFS.open(_filePath, "r");
-
-    // use defaults if no config found
-    if (configFile) {
-      // Protect against bad data uploaded to SPIFFS
-      // We never expect the config file to get very large, so cap it.
-      size_t size = configFile.size();
-      if (size <= MAX_SETTINGS_SIZE) {
-        DynamicJsonBuffer jsonBuffer;
-        JsonObject& root = jsonBuffer.parseObject(configFile);
-        if (root.success()) {
-          readFromJsonObject(root);
-          configFile.close();
-          return;
-        }
-      }
-      configFile.close();
-    }
-
-    // If we reach here we have not been successful in loading the config,
-    // hard-coded emergency defaults are now applied.
-    applyDefaultConfig();
-  }
-
   void fetchConfig(AsyncWebServerRequest *request){
     AsyncJsonResponse * response = new AsyncJsonResponse();
     writeToJsonObject(response->getRoot());
@@ -91,7 +36,7 @@ class SettingsService {
     if (json.is<JsonObject>()){
       JsonObject& newConfig = json.as<JsonObject>();
       readFromJsonObject(newConfig);
-      writeToSPIFFS();
+      writeToFS();
 
       // write settings back with a callback to reconfigure the wifi
       AsyncJsonCallbackResponse * response = new AsyncJsonCallbackResponse([this] () {onConfigUpdated();});
@@ -108,28 +53,13 @@ class SettingsService {
     // will serve setting endpoints from here
     AsyncWebServer* _server;
 
-    // will store and retrieve config from the file system
-    FS* _fs;
-
-    // reads the local config from the
-    virtual void readFromJsonObject(JsonObject& root){}
-    virtual void writeToJsonObject(JsonObject& root){}
-
     // implement to perform action when config has been updated
     virtual void onConfigUpdated(){}
 
-    // We assume the readFromJsonObject supplies sensible defaults if an empty object
-    // is supplied, this virtual function allows that to be changed.
-    virtual void applyDefaultConfig(){
-      DynamicJsonBuffer jsonBuffer;
-      JsonObject& root = jsonBuffer.createObject();
-      readFromJsonObject(root);
-    }
-
   public:
 
     SettingsService(AsyncWebServer* server, FS* fs, char const* servicePath, char const* filePath):
-    _filePath(filePath), _server(server), _fs(fs){
+      SettingsPersistence(fs, servicePath, filePath), _server(server) {
 
       // configure fetch config handler
       _server->on(servicePath, HTTP_GET, std::bind(&SettingsService::fetchConfig, this, std::placeholders::_1));
@@ -145,7 +75,7 @@ class SettingsService {
     virtual ~SettingsService() {}
 
     virtual void begin() {
-      readFromSPIFFS();
+      readFromFS();
     }
 
 };