ESPFlash

An abstraction layer that simplifies the storing of vectorised data in the filesystem on the ESP8266 and ESP32.

ESPFlash is a lightweight library that was created to make SPIFFS usage simple and easy to understand on the ESP8266 and ESP32.

Features

• Simple template based interface to store and retrieve generic vectorised data in flash memory using SPIFFS with ESPFlash.
• Implementation of simple SPIFFS based integer counter with ESPFlashCounter.
• Implementation of simple SPIFFS based string storer using ESPFlashString.

Why Would I Want This?

• ESPFlash enables the storage of generic data in a persistant matter. This is data that will exist through multiple power cycles or software resets.
• ESPFlash takes care of a lot of the nastiness that exists when using SPIFFS using the concept of vectorised data. This includes the following functionailty:
  • Automatically starts SPIFFS if it has not already been started.
  • Automatically truncates filenames that are over 32 characters in length.
  • Calculates the number of generic "elements" stored in a file.
  • Overwrites elements.
  • Appends elements.
  • Gets elements.
  • Clears elements.

One Thing to Keep In Mind

SPIFFS is not particularly fast. It is not designed to be used in a manner that requires high-throughput data input/output. ESPFlash does not significantly increase the performance issues of SPIFFS, but you should consider if SPIFFS usage is suitable for your application.

Installation

Download this file as a zip, and extract the resulting folder into your Arduino Libraries folder. See Installing Additional Arduino Libraries. Alternatively, use the Arduino IDE and library manager to find and install ESPFlash.

Examples

The blog post ESPFlash: An Arduino Library for Storing Data in the ESP Filesystem contains some useful comparisons between ESPFlash usage and SPIFFS usage. In addition, here are some basic ESPFlash example:

• Simple ESPFlash integer example - Create ESPFlash instance with file name of "exampleInteger". Set a single elements value, and get it back.

SPIFFS.begin()
ESPFlash<int> espFlashInteger("/exampleInteger");
espFlashInteger.set(10);
int testInteger = espFlashInteger.get();

• Simple ESPFlash vector example - Create ESPFlash instance with file name of "exampleInteger". Append 10 randomly generated elements. Get the elements back.

SPIFFS.begin()
ESPFlash<int> espFlashInteger("/exampleArray");
for(int ii = 0; ii < 10; ii++)
{
  espFlashInteger.append(random(100));
}
int testGet[10];
espFlashInteger.getFrontElements(testGet, sizeof(testGet));

• Simple ESPFlash vector example - Create ESPFlash instance with file name of "exampleInteger". Append 50 randomly generated elements. Get the last 10 elements back.

SPIFFS.begin()
ESPFlash<int> espFlashInteger("/exampleArray");
for(int ii = 0; ii < 50; ii++)
{
  espFlashInteger.append(random(100));
}
int testGet[10];
espFlashInteger.getBackElements(testGet, sizeof(testGet));

• Simple ESPFlashCounter example - Create ESPFlashCounter instance with file name of "exampleCounter". Increment the counter. Get the Counter

SPIFFS.begin()
ESPFlashCounter exampleCounter("/exampleCounter");
exampleCounter.increment();
int testGet = exampleCounter.get();

• Simple ESPFlashString example - Create ESPFlashString instance with file name of "exampleString". Set a string. Get the string.

SPIFFS.begin()
ESPFlashCounter exampleString("/exampleString");
exampleString.set("Hello!");
String string = exampleString.get();

Further Examples

millisArray.ino

powerCycleCounter.ino

ssidStorage.ino