EpoxyFS

EpoxyFS

An implementation of the FS filesystem interface for ESP8266 (https://arduino-esp8266.readthedocs.io/en/latest/filesystem.html) that runs on a Linux (and hopefully on a MacOS) machine using EpoxyDuino.

Usage

The FS class in EpoxyFS is compatible with the FS class on the ESP8266 platform. Unfortunately, the FS class under the ESP32 is slightly different. This means that we cannot use FS as a common interface across platforms. Instead we use a #define FILE_SYSTEM to set the correct file system instance, and use FILE_SYSTEM everywhere where we would have used a LittleFS, or LITTLEFS or fs::EpoxyFS instance.

#include <Arduino.h>

#if defined(EPOXY_DUINO)
  #include <EpoxyFS.h>
  #define FILE_SYSTEM fs::EpoxyFS
#elif defined(ESP8266)
  #include <LittleFS.h>
  #define FILE_SYSTEM LittleFS
#elif defined(ESP32)
  #include <LITTLEFS.h>
  #define FILE_SYSTEM LITTLEFS
#else
  #error Unsupported platform
#endif

void doStuff() {
}
  
void setup() {
  SERIAL_PORT_MONITOR.begin(115200);
  while (!SERIAL_PORT_MONITOR); // For Leonardo/Micro
  ...

  if (FILE_SYSTEM.begin()){
    SERIAL_PORT_MONITOR.println(F("Filesystem initialized."));
  } else {
    SERIAL_PORT_MONITOR.println(F("Filesystem failed."));
  }
  ...
}

void loop() {
  ...
}

Root of the File System

By default, the root of the file system is located in a directory named ./epoxyfsdata in the current directory. This location can be changed by setting the

• EPOXY_FS_ROOT

environment variable. For example, setting

• $ export EPOXY_FS_ROOT=/tmp/epoxyfsdata

sets the root to the /tmp/epoxyfsdata directory.

DANGER: The EpoxyFS::format() method creates a blank file system. To achieve that, the method recursively removes all files and directories under the EPOXY_FS_ROOT directory. If you set the EPOXY_FS_ROOT to an incorrect value, you may remove a lot of files quickly and permanently. Be very careful!

Bugs and LImitation

• A number of functions and methods are not yet implemented. See the TODO notes in src/EpoxyFS.h.
• I have not tested all of the FS::open() modes: "r", "w", "a", "r+" etc.
• The document for ESP8266 Filesystem says that "Subdirectories are automatically created when you attempt to create a file in a subdirectory, and when the last file in a subdirectory is removed the subdirectory itself is automatically deleted. This is because there was no mkdir() method in the existing SPIFFS filesystem."
  • This has not been implemented in EpoxyFS.