littlefs | A little fail-safe filesystem designed for microcontrollers

I'm using an esp32 microcontroller for my web server backend. I use a template processor function to build the page on the backend because i can't use more then 8 socket connection because the MCU will crash.

In order to load my page faster, i try to save a relatively huge language JSON file on the client's localStorage. The backend does not know if it is "cached" on client side so when i set the language file in local storage, i set a cookie with it to indicate that it is saved, so the backend knows about the cached json and does not build it into the page.

On the backend, i check if there is a cookie called "cachedLang" which is equal to the language ID for the client. Like "HU" or "EN". If this cookie is equal to the actual clientLanguage cookie, the same language file is cached on the client side so the backend don't have to render it again, instead it puts a "useCached" string into the place of the actual language json when rendering the page.

The client will check if it is the string "useCached", if it is, it will read the cached language JSON from it's localStorage and use it. If this string is not "useCached" then it is a json language file and using that.

This is working properly on desktop. But on mobile, there is no localStorage and no Cookie on page load. It's just empty, and the backend will always render the huge language file into the html page. I tryed on IOS and Android too.

Here is the backend code:

I'm working on a project around embedded systems that needs to use filesystem. I want to use liitlefs crate in rust but it uses mem::uninitialized that deprecated since 1.39.0 . https://github.com/brandonedens/rust-littlefs

I am trying to dynamically allocate memory for a char pointer stored in the flash memory.

I need to read a file from flash memory using LittleFS file system and copy it to a character array which also needs to be stored in the flash memory using PROGMEM. I cannot store it in the RAM because of limited space. Also I cannot hardcode the character array directly in the sketch, because I need the ability to change the file during runtime and have it persist after reboot.

If I don't use PROGMEM for the char pointer, the sketch works fine. But adding PROGMEM causes the ESP8266 to throw an exception and reboot and become an infinite loop. This is a simplified sketch showing what I'm trying to achieve.

First the problem.

The user can upload file from the web with ajax. If the file is relatively big, the uploading takes a while. If the user's connection is lost or something happens during the uploading process, the file is going to be damaged or empty.

How should I secure the upload process so the file remains the same if it fails for some reason?

I'm using the following libraries on the Arduino ESP32:

• ESPAsyncWebServer
• LITTLEFS

I have a basic file upload handler on my esp32 which looks like this:

Noob question, I'm very knew here, I'm trying tu use wifi manager and modem sleep, but once I turn off the wifi I can't reconnect again. I know what I'm missing is the configuration to connect to the wifi after it has been turned off but I don't know how to do it if I'm using WiFi Manager.

These are the steps:

1. Power on ESP8266
2. Call WiFi Manager and set the credential. Save them for the next time
3. Turn the WiFi Off (In order to collect data from a sensor without power consumption)
4. Collected my 5 data I need to power on the WiFi and connect to it

I made two functions, one to turn off wifi and one to turn it on

I am trying to do something with ESPAsyncWebServer library. I have a class in ServerManager.h called MyServerManager. When I compile the code I get this error. What am I doing wrong? How can I fix it?

25:67 is the bold word "this"

src\ServerManager.cpp: In lambda function: src\ServerManager.cpp:25:67: error: 'this' was not captured for this lambda function request->send(LittleFS, "/status.html", String(), false, [this](const String &var) -> String { return statusProcessor(var); });

*** [.pio\build\nodemcuv2\src\ServerManager.cpp.o] Error 1

in ServerManager.cpp file

On my ESP8266 I run a small Webserver. On one page I am able to upload a binary file for the firmware and hit update. The Esp8266 updates its code and makes a reboot. After this the new code is run. So far so good. In my webserver on the ESP8266 I have some files to provide like index.html and some javascript files. I packed these files in the data directory and created a LittleFS partition. I can make changes in Platformio and upload the littleFS.bin and after a reboot the new files are served.

Now I would like to upload the littleFS.bin also to the ESP8266 an make an update via the website. But this fails.

Here is some code I tried but I get Error messages all the time.

I run some command before the actual build