Migrating from me-no-dev/ESPAsyncWebServer

[DeeEmm]

Hi all. great to see some movement with this library. It is a truly great resource that really deserves it.

I've decided to migrate my project from the old me-no-dev/ESPAsyncWebServer library (actually the esphome/ESPAsyncWebServer-esphome fork) to this one but have come across a couple of issues.

The first one was an error thrown on compilation relating to const declaration...

ESP32/DIY-Flow-Bench/webserver.cpp: In static member function 'static void Webserver::saveConfigurationForm(AsyncWebServerRequest*)':
ESP32/DIY-Flow-Bench/webserver.cpp:590:26: error: invalid conversion from 'const AsyncWebParameter*' to 'AsyncWebParameter*' [-fpermissive]
     p = request->getParam(i);

I resolved this by adding the const keyword to the declaration, I assume that this is okay.

const AsyncWebParameter* p;

This allowed the project to compile with a few warnings about deprecated methods, which I also resolved...

beginResponse_P changed to beginResponse
Send_P changed to Send

However when running the project, trying to access the webpage just hangs. The page appears to start loading, I can see the HTML source come in, but it hangs on the CSS and Javascript files.

Eventually after some time I get a WD error reported to the serial monitor...

E (59485) task_wdt: Task watchdog got triggered. The following tasks did not reset the watchdog in time:
E (59485) task_wdt:  - async_tcp (CPU 0/1)
E (59485) task_wdt: Tasks currently running:
E (59485) task_wdt: CPU 0: IDLE0
E (59485) task_wdt: CPU 1: async_tcp
E (59485) task_wdt: Aborting.

abort() was called at PC 0x40100408 on core 0


Backtrace: 0x40083ba5:0x3ffc1f6c |<-CORRUPTED

So looks to be an issue with async_tcp.

The project works fine with the old library.

My test code can be found HERE

The only changes from the working code are as described above and shown HERE

Any help resolving this would be very much appreciated.

Cheers.

/DM

[DeeEmm]

Additional info...

If I clear the cache the index page takes 2-3 secs to load.

[vortigont]

As I see from your code your handling of static content (js/css) is horribly wrong. You spawn a decompressor to ungz the data into string then feed to the server as a stream, it is very mem hungry in inefficient. You can just feed compressed data to the browser with content-encoding: gzip header, also if you add some cache/etag headers browser will only have to download it once time ever.
Refactor your code to handle static content in a more efficient way.

[DeeEmm]

Thanks vortigont. I will take a look at this.

[DeeEmm]

OK so a quick look at this and I have a facepalm moment. Of course - why am I compressing the file to then uncompress it. Obvious when it is pointed out, so thank you for that. 👍

I only recently moved from serving the files from SPIFFs to compressing and storing them in PROGMEM and so I moved everything across without really thinking about it. More fool me. 😄

So I did try a quick test (below) but now realise that as well as compressing the files I am also converting them to a byte array, so sending the data in its current format is not being handled by the browser. It did however not hang and so I think that this is on the right track

  // CSS request handler
  server->on("/style.css", HTTP_ANY, [](AsyncWebServerRequest *request){
        PublicHTML _public_html;
        AsyncWebServerResponse *response = request->beginResponse_P(200, "text/css", style_css, style_css_len);
        response->addHeader("Content-Encoding", "gzip");
        request->send(response);
      });

  // Javascript.js request handler
  server->on("/index.js", HTTP_ANY, [](AsyncWebServerRequest *request){
        PublicHTML _public_html;
        AsyncWebServerResponse *response = request->beginResponse_P(200, "text/javascript", index_js, index_js_len);
        response->addHeader("Content-Encoding", "gzip");
        request->send(response);
      });

I need to change the way that I convert and store the static files so that they are stored in binary format instead of as a byte array.

[vortigont]

another hint - you can use predefined literals from the webserver header and save some bytes of your code
i.e. response->addHeader(asyncsrv::T_Content_Encoding, asyncsrv::T_gzip));
same you can replace content type literals, see more in literals.h

Also you should not use _P methods with ESP32

[DeeEmm]

Thanks vortigont.

The compiler reminded me of that when I tried to test. 😆

I now have this working. I had to change the format of the compressed data for the static files from zlib to gzip which was a fairly simple change.

I will definitely take a look at the predefined literals. We are just heading towards our first full release so code optimisation is high on the agenda.

Thanks for your very prompt help. It is very much appreciated. 😄 👍