(Possibly) Memory leak with HTTPclient -> GET()?

[EldinZenderink]

Basic Infos

Memory Loss when generating HTTP get request using HTTPClient.

Hardware

Hardware: ESP-01s
Core Version: 2.4.0-rc2

Description

Problem description
I am trying to do a http get request to a date/time api, but somehow on generating the HTTP request I lose bytes, am I doing something wrong, or is this something internally?

Settings in IDE

Module: Generic ESP8266 Module
Flash Size: 512K(no SPIFFS)
CPU Frequency: 80Mhz
Flash Mode: dio
Flash Frequency: 40Mhz
Upload Using: SERIAL
Reset Method: ck

Sketch

As you can see, from line 232 to 239 I seem to lose around 900 bytes. I am not sure if I am forgetting something or that there is something internally happening with the HTTPclient.

Ok, so while writing this, I figured people will ask for a simplified version of the code to reproduce the situation. So I just took the BasicHttpClient example and added the getFreeHeap method (and used the same url).

As you can see, even here there is a bit of memory lost, albeit being less. Hence somewhat confirming that the problem that I am experiencing isn't directly related to my own code... right?

[EldinZenderink]

I might have found the solution myself... after experimenting with WifiClient example, and adding these defines to WifiClient.h (not sure if it really helped me) :

#define TCP_DEFAULT_KEEPALIVE_IDLE_SEC          3600 // 1 hours
#define TCP_DEFAULT_KEEPALIVE_INTERVAL_SEC      5 // 5 sec
#define TCP_DEFAULT_KEEPALIVE_COUNT             3   // fault after 3 failures

And changing

  while(client.available()){
    String line = client.readStringUntil('\r');
    Serial.print(line);
  }

to

char* cBuf;
while(1){
      int howmuch = client.available();
      if(howmuch>0){
           cBuf = (char*) malloc(sizeof(char) * howmuch + 1);
           client.read((uint8_t*)cBuf, howmuch);
      } else {
           break;
      }
}

Seemed to solve my issue, after few runs it settles in and hasn't leaked memory since.

Not the most elegant and I haven't thoroughly tested what did and didn't solved my issues exactly, but it works.