WiFiClient::connected() not working

Question

I use an ESP32 to open an access point and listen for TCP connections over a WiFiServer object.

When I get a client on the server I want to know when it has disconnected.

Currently I have a simple piece of code on both the client and the server side. I connect using a TcpClient in C#.

When I call client.close() on the client side, the client.connected() loop on the server just continues forever.

Here is the ESP code:

void setup()
{
   WiFi.mode(WIFI_AP);

   WiFi.softAP("test");

   WiFi.softAPConfig(IPAddress(192, 168, 4, 1), IPAddress(192, 168, 4, 1), IPAddress(255, 255, 255, 0));

   Serial.println(WiFi.localIP());

   server.begin();
}

void loop()
{
    while (!client)
    {
        client = server.available();

        delay(10);
    }

    while (client.connected())
    {
        Serial.println("ok");

        delay(1000);

        client.read();
    }
}

C# code:

static void Main(string[] args)
{
     TcpClient client = new TcpClient("192.168.4.1", 222);

     client.Close();
}

Answer 1

This is a bug in a previous version of the library as mentioned on https://github.com/bportaluri/WiFiEsp/issues/14

You can alternatively use WiFi.softAPgetStationNum() to get the count of stations connected to the AP interface.

Answer 2

My actual answer

You can try to inquire client.status() as a workaround. When no one is connected it should return 0.

Context

What are you building on? I tried to reproduce your problem but everything works as expected, the serial stops printing "ok" when I disconnect.

Also, what libraries are you using exactly? I included ESP8266WiFi.h and WiFiClient.h.

I used platformio v3.4 on an ESP8266-01 module and a simple Android netcat app as client.