add 2 exemples for communication between to esp32

[techno94]

Hello,
i've add 2 exemples for client and server to send and receive data to each other.
tested and working well

[wuzipu123]

Hello @techno94 thank you for sharing your example. I am using it for a project and it is working pretty fine.
There is only one problem, when the Client loses connection to the Server the Client-ESP32 just reboots because it tries to read from the Server. Following error message appears:

[E][BLERemoteCharacteristic.cpp:438] readValue(): Disconnected
abort() was called at PC 0x401867fb on core 1
Backtrace: 0x400910a0:0x3ffd60f0 0x400912a3:0x3ffd6110 0x401867fb:0x3ffd6130 0x40186842:0x3ffd6150 0x401742db:0x3ffd6170 0x400d7609:0x3ffd6190 0x400d41f6:0x3ffd61d0 0x4018f3fc:0x3ffd6230
Rebooting...

So I was wondering if it is possible that the Client can check if it is still connected to the server before it tries to read a value from it?

[chegewara]

@wuzipu123 You can do it in your code.

[wuzipu123]

@chegewara Thank you could you please tell me how?

[techno94]

may be change the : if (deviceConnected) {

by : if (doConnect == true) {
line 107 and 120

or put the code of the : readValue
in the : if (connectToServer(*pServerAddress)) {

when you find solution show me the soluion you find actualy i don't have the time to try.

[wuzipu123]

I made it work by adding following lines to the void loop()

    if(deviceConnected && !pClient->isConnected())
    {
        deviceConnected=false;    
        Serial.println("We disconnected from our device!");
    } 

therefore BLEDevice* pClient needs to be initialized outside the bool ConnectToServer(....) function

It's not perfect because reconnecting doesn't always work but it's something

[wuzipu123]

Alright so the reconnecting problem is solved by adding

pClient->disconnect();

after realizing that you are not connected to the server anymore.