ESP32 to ESP32 WiFi Server/Client Problem - c++

Question

I've got one ESP32 acting as client and another ESP32 acting as an access-point for direct communication and outdoor use.
I have set up a server on the AP end and would like the client to communicate with it but I can't seem to make this work.
I would like to know two things:
How do I send or write data to the server from the client?
How do I read and display the data that was sent to the server from the client?
I have attached the code below:
Code for AP/Server
//SERVER
//Load Wi-Fi library
#include <WiFi.h>
// Replace with your network credentials
const char* ssid = "ESP32-Access-Point";
const char* password = "SyedAhmedAli";
//Set web server port number to 80
WiFiServer server(80);
void setup() {
Serial.begin(115200);
Serial.println("Setting AP (Access Point)…");
WiFi.softAP(ssid, password);
IPAddress IP = WiFi.softAPIP();
Serial.print("AP IP address ");
Serial.println(IP);
Serial.print("MAC address ");
Serial.println(WiFi.softAPmacAddress());
server.begin();
}
void loop(){
WiFiClient client = server.available(); //Listen for incoming clients
if (client)
{ //If a new client connects,
Serial.println("New Client."); //print a message out in the serial port
while (client.connected())
{
Serial.println("Client connected.");
Serial.println(client.available());
if (client.available() > 0)
{
// read the bytes incoming from the client:
char thisChar = client.read();
// echo the bytes back to the client:
server.write(thisChar);
// echo the bytes to the server as well:
Serial.write(thisChar);
}
}
client.stop();
Serial.println("Client disconnected.");
Serial.println();
}
}
Code for Client
//Client
#include <WiFi.h>
const char* ssid = "ESP32-Access-Point";
const char* password = "SyedAhmedAli";
WiFiClient client;
IPAddress server(192, 168, 4, 1);
void setup()
{
Serial.begin(115200);
Serial.println();
Serial.printf("Connecting to %s ", ssid);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED)
{
delay(500);
Serial.print(".");
}
Serial.println(" connected");
if(client.connect(server, 80))
{
Serial.println("connected to server");
client.write("Data");
}
else
{
Serial.println("failed to connect to server");
}
}
void loop()
{
}

Answer 1

Alternatively to the previous answer, you could use espnow as a protocol between various esp32. Here an example.

Answer 2

You must implement some sort of protocol like TCP, UDP to exchange data.
Example Project using TCP
https://www.instructables.com/id/WiFi-Communication-Between-Two-ESP8266-Based-MCU-T/
Example Project using UDP
https://circuits4you.com/2018/01/01/esp-to-esp-communication/

Answer 3

Look at this very handy function:
void SetWifi(const char *name, const char *password) { // Turn on wifi with server
Serial.println("Starting server");
WiFi.disconnect();
WiFi.softAP(name, password);
delay(2000);
IPAddress IP = WiFi.softAPIP();
Serial.print("Server IP : ");
Serial.println(IP);
server.begin();
server.setNoDelay(true);
Serial.println("Server started");
}
You can write data with this function :
void sendDataTCP(String message) { // function to send message back to client
if (client && client.connected()) { //check if client is there
client.println(message);
}
client.flush();
}
Receive data with this function:
void availableMessage() {
if (client.available()) {//check if client is there
while (client.available()) {
String message = client.readStringUntil('\n'); //read string until enter (end of message)
Serial.println("Received: " + message);
message.toCharArray(buffer, BUFFER); // put message in char array (buffer)
client.flush(); // discard all bytes that have been read
}
}
}
Check if someone has connected:
void connectClient() {
if (server.hasClient()) // if server has a client
{
if (client = server.available()) { // if client is connected
Serial.println("Connected");
}
}
}
I think this will get you in the direction of accomplishing your goal, good luck!