ESP32 Server

Introduction to MicroPython Socket Module

Purpose: Network communication in MicroPython.
Comparison with CPython socket module.
Basic socket operations: create, bind, listen, accept connections.

Socket Creation and Address Binding

socket.socket(): Creating a new socket.
socket.bind(address): Binding the socket to an address.
Address formats: IPv4, IPv6, raw addresses.

Listening and Accepting Connections

socket.listen([backlog]): Prepares socket to accept connections.
socket.accept(): Accepts a new connection.
Importance of managing backlog in connections.

Sending and Receiving Data

socket.send(bytes): Sends data over the socket.
socket.recv(bufsize): Receives data from the socket.
Data handling and buffer management.

Closing Sockets and Resource Management

socket.close(): Closes the socket.
Importance of releasing resources to prevent leaks.
Exception handling for socket operations.

Example - Creating and Binding a Socket

import socket 
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
s.bind(('localhost', 80))

Example - Listening and Accepting Connections

s.listen(5) 
conn, addr = s.accept()

Example - Sending and Receiving Data

data = conn.recv(1024)
conn.send(data)

Socket Options and Advanced Features

Setting and getting socket options.
Non-blocking sockets and timeouts.
Advanced socket functionalities.

Conclusion and Further Reading

Recap of MicroPython socket capabilities.
Encouragement to experiment with socket programming.
Reference: MicroPython socket documentation.

import network, socket, time
from machine import Pin

wlan = network.WLAN(network.AP_IF) # Initializes the access point interface
wlan.active(False) # Deactivates the first AP interface
time.sleep(0.1) # Waits for 0.1 seconds to ensure the interface is properly deactivated
wlan.active(True) # Reactivates the first AP interface
wlan.config(ssid='TedESP32AP') # YourAP Name
wlan_ip = wlan.ifconfig()[0]
print('AP IP:', wlan_ip) # Displays the IP address of the ESP32 in AP mode

led=Pin(16,Pin.OUT)
led.value(0)

TCP Server Example - Control LED

def setup_server(wlan_ip):
    # Create STREAM TCP socket
    server=socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    server.bind((wlan_ip, 80))
    server.listen(1)

    print("tcp server is listening")
    tcp_conn, client_addr = server.accept()
    print(client_addr, "Client connects sucessfully")
    return tcp_conn

TCP Server Example - Control LED

def server_task(tcp_conn):
    count = 0
    while True:
        msg = tcp_conn.recv(128).decode("utf-8").lower()
        if "on" in msg:
           led.value(1)
        elif "off" in msg:
           led.value(0)
        elif "exit" in msg:
           break       
        print(f"receive {count} message {msg}")
        if count > 5:
           break
        count += 1    
        
    tcp_conn.close()
    server.close()    

if wlan_ip is not None:
    tcp_conn = setup_server(wlan_ip)
    server_task(tcp_conn)

TCP Server Example - Control LED

Test App

IOS

UDP / TCP / Rest Network Test Utility

UDP/TCP/REST Network Utility

Adroid

TCP Client

Adroid TCP Client

ESP32 HTTP Server

reference

https://randomnerdtutorials.com/esp32-esp8266-micropython-web-server/

Online HTML Editor

https://onlinehtmleditor.dev/

Web Server code

ESP32 HTTP Server

import network, socket, time
from machine import Pin

wlan = network.WLAN(network.AP_IF) # Initializes the access point interface
wlan.active(False) # Deactivates the first AP interface
time.sleep(0.1) # Waits for 0.1 seconds to ensure the interface is properly deactivated
wlan.active(True) # Reactivates the first AP interface
wlan.config(ssid='TedESP32AP') # YourAP Name
wlan_ip = wlan.ifconfig()[0]
print('AP IP:', wlan_ip) # Displays the IP address of the ESP32 in AP mode

led=Pin(16,Pin.OUT)
led.value(0)

ESP32 HTTP Server

def setup_server(wlan_ip):
    # Create STREAM TCP socket
    server=socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    server.bind((wlan_ip, 80))
    server.listen(1)
    print("HTTP Server is listening")
    return server

ESP32 HTTP Server

def server_task(server):
    while True:
        conn, client_addr = server.accept()
        print(client_addr, "Client connects sucessfully")
        msg = conn.recv(1024).decode("utf-8").lower()
        if "get /?led=on" in msg:
           led.value(1)
        elif "get /?led=off" in msg:
           led.value(0)
        else:
           pass    
        print(f"receive message {msg}")
        response = web_page()
        conn.send('HTTP/1.1 200 OK\n')
        conn.send('Content-Type: text/html\n')
        conn.send('Connection: close\n\n')
        conn.sendall(response)
        conn.close()
    server.close()

ESP32 HTTP Server

def web_page():
    if led.value() == 1:
       gpio_state="ON"
    else:
       gpio_state="OFF"
  
    html = """<html>
              <head> 
                <title>ESP Web Server</title> 
                <meta name="viewport" content="width=device-width, initial-scale=1">
                <link rel="icon" href="data:,"> 
                <style> 
                        html{font-family: Helvetica; display:inline-block; margin: 0px auto; text-align: center;}
                        h1{color: #0F3376; padding: 2vh;}
                        p{font-size: 1.5rem;}
                        .button{display: inline-block; background-color: #e7bd3b; border: none; 
                                border-radius: 4px; color: white; padding: 16px 40px; 
                                text-decoration: none; font-size: 30px; margin: 2px; cursor: pointer;}
                        .button2{background-color: #4286f4;}
                </style>
              </head>
              <body> 
                    <h1>ESP Web Server</h1> 
                    <p>GPIO state: <strong>""" + gpio_state + """</strong></p>
                    <p><a href="/?led=on"><button class="button">ON</button></a></p>
                    <p><a href="/?led=off"><button class="button button2">OFF</button></a></p>
              </body>
              </html>"""
    return html

ESP32 HTTP Server

if wlan_ip is not None:
    server = setup_server(wlan_ip)
    server_task(server)