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

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

UDP/TCP/REST Network Utility

UDP/TCP/REST Network Utility

Adroid

TCP Client

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)

ESP32 Server

By wschen

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ESP32 Server

This presentation introduces the ESP32 Server and its features, such as Socket Creation, Sending and Receiving Data, and Socket Options. It also includes examples and further reading materials. Explore how to control LED using TCP Server Example and learn about the ESP32 HTTP Server.

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