Pico/MicroPython + ESP-01S (AT Command) act as TCP Client connect to Raspberry Pi/Python TCP Server

This exercise program Raspberry Pi Pico in MicroPython, using ESP-01S (ESP8266) as WiFi co-processor, act as TCP Client.

The ESP-01S is flashed with AT command firmware, version:

AT version:1.7.4.0(May 11 2020 19:13:04)
SDK version:3.0.4(9532ceb)
compile time:May 27 2020 10:12:17
Bin version(Wroom 02):1.7.4

For the connection between Pico and ESP-01S, refer to previous post "Connect ESP-01S (ESP8266) to Raspberry Pi Pico/MicroPython, using AT Command".

The TCP server side is implemented using Python3 socketserver. It's copied and modified from Python Document > socketserver.

Both TCP server and client have to be connected in the same WiFi network.

mpyPico_ESP-01S_TCPclient_2021-02-21a.py, client side run on Raspberry Pi Pico, programmed in MicroPython.

import uos
import machine
import utime
"""
Raspberry Pi Pico/MicroPython + ESP-01S exercise

ESP-01S(ESP8266) with AT-command firmware:
AT version:1.7.4.0(May 11 2020 19:13:04)

Pico send AT command to ESP-01S via UART,
- set in station mode
- join AP
- connect to server ip:port 9999
- send text and wait response
"""
#server port & ip hard-coded,
#have to match with server side setting
server_ip="192.168.12.147"
server_port=9999

print()
print("Machine: \t" + uos.uname()[4])
print("MicroPython: \t" + uos.uname()[3])

#indicate program started visually
led_onboard = machine.Pin(25, machine.Pin.OUT)
led_onboard.value(0)     # onboard LED OFF/ON for 0.5/1.0 sec
utime.sleep(0.5)
led_onboard.value(1)
utime.sleep(1.0)
led_onboard.value(0)

uart0 = machine.UART(0, baudrate=115200)
print(uart0)

def sendCMD_waitResp(cmd, uart=uart0, timeout=2000):
    print("CMD: " + cmd)
    uart.write(cmd)
    waitResp(uart, timeout)
    print()
    
def waitResp(uart=uart0, timeout=2000):
    prvMills = utime.ticks_ms()
    resp = b""
    while (utime.ticks_ms()-prvMills)<timeout:
        if uart.any():
            resp = b"".join([resp, uart.read(1)])
    print("resp:")
    try:
        print(resp.decode())
    except UnicodeError:
        print(resp)
        
# send CMD to uart,
# wait and show response without return
def sendCMD_waitAndShow(cmd, uart=uart0):
    print("CMD: " + cmd)
    uart.write(cmd)
    while True:
        print(uart.readline())
        
def espSend(text="test", uart=uart0):
    sendCMD_waitResp('AT+CIPSEND=' + str(len(text)) + '\r\n')
    sendCMD_waitResp(text)
    
sendCMD_waitResp('AT\r\n')          #Test AT startup
sendCMD_waitResp('AT+GMR\r\n')      #Check version information
#sendCMD_waitResp('AT+RESTORE\r\n')  #Restore Factory Default Settings

sendCMD_waitResp('AT+CWMODE?\r\n')  #Query the Wi-Fi mode
sendCMD_waitResp('AT+CWMODE=1\r\n') #Set the Wi-Fi mode 1 = Station mode
#sendCMD_waitResp('AT+CWMODE=2\r\n') #Set the Wi-Fi mode 2 = S0ftAP mode
sendCMD_waitResp('AT+CWMODE?\r\n')  #Query the Wi-Fi mode again

#sendCMD_waitResp('AT+CWLAP\r\n', timeout=10000) #List available APs
sendCMD_waitResp('AT+CWJAP="ssid","password"\r\n', timeout=5000) #Connect to AP
sendCMD_waitResp('AT+CIFSR\r\n')    #Obtain the Local IP Address
#sendCMD_waitResp('AT+CIPSTART="TCP","192.168.12.147",9999\r\n')
sendCMD_waitResp('AT+CIPSTART="TCP","' +
                 server_ip +
                 '",' +
                 str(server_port) +
                 '\r\n')
espSend()

while True:
    print('Enter something:')
    msg = input()
    #sendCMD_waitResp('AT+CIPSTART="TCP","192.168.12.147",9999\r\n')
    sendCMD_waitResp('AT+CIPSTART="TCP","' +
                 server_ip +
                 '",' +
                 str(server_port) +
                 '\r\n')
    espSend(msg)

pyMyTCPServer_2021-02-21a.py, run on Raspberry Pi, programmed in Python.

"""
ref:
https://docs.python.org/3/library/socketserver.html
"""
import socketserver
import platform

print("sys info:")
for info in platform.uname():
    print(info)

class MyTCPHandler(socketserver.BaseRequestHandler):
    """
    The request handler class for our server.

    It is instantiated once per connection to the server, and must
    override the handle() method to implement communication to the
    client.
    """

    def handle(self):
        # self.request is the TCP socket connected to the client
        self.data = self.request.recv(1024).strip()
        print("{} wrote:".format(self.client_address[0]))
        print(self.data)
        # just send back the same data, but upper-cased
        self.request.sendall(self.client_address[0].encode())
        self.request.sendall(self.data.upper())
        self.request.sendall(b'\r\n')

if __name__ == "__main__":
    HOST, PORT = "localhost", 9999

    # Create the server, binding to localhost on port 9999
    #with socketserver.TCPServer((HOST, PORT), MyTCPHandler) as server:
    with socketserver.TCPServer(('', PORT), MyTCPHandler) as server:
        # Activate the server; this will keep running until you
        # interrupt the program with Ctrl-C

        server.serve_forever()

Next:
~ TCP socket communication between (RPi Pico+ESP-01S) and ESP32 via WiFi