Socket socket (module): responsible for receiving data from the transport layer, processing it, and handing it to the operating system from the bottom layer.

• Effect
  • To avoid the use of interfaces and protocols in each layer of computer learning, socket has encapsulated all interfaces, which is convenient to use and improves development efficiency.
  • socket is essentially a module. By using the function provided by the learning module, the communication between the client and the server is established, which is convenient to use.

Socket realizes single communication between a single customer and the server:

• Server:

  import socket
  
  # 1. Create socket object (buy mobile phone)
  phone = socket.socket() # Can default not to write
  
  # 2. Bind ip address and port (card handling)
  phone.bind(('127.0.0.1', 8848))  # Local loopback address
  
  # 3. Monitoring (power on)
  phone.listen(5)
  
  # 4. Receive connection
  print('start')
  conn, addr = phone.accept()  # The program temporarily enters the standby mode and waits for the client to send information
  print(conn,addr)
  
  from_client_data = conn.recv(1024)  #Receive up to 1024 bytes
  print(f'From client{addr}news{from_client_data.decode("utf-8")}')
  to_client = input('>>>')
  conn.send(to_client.encode('utf-8'))
  
  conn.close()
  phone.close()

• Client:

  import socket
  
  # Create socket object (buy mobile phone)
  phone = socket.socket() # Can default not to write
  
  # Connecting server ip address and port
  phone.connect(('127.0.0.1', 8848))
  
  # Send news
  to_server = input('>>>').strip()
  phone.send(to_server.encode('utf-8'))
  # receive messages
  from_server_data = phone.recv(1024)  # The program temporarily enters the standby mode and waits for the data from the server to be transmitted.
  
  print(f'From server message:{from_server_data.decode("utf-8")}')
  
  # Shutdown
  phone.close()

socket realizes communication cycle:

• Server:

  import socket
  
  phone = socket.socket()
  
  phone.bind(('127.0.0.1', 8888))
  
  phone.listen(5)
  
  # Receiving connection
  
  while 1:
      print('start')
      conn, addr = phone.accept()  # Program enters standby mode
      print(conn,addr)
      while 1:
          try:
              from_client_data = conn.recv(1024)  #Receive up to 1024 bytes
              if from_client_data == b'q':
                  break
              print(f'From client{addr}news{from_client_data.decode("utf-8")}')
              to_client = input('>>>')
              conn.send(to_client.encode('utf-8'))
          except ConnectionResetError:
              break
      conn.close()
  phone.close()

• Client:

  import socket
  
  # Create socket object (buy mobile phone)
  phone = socket.socket() 
  
  # Connecting server ip address and port
  phone.connect(('127.0.0.1', 8888))
  
  # Send news
  while 1:
      to_server = input('>>>').strip()
      if to_server.upper() == 'Q':
          phone.send('q'.encode('utf-8'))
          break
      phone.send(to_server.encode('utf-8'))
      # receive messages
      from_server_data = phone.recv(1024)  # Standby, waiting to receive data from the server
      print(f'From server message:{from_server_data.decode("utf-8")}')
  
  # Shutdown
  phone.close()

socket realizes communication and connection cycle:

• Server:

  import socket
  
  phone = socket.socket() 
  
  # 2. Bind ip address and port (card handling)
  phone.bind(('127.0.0.1', 8888))  
  
  # 3. Monitoring (power on)
  phone.listen(5)
  
  # 4. Receive connection
  print('start')
  conn, addr = phone.accept()  # Program tamping
  while 1:
      try:
          from_client_data = conn.recv(1024)  #Receive up to 1024 bytes
          if from_client_data == b'q':
              break
          print(f'From client{addr}news{from_client_data.decode("utf-8")}')
          to_client = input('>>>')
          conn.send(to_client.encode('utf-8'))
      except ConnectionResetError:
          break
  conn.close()
  phone.close()

• Client:

  import socket
  
  # 1. Create socket object (buy mobile phone)
  phone = socket.socket() # Can default not to write
  
  # Connecting server ip address and port
  phone.connect(('127.0.0.1', 8888))
  
  # Send news
  while 1:
      to_server = input('>>>').strip()
      if to_server.upper() == 'Q':
          phone.send('q'.encode('utf-8'))
          break
      phone.send(to_server.encode('utf-8'))
      # receive messages
      from_server_data = phone.recv(1024)  # Hold it and wait for the data from the server to come.
      print(f'From server message:{from_server_data.decode("utf-8")}')
  
  # Shutdown
  phone.close()

socket to obtain the remote command:

• Server:

  import socket
  import subprocess
  
  phone = socket.socket()
  
  phone.bind(('127.0.0.1', 8888))
  
  phone.listen(5)
  
  # 4. Receive connection
  print('start')
  conn, addr = phone.accept()
  while 1:
      try:
          cmd = conn.recv(1024) #  dir
          obj = subprocess.Popen(cmd.decode('utf-8'),
                                 shell=True,
                                 stdout=subprocess.PIPE,
                                 stderr=subprocess.PIPE,
                                 )
  
          result = obj.stdout.read() + obj.stderr.read()
          conn.send(result)
      except ConnectionResetError:
          break
  conn.close()
  phone.close()

• User side:

  import socket
  
  phone = socket.socket()
  
  phone.connect(('127.0.0.1', 8888))
  
  # Send news
  while 1:
      cmd = input('>>>').strip()
      phone.send(cmd.encode('utf-8'))
      # receive messages
      result = phone.recv(1024)  # Hold it and wait for the data from the server to come.
      print(result.decode('gbk'))
  
  # Shutdown
  phone.close()