Simple UDP Sensor Server in Python <=> Object Pascal

2023.09.27 17:37

me Views:184

# This is needed for accessing sensor data which library supports only python or c++

import socket            # For UDP Communication to PC
import struct            # For ??
import sys               # For sys.stderr (Print to screen)

myip = '127.0.0.1'       # Development Mode (Local IP)
machinename = 'SENSE-NET'

message    = ''
old_ar_rcv = ''
shortstr   = ''
multicast_group = (myip, 6767)   # Actual Run Mode in PI (PC(Overmind)'s IP)
sockettimeout = 2.2

# Create the datagram socket
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

# Set a timeout so the socket does not block indefinitely when trying
# to receive data.
sock.settimeout(sockettimeout) # original (0.2)

# Set the time-to-live for messages to 1 so they do not go past the
# local network segment.
ttl = struct.pack('b', 1)
sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, ttl)

try:
   # Send data to multicast group
   # bytesToSend = str.encode(msgFromServer)
   sent = sock.sendto(str.encode(machinename), multicast_group)

   while True:   #keep going
      try:
         # Get message from Arduino
#         ar_rcv = ar_port.readline() # read 30 characters
#         ar_rcv = ar_rcv.strip('\n')
#         if len(ar_rcv) < 2:
#            ar_rcv = old_ar_rcv
#         else:
#            if old_ar_rcv != ar_rcv :
#               print >> sys.stderr, ar_rcv
#               old_ar_rcv = ar_rcv
#               sent == sock.sendto(ar_rcv, multicast_group)
               # to write to arduino, use: ar_port.write('My Message')

         data, server = sock.recvfrom(10)

         # print >> sys.stderr, 'received "%s" from %s' % (data, server)
         if data != '.':
            if message != data :
               message = ''
            #   ar_port.write(data)
               print >> sys.stderr, 'to ar. "%s" ' % (data)
            #   print('to ar. "%s" ' % (data))
               sent == sock.sendto(str.encode(data), multicast_group)
               message = data
      except socket.timeout:
         print >> sys.stderr, 'UDP Timeout' % (data, server)
         #print('UDP Timeout')
         break
      else:
         if data != '.':   # If data from Overmind is not '.'
            #i = 1   # dummy, do nothing
            print >> sys.stderr, 'received "%s" from %s' % (data, server)

finally:
   print >>sys.stderr, 'closing socket'
   #print('Error : closing socket')
   sock.close()
   exit()

I want to

List

Comment 1

me

2023.09.27 17:38

// Comminicating to above UDP server from Object Pascal

unit UDPTest;

{$mode objfpc}{$H+}

interface

uses
Classes, SysUtils, Forms, Controls, Graphics, Dialogs, ExtCtrls, StdCtrls,
UTF8Process, lNetComponents, lNet;

type

{ TfrmUDPTest }

TfrmUDPTest = class(TForm)
    cbKeepAlive: TCheckBox;
    eExecCommand: TEdit;
    eUDPCommand: TEdit;
    eHost: TEdit;
    ePort: TEdit;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Label4: TLabel;
    lblHeart: TLabel;
    lblStatus1: TLabel;
    LUDP: TLUDPComponent;
    m: TMemo;
    mTokenBOT: TMemo;
    mRecv: TMemo;
    ProcessUTF8_1: TProcessUTF8;
    tAlive: TTimer;
    TimerQuit: TTimer;
    tSecond: TTimer;
    procedure eExecCommandKeyPress(Sender: TObject; var Key: char);
    procedure eUDPCommandKeyPress(Sender: TObject; var Key: char);
    procedure FormClose(Sender: TObject; var CloseAction: TCloseAction);
    procedure FormCreate(Sender: TObject);
    procedure LUDPError(const msg: string; aSocket: TLSocket);
    procedure LUDPReceive(aSocket: TLSocket);
    procedure mRecvChange(Sender: TObject);
    procedure tAliveTimer(Sender: TObject);
    procedure TimerQuitTimer(Sender: TObject);
    procedure tSecondTimer(Sender: TObject);
private

public
    FValueQueue : array[1..132] of Byte;
    FQueueHead, FQueueMax : integer;

    FNet: TLConnection;
    FIsServer, FirstInited: Boolean;
    secno, HeartbeatNo : integer;
    s, ts: string;

    procedure SendToAll(const aMsg: string);
    procedure SendMsg(const aMsg: string);
end;

var
frmUDPTest: TfrmUDPTest;

implementation

{$R *.lfm}

{ TfrmUDPTest }

procedure TfrmUDPTest.SendToAll(const aMsg: string);
   var
     n: Integer;
begin
   if FNet is TLUdp then begin // UDP, use broadcast
      n := TLUdp(FNet).SendMessage(aMsg, LADDR_BR);
      if n < Length(aMsg) then
         m.Append('Error on send [' + IntToStr(n) + ']');
   end;
end;

procedure TfrmUDPTest.SendMsg(const aMsg: string);
begin
   LUDP.Host := eHost.text;
   if Length(aMsg) > 0 then begin

      FIsServer := false;
      FNet.SendMessage(aMsg);

      FIsServer := True;
   end;
end;

procedure TfrmUDPTest.tSecondTimer(Sender: TObject);
begin
   inc(secno);

   if (secno mod 10) = 9 then lblHeart.visible := true;
   if (secno mod 10) = 0 then lblHeart.visible := false;
end;

procedure TfrmUDPTest.eExecCommandKeyPress(Sender: TObject; var Key: char);
begin
   if Key = #13 then begin
      ProcessUTF8_1.CommandLine:= eExecCommand.Text;
      ProcessUTF8_1.Execute;
      m.Lines.LoadFromStream(ProcessUTF8_1.Output);
   end;
end;

procedure TfrmUDPTest.eUDPCommandKeyPress(Sender: TObject; var Key: char);
   var
     str: String;
     rst : integer;
begin
   if Key = #13 then begin
      str := eUDPCommand.Text;
//   if NewLine_CB.Checked then
//     str := str; // + #13#10;
//   rst := SerialESP.WriteData(str);
      SendMsg(str);
      m.lines.add('Sents : ' + str);
   end;
end;

procedure TfrmUDPTest.FormClose(Sender: TObject; var CloseAction: TCloseAction);
begin
   if FNet.Connected then
      begin
         CloseAction := caNone; // make sure we quit gracefuly
         FNet.Disconnect; // call disconnect (soft)
         TimerQuit.Enabled := True; // if time runs out, quit ungracefully
      end;   // TimerQuit gives 200 ms deley before close;
end;

procedure TfrmUDPTest.FormCreate(Sender: TObject);
begin
   FNet := LUDP;
   FIsServer := False;
   FirstInited := False; // First received message to activate
//   eHost.text := '192.168.1.133';
   LUDP.Host := '127.0.0.1';
   FNet.Connect('127.0.0.1', 6767);
   FIsServer := False;

   // To run it as server mode, unblock following code.
//   if FNet.Listen(StrToInt(ePort.text)) then begin
//      lblStatus1.caption := 'Accepting signal';
//      FIsServer := True;
//   end;
end;

procedure TfrmUDPTest.LUDPError(const msg: string; aSocket: TLSocket);
begin
   m.Append(msg);
end;

procedure TfrmUDPTest.LUDPReceive(aSocket: TLSocket);
   var
     s1: string;
begin
   if aSocket.GetMessage(s1) > 0 then begin
      if s1 <> '.' then begin
         if s1[1] = '|' then   // Message from Arduino
            begin
               if mTokenBOT.lines.count > 7 then
                  mTokenBOT.lines.clear;
               mTokenBOT.Append(s1);
            end
         else
            begin              // Message from PI2
               if mRecv.lines.count > 7 then
                  mRecv.lines.clear;
               mRecv.Append(s1);
            end;
      end;

      // activate if first message is received to avoid crash
      if not FirstInited then begin
           HeartbeatNo := 0;
           if not cbKeepAlive.checked then cbKeepAlive.checked := true;
           FirstInited := true;
           tSecond.enabled := true;
       end;
     end;
end;

procedure TfrmUDPTest.mRecvChange(Sender: TObject);
begin

end;

procedure TfrmUDPTest.tAliveTimer(Sender: TObject);
begin
   if not FirstInited then exit;
   if not cbKeepAlive.checked then exit;
   inc(HeartbeatNo);
   LUDP.Host := eHost.text;
   FIsServer := false;
   FNet.SendMessage('.');
//   lblStatus1.caption := 'HEART : ' + inttostr(HeartbeatNo)
//      + ' @ ' + formatdatetime('HH:NN', now);
   FIsServer := True;
end;

// .2 second delay close
procedure TfrmUDPTest.TimerQuitTimer(Sender: TObject);
begin
   close;
end;

end.

Comment

List

No.	Subject	Author	Date	Views
16	OpenCV for Object Pascal in Linux	me	2024.09.25	34
15	My DCM => JPG with Lazarus IDE	me	2024.01.05	229
14	i2c ADC 4 channel (ADS1115)	me	2023.12.20	175
13	Ultrasonic with free pascal	me	2023.12.05	186
12	Trigger Test with pascalio	me	2023.12.04	174
11	3. my note for pascalio with MCP23017 - 16 bit I/O expanding board.	me	2023.12.03	211
10	2. my note for pascalio with MCP23017 - 16 bit I/O expanding board.	me	2023.12.03	196
9	Bitwise Operation in Object Pascal	me	2023.11.25	238
8	Making BNO-055 Library for Linux SBC in Object Pascal [1]	me	2023.11.22	230
7	Nano Seconds Control : Failed, but micro seconds levels worked.	me	2023.11.22	195
6	1. my note for pascalio with MCP23017 - 16 bit I/O expanding board.	me	2023.11.20	205
5	pascalio on Orange Pi 5 for I2C control	me	2023.11.20	238
4	Working UDP between Orange Pi 5 <=> PC	me	2023.09.29	258
»	Simple UDP Sensor Server in Python <=> Object Pascal [1]	me	2023.09.27	184
2	Simple Joystick with SdpoJoystick Component on Linux	me	2023.09.22	162
1	Virtual Lidar for test [1]	me	2023.07.20	252

First Page 1 Last Page

Write

Tag