Atelier du 16/11/2019

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import os
import io
import json

class Pipes:
    'Définit et met en oeuvre la communication au travers de tubes nommés'

    def __init__(self, path):
        self._mainPath = path
        
    def __enter__(self):
        self._createPipe(self._mainPath)
        self._fifo = io.open(self._mainPath, "rb", buffering=0)
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        self._fifo.close()
        self._deletePipe(self._mainPath)
        
    def getMainPath(self):
        return self._mainPath

    def _createPipe(self, path):
        try:
            os.mkfifo(path)
            print("Tube créé (" + path + ").")
        except FileExistsError:
            print("Tube déjà existant (" + path + ").")

    def _deletePipe(self, path):
        os.remove(path)
        print("Tube supprimé (" + path +")")
        
    def sendMessage(self, message):
        with open(self.__mainPath, "w") as fifo:
            fifo.write(message)
        fifo.close()

    def readMessage(self):
        s = bytearray()
        while self._fifo.readable():
            try:
                s.append(self._fifo.read(1)[0])
            except IndexError:    # read vide !
                return None
                break
            
#            print(s)
            try:
                dec = json.loads(s)
                return dec
                break
            except json.JSONDecodeError as e:
#                    print(e)
                pass
            
#        return dec
        
if __name__ == "__main__":
    modules = []
    with Pipes() as pipes:
        while True:
            r = pipes.readMessage()
            if r:
                try:
                    e = r['hello']
                    pipes._createPipe('/tmp/' + e)
                    modules.add('/tmp/' + e);
                except KeyError:
                    print("Je n'ai pas trouvé hello, message ignoré !")
                    continue
                
                print(e)
                
            else:
                break