pydeen 0.3.0

Python Data Engineer Enterprise Notebook

PYDEEN

Python Data Engineer Enterprise Notebook

(work in progress)

How to use the websocket listener

The pydeen package includes a simple websocket client to listen to external messages. A simple command mode is implemented and other message formats and commands can be enhanced.

The built-in command mode

If activated, the websocket listener can handle simple commands like echo, ping, info, quit, message.

The syntax is <command>::<receiver>::[payload].

The separator is predefined as "::" and the payload is optional. The receiver information can be:

• a single client ID like "MyClientID"

• a wildcard like "*" or "[]"

• a group ID

• or a list of groups and client id.

Some Examples:

• echo::MyClientID:this is the echo payload

• ping::*

• message::["group1","group2"]::My Message Text

Code Example

This example uses the free socket test server https://www.piesocket.com. Check the output and send commands with https://www.piesocket.com/websocket-tester.

Cancel the service with CTRL-C or send a "quit" command.

from pydeen.wsocket import WebSocketService

from pydeen.http import HTTPBackend



# create backend & service

backend = HTTPBackend("Free PieSocket Server", "wss://demo.piesocket.com/v3/channel_1?api_key=VCXCEuvhGcBDP7XhiJJUDvR1e1D3eiVjgZ9VRiaV&notify_self")  

service = WebSocketService(backend)  



# configure service: set my client id and initialize command mode  

service.set_client_id("MyClientID")  

service.set_command_mode()  



# start the service now in an endless loop      

service.run()  

Register to groups

Add the registration to groups in the configure section.

service.register_group("testgruppe")  

service.register_group("lager1")

Implement and register custom commands

Redefine the ServiceCommand and register it before starting the service.

from pydeen.service import ServiceCommand  



class MyServiceCommand(ServiceCommand):



    def __init__(self, command, description):

        super().__init__(command, description)



    def handle(self, command, payload, service) -> bool:

        print("MY COMMAND CALLED")

        return True



service_command = MyServiceCommand("custom_cmd", "My Custom Command Handler")  

service.register_command(service_command)

Service authentification

To use authentification an Auth-Object has been set to the backend. At the moment only AuthBasic is supported.

from pydeen.auth import AuthBasic



myauth = AuthBasic()

myauth.set_basic_auth("user", "password")



backend = HTTPBackend("MySocketServer", "ws://<host>/path/to/socket", auth=myauth)

Implement and register an own action handler

A custom message handler can be implemented if you want to process your own messages. A custom service action has to be redefined from ServiceAction and registered to the service.

To methods have to be redefined:

• parse - to check the incoming payload

• handle - to process the message

`

from pydeen.service import ServiceAction  



class MyServiceAction(ServiceAction):  



    def parse(self, payload) -> bool:  

        print("MY ACTION CALLED")  

        if payload.find("{") == 0:  

            return True  

        else:  

            return False      



    def handle(self, payload, service):  

        print("MY ACTION HANDLED")  

        return False  



service_action = MyServiceAction()  

service.register_action(service_action)  

`

CHANGELOG

0.3.0 2022-08-04 sap abap odata support

• command line menu framework

• redesign pyodata support

• support for sap abap odata gateway

0.2.0 2022-06-30 odata v1

• doc for websocket usage

• websocket restart mode

• odata v2 access (pyodata) - early access

0.1.0 2022-06-21 initial pre-alpha release

---

• core types

• config file handling

• websocket scenario with default command handler for SAP APC