beremiz

make clipboard open minimal time as wxPython documentation recommends

2018-05-25, Andrey Skvortsov
5ce6d08ff2c7
make clipboard open minimal time as wxPython documentation recommends

https://wxpython.org/Phoenix/docs/html/wx.Clipboard.html#wx.Clipboard.GetData

"Call wx.Clipboard.Open to get ownership of the clipboard. If this
operation returns True, you now own the clipboard. Call
wx.Clipboard.SetData to put data on the clipboard, or
wx.Clipboard.GetData to retrieve data from the clipboard. Call
wx.Clipboard.Close to close the clipboard and relinquish ownership.
You should keep the clipboard open only momentarily."

Maybe it makes situation with pretty annoying error 'clipboard already
open' a little bit better.

traceback:
File "/home/developer/WorkData/PLC/beremiz/avangard-beremiz-ide/src/../../beremiz/BeremizIDE.py", line 955, in OnSaveProjectMenu
self.RefreshAfterSave()
File "/home/developer/WorkData/PLC/beremiz/avangard-beremiz-ide/src/../../beremiz/BeremizIDE.py", line 946, in RefreshAfterSave
self._Refresh(TITLE, FILEMENU, EDITMENU, PAGETITLES)
File "/home/developer/WorkData/PLC/beremiz/avangard-beremiz-ide/src/../../beremiz/IDEFrame.py", line 926, in _Refresh
self.RefreshFunctions[element]()
File "/home/developer/WorkData/PLC/beremiz/avangard-beremiz-ide/src/../../beremiz/BeremizIDE.py", line 766, in RefreshEditMenu
IDEFrame.RefreshEditMenu(self)
File "/home/developer/WorkData/PLC/beremiz/avangard-beremiz-ide/src/../../beremiz/IDEFrame.py", line 1185, in RefreshEditMenu
if self.GetCopyBuffer() is not None:
File "/home/developer/WorkData/PLC/beremiz/avangard-beremiz-ide/src/../../beremiz/IDEFrame.py", line 956, in GetCopyBuffer
if wx.TheClipboard.Open():
File "/usr/lib/python2.7/dist-packages/wx-3.0-gtk3/wx/_misc.py", line 5793, in Open
return _misc_.Clipboard_Open(*args, **kwargs)
: C++ assertion "!m_open" failed at ../src/gtk/clipbrd.cpp(598) in Open(): clipboard already open
Beremiz and Beremiz_service connectors
======================================
To connect a PLC, Beremiz provides 2 types of connectors :
* a Pyro connector
* a WAMP connector
To configure the connection, you have to set the *URI_location* in your project Config tab according to this documentation.
The Pyro connector
----------------------------
Pyro is an advanced and powerful Distributed Object Technology system written entirely in Python.
Beremiz_service spawns a Pyro server, serving a PLCObject (see runtime/PLCObject.py). Therefore, Beremiz acts as a Pyro client.
TODO:: link to PLCObject API documentation
URI_location :
* LOCAL:// is a facility that starts the PLC service locally and connect Beremiz to it via Pyro.
This is intended for use in development stage.
* PYRO://<ip:port> normal connection to a remote PLC. PLC default port is 3000.
* PYROS://<ip:port> SSL connection to a remote PLC, see below.
more information about Pyro can be found on http://pythonhosted.org//Pyro/1-intro.html
===========================
Setup a Pyro SSL connection
===========================
Pyro v3 has a limited TLS/SSL support based on m2crypto. Pyro v4 had dropped it.
In order to have a full and reliable SSL, we recommand to use a TLS/SSL wrapper as nginx, stub or stunnel.
--------------------
TLS-PSK with stunnel
--------------------
In this example, we setup a simple TLS-PSK connection according to rfc4279.
This ciphersuite avoid the need for public key operations and certificate management.
It is perfect for a performance-constrained environments with limited CPU power as a PLC.
Needed :
* stunnel >= 5.09
verify openssl support for PSK cipher::
openssl ciphers -v 'PSK'
----------------------
Client setup (Beremiz)
----------------------
You need to choose an identity for your client, here *client1*.
generate a valid and strong key::
$ echo client1:$(openssl rand -base64 48) > pskclient1.txt
write a stunnel client configuration file *stunnel-client.conf*::
output = stunnel-client.log
client = yes
[beremiz]
accept = 3002
connect = [PLC]:3001
PSKidentity = client1
PSKsecrets = pskclient1.txt
start stunnel client side::
stunnel stunnel-client.conf
You could now connect beremiz with classic URI_location = PYRO://127.0.0.1:3002
--------------------
Server setup (PLC)
--------------------
import the client key in a keyfile psk.txt, concatening all client key.
write a stunnel server configuration file *stunnel-server.conf*::
output = stunnel-server.log
[beremiz]
accept = 3001
connect = 127.0.0.1:3000
PSKsecrets = psk.txt
start stunnel server side::
stunnel stunnel-server.conf
more documentation on stunnel http://www.stunnel.org/docs.html
The WAMP connector
------------------
WAMP is an open standard WebSocket subprotocol that provides two application messaging
patterns in one unified protocol: Remote Procedure Calls + Publish & Subscribe.
Beremiz WAMP connector implementation uses Autobahn and crossbar.
URI_location :
* WAMP://127.0.0.1:8888#Automation#2534667845
more information about WAMP can be found on http://wamp.ws/