Pure Python OPC-UA / IEC 62541 Client and Server Python 2, 3 and pypy . http://freeopcua.github.io/, https://github.com/FreeOpcUa/python-opcua
OPC-UA binary protocol implementation is quasi complete and has been tested against many different OPC-UA stacks. API offers both a low level interface to send and receive all UA defined structures and high level classes allowing to write a server or a client in a few lines. It is easy to mix high level objects and low level UA calls in one application.
Most code is autogenerated from xml specification using same code as the one that is used for freeopcua C++ client and server, thus adding missing functionnality to client and server shoud be trivial.
Using Python > 3.4 the only dependency is cryptography. If using python 2.7 or pypy < 3 you need to install enum34, trollius(asyncio), and futures(concurrent.futures), with pip for example.
coveryage.py reports a test coverage of over 90% of code, most of non-tested code is autogenerate code that is not used yet.
Some documentation is available at http://python-opcua.readthedocs.org/en/latest/
A simple GUI client is available: https://github.com/FreeOpcUa/opcua-client-gui
Examples: https://github.com/FreeOpcUa/python-opcua/tree/master/examples
Minimal client example: https://github.com/FreeOpcUa/python-opcua/tree/master/examples/minimal-client.py Minimal server example: https://github.com/FreeOpcUa/python-opcua/tree/master/examples/minimal-server.py
A set of command line tools also available: https://github.com/FreeOpcUa/python-opcua/tree/master/tools
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uadiscover (find_servers, get_endpoints and find_servers_on_network calls)
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uals (list children of a node)
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uahistoryread
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uaread (read attribute of a node)
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uawrite (write attribute of a node)
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uasubscribe (subscribe to a node and print datachange events)
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uaclient (connect to server and start python shell)
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uaserver (starts a demo OPC-UA server)
tools/uaserver --populate --certificate cert.pem --private_key pk.pem
Client: what works:
- connection to server, opening channel, session
- browsing and reading attributes value
- gettings nodes by path and nodeids
- creating subscriptions
- subscribing to items for data change
- subscribing to events
- adding nodes
- method call
- user and password
- history read
- login with certificate
- communication encryption
- removing nodes
Tested servers: freeopcua C++, freeopcua Python, prosys, kepware, beckoff
Client: what is not implemented yet
- localized text feature
- adding some missing modify methods
- XML protocol
Server: what works:
- creating channel and sessions
- read/set attributes and browse
- gettings nodes by path and nodeids
- autogenerate addres space from spec
- adding nodes to address space
- datachange events
- events
- methods
- basic user implementation (one existing user called admin, which can be disabled, all others are read only)
- encryption
- certificate handling
- removing nodes
- history support for data change and events
Tested clients: freeopcua C++, freeopcua Python, uaexpert, prosys, quickopc
Server: what is not implemented
- alarms
- XML protocol
- views
- localized text features
- better securty model with users and password
- adding some missing modify methods
Server: Running on a Raspberry Pi
Setting up the standard address-space from scratch is the most time-consuming step of the startup process which may lead to long startup times on less powerful devices like a Raspberry Pi. By passing a path to a cache-file to the server constructor, a shelve holding the address space will be created during the first startup. All following startups will make use of the cache-file which leads to significantly better startup performance (~3.5 vs 125 seconds on a Raspbery Pi Model B).
Code follows PEP8 apart for line lengths which should be max 120 characters and OPC UA enums that keep camel case from XML definition.
All code is under opcua directory
- ua contains all UA structures from specification
- common contains high level objects and methods used both in server and client
- client contains client specific code
- server contains server specific code
- utils contains some utilities not really related to OPC-UA
- tools contains command lines tools
python tests.py
coverage run tests.py
coverage html
firefox htmlcov/index.html