[Haskell-cafe] [ANN] opc-xml-da-client, a client for the OPC XML-DA protocol

Olaf Klinke olf at aatal-apotheke.de
Mon Jan 31 20:10:25 UTC 2022

Dear Haskell Café, 

I am pleased to announce opc-xml-da-client [1,2], an implementation of
(the client side of) the OPC XML-DA data access protocol. 
While the OPC XML-DA protocol is quite dated (2003) and has largely
been superseded by other OPC flavours, it is still being used in
industrial environments. OPC XML-DA is based on SOAP and the data types
in the Haskell package closely reflect the protocol specification as a
web services description language document [5]. 

This package was developed by Mlabs [3] as contract work for my
employer. We release it as FOSS, with Mlabs kindly hosting the project
under their Github account. To my knowledge, besides PyOPC [4] this is
the only freely available OPC XML-DA library and the only Haskell OPC
library. We stopped using PyOPC because Python hit performance limits
while parsing the XML. 

Feel free to contact me or Nikita Volkov at Mlabs if you have further


[1] https://github.com/mlabs-haskell/opc-xml-da-client
[2] https://hackage.haskell.org/package/opc-xml-da-client
[3] https://mlabs.city
[4] https://pypi.org/project/PyOPC/
[5] https://opcfoundation.org/XMLDA/1.0/OpcXmlDa1.00.wsdl

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