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Data extraction methods


There are several possibilities for users to access NXCALS data.

In this guide we will explain and give examples how to extract data using different methods:


Authorization is required for any of those methods in the form of a Kerberos token. A Kerberos keytab file must be generated and optionally the client machine must provide a valid CERN grid CA certificate. Moreover, the user must be registered on the NXCALS service to access the data.

Supported Java and Python versions

Please note that NXCALS requires a specific version of Java and Python runtimes.

Deprecated Access Methods

  • python builders were moved from to
  • java builders were moved from to
  • DevicePropertyQuery has been renamed to DevicePropertyDataQuery
  • KeyValuesQuery and VariableQuery were unified into 'DataQuery', accessible via byEntities() and byVariables() respectively

Java API

A Java examples project can be cloned from GitLab by following steps described here.


To set up you python environment, please check Setting up Python environments page. Currently, NXCALS provides a Python API only for Data Extraction API. There is a possibility of accessing from Python other NXCALS Java APIs such as:

by using Py4J or JPype.