The DataSHIELD Interface (DSI) defines a set of S4 classes and generic methods that can be implemented for accessing a data repository supporting the DataSHIELD infrastructure: controlled R commands to be executed on the server side are garanteeing that non disclosive information is returned to client side.

Learn more about DataSHIELD.

Class Structure

The DSI classes are:

  • DSObject a common base class for all DSI,
  • DSDriver drives the creation of a connection object,
  • DSConnection allows the interaction with the remote server; DataSHIELD operations such as aggregation and assignment return a result object; DataSHIELD setup status check can be performed (dataset access, configuration comparision),
  • DSResult wraps access to the result, which can be fetched either synchronously or asynchronously depending on the capabilities of the data repository server.

All classes are virtual: they cannot be instantiated directly and instead must be subclassed. See DSOpal for a reference implementation of DSI based on the Opal data warehouse. See also DSLite for a server-less implementation of DSI for local datasets.

These S4 classes and generic methods are meant to be used for implementing connection to a DataSHIELD-aware data repository.

Higher Level Functions

In addition to these S4 classes, DSI provides functions to handle a list of remote data repository servers:

  • datashield.login and datashield.logout will make use of the DSDriver paradigm to create DSConnections to the data repositories,
  • datashield.aggregate and datashield.assign will perform typical DataSHIELD operations on DSConnections, which result will be fetched through DSResult objects,
  • datashield.connections, datashield.connections_default and datashield.connections_find are functions for managing the list of DSConnection objects that will be discovered and used by the client-side analytic functions.
  • datashield.errors will report the last R errors that may have occurred after a datashield.assign or datashield.aggregate call.
  • Other data management functions are provided by the DSConnection objects:
    • datashield.workspaces, datashield.workspace_save and datashield.workspace_rm allow to manage R images of the remote DataSHIELD sessions (to speed up data analysis sessions),
    • datashield.symbols and datashield.symbol_rm offer a minimalistic management of the R symbols living in the remote DataSHIELD sessions,
    • datashield.tables, datashield.table_status list the tables and their accessibility across a set of data repositories,
    • datashield.resources, datashield.resource_status list the resources and their accessibility across a set of data repositories,
    • datashield.pkg_status, datashield.method_status and datashield.methods are utility functions to explore the DataSHIELD setup across a set of data repositories.
    • datashield.profiles lists the DataSHIELD profiles that can be selected at login time.

These datashield.* functions are meant to be used by DataSHIELD packages developers and users.

Options

Some options can be set to modify the behavior of the DSI:

  • datashield.env is the R environment in which the DSConnection object list is to be looking for. Default value is the Global Environment: globalenv().
  • datashield.progress is a logical to enable the visibility of the progress bars. Default value is TRUE.
  • datashield.progress.clear is a logical to make the progress bar disappear after it has been completed. Default value is FALSE.
  • datashield.errors.stop is a logical to alter error handling behavior: if TRUE an error is raised when at least one server has failed, otherwise a warning message is issued. Default value is TRUE.
  • datashield.polling.sleep.0 time in seconds to wait before checking async calls completion, before ~1 second. Default value 50 milliseconds.
  • datashield.polling.sleep.1 base time in seconds to wait before checking async calls completion, after ~1 second. Default value is 1 second.
  • datashield.polling.sleep.10 time in seconds to wait before checking async calls completion, after ~10 seconds. Default value is x2 the base time (2 seconds).
  • datashield.polling.sleep.60 time in seconds to wait before checking async calls completion, after ~1 minute. Default value is x10 the base time (10 seconds).
  • datashield.polling.sleep.600 time in seconds to wait before checking async calls completion, after ~10 minutes. Default value is x60 the base time (1 minute).
  • datashield.polling.sleep.3600 time in seconds to wait before checking async calls completion, after ~1 hour. Default value is x600 the base time (10 minutes).