Opal is connected with a R server. Each Opal user having the appropriate permissions can create a R session on the server side through Opal. See the R Server documentation page that explains the relationship beteen Opal and the R server. The Opal R package exposes data management related functions:
Note that these functions do create a R session on the server side.
Setup the connection with Opal:
library(opalr)
o <- opal.login("administrator", "password", "https://opal-demo.obiba.org")Assign a Opal table to a data.frame (if user has permission to see values of the Opal table):
opal.assign.table(o, symbol = "df", value = "datashield.CNSIM1")In place of a standard data.frame, Opal can assign data into a tibble which has the advantage of containing the data dictionary:
opal.assign.table.tibble(o, symbol = "tbl", value = "datashield.CNSIM1")List the R symbols that lives in the remote R session:
opal.symbols(o)R expressions can be executed on the server side:
opal.execute(o, script = "names(tbl)")The remote data can be downloaded into the client side R session:
tbl <- opal.execute(o, script = "tbl")The image of the remote R session can be saved in a workspace (to be restored at login time):
opal.workspace_save(o, save="cnsim1")
opal.workspaces(o)Good practice is to free server resources by sending a logout request:
opal.logout(o)