| messageDS {dsBase} | R Documentation |
This function allows for error messages arising from the running of a server-side assign function to be returned to the client-side
messageDS(message.object.name)
message.object.name |
is a character string, containing the name of the list containing the message. See the header of the client-side function ds.message for more details. |
Errors arising from aggregate server-side functions can be returned directly to the client-side. But this is not possible for server-side assign functions because they are designed specifically to write objects to the server-side and to return no meaningful information to the client-side. Otherwise, users may be able to use assign functions to return disclosive output to the client-side. ds.message calls messageDS which looks specifically for an object called $serversideMessage in a designated list on the server-side. Server-side functions from which error messages are to be made available, are designed to be able to write the designated error message to the $serversideMessage object into the list that is saved on the server-side as the primary output of that function. So only valid server-side functions of DataSHIELD can write a $studysideMessage, and as additional protection against unexpected ways that someone may try to get round this limitation, a $studysideMessage is a string that cannot exceed a length of nfilter.string a default of 80 characters.
a list object from each study, containing whatever message has been written by DataSHIELD into $studysideMessage.
Burton PR