embed credentials for protected GraphDB in cURL?

Question

I like to explore the contents of my triplestores with either the rrdf or SPARQL packages in R. I believe they use cURL under the hood. They can take additional parameters, beyond the endpoint address and the query itself.

Here's GraphDB's notes on cURL-based queries: http://graphdb.ontotext.com/documentation/standard/quick-start-guide.html#query-data-programmatically

I could swear I connected to some password-protected triplestore from R in the past, but I can't remember how I did it. It might have been Stardog or Blazegraph.

I'll be connecting over a VPN. I hope that I can relax the usual rule about not embedding sensitive data (like a password) in a plain text URL.

• Can I connect to a password-protected GraphDB (or any other RDF4J compliant triplestore) by including the username and password as part of the URL?
• Or, can I establish an authenticated connection/session with GraphDB over cURL, as opposed to establishing a secure connection within some Java or Scala code?

Answer 1

From RCurl: HTTP Authentication When Site Responds With HTTP 401 Code Without WWW-Authenticate:

the key is specifying the type of authentication (httpauth) as a bitmap option (1L), to be passed to rCURL.

library(SPARQL)

graphdb.address.port <- "http://localhost:7200"

selected.repo <- "mymedicalrecrods"

sparql.base <-
  paste0(graphdb.address.port, "/repositories/", selected.repo)

sparql.prefixes <- ""

api.user <- "markmiller"
api.pass <- rstudioapi::askForPassword()

placeholder.q <- paste0(
'
PREFIX owl: <http://www.w3.org/2002/07/owl#>
select *
where {
    graph ?g {
        ?s ?p ?o
    }
}
limit 9
')

sparql.result <-
  SPARQL::SPARQL(
    url = sparql.base,
    query = placeholder.q,
    curl_args = list('userpwd' = paste0(api.user,":", api.pass), "httpauth" = 1L)
  )
sparql.result<- sparql.result$results