R/limer_get_session_key.R

In limonaid: Working with 'LimeSurvey' Surveys and Responses

#' Get a LimeSurvey API session key
#'
#' This function logs into the LimeSurvey API and provides an access
#' session key. It was
#' adapted by Gjalt-Jorn Peters from a function originally written by Andrew
#' Heiss.
#'
#' @param username LimeSurvey username.
#' Defaults to value set in \code{options()}.
#' @param password LimeSurvey password.
#' Defaults to value set in \code{options()}.
#' @param hostname The host to use (if not using the one specified in
#' the options). If no hostname is specified in the `'lime_api'` option and
#' no host name is passed as `hostname`, the subdomain stored in
#' `limonaid::opts$get("ls_subdomain")` will be combined with the
#' domain stored in `limonaid::opts$get("ls_domain")` to create the
#' host name. You can change these using the `limonaid::opts$set()` function.
#'
#' @return API token
#' @import httr
#' @export
#' @examples \dontrun{
#' get_session_key()
#' }

get_session_key <- function(username = getOption('lime_username'),
                            password = getOption('lime_password'),
                            hostname = getOption('lime_api')) {

  if (is.null(hostname)) {
    hostname <-
      paste0(
        limonaid::opts$get("ls_subdomain"),
        ".",
        limonaid::opts$get("ls_domain")
      );
  }

  body.json = list(method = "get_session_key",
                   id = " ",
                   params = list(admin = username,
                                 password = password));

  # Need to use jsonlite::toJSON because single elements are boxed in httr, which
  # is goofy. toJSON can turn off the boxing automatically, though it's not
  # recommended. They say to use unbox on each element, like this:
  #   params = list(admin = unbox("username"), password = unbox("password"))
  # But that's a lot of extra work. So auto_unbox suffices here.
  # More details and debate: https://github.com/hadley/httr/issues/159

  r <-
    httr::POST(
      hostname,
      httr::content_type_json(),
      body = jsonlite::toJSON(body.json, auto_unbox = TRUE)
    );

  session_key <-
    as.character(
      jsonlite::fromJSON(
        httr::content(
          r,
          encoding="utf-8"
        )
      )$result
    );

  session_cache$session_key <- session_key;

  options(limonaid_cache_session_key = session_key);

  return(session_key);
}

# Start a new environment to hold the session key so all other functions can access it
# See http://trestletech.com/2013/04/package-wide-variablescache-in-r-package/
session_cache <- new.env(parent = emptyenv())