add skeleton to load API key

NAMESPACE

@@ -1,2 +1,3 @@
 # Generated by roxygen2: do not edit by hand
 
+export(get_key)

R/get_key.R

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+#' Get or Set Up API Key for TERN
+#'
+#' Checks first to get key from your .Rprofile or .Renviron (or similar) file.
+#'   If it's not found, then it suggests setting it up.  Can be used to check
+#'   that your key that \R is using is the key that you wish to be using or for
+#'   guidance in setting up the keys.
+#'
+#' @details
+#' The suggestion is to use your .Renviron to set up the API key. However, if
+#'  you regularly interact with the APIs outside of \R using some other
+#'  language you may wish to set these up in your .bashrc, .zshrc, or
+#'  config.fish for cross-language use.
+#'
+#' @return A string value with your \acronym{API} key value.
+#'
+#' @examples
+#' \dontrun{
+#' get_key()
+#' }
+#'
+#' @export
+get_key <- function() {
+  TERN_API_KEY <- Sys.getenv("TERN_API_KEY")
+
+  if (!nzchar(TERN_API_KEY)) {
+    .set_tern_key()
+  } else {
+    return(TERN_API_KEY)
+  }
+}
+
+#' Help the User Request an API Key for the TERN API
+#'
+#' Opens a browser window at the TERN API key request URL and provides
+#'   instruction on how to store the key. After filling the form you will get
+#'   the key soon, but not immediately.
+#'
+#' @keywords internal
+#' @noRd
+#' @return Called for its side-effects, opens a browser window at the TERN
+#'   weather data API key request form.
+.set_tern_key <- function() {
+  if (interactive()) {
+    utils::browseURL("https://ternapikeydetails")
+  }
+
+  stop(
+    "You need to set your TERN API key.\n",
+    "After getting your key set it as 'DPIRD_API_KEY' in .Renviron.\n",
+    "TERN_API_KEY='youractualkeynotthisstring'\n",
+    "For that, use `usethis::edit_r_environ()`"
+  )
+
+  invisible("https://ternapikeydetails")
+}