Rework gmail_auth to take secret file parameter

Also reoxygenate

NAMESPACE

@@ -83,6 +83,7 @@ export(untrash_message)
 export(untrash_thread)
 export(update_label)
 export(update_label_patch)
+export(use_secret_file)
 import(base64enc)
 import(httr)
 importFrom(magrittr,"%>%")

R/gmailr.R

@@ -43,25 +43,36 @@ clear_token <- function() {
 }
 
 #' Setup oauth authentication for your gmail
-#' @param secret_file the secret json file downloaded from \url{https://cloud.google.com/console#/project}
+#'
 #' @param scope the authentication scope to use
+#' @param id the client_id to use for authentication
+#' @param secret the client secret to use for authentication
+#' @param secret_file the secret json file downloaded from \url{https://cloud.google.com/console#/project}
+#' @seealso use_secret_file to set the default id and secret to a different
+#'   value than the default.
 #' @export
 #' @examples
 #' \dontrun{
-#' gmail_auth("file", "compose")
+#' gmail_auth("compose")
 #' }
-gmail_auth <- function(secret_file=NULL,
+gmail_auth <- function(scope=c("read_only", "modify", "compose", "full"),
                       id = the$id,
                       secret = the$secret,
-                      scope=c("read_only", "modify", "compose", "full")) {
-
-  if(is.null(secret_file)){
-    myapp <- oauth_app("google", id, secret)
-  } else {
-    info <- jsonlite::fromJSON(readChar(secret_file, nchars=1e5))
-    myapp <- oauth_app("google", info$installed$client_id, info$installed$client_secret)
+                      secret_file = NULL) {
+
+  if(!is.null(secret_file)){
+    if (!(missing(id) && missing(secret))) {
+      stop("You should set either ", sQuote("secret_file"), " or ",
+           sQuote("id"), " and ", sQuote("secret"), ", not both",
+           call. = FALSE)
+    }
+    use_secret_file(secret_file)
+
+    # Use new ID and secret
+    id <- the$id
+    secret <- the$secret
   }
-
+  myapp <- oauth_app("google", id, secret)
 
   scope <- switch(match.arg(scope),
                  read_only = "https://www.googleapis.com/auth/gmail.readonly",
@@ -73,6 +84,18 @@ gmail_auth <- function(secret_file=NULL,
   the$token <- oauth2.0_token(oauth_endpoints("google"), myapp, scope = scope)
 }
 
+#' Use information from a secret file
+#'
+#' This function sets the default secret and client_id to those in the secret
+#' file
+#' @param filename the filename of the file
+#' @export
+use_secret_file <- function(filename) {
+  info <- jsonlite::fromJSON(readChar(secret_file, nchars=1e5))
+  the$secret <- info$installed$client_secret
+  the$client_id <- info$installed$client_id
+}
+
 #' Get the body text of a message or draft
 #' @param x the object from which to retrieve the body
 #' @param ... other parameters passed to methods