New PR for (r-lib#460)

* added config argument for oauth2.0 and init_oauth

* updatign so I can merge

* Fixing r-lib#411 (review) and example for write_stream.  Added to news.

* fixing odd rproj

* Splitting the PR for later.

* Updating news.

* updated back to roxygennote

* updated with styling

*  fixing indenting!!!!

NEWS.md

@@ -1,5 +1,10 @@
 # httr 1.2.1.9000
 
+
+* Fix reddit demo where `user_agent` was being overloaded.  Now can pass 
+  `user_agent` using `config_init` to `init_oauth2.0` and `Token2.0$new()` 
+  (@muschellij2 @hadley #363).
+
 * `RETRY()` gains a new parameter `terminate_on` that gives caller greater 
   control over which status codes make it stop retrying. It also retries 
   if an error occurs during the request (@asieira, #404)

R/oauth-init.R

@@ -62,12 +62,14 @@ init_oauth1.0 <- function(endpoint, app, permission = NULL,
 #'     retrieve the token. Some authorization servers require this.
 #'     If \code{FALSE}, the default, retrieve the token by including the
 #'     app key and secret in the request body.
+#' @param config_init Additional configuration settings sent to
+#'     \code{\link{POST}}, e.g. \code{\link{user_agent}}.
 #' @export
 #' @keywords internal
 init_oauth2.0 <- function(endpoint, app, scope = NULL, user_params = NULL,
                           type = NULL, use_oob = getOption("httr_oob_default"),
                           is_interactive = interactive(),
-                          use_basic_auth = FALSE) {
+                          use_basic_auth = FALSE, config_init = list()) {
 
   scope <- check_scope(scope)
   use_oob <- check_oob(use_oob)
@@ -108,11 +110,19 @@ init_oauth2.0 <- function(endpoint, app, scope = NULL, user_params = NULL,
   }
 
   if (isTRUE(use_basic_auth)) {
-    req <- POST(endpoint$access, encode = "form", body = req_params,
-      authenticate(app$key, app$secret, type = "basic"))
+    req <- POST(endpoint$access,
+      encode = "form",
+      body = req_params,
+      authenticate(app$key, app$secret, type = "basic"),
+      config = config_init
+    )
   } else {
     req_params$client_secret <- app$secret
-    req <- POST(endpoint$access, encode = "form", body = req_params)
+    req <- POST(endpoint$access,
+      encode = "form",
+      body = req_params,
+      config = config_init
+    )
   }
 
   stop_for_status(req, task = "get an access token")

R/oauth-token.r

@@ -197,10 +197,12 @@ oauth2.0_token <- function(endpoint, app, scope = NULL, user_params = NULL,
                            type = NULL, use_oob = getOption("httr_oob_default"),
                            as_header = TRUE,
                            use_basic_auth = FALSE,
-                           cache = getOption("httr_oauth_cache")) {
+                           cache = getOption("httr_oauth_cache"),
+                           config_init = list()) {
   params <- list(scope = scope, user_params = user_params, type = type,
       use_oob = use_oob, as_header = as_header,
-      use_basic_auth = use_basic_auth)
+      use_basic_auth = use_basic_auth,
+      config_init = config_init)
 
   Token2.0$new(app = app, endpoint = endpoint, params = params,
     cache_path = cache)
@@ -213,7 +215,8 @@ Token2.0 <- R6::R6Class("Token2.0", inherit = Token, list(
     self$credentials <- init_oauth2.0(self$endpoint, self$app,
       scope = self$params$scope, user_params = self$params$user_params,
       type = self$params$type, use_oob = self$params$use_oob,
-      use_basic_auth = self$params$use_basic_auth)
+      use_basic_auth = self$params$use_basic_auth,
+      config_init = self$params$config_init)
   },
   can_refresh = function() {
     !is.null(self$credentials$refresh_token)

demo/oauth2-reddit.R

@@ -15,3 +15,12 @@ token <- oauth2.0_token(reddit, app,
   scope = c("read", "modposts"),
   use_basic_auth = TRUE
 )
+
+# 3b. If get 429 too many requests, the default user_agent is overloaded.
+# If you have an application on Reddit then you can pass that using:
+token <- oauth2.0_token(
+  reddit, app,
+  scope = c("read", "modposts"),
+  use_basic_auth = TRUE,
+  config_init = user_agent("YOUR_USER_AGENT")
+)