From 14ba322745838eb8d27a1223236ba243def8ff92 Mon Sep 17 00:00:00 2001
From: nielsoledam <nielsoledam@Niels-Ole-Dam.local>
Date: Fri, 4 Aug 2017 19:56:48 +0200
Subject: [PATCH 1/3] Has re-added code for using value of "retry-after" header
 as waiting time if status_code = 429. Now also respects value of pause_min.

---
 R/retry.R | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/R/retry.R b/R/retry.R
index d1cb29a6..c62d7015 100644
--- a/R/retry.R
+++ b/R/retry.R
@@ -91,6 +91,10 @@ backoff_full_jitter <- function(i, resp, pause_base = 1, pause_cap = 60,
       error_description <- ""
       status <- status_code(resp)
     }
+    if (status == 429) {
+      length_429 <- as.numeric(resp$headers[["retry-after"]])
+      if (!is.null(length_429) && length_429 >= pause_min) length <- length_429
+    }
     message(error_description, "Request failed [", status, "]. Retrying in ", round(length, 1), " seconds...")
   }
   Sys.sleep(length)

From d4e869efc3f0a8d9de95028662efa50ff6f38973 Mon Sep 17 00:00:00 2001
From: nielsoledam <nielsoledam@Niels-Ole-Dam.local>
Date: Fri, 4 Aug 2017 21:56:09 +0200
Subject: [PATCH 2/3] Fixed error in if logic and added documentation.

---
 NEWS.md   | 4 ++++
 R/retry.R | 6 ++++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index b2ff253d..b6468cc6 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -71,6 +71,10 @@
 * More forms of empty query are recognized as such. Eliminates a source of 
   spurious trailing `?` and `?=` in URLs produced by `modify_url()`. 
   (@jennybc, #452)
+  
+* If the server returns HTTP status code 429 and specifies a `retry-after` 
+  value, that value will now be used instead of exponential backoff with 
+  jitter, unless it's smaller than `pause_min`. (@nielsoledam, #472)
 
 # httr 1.2.1
 
diff --git a/R/retry.R b/R/retry.R
index c62d7015..328bdf9d 100644
--- a/R/retry.R
+++ b/R/retry.R
@@ -9,6 +9,8 @@
 #' randomly waits up to twice as long. (Technically it uses exponential
 #' backoff with jitter, using the approach outlined in
 #' \url{https://www.awsarchitectureblog.com/2015/03/backoff.html}.)
+#' If the server returns status code 429 and specifies a \code{retry-after} value, that
+#' value will be used instead, unless it's smaller than \code{pause_min}.
 #'
 #' @inheritParams VERB
 #' @inheritParams GET
@@ -92,8 +94,8 @@ backoff_full_jitter <- function(i, resp, pause_base = 1, pause_cap = 60,
       status <- status_code(resp)
     }
     if (status == 429) {
-      length_429 <- as.numeric(resp$headers[["retry-after"]])
-      if (!is.null(length_429) && length_429 >= pause_min) length <- length_429
+      retry_after <- resp$headers[["retry-after"]]
+      if (!is.null(retry_after)) length <- max(pause_min, as.numeric(retry_after))
     }
     message(error_description, "Request failed [", status, "]. Retrying in ", round(length, 1), " seconds...")
   }

From 33ad8bd9d2e60212b469901b40c7e451566718c3 Mon Sep 17 00:00:00 2001
From: nielsoledam <nielsoledam@Niels-Ole-Dam.local>
Date: Fri, 4 Aug 2017 22:17:43 +0200
Subject: [PATCH 3/3] Added {} and indented condition code to match rest of
 code.

---
 R/retry.R | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/R/retry.R b/R/retry.R
index 328bdf9d..766fab84 100644
--- a/R/retry.R
+++ b/R/retry.R
@@ -95,7 +95,9 @@ backoff_full_jitter <- function(i, resp, pause_base = 1, pause_cap = 60,
     }
     if (status == 429) {
       retry_after <- resp$headers[["retry-after"]]
-      if (!is.null(retry_after)) length <- max(pause_min, as.numeric(retry_after))
+      if (!is.null(retry_after)) {
+        length <- max(pause_min, as.numeric(retry_after))
+      }
     }
     message(error_description, "Request failed [", status, "]. Retrying in ", round(length, 1), " seconds...")
   }