Implement resp_request() (#615)

Fixes #604

NEWS.md

@@ -1,5 +1,6 @@
 # httr2 (development version)
 
+* New `resp_request()` aids debugging by returning the request associated with a response (#604).
 * `print.request()` now correctly escapes `{}` in headers (#586).
 * New `req_headers_redacted()` provides a user-friendlier way to set redacted headers (#561).
 * `resp_link_url()` now works if there are multiple `Link` headers (#587).

R/resp-request.R

@@ -0,0 +1,16 @@
+#' Find the request responsible for a response
+#'
+#' To make debugging easier, httr2 includes the request that was used to
+#' generate every response. You can use this function to access it.
+#'
+#' @inheritParams resp_header
+#' @export
+#' @examples
+#' req <- request_test()
+#' resp <- req_perform(req)
+#' resp_request(resp)
+resp_request <- function(resp) {
+  check_response(resp)
+
+  resp$request
+}

tests/testthat/test-resp-request.R

@@ -0,0 +1,5 @@
+test_that("can extract request", {
+  req <- request_test()
+  resp <- req_perform(req)
+  expect_equal(resp_request(resp), req)
+})