First stab at req_perform_sequential()

R/multi-req.R

@@ -19,7 +19,9 @@
 #' * Consults the cache set by [req_cache()] before/after all requests.
 #'
 #' In general, where [req_perform()] might make multiple requests due to retries
-#' or OAuth failures, `req_perform_parallel()` will only make 1.
+#' or OAuth failures, `req_perform_parallel()` will only make 1. If any of
+#' these limitations are problematic, you may want to use
+#' [req_perform_sequential()] instead.
 #'
 #' @param reqs A list of [request]s.
 #' @param paths An optional list of paths, if you want to download the request

R/sequential.R

@@ -0,0 +1,48 @@
+#' Perform multiple requests in sequence
+#'
+#' Given a list of requests, this function requests each one turn, returning
+#' a list of responses.
+#'
+#' @inheritParams req_perform_sequential
+#' @inheritParams req_perform_iteratively
+#' @export
+#' @examples
+#' req <- request("https://api.restful-api.dev/objects")
+#' ids <- sort(sample(100, 50))
+#' chunks <- split(ids, (seq_along(ids) - 1) %/% (length(ids) / 10))
+#' reqs <- chunks %>% lapply(\(idx) req %>% req_url_query(id = idx, .multi = "comma"))
+#' resps <- reqs %>% req_perform_sequential()
+#' resps_data(resps, \(resp) resp_body_json(resp))
+req_perform_sequential <- function(reqs, paths = NULL, progress = TRUE) {
+  if (!is.list(reqs)) {
+    stop_input_type(reqs, "a list")
+  }
+  if (!is.null(paths)) {
+    if (length(reqs) != length(paths)) {
+      cli::cli_abort("If supplied, {.arg paths} must be the same length as {.arg req}.")
+    }
+  }
+
+  progress <- create_progress_bar(
+    total = length(reqs),
+    name = "Iterating",
+    config = progress
+  )
+
+  resps <- rep_along(reqs, list())
+
+  tryCatch({
+    for (i in seq_along(reqs)) {
+      check_request(reqs[[i]], arg = glue::glue("req[[{i}]]"))
+      resps[[i]] <- req_perform(reqs[[i]], path = paths[[i]])
+      progress$update()
+    }
+  }, interrupt = function(cnd) {
+    cli::cli_alert_warning(
+      "Terminating iteration; returning {i} response{?s}."
+    )
+  })
+  progress$done()
+
+  resps
+}