Control how spaces are handed in query strings

NEWS.md

@@ -1,5 +1,6 @@
 # httr2 (development version)
 
+* `req_url_query()` gains the ability to control how spaces are encoded (#432).
 * `url_parse()` now uses `curl::curl_parse_url()` which is much faster and more correct (#577).
 * `req_retry()` now defaults to `max_tries = 2` with a message.
   Set to `max_tries = 1` to disable retries.

R/req-url.R

@@ -60,12 +60,17 @@ req_url <- function(req, url) {
 #'   If none of these options work for your needs, you can instead supply a
 #'   function that takes a character vector of argument values and returns a
 #'   a single string.
+#' @param .space How should spaces in query params be escaped? The default,
+#'   "percent", uses standard percent encoding (i.e. `%20%`), but you can opt-in
+#'   to "form" encoding, which uses `+` instead.
 req_url_query <- function(.req,
                           ...,
-                          .multi = c("error", "comma", "pipe", "explode")) {
+                          .multi = c("error", "comma", "pipe", "explode"),
+                          .space = c("percent", "form")
+                          ) {
   check_request(.req)
 
-  dots <- multi_dots(..., .multi = .multi)
+  dots <- multi_dots(..., .multi = .multi, .space = .space)
 
   url <- url_parse(.req$url)
   url$query <- modify_list(url$query, !!!dots)

R/url.R

@@ -163,14 +163,19 @@ elements_build <- function(x, name, collapse, error_call = caller_env()) {
 format_query_param <- function(x,
                                name,
                                multi = FALSE,
+                               form = FALSE,
                                error_call = caller_env()) {
   check_query_param(x, name, multi = multi, error_call = error_call)
 
   if (inherits(x, "AsIs")) {
     unclass(x)
   } else {
     x <- format(x, scientific = FALSE, trim = TRUE, justify = "none")
-    curl::curl_escape(x)
+    x <- curl::curl_escape(x)
+    if (form) {
+      x <- gsub("%20", "+", x, fixed = TRUE)
+    }
+    x
   }
 }
 check_query_param <- function(x, name, multi = FALSE, error_call = caller_env()) {

R/utils-multi.R

@@ -1,12 +1,15 @@
 multi_dots <- function(...,
                        .multi = c("error", "comma", "pipe", "explode"),
+                       .space = c("percent", "form"),
                        error_arg = "...",
                        error_call = caller_env()) {
   if (is.function(.multi)) {
     check_function2(.multi, call = error_call, arg = ".multi")
   } else {
     .multi <- arg_match(.multi, error_arg = ".multi", error_call = error_call)
   }
+  .space <- arg_match(.space, call = error_call)
+  form <- .space == "form"
 
   dots <- list2(...)
   if (length(dots) == 0) {
@@ -31,20 +34,20 @@ multi_dots <- function(...,
   n <- lengths(dots)
   if (any(n > 1)) {
     if (is.function(.multi)) {
-      dots[n > 1] <- imap(dots[n > 1], format_query_param, multi = TRUE)
+    dots[n > 1] <- imap(dots[n > 1], format_query_param, multi = TRUE, form = form)
       dots[n > 1] <- lapply(dots[n > 1], .multi)
       dots[n > 1] <- lapply(dots[n > 1], I)
     } else if (.multi == "comma") {
-      dots[n > 1] <- imap(dots[n > 1], format_query_param, multi = TRUE)
+      dots[n > 1] <- imap(dots[n > 1], format_query_param, multi = TRUE, form = form)
       dots[n > 1] <- lapply(dots[n > 1], paste0, collapse = ",")
       dots[n > 1] <- lapply(dots[n > 1], I)
     } else if (.multi == "pipe") {
-      dots[n > 1] <- imap(dots[n > 1], format_query_param, multi = TRUE)
+      dots[n > 1] <- imap(dots[n > 1], format_query_param, multi = TRUE, form = form)
       dots[n > 1] <- lapply(dots[n > 1], paste0, collapse = "|")
       dots[n > 1] <- lapply(dots[n > 1], I)
     } else if (.multi == "explode") {
       dots <- explode(dots)
-      dots[n > 1] <- imap(dots[n > 1], format_query_param, multi = TRUE)
+      dots[n > 1] <- imap(dots[n > 1], format_query_param, multi = TRUE, form = form)
       dots[n > 1] <- lapply(dots[n > 1], I)
     } else if (.multi == "error") {
       cli::cli_abort(
@@ -58,7 +61,12 @@ multi_dots <- function(...,
   }
 
   # Format other params
-  dots[n == 1] <- imap(dots[n == 1], format_query_param, error_call = error_call)
+  dots[n == 1] <- imap(
+    dots[n == 1],
+    format_query_param,
+    form = form,
+    error_call = error_call
+  )
   dots[n == 1] <- lapply(dots[n == 1], I)
 
   dots

tests/testthat/_snaps/req-url.md

@@ -1,3 +1,11 @@
+# can control space handling
+
+    Code
+      req_url_query(req, a = " ", .space = "bar")
+    Condition
+      Error in `multi_dots()`:
+      ! `.space` must be one of "percent" or "form", not "bar".
+
 # can handle multi query params
 
     Code

tests/testthat/test-req-url.R

@@ -52,6 +52,17 @@ test_that("can set query params", {
   expect_equal(req_url_query(req, !!!list(a = 1, a = 2))$url, "http://example.com/?a=1&a=2")
 })
 
+test_that("can control space handling", {
+  req <- request("http://example.com/")
+  expect_equal(req_url_query(req, a = " ")$url, "http://example.com/?a=%20")
+  expect_equal(req_url_query(req, a = " ", .space = "form")$url, "http://example.com/?a=+")
+
+  expect_snapshot(
+    req_url_query(req, a = " ", .space = "bar"),
+    error = TRUE
+  )
+})
+
 test_that("can handle multi query params", {
   req <- request("http://example.com/")