Implement stabilize_string().

Closes #13.

DESCRIPTION

@@ -19,7 +19,8 @@ Imports:
     httr2 (>= 0.2.3.9000),
     jsonlite,
     purrr,
-    rlang
+    rlang,
+    stbl
 Suggests: 
     covr,
     testthat (>= 3.0.0)

NAMESPACE

@@ -5,5 +5,6 @@ S3method(.add_body,multipart)
 export(call_api)
 export(compact_nested_list)
 export(security_api_key)
+export(stabilize_string)
 importFrom(fs,path)
 importFrom(rlang,":=")

R/security.R

@@ -1,6 +1,3 @@
-# @param ... Additional arguments, which depend on the location of the API key.
-
-
 #' Authenticate with an API key
 #'
 #' Many APIs provide API keys that can be used to authenticate requests (or,

R/stabilize.R

@@ -0,0 +1,42 @@
+#' Ensure an argument is a length-1 character
+#'
+#' Calls to APIs often require a string argument. This function ensures that
+#' those arguments are length-1, non-`NA` character vectors, or length-1,
+#' non-`NA` vectors that can be coerced to character vectors. This is intended
+#' to ensure that calls to the API will not fail with predictable errors, thus
+#' avoiding unnecessary internet traffic.
+#'
+#' @inheritParams rlang::args_error_context
+#' @inheritParams stbl::stabilize_chr_scalar
+#' @inheritDotParams stbl::stabilize_chr_scalar x_class
+#'
+#' @return `x` coerced to a length-1 character vector, if possible.
+#' @export
+#'
+#' @examples
+#' stabilize_string("a")
+#' stabilize_string(1.1)
+#' x <- letters
+#' try(stabilize_string(x))
+#' x <- NULL
+#' try(stabilize_string(x))
+#' x <- character()
+#' try(stabilize_string(x))
+#' x <- NA
+#' try(stabilize_string(x))
+stabilize_string <- function(x,
+                             ...,
+                             regex = NULL,
+                             arg = rlang::caller_arg(x),
+                             call = rlang::caller_env()) {
+  stbl::stabilize_chr_scalar(
+    x,
+    allow_null = FALSE,
+    allow_zero_length = FALSE,
+    allow_na = FALSE,
+    regex = regex,
+    x_arg = arg,
+    call = call,
+    ...
+  )
+}

tests/testthat/test-stabilize.R

@@ -0,0 +1,10 @@
+test_that("stabilize_string() checks strings", {
+  expect_error(stabilize_string(letters), class = "stbl_error_non_scalar")
+  expect_error(stabilize_string(NULL), class = "stbl_error_bad_null")
+  expect_error(stabilize_string(character()), class = "stbl_error_bad_empty")
+  expect_error(stabilize_string(NA), class = "stbl_error_bad_na")
+  expect_identical(
+    stabilize_string("a"),
+    "a"
+  )
+})