#353 allow for choosing from a couple different base ulrs for ghcnd()…

…, bump version

DESCRIPTION

@@ -7,7 +7,7 @@ Description: Client for many 'NOAA' data sources including the 'NCDC' climate
     for 'NOAA' sea ice data, the 'NOAA' severe weather inventory, 'NOAA' Historical
     Observing 'Metadata' Repository ('HOMR') data, 'NOAA' storm data via 'IBTrACS',
     tornado data via the 'NOAA' storm prediction center, and more.
-Version: 0.9.6.98
+Version: 0.9.6.99
 License: MIT + file LICENSE
 Encoding: UTF-8
 Language: en-US

R/ghcnd.R

@@ -28,6 +28,20 @@
 #' one year. In addition to measurements, columns are included for certain
 #' flags, which add information on observation sources and quality and are
 #' further explained in NOAA's README file for the data.
+#' 
+#' @section Base URL:
+#' The base url for data requests can be changed. The allowed urls are:
+#' https://www1.ncdc.noaa.gov/pub/data/ghcn/daily/all (default),
+#' ftp://ftp.ncei.noaa.gov/pub/data/ghcn/daily/all,
+#' ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/daily/all
+#' 
+#' You can set the base url using the `RNOAA_GHCND_BASE_URL` environment
+#' variable; see example below.
+#' 
+#' The reason for this is that sometimes one base url source is temporarily
+#' down, but another base url may work. It doesn't make sense to allow 
+#' an arbitrary base URL; open an issue if there is another valid 
+#' base URL for GHNCD data that we should add to the allowed set of base urls.
 #'
 #' @details  This function saves the full set of weather data for the queried
 #' site locally in the directory specified by the \code{path} argument.
@@ -76,6 +90,14 @@
 #' # Read in a .dly file you've already downloaded
 #' path <- system.file("examples/AGE00147704.dly", package = "rnoaa")
 #' ghcnd_read(path)
+#' 
+#' # change the base url for data requests
+#' Sys.setenv(RNOAA_GHCND_BASE_URL =
+#'   "ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/daily/all")
+#' ghcnd(stations$id[45], verbose = TRUE)
+#' ## must be in the allowed set of urls
+#' # Sys.setenv(RNOAA_GHCND_BASE_URL = "https://google.com")
+#' # ghcnd(stations$id[58], verbose = TRUE)
 #' }
 ghcnd <- function(stationid, refresh = FALSE, ...) {
   csvpath <- ghcnd_local(stationid)
@@ -215,7 +237,22 @@ ghcnd_GET <- function(stationid, ...){
   return(dat)
 }
 
-ghcndbase <- function() "ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/daily/all"
+ghcnd_allowed_urls <- c(
+  "https://www1.ncdc.noaa.gov/pub/data/ghcn/daily/all",
+  "ftp://ftp.ncei.noaa.gov/pub/data/ghcn/daily/all",
+  "ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/daily/all"
+)
+ghcndbase <- function() {
+  x <- Sys.getenv("RNOAA_GHCND_BASE_URL", "")
+  if (identical(x, "")) {
+    x <- "https://www1.ncdc.noaa.gov/pub/data/ghcn/daily/all"
+  }
+  if (!x %in% ghcnd_allowed_urls) {
+    stop("the RNOAA_GHCND_BASE_URL environment variable must be in set:\n",
+      paste0(ghcnd_allowed_urls, collapse = "  \n"))
+  }
+  return(x)
+}
 ghcnd_remote <- function(stationid) {
   file.path(ghcndbase(), paste0(stationid, ".dly"))
 }

tests/testthat/test-ghcnd.R

@@ -89,3 +89,12 @@ test_that("get data", {
   expect_lt(NROW(aa), NROW(bb))
   expect_lt(NROW(cc), NROW(bb))
 })
+
+test_that("alternative base urls", {
+  expect_equal(Sys.getenv("RNOAA_GHCND_BASE_URL"), "")
+
+  Sys.setenv(RNOAA_GHCND_BASE_URL = "https://google.com")
+  expect_error(ghcnd("ASN00008179"), "must be in set")
+
+  Sys.unsetenv("RNOAA_GHCND_BASE_URL")
+})