Make specifying url DRY

Add tests for safe_to_download

R/utils.R

@@ -292,14 +292,17 @@ is_unique <- function(x, allow_na = TRUE) {
 #'
 #' @param url Character vector of length 1; URL pointing to zip file to
 #' download ie "https://data.canadensys.net/ipt/archive.do?r=vascan&v=37.12"
+#' @param online Logical vector of length 1; is this computer connected to the
+#' internet? Defaults to curl::has_internet(), but provided for testing
+#' purposes.
 #'
 #' @return Logical vector of length 1.
 #' @noRd
 #' @autoglobal
-safe_to_download <- function(url) {
+safe_to_download <- function(url, online = curl::has_internet()) {
   get_safely <- purrr::safely(httr::GET)
   # Check for internet connection
-  if (!curl::has_internet()) {
+  if (!online) {
     return(FALSE)
   }
   # Check for functioning URL

inst/extdata/vascan_url.R

@@ -0,0 +1,5 @@
+# The URL for the Vascular Plants of Canada is used in multiple places,
+# so specify it here and source it as needed.
+
+## ---- set-url
+vascan_url <- "https://data.canadensys.net/ipt/archive.do?r=vascan&v=37.12"

tests/testthat/test-utils.R

@@ -281,7 +281,20 @@ test_that("check_fill_usage_id_name() works", {
 })
 
 test_that("Check for zip file ready to download works", {
+  # Simulate being offline
+  expect_equal(
+    safe_to_download(vascan_url, online = FALSE),
+    FALSE
+  )
+  # Rest of tests require an internet connection
   skip_if_offline(host = "r-project.org")
+  # URL used in vignette should work
+  # - load URL
+  source(system.file("extdata", "vascan_url.R", package = "dwctaxon"))
+  expect_equal(
+    safe_to_download(vascan_url),
+    TRUE
+  )
   # Check for 404
   expect_equal(
     safe_to_download(

vignettes/real-data.Rmd

@@ -15,6 +15,8 @@ knitr::opts_chunk$set(
 
 # Increase width for printing tibbles
 old <- options(width = 140)
+
+knitr::read_chunk(system.file("extdata", "vascan_url.R", package = "dwctaxon"))
 ```
 
 This vignette demonstrates using dwctaxon on "real life" data found in the wild. Our goal is to import the data and validate it.
@@ -34,10 +36,23 @@ We will use the [Database of Vascular Plants of Canada (VASCAN)](http://data.can
 
 The data can be obtained manually by going to the [VASCAN website](http://data.canadensys.net/ipt/resource.do?r=vascan), downloading the Darwin Core Archive, and unzipping it^[If you download the data manually, it may be a different version than the one used here, v37.12].
 
+Alternatively, it can be downloaded and unzipped with R. First, we set up some temporary folders for downloading and specify the URL:
+
+```{r download-setup}
+# - Specify temporary folder for downloading data
+temp_dir <- tempdir()
+# - Set name of zip file
+temp_zip <- paste0(temp_dir, "/dwca-vascan.zip")
+# - Set name of unzipped folder
+temp_unzip <- paste0(temp_dir, "/dwca-vascan")
+```
+
+```{r, set-url}
+```
+
 ```{r, echo = FALSE, results = "asis"}
 # Check if file can be downloaded safely, quit early if not
 # Make sure this URL matches the one in the next chunk
-vascan_url <- "https://data.canadensys.net/ipt/archive.do?r=vascan&v=37.12"
 if (!dwctaxon:::safe_to_download(vascan_url)) {
   cat(
     paste0(
@@ -50,22 +65,11 @@ if (!dwctaxon:::safe_to_download(vascan_url)) {
 }
 ```
 
-Alternatively, it can be downloaded and unzipped with R:
+Next, download and unzip the zip file.
 
 ```{r download-unzip}
-# Set up folders:
-# - Specify temporary folder for downloading data
-temp_dir <- tempdir()
-# - Set name of zip file
-temp_zip <- paste0(temp_dir, "/dwca-vascan.zip")
-# - Set name of unzipped folder
-temp_unzip <- paste0(temp_dir, "/dwca-vascan")
-
 # Download data
-download.file(
-  url = "https://data.canadensys.net/ipt/archive.do?r=vascan&v=37.12",
-  destfile = temp_zip, mode = "wb"
-)
+download.file(url = vascan_url, destfile = temp_zip, mode = "wb")
 
 # Unzip
 unzip(temp_zip, exdir = temp_unzip)
@@ -74,7 +78,7 @@ unzip(temp_zip, exdir = temp_unzip)
 list.files(temp_unzip)
 ```
 
-Next, load the taxonomic data (`taxon.txt`) into R. It is a tab-separated text file, so we use `readr::read_tsv()` to load it.
+Finally, load the taxonomic data (`taxon.txt`) into R. It is a tab-separated text file, so we use `readr::read_tsv()` to load it.
 
 ```{r load-data}
 vascan <- read_tsv(paste0(temp_unzip, "/taxon.txt"))