Do not require 'curl' in webR

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: magick
 Type: Package
 Title: Advanced Graphics and Image-Processing in R
-Version: 2.8.1
+Version: 2.8.2
 Authors@R: person("Jeroen", "Ooms", role = c("aut", "cre"), email = "jeroen@berkeley.edu",
     comment = c(ORCID = "0000-0002-4035-0289"))
 Description: Bindings to 'ImageMagick': the most comprehensive open-source image

NEWS

@@ -1,6 +1,7 @@
 2.8.2
   - Fix image_draw() for small images: #317
   - Change image_shadow() to transparent background by default
+  - Downloading from a URL no longer requires 'curl' (to work in webR)
 
 2.8.1
   - Windows: update to libmagick 6.9.12-98

R/utils.R

@@ -27,21 +27,25 @@ replace_url <- function(path){
   }
 }
 
+# Uses file extension from HTTP content-type if available to help IM guess type.
 download_url <- function(url){
-  req <- curl::curl_fetch_memory(url)
-  if(req$status_code >= 400)
-    stop(sprintf("Failed to download %s (HTTP %d)", url, req$status))
-  headers <- curl::parse_headers_list(req$headers)
-  ctype <- headers[['content-type']]
-  matches <- match(ctype, mimetypes$type)
-  extension <- if(length(matches) && !is.na(matches) && !grepl("(text|octet)", ctype)){
-    sub("*.", ".", mimetypes$pattern[matches[1]], fixed = TRUE)
+  tmp <- tempfile(fileext = sub("\\?.*", "", basename(url)))
+  if(requireNamespace('curl', quietly = TRUE)){
+    h <- curl::new_handle()
+    curl::curl_download(url, tmp, handle = h)
+    headers <- curl::parse_headers_list(curl::handle_data(h)$headers)
+    ctype <- headers[['content-type']]
+    matches <- match(ctype, mimetypes$type)
+    if(length(matches) && !is.na(matches) && !grepl("(text|octet)", ctype)){
+      extension <- sub("*.", ".", mimetypes$pattern[matches[1]], fixed = TRUE)
+      outfile <- tempfile(fileext = extension)
+      file.rename(tmp, outfile)
+      return(outfile)
+    }
   } else {
-    sub("\\?.*", "", basename(url))
+    utils::download.file(url, tmp, quiet = TRUE) #Fallback for webR
   }
-  filename <- tempfile(fileext = extension)
-  writeBin(req$content, filename)
-  return(filename)
+  return(tmp)
 }
 
 assert_image <- function(image){

configure

@@ -82,5 +82,10 @@ fi
 # Write to Makevars
 sed -e "s|@cflags@|$PKG_CFLAGS|" -e "s|@libs@|$PKG_LIBS|" src/Makevars.in > src/Makevars
 
+# Dont use curl on webR
+if [ `uname` = "Emscripten" ]; then
+sed -i.bak 's/curl/utils/g' DESCRIPTION
+fi
+
 # Success
 exit 0