fix(export): don't fail when trying to write a file name > 255 bytes

app/lib/download_manager/parallel_download_queue.rb

@@ -28,7 +28,7 @@ module DownloadManager
 
     # can't be used with typhoeus, otherwise block is closed before the request is run by hydra
     def download_one(attachment:, path_in_download_dir:, http_client:)
-      attachment_path = File.join(destination, path_in_download_dir)
+      attachment_path = File.join(destination, sanitize_filename(path_in_download_dir))
       attachment_dir = File.dirname(attachment_path)
 
       FileUtils.mkdir_p(attachment_dir) if !Dir.exist?(attachment_dir) # defensive, do not write in undefined dir
@@ -49,5 +49,16 @@ module DownloadManager
         http_client.queue(request)
       end
     end
+
+    private
+
+    def sanitize_filename(filename)
+      return filename if filename.bytesize <= 255
+
+      ext = File.extname(filename)
+      basename = File.basename(filename, ext).byteslice(0, 255 - ext.bytesize)
+
+      basename + ext
+    end
   end
 end

spec/lib/download_manager/parallel_download_queue_spec.rb

@@ -40,5 +40,16 @@ describe DownloadManager::ParallelDownloadQueue do
         # expect(downloadable_manager.errors).to have_key(destination)
       end
     end
+
+    context 'with a destination filename too long' do
+      let(:destination) { 'a' * 252 + '.txt' }
+
+      it 'limit the file path to 255 bytes' do
+        target = File.join(download_to_dir, 'a' * 251 + '.txt')
+        expect { subject }.to change { File.exist?(target) }
+        attachment.file.rewind
+        expect(attachment.file.read).to eq(File.read(target))
+      end
+    end
   end
 end