Fix bug in ZipDownloadJob when titles contains /

A newly added album in production[1] caused the ZipDownloadJob to fail
because the album title contained a `/` which later code considered to
be part of the file path.

This commit fixes that issue and a similar one in track titles by
sanitizing the generated filenames using the Zaru gem.

[1] https://jam.coop/artists/kristoffer-lislegaard/albums/floating-body-diving-mind
[2] https://github.com/madrobby/zaru

Gemfile

@@ -30,6 +30,7 @@ gem 'stripe', '~> 10.0'
 gem 'tailwindcss-rails'
 gem 'turbo-rails'
 gem 'tzinfo-data', platforms: %i[mingw mswin x64_mingw jruby]
+gem 'zaru', '~> 1.0'
 
 group :development, :test do
   gem 'debug', platforms: %i[mri mingw x64_mingw]

Gemfile.lock

@@ -348,6 +348,7 @@ GEM
     websocket-extensions (0.1.5)
     xpath (3.2.0)
       nokogiri (~> 1.8)
+    zaru (1.0.0)
     zeitwerk (2.6.12)
 
 PLATFORMS
@@ -392,6 +393,7 @@ DEPENDENCIES
   tailwindcss-rails
   turbo-rails
   tzinfo-data
+  zaru (~> 1.0)
 
 RUBY VERSION
    ruby 3.2.2p53

app/jobs/zip_download_job.rb

@@ -9,7 +9,7 @@ def perform(album, format: :mp3v0)
     Dir.mktmpdir do |dir|
       filenames = download_all_tracks(album, format, dir)
 
-      zipfile_name = "#{album.artist.name} - #{album.title}.zip"
+      zipfile_name = Zaru.sanitize!("#{album.artist.name} - #{album.title}.zip")
 
       Zip::File.open(File.join(dir, zipfile_name), create: true) do |zipfile|
         filenames.each do |filename|
@@ -42,7 +42,7 @@ def download_all_tracks(album, format, dir)
   end
 
   def track_filename(track, format)
-    "#{track.position.to_s.rjust(2, '0')} - #{track.title}.#{extension(format)}"
+    Zaru.sanitize!("#{track.position.to_s.rjust(2, '0')} - #{track.title}.#{extension(format)}")
   end
 
   def extension(format)

test/jobs/zip_download_job_test.rb

@@ -38,4 +38,25 @@ class ZipDownloadJobTest < ActiveJob::TestCase
     ZipDownloadJob.perform_now(album)
     assert_equal 1, album.reload.downloads.count
   end
+
+  test 'creates a zip file when the album title contains a /' do
+    album = create(:album, title: 'Slash / Slash')
+    track = create(:track, album:, title: 'First / Track', position: 1)
+    create(:transcode, track:, format: :mp3v0)
+
+    ZipDownloadJob.perform_now(album)
+
+    assert_equal 1, album.downloads.count
+
+    entries = []
+    album.downloads.last.file.open do |zip_file|
+      Zip::File.open(zip_file) do |zip|
+        zip.each do |entry|
+          entries << entry.name
+        end
+      end
+    end
+
+    assert entries.include? '01 - First Track.mp3'
+  end
 end