Unhandled exception when ZIP download is cancelled

[robinkar]

We noticed that when a user cancels a ZIP download in the file browser (i.e. client disconnects), a FATAL exception with backtrace is logged as there is an unhandled exception.

Backtrace

1738223552 2025 Jan 30 09:52:32 ood user notice ondemand_passenger  App 68454 output: [2025-01-30 09:52:32 +0200 ] FATAL "ActionController::UnknownFormat (ActionController::UnknownFormat):
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/actionpack-6.1.7.6/lib/action_controller/metal/mime_responds.rb:216:in `respond_to'
  /var/www/ood/apps/sys/dashboard/app/controllers/files_controller.rb:111:in `rescue in fs'
  /var/www/ood/apps/sys/dashboard/app/controllers/files_controller.rb:7:in `fs'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/actionpack-6.1.7.6/lib/action_controller/metal/basic_implicit_render.rb:6:in `send_action'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/actionpack-6.1.7.6/lib/abstract_controller/base.rb:228:in `process_action'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/actionpack-6.1.7.6/lib/action_controller/metal/rendering.rb:30:in `process_action'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/actionpack-6.1.7.6/lib/abstract_controller/callbacks.rb:42:in `block in process_action'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/activesupport-6.1.7.6/lib/active_support/callbacks.rb:106:in `run_callbacks'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/actionpack-6.1.7.6/lib/abstract_controller/callbacks.rb:41:in `process_action'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/actionpack-6.1.7.6/lib/action_controller/metal/rescue.rb:22:in `process_action'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/actionpack-6.1.7.6/lib/action_controller/metal/instrumentation.rb:34:in `block in process_action'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/activesupport-6.1.7.6/lib/active_support/notifications.rb:203:in `block in instrument'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/activesupport-6.1.7.6/lib/active_support/notifications/instrumenter.rb:24:in `instrument'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/activesupport-6.1.7.6/lib/active_support/notifications.rb:203:in `instrument'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/actionpack-6.1.7.6/lib/action_controller/metal/instrumentation.rb:33:in `process_action'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/actionpack-6.1.7.6/lib/action_controller/metal/params_wrapper.rb:249:in `process_action'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/actionpack-6.1.7.6/lib/abstract_controller/base.rb:165:in `process'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/actionview-6.1.7.6/lib/action_view/rendering.rb:39:in `process'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/actionpack-6.1.7.6/lib/action_controller/metal/live.rb:261:in `block (2 levels) in process'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/activesupport-6.1.7.6/lib/active_support/dependencies/interlock.rb:42:in `block in running'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/activesupport-6.1.7.6/lib/active_support/concurrency/share_lock.rb:162:in `sharing'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/activesupport-6.1.7.6/lib/active_support/dependencies/interlock.rb:41:in `running'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/actionpack-6.1.7.6/lib/action_controller/metal/live.rb:253:in `block in process'
  /opt/ood/ondemand/root/usr/share/gems/3.1/ondemand/3.1.10-1/gems/actionpack-6.1.7.6/lib/action_controller/metal/live.rb:303:in `block in new_controller_thread'"

It seems that format.zip is missing from here.
However, it seems like the reason that we reach that rescue block at all is that the previous rescue block for sending a ZIP raises an exception itself, header already sent (ActionDispatch::IllegalStateError).

Adding the format.zip to the respond_to block seems to resolve the issue, but might not be the correct solution. Catching ActionController::Live::ClientDisconnected (and do nothing?) might be a more correct solution.