allow most recent version of file to be downloaded.

[blancoj]

Fixes #4274

When a depositor or an admin wants to add a new version of a file, they download the file, edit it and upload it back as a new version. After uploading the new version, they download it to check it. Before this change, hyrax downloaded the old version. After this PR, it downloads the most recent change.

The reason this was happening was because date_modified was not being updated when a new version was being uploaded. The call to update_metadata ensures that the modified_date is updated. This date is used to build the header when downloading, specifically the Last-Modified portion of the header. The browser then knows that when this date has changed, it does not use the cache.

Guidance for testing, such as acceptance criteria or new user interface behaviors:

• Download a txt file attached to a work
• Edit it
• Go to the Version option for the files, upload the new version
• Check the new version is uploaded in the version history
• Click on Download this file button, and it should download the most recent version of the file and not previous uploaded version.

@samvera/hyrax-code-reviewers

[no-reply]

awesome! this looks like a big improvement.

would you mind looping back and adding a matching controller test?

[no-reply]

candidate for backport to 2.x-stable