Reduce bitstream authorization requests for item page

[tinsch]

Description

This PR reduces the number of calls to the REST API by executing certain authorization requests only conditionally if the normal download is not possible for the user. Before, the authorization request "canRequestACopy" was always sent for every bitstream, now this only happens if the "canDownload" request returns false. This improves the response time performance for items with a large number of bitstreams and a large pagesize (>=50), as can be seen in a graph below.

Instructions for Reviewers

Currently the response time is slow for items with a large number of bitstreams. The current workaround are small pageSizes for the item's bitstreams per default. However, from a UX standpoint it would be nice to be able to show a larger list of bitstreams to the users, especially in the case of uploaded research data.

How to test this PR:

• create an Item with >=50 bitstreams
• edit some bitstreams, so that they are embargoed, or the access is otherwise restricted to anonymous users
• set item.bitstream.pageSize to 50 (or more)
• check that the response time is slower without this PR on the item page, and faster with the PR changes
• check that the "Request a copy" functionality still works for embargoed and otherwise restricted items

Here is a comparison of the reponse time of an item page, varied in the page size:

Related Issues, former issues with item bitstream pagesize:

DSpace/DSpace#8648
#2065

Checklist

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Co-funded by the European Union and Universitätsbibliothek TU Berlin (DSpaceQPO project)

[tinsch]

Please note: I am not a frontend dev, so I would be grateful for a review by a more experienced frontend developer :) especially concerning the revised tests

[EikLoe]

@tinsch Thanks for the PR!
I tested it and it worked fine for me! I only saw the backend requests for the restricted bitstreams. 👍🏾

[tinsch]

Any news on this? I think @EikLoe tested it, but did not do a code review. I'm asking because I am not sure if my contribution counts as a feature or a bug fix for DSpace 10.

[tdonohue]

@tinsch : This would be considered a bug fix. It's still waiting on a code review but is in our "Reviewer Approved" column of the board. I was waiting to see if @artlowel had a chance to take a quick look at it since he previously volunteered. Otherwise, I'll get back to this hopefully in the next week or two.

[kshepherd]

+1 this looks good to me, thanks @tinsch
I can confirm that in item with 60 bitstreams including 8 non-public bitstreams (4 embargoes, 4 totally restricted), I got the request-a-copy links I expected, and the number of requests for the "canRequestACopy" feature were reduced down to 8, after the false canDownload feature was evaluated for each of those bitstreams.

I didn't see quite the stark contrast in page load time in my own local instance (~2800ms vs ~3500ms) but it's definitely quicker and more efficient.

I also confirmed that the links to restricted items work as expected when the Request-a-Copy feature is disabled.

[tdonohue]

Thanks @tinsch ! As this is at +2, I think this is ready to merge. The code looks reasonable to me as well.

I'm going to attempt to backport this automatically to 9.x (as I think it should work cleanly). Backports to 8.x and 7.x are also welcome, but those are likely to need to be done manually (as the code of this component is a bit different in those releases). If anyone is interested, feel free to create the backport PRs.

[dspace-bot]

Successfully created backport PR for dspace-9_x:

• [Port dspace-9_x] Reduce bitstream authorization requests for item page #5221

[tinsch]

Thanks @tdonohue! I'll have a look into the 7.x and 8.x codebase and see if a backport is feasible 👍