[feature:lib] Allow searching by last_updated_date

[xuanxu]

Checklist

• All old and new tests pass (ran bundle exec rspec spec in the root directory).
• Read the contribution guidelines.
• Updated documentation (if necessary).

Reason (or issue)

ArXiv allows to include lastUpdatedDate in the search_query param.

Description

This PR adds support for using lastUpdatedDate in the search API

[eonu]

Hey! Thanks again for the help :)

Looking into this, it seems that lastUpdatedDate doesn't belong in the search_query with other fields like title and author (at least based on what it says here), and therefore it might not be possible to use it in the way that you've implemented.

Instead, it can only be specified in sortBy. It looks like sorting by lastUpdateDate is already implemented in Arx (although it is incorrectly implemented as lastUpdated instead of lastUpdatedDate, and probably doesn't work because of this – I will fix this).

I think this means that with the arXiv search API, you can only sort by last updated date, but not search for a specific last updated date.

[eonu]

Hmm, just had a further look and it seems that I'm wrong, and that you can actually search by last updated date, despite it not being documented on arXiv.

Instead of specifying a not very user-friendly range like search_query=lastUpdatedDate:[200712310900+TO+200712310959] in the usual way:

Arx.search do |q|
  q.last_updated_date '[200712310900+TO+200712310959]'
end

it would be cool if it could be specified as a DateTime range

Arx.search do |q|
  q.last_updated_date DateTime.new(2006, 1, 1)..DateTime.new(2008, 1, 1)
end

but maybe we can leave that for another PR, as it would require quite a lot to be changed.

It also looks like the same can be done with submittedDate, so maybe we can do that in another PR.

[xuanxu]

Hmm, just had a further look and it seems that I'm wrong, and that you can actually search by last updated date, despite it not being documented on arXiv.

Yeah, the arXiv API docs are quite incomplete.

Instead of specifying a not very user-friendly range like search_query=lastUpdatedDate:[200712310900+TO+200712310959] in the usual way
it would be cool if it could be specified as a DateTime range

That would be great!
I wanted to be consistent with the existing code accepting strings and respect the current structure.

but maybe we can leave that for another PR, as it would require quite a lot to be changed.
It also looks like the same can be done with submittedDate, so maybe we can do that in another PR.

I agree, we can think about how to accept different value types with the current workflow, maybe adding specific checks by method name in the validations or something like that.

[eonu]

@xuanxu, just a note – instead of

Arx.search {|q| q.updated_at '[200712310900+TO+200712310959]'}

you have to remove the URL-encoded +, so

Arx.search {|q| q.updated_at '[200712310900 TO 200712310959]'}