streamline data situation

[maxheld83]

We seem to be running into a similar problem in several projects, including http://github.com/subugoe/hoad/, http://github.com/subugoe/openairegraph/ and the crossref dump situation http://github.com/njahn82/cr_dump/:

There's big-ish (>1MB) serialised data, usually JSON, CSV or the same compressed, which is either/or

• expensive to recompute
• very large / slow to download.

(I'm not talking about databases here, that's a separate concern).

These files cause several problems / face limitations:

• they're too big/expensive to recompute often
• they can't be git commited (too large)
• they can make or break results; i.e. they are crucial for reproducibility
• we need them in CI and for tests
• we need to share them

Possible straightforward solutions might be:

• store only locally (no reproducibility)
• store on a network drive (no reproducibility)
• setting up a database (too expensive/too much hassle unless absolutely necessary)
• store in github releases (not easily automated, very limited storage)
• ...

I think we need something else which neatly abstracts away all this.
There's probably a good solution out there already.

One avenue to pursue would be git lfs.

Ideally, we should have a solution which understands serialised data, and has a better understanding of diffing rows. (order does not matter).

Anyway, this shouldn't be too complicated and we might start with something small.

I'm going to look into this when I have the time.
I think this could save us all a lot of time.

[maxheld83]

among other things, the repeated downloads of the big dumps via download.file() should be transparently cached.

[maxheld83]

this would also actually be a feature for a lot of users, who might face the same problem when they run this in CI or collaboratively.