Customizable album ordering

[arahayrabedian]

It works, ~it still needs a final passthrough/review on my part~, but just for final-state-ish awareness I opened the PR. ~I still need to look at the PR itself,~ I'm sure there are glaring mistakes.

How it works at a very very high level:

• On album initialization look for an ordering.yml file in the bucket
• Retrieve, parse, preprocess and then cache the ordering.yml in to an AlbumOrderingConfig object
• Use the AlbumOrderingConfig in order to create an AlbumOrdering object, which gets passed around with the actual ordering of an album. This AlbumOrdering is a definitive definition of an Album's ordering, and is used both with and without an ordering.yml file being present

Failure modes that are handled (barring bugs or oversights):

• No ordering.yml file (this is case is negatively cached)
• malformed ordering.yml file (does not parse as yml) (this case is negatively cached)
• the basic rules outlined below:

We also follow some ground rules (commented in the code in the relevant section):

//okay, now we're ready for processing and merging.
//some ground rules:
//0) if there is no ordering file, or an error retrieving/parsing the file, everything must work as
//   if there was never an ordering file in the first place.
//1) if an image is in the config but not in the bucket, it's silently dropped*
//2) ordering of keys in config come before ordering of keys in bucket (i.e: listed in config THEN non-listed)
//3) each section is independent and optional but has some interlinkages, (this gets difficult because you
//   don't want to pick out the same photo for both cover and thumbnail.

* i say silently, but there is a message printed.

Things to do:

• [x] Double check I didn't accidentally kill some critical error checking around the template retrieval parts.
  • [x] write up relevant section in README with examples so that people can actually use it correctly :)
  • [ ] ~clean up path prefixing and url manipulation parts, I feel like I've really clobbered this, need to play around with it somewhat~
  • [ ] look in to caching the AlbumOrdering object itself, as this alone has a bit of a cost to generate (though no network costs)

Let me know what you think.

[theonejb]

Hey man! Thanks for all the work you've put into this. I gave a quick look and it looks like you did a lot of work here!

Give me a week to go through this, as I'll probably only be able to get to it by next weekend. I should have some comments by next Saturday.

[arahayrabedian]

it was a little more involved than I was expecting to be honest, if you see a way to simplify it i'm all ears.

take your time on checking it out, I'm probably still gonna throw in minor modifications.

[theonejb]

@arahayrabedian I'll admit I don't gork this completely as it's a large change. But it looks good on the surface. I assume you've tested it on the older config format to make sure it works in a backwards compatible method.

There's just one comment I added. Once you've looked at that, we can go ahead and merge this. I'll probably go through the code afterwards – if I ever find the time!

Looks good overall. Thanks for all the work you've put into this. Let's get this released!

[arahayrabedian]

@theonejb yeah it's mostly plumbing, but I think it'd be a good idea for you to understand what you pull in to your project, i'm happy to wait (i can run this experimentally from a branch until you're comfortable with it)

It doesn't have anything to be backward compatible per-se, it does not make any changes to the config file, it only looks for a ordering.yaml file in the bucket, attempting to parse/use it if it's found.

one issue could be users being presented with a blank image in their album if they add in a ordering.yaml file prior to upgrading, i think that's about it (and is easily avoidable revertible by dropping the file from the bucket)

[arahayrabedian]

if there's any particular concerns i'm more than happy to clarify them

[arahayrabedian]

sweet, you're going to love what i have in store in 2 minutes :) i promise it's quick