Comment by midgetjones

Good question!

The primary reason was to learn Elixir, so this was just a well-timed excuse to explore the language (and Phoenix, the web framework).

The secondary reason was that my wife was the main client, and she doesn't respond well to raw JSON. Each tweet would be just the cat's name, photo, and a link to the website. I also did some filtering as certain cats have safety requirements we couldn't meet, e.g. no neighbouring cats, no children)

One of the main issues I had to figure out early on, was "how do I distinguish which cats are new, compared to the previous response?". This was made harder because I couldn't rely on the ordering; occasionally previously-posted cats would have details updated and they would move position. Postgres UPSERT was new (to me, at least) at the time, and it seemed like a very handy way to offload the responsibility. There were never more than 50 cats listed at any one time, so it was reasonable enough to request all the animals at once, and let the database figure out which cats were new, based on a combination of identifiers that would make them unique. I could also filter the updated records to see _what_ had been updated, e.g. the cat had now been rehomed.

Another thing Elixir did really well was the polling mechanism. It's absolutely trivial to spawn a worker that can repeatedly perform a task and asynchronously hand it off to be processed.

Hope that answers your question!