pruncalc/cache.py

import lzma
import pathlib
import time
import typing

import cbor2
import httpx
import urllib.parse

if typing.TYPE_CHECKING:
	import httpx._types

CACHE_DIR = pathlib.Path(__file__).parent / 'cache'
client = httpx.Client(transport=httpx.HTTPTransport(http2=True, retries=2))

def get(url: str, *, headers: httpx._types.HeaderTypes|None=None) -> typing.Any:
	parsed = urllib.parse.urlparse(url)
	assert parsed.hostname is not None
	cache_path = CACHE_DIR / parsed.hostname / (urllib.parse.quote(parsed.path.removeprefix('/'), safe='') + '.cbor.xz')

	try:
		if cache_path.stat().st_mtime > time.time() - 600: # less than 10 minutes old
			with lzma.open(cache_path, 'rb') as f:
				return cbor2.load(f)
	except FileNotFoundError:
		pass # fall through

	r = client.get(url, headers=headers).raise_for_status()
	cache_path.parent.mkdir(parents=True, exist_ok=True)
	with lzma.open(cache_path, 'wb') as f:
		data = r.json()
		cbor2.dump(data, f)
	return data