cached_url_for.py

from collections import defaultdict
import json

from flask import url_for


class CachedUrlFor():
    def __init__(self):
        self._cache = defaultdict(dict)

    def get(self, endpoint, **values):
        details = tuple(sorted(values.items()))
        url = self._cache.get(endpoint, {}).get(details)

        if not url:
            url = url_for(endpoint, **values)
            self._cache[endpoint][details] = url

        return url

    def clear_cache(self):
        self._cache = defaultdict(dict)

    def store_cache(self, file_name):
        with open(file_name, mode="w") as f:
            f.write(json.dumps(self._cache))

    def load_cache(self, file_name):
        with open(file_name) as f:
            self._cache = defaultdict(dict, {**self._cache, **json.loads(f)})


cached_url = CachedUrlFor()
cached_url.get('profile', username='John Doe')