| 1 | | "Single-process in-memory cache backend." |
| 2 | | |
| 3 | | from django.core.cache.backends.base import BaseCache |
| 4 | | import time |
| 5 | | |
| 6 | | class CacheClass(BaseCache): |
| 7 | | def __init__(self, host, params): |
| 8 | | BaseCache.__init__(self, params) |
| 9 | | self._cache = {} |
| 10 | | self._expire_info = {} |
| 11 | | |
| 12 | | max_entries = params.get('max_entries', 300) |
| 13 | | try: |
| 14 | | self._max_entries = int(max_entries) |
| 15 | | except (ValueError, TypeError): |
| 16 | | self._max_entries = 300 |
| 17 | | |
| 18 | | cull_frequency = params.get('cull_frequency', 3) |
| 19 | | try: |
| 20 | | self._cull_frequency = int(cull_frequency) |
| 21 | | except (ValueError, TypeError): |
| 22 | | self._cull_frequency = 3 |
| 23 | | |
| 24 | | def add(self, key, value, timeout=None): |
| 25 | | if len(self._cache) >= self._max_entries: |
| 26 | | self._cull() |
| 27 | | if timeout is None: |
| 28 | | timeout = self.default_timeout |
| 29 | | if key not in self._cache.keys(): |
| 30 | | self._cache[key] = value |
| 31 | | self._expire_info[key] = time.time() + timeout |
| 32 | | |
| 33 | | def get(self, key, default=None): |
| 34 | | now = time.time() |
| 35 | | exp = self._expire_info.get(key) |
| 36 | | if exp is None: |
| 37 | | return default |
| 38 | | elif exp < now: |
| 39 | | del self._cache[key] |
| 40 | | del self._expire_info[key] |
| 41 | | return default |
| 42 | | else: |
| 43 | | return self._cache[key] |
| 44 | | |
| 45 | | def set(self, key, value, timeout=None): |
| 46 | | if len(self._cache) >= self._max_entries: |
| 47 | | self._cull() |
| 48 | | if timeout is None: |
| 49 | | timeout = self.default_timeout |
| 50 | | self._cache[key] = value |
| 51 | | self._expire_info[key] = time.time() + timeout |
| 52 | | |
| 53 | | def delete(self, key): |
| 54 | | try: |
| 55 | | del self._cache[key] |
| 56 | | except KeyError: |
| 57 | | pass |
| 58 | | try: |
| 59 | | del self._expire_info[key] |
| 60 | | except KeyError: |
| 61 | | pass |
| 62 | | |
| 63 | | def has_key(self, key): |
| 64 | | return key in self._cache |
| 65 | | |
| 66 | | def _cull(self): |
| 67 | | if self._cull_frequency == 0: |
| 68 | | self._cache.clear() |
| 69 | | self._expire_info.clear() |
| 70 | | else: |
| 71 | | doomed = [k for (i, k) in enumerate(self._cache) if i % self._cull_frequency == 0] |
| 72 | | for k in doomed: |
| 73 | | self.delete(k) |