90c1cdef34
- Fix code linting issues - Update README with detailed documentation - Configure database paths for the current environment - Create necessary directory structure The News Aggregation Service is now ready to use with FastAPI and SQLite.
98 lines
2.9 KiB
Python
98 lines
2.9 KiB
Python
import time
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from typing import Dict, Any, Optional, Callable, TypeVar, Generic
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import logging
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logger = logging.getLogger(__name__)
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T = TypeVar('T')
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class Cache(Generic[T]):
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"""
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A simple in-memory cache implementation with TTL (time to live).
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"""
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def __init__(self, ttl: int = 300):
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"""
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Initialize the cache.
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Args:
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ttl: Time to live for cache entries in seconds. Default is 300 seconds (5 minutes).
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"""
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self._cache: Dict[str, Dict[str, Any]] = {}
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self.ttl = ttl
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def get(self, key: str) -> Optional[T]:
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"""
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Get a value from the cache.
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Args:
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key: The cache key.
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Returns:
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The cached value if it exists and hasn't expired, None otherwise.
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"""
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if key in self._cache:
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entry = self._cache[key]
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if entry["expires"] > time.time():
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logger.debug(f"Cache hit for key: {key}")
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return entry["value"]
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else:
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# Remove expired entry
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logger.debug(f"Cache expired for key: {key}")
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del self._cache[key]
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return None
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def set(self, key: str, value: T, ttl: Optional[int] = None) -> None:
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"""
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Set a value in the cache.
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Args:
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key: The cache key.
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value: The value to cache.
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ttl: Optional custom TTL for this entry. If not provided, the default TTL is used.
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"""
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expiry = time.time() + (ttl if ttl is not None else self.ttl)
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self._cache[key] = {"value": value, "expires": expiry}
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logger.debug(f"Cache set for key: {key}")
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def delete(self, key: str) -> None:
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"""
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Delete a value from the cache.
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Args:
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key: The cache key.
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"""
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if key in self._cache:
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del self._cache[key]
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logger.debug(f"Cache deleted for key: {key}")
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def clear(self) -> None:
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"""
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Clear all entries from the cache.
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"""
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self._cache.clear()
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logger.debug("Cache cleared")
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def get_or_set(self, key: str, value_func: Callable[[], T], ttl: Optional[int] = None) -> T:
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"""
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Get a value from the cache, or set it if it doesn't exist.
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Args:
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key: The cache key.
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value_func: A function that returns the value to cache if it doesn't exist.
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ttl: Optional custom TTL for this entry. If not provided, the default TTL is used.
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Returns:
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The cached value.
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"""
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value = self.get(key)
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if value is None:
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value = value_func()
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self.set(key, value, ttl)
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return value
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# Create global cache instance
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cache = Cache(ttl=300) # 5 minutes TTL
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api_cache = Cache(ttl=60) # 1 minute TTL for API responses |