Implement In-Memory Weather Response Caching for /weather Endpoint

[AYUSH-P-SINGH]

closes issue 245

Description

Overview

This PR introduces an in-memory caching mechanism for weather responses in the /weather endpoint to reduce redundant OpenWeatherMap API calls and improve response times.

Changes Made

• Added a global weather cache store.
• Added configurable cache expiration (CACHE_DURATION = 600 seconds).
• Generated unique cache keys using city, state, and country.
• Implemented cache lookup before external API requests.
• Returned cached responses when available and valid.
• Stored newly generated weather responses in cache.
• Added cache hit/miss logging for debugging and verification.

Example Flow

Before

Request
  ↓
Geocoding API
  ↓
Weather API
  ↓
Forecast API
  ↓
Response

After

Request
  ↓
Cache Check
  ↓
Cache Hit → Return Cached Response

OR

Cache Miss
  ↓
Geocoding API
  ↓
Weather API
  ↓
Forecast API
  ↓
Store in Cache
  ↓
Response

Benefits

• Faster response times for repeated searches.
• Reduced external API usage.
• Lower risk of rate limiting.
• Improved backend efficiency.
• No changes required to the frontend.

Files Modified

backend/alertsystem.py

Type of Change

Feature
Backend Enhancement
Performance Optimization