ThoughtMCP

/** * Result Cache for Full-Text Search * * LRU cache with TTL for search results to improve performance. * * Requirements: 4.1, 4.2, 4.3, 4.4, 4.5 */ import type { FullTextSearchQuery, FullTextSearchResponse } from "./types"; /** * Cache entry with TTL */ interface CacheEntry { value: FullTextSearchResponse; expiresAt: number; } /** * Cache statistics */ export interface CacheStatistics { hits: number; misses: number; size: number; maxSize: number; hitRate: number; } /** * LRU cache with TTL for search results */ export class ResultCache { private readonly cache: Map<string, CacheEntry>; private readonly maxSize: number; private readonly ttl: number; // TTL in milliseconds private hits: number = 0; private misses: number = 0; constructor(config: { maxSize: number; ttl: number }) { this.cache = new Map(); this.maxSize = config.maxSize; this.ttl = config.ttl * 1000; // Convert seconds to milliseconds } /** * Get cached search result * * @param key - Cache key * @returns Cached result or null if not found/expired */ get(key: string): FullTextSearchResponse | null { const entry = this.cache.get(key); if (!entry) { this.misses++; return null; } // Check if expired if (Date.now() > entry.expiresAt) { this.cache.delete(key); this.misses++; return null; } // Move to end (most recently used) this.cache.delete(key); this.cache.set(key, entry); this.hits++; return entry.value; } /** * Cache search result * * @param key - Cache key * @param value - Search result to cache */ set(key: string, value: FullTextSearchResponse): void { // Remove oldest entry if cache is full if (this.cache.size >= this.maxSize && !this.cache.has(key)) { const firstKey = this.cache.keys().next().value; if (firstKey !== undefined) { this.cache.delete(firstKey); } } // Add new entry with expiration time const entry: CacheEntry = { value, expiresAt: Date.now() + this.ttl, }; this.cache.set(key, entry); } /** * Generate cache key from query parameters * * Excludes pagination parameters (maxResults, offset) so paginated * queries can share the same cached result set. * * @param query - Search query * @returns Cache key string */ generateKey(query: FullTextSearchQuery): string { const keyParts = [ query.query, query.language ?? "english", query.rankingMode ?? "rank", query.userId ?? "", query.minStrength?.toString() ?? "", query.minSalience?.toString() ?? "", ]; return keyParts.join("|"); } /** * Clear all cached results */ clear(): void { this.cache.clear(); this.hits = 0; this.misses = 0; } /** * Get cache statistics * * @returns Cache performance statistics */ getStats(): CacheStatistics { const total = this.hits + this.misses; const hitRate = total > 0 ? this.hits / total : 0; return { hits: this.hits, misses: this.misses, size: this.cache.size, maxSize: this.maxSize, hitRate, }; } /** * Remove expired entries * * Called periodically to clean up expired cache entries */ cleanup(): void { const now = Date.now(); const keysToDelete: string[] = []; for (const [key, entry] of this.cache.entries()) { if (now > entry.expiresAt) { keysToDelete.push(key); } } for (const key of keysToDelete) { this.cache.delete(key); } } }