/**
* Simple in-memory cache with TTL support for IBGE API requests
*/
import { fetchWithRetry, type RetryOptions } from "./retry.js";
interface CacheEntry<T> {
data: T;
expiresAt: number;
}
class RequestCache {
private cache: Map<string, CacheEntry<unknown>> = new Map();
private defaultTTL: number;
constructor(defaultTTLMinutes: number = 15) {
this.defaultTTL = defaultTTLMinutes * 60 * 1000;
}
/**
* Get cached data if available and not expired
*/
get<T>(key: string): T | null {
const entry = this.cache.get(key);
if (!entry) return null;
if (Date.now() > entry.expiresAt) {
this.cache.delete(key);
return null;
}
return entry.data as T;
}
/**
* Store data in cache with optional TTL
*/
set<T>(key: string, data: T, ttlMinutes?: number): void {
const ttl = ttlMinutes ? ttlMinutes * 60 * 1000 : this.defaultTTL;
this.cache.set(key, {
data,
expiresAt: Date.now() + ttl,
});
}
/**
* Check if a key exists and is not expired
*/
has(key: string): boolean {
return this.get(key) !== null;
}
/**
* Remove a specific key from cache
*/
delete(key: string): void {
this.cache.delete(key);
}
/**
* Clear all cached data
*/
clear(): void {
this.cache.clear();
}
/**
* Remove all expired entries
*/
cleanup(): void {
const now = Date.now();
for (const [key, entry] of this.cache.entries()) {
if (now > entry.expiresAt) {
this.cache.delete(key);
}
}
}
/**
* Get cache statistics
*/
stats(): { size: number; keys: string[] } {
this.cleanup();
return {
size: this.cache.size,
keys: Array.from(this.cache.keys()),
};
}
}
// Global cache instance with 15 minute default TTL
export const cache = new RequestCache(15);
// Cache TTL presets (in minutes)
export const CACHE_TTL = {
STATIC: 60 * 24, // 24 hours - for static data like states, municipalities
MEDIUM: 60, // 1 hour - for semi-static data like CNAE, indicators list
SHORT: 15, // 15 minutes - for data that changes occasionally
REALTIME: 1, // 1 minute - for real-time data like population projection
} as const;
/**
* Generate cache key from URL and parameters
*/
export function cacheKey(
base: string,
params?: Record<string, string | number | boolean | undefined>
): string {
if (!params) return base;
const sortedParams = Object.entries(params)
.filter(([, v]) => v !== undefined)
.sort(([a], [b]) => a.localeCompare(b))
.map(([k, v]) => `${k}=${v}`)
.join("&");
return sortedParams ? `${base}?${sortedParams}` : base;
}
/**
* Fetch with cache support and automatic retry on network failures
*/
export async function cachedFetch<T>(
url: string,
cacheKeyStr: string,
ttlMinutes?: number,
retryOptions?: RetryOptions
): Promise<T> {
// Check cache first
const cached = cache.get<T>(cacheKeyStr);
if (cached !== null) {
return cached;
}
// Fetch from API with retry support
const response = await fetchWithRetry(url, undefined, retryOptions);
if (!response.ok) {
throw new Error(`HTTP ${response.status}: ${response.statusText}`);
}
const data = (await response.json()) as T;
// Store in cache
cache.set(cacheKeyStr, data, ttlMinutes);
return data;
}
