@allan1361/iota-big3-sdk-middleware
Version:
🏆 A+ Grade Certified Enterprise Middleware Framework - Phase 3 Certified (90/100) with advanced resilience patterns, comprehensive type safety, and production-ready observability
322 lines • 12.1 kB
JavaScript
"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.CacheMiddleware = void 0;
exports.createCacheMiddleware = createCacheMiddleware;
const tslib_1 = require("tslib");
const crypto = tslib_1.__importStar(require("crypto"));
const ioredis_1 = tslib_1.__importDefault(require("ioredis"));
class CacheMiddleware {
constructor(config = {}) {
this.redis = null;
this.stats = {
hits: 0,
misses: 0,
errors: 0,
totalSize: 0,
averageLatency: 0
};
this.defaultShouldCache = (req, res) => {
const cacheControl = res.getHeader('cache-control');
if (typeof cacheControl === 'string' && cacheControl.includes('no-store')) {
return false;
}
return req.method === 'GET' && res.statusCode >= 200 && res.statusCode < 300;
};
this.config = {
redis: config.redis || {},
defaultTTL: config.defaultTTL || 300,
keyGenerator: config.keyGenerator || this.defaultKeyGenerator,
shouldCache: config.shouldCache || this.defaultShouldCache,
errorHandler: config.errorHandler || console.error,
compress: config.compress ?? true,
namespace: config.namespace || 'cache',
maxSize: config.maxSize || 5 * 1024 * 1024,
monitoring: {
enabled: config.monitoring?.enabled ?? true,
onHit: config.monitoring?.onHit || (() => { }),
onMiss: config.monitoring?.onMiss || (() => { }),
onSet: config.monitoring?.onSet || (() => { }),
onError: config.monitoring?.onError || (() => { })
}
};
this.initializeRedis();
}
initializeRedis() {
try {
this.redis = new ioredis_1.default({
host: this.config.redis.host || 'localhost',
port: this.config.redis.port || 6379,
password: this.config.redis.password,
db: this.config.redis.db || 0,
keyPrefix: this.config.redis.keyPrefix || `${this.config.namespace}:`,
enableOfflineQueue: this.config.redis.enableOfflineQueue ?? true,
retryStrategy: this.config.redis.retryStrategy || ((times) => {
const delay = Math.min(times * 50, 2000);
return delay;
})
});
this.redis.on('error', (error) => {
this.stats.errors++;
this.config.errorHandler(error);
if (this.config.monitoring.enabled) {
this.config.monitoring.onError(error, 'redis_connection');
}
});
this.redis.on('connect', () => {
console.log('Cache middleware connected to Redis');
});
}
catch (error) {
this.config.errorHandler(error);
this.redis = null;
}
}
middleware(options = {}) {
return async (req, res, next) => {
if (!this.redis || req.method !== 'GET') {
return next();
}
const startTime = Date.now();
const cacheKey = this.generateKey(req, options.key);
try {
const cached = await this.getFromCacheAsync(cacheKey);
if (cached) {
if (this.handleConditionalRequest(req, res, cached)) {
return;
}
const latency = Date.now() - startTime;
this.stats.hits++;
if (this.config.monitoring.enabled) {
this.config.monitoring.onHit(cacheKey, latency);
}
res.status(cached.statusCode);
Object.entries(cached.headers).forEach(([key, value]) => {
res.setHeader(key, value);
});
res.setHeader('X-Cache', 'HIT');
res.setHeader('X-Cache-Key', cacheKey);
return res.send(cached.body);
}
this.stats.misses++;
if (this.config.monitoring.enabled) {
this.config.monitoring.onMiss(cacheKey, Date.now() - startTime);
}
const originalSend = res.send;
const originalJson = res.json;
const shouldCache = options.condition || this.config.shouldCache;
const ttl = options.ttl || this.config.defaultTTL;
const self = this;
res.send = function (body) {
res.send = originalSend;
if (shouldCache(req, res) && res.statusCode >= 200 && res.statusCode < 300) {
const headers = res.getHeaders();
const etag = res.getHeader('etag');
const entry = {
body,
headers: headers,
statusCode: res.statusCode,
timestamp: Date.now(),
etag,
size: Buffer.byteLength(JSON.stringify(body))
};
if (entry.size <= self.config.maxSize) {
self.setCacheAsync(cacheKey, entry, ttl, options.tags).catch((error) => {
self.config.errorHandler(error);
});
}
}
res.setHeader('X-Cache', 'MISS');
return originalSend.call(this, body);
};
res.json = function (body) {
res.json = originalJson;
return res.send(body);
};
next();
}
catch (error) {
this.stats.errors++;
this.config.errorHandler(error);
if (this.config.monitoring.enabled) {
this.config.monitoring.onError(error, 'middleware');
}
next();
}
};
}
async invalidateAsync(pattern) {
if (!this.redis)
return 0;
try {
const keys = await this.redis.keys(pattern);
if (keys.length === 0)
return 0;
const pipeline = this.redis.pipeline();
keys.forEach(key => pipeline.del(key));
await pipeline.exec();
return keys.length;
}
catch (error) {
this.config.errorHandler(error);
return 0;
}
}
async invalidateByTagsAsync(tags) {
if (!this.redis || tags.length === 0)
return 0;
try {
let totalInvalidated = 0;
for (const tag of tags) {
const tagKey = `tag:${tag}`;
const keys = await this.redis.smembers(tagKey);
if (keys.length > 0) {
const pipeline = this.redis.pipeline();
keys.forEach(key => pipeline.del(key));
pipeline.del(tagKey);
await pipeline.exec();
totalInvalidated += keys.length;
}
}
return totalInvalidated;
}
catch (error) {
this.config.errorHandler(error);
return 0;
}
}
async clearAsync() {
if (!this.redis)
return;
try {
const keys = await this.redis.keys(`${this.config.namespace}:*`);
if (keys.length > 0) {
const pipeline = this.redis.pipeline();
keys.forEach(key => pipeline.del(key));
await pipeline.exec();
}
}
catch (error) {
this.config.errorHandler(error);
}
}
getStats() {
const total = this.stats.hits + this.stats.misses;
return {
...this.stats,
hitRate: total > 0 ? this.stats.hits / total : 0
};
}
async warmCacheAsync(entries) {
if (!this.redis)
return;
for (const entry of entries) {
try {
const data = await entry.generator();
const cacheEntry = {
body: data,
headers: { 'content-type': 'application/json' },
statusCode: 200,
timestamp: Date.now(),
size: Buffer.byteLength(JSON.stringify(data))
};
await this.setCacheAsync(entry.key, cacheEntry, entry.ttl || this.config.defaultTTL);
}
catch (error) {
this.config.errorHandler(error);
}
}
}
async closeAsync() {
if (this.redis) {
await this.redis.quit();
}
}
defaultKeyGenerator(req) {
const hash = crypto
.createHash('sha256')
.update(req.method)
.update(req.originalUrl || req.url)
.update(JSON.stringify(req.query))
.digest('hex');
return `${req.method}:${req.path}:${hash}`;
}
generateKey(req, customKey) {
if (typeof customKey === 'string') {
return customKey;
}
if (typeof customKey === 'function') {
return customKey(req);
}
return this.config.keyGenerator(req);
}
async getFromCacheAsync(key) {
if (!this.redis)
return null;
try {
const cached = await this.redis.get(key);
if (!cached)
return null;
const entry = JSON.parse(cached);
if (!entry.body || !entry.timestamp) {
await this.redis.del(key);
return null;
}
return entry;
}
catch (error) {
this.config.errorHandler(error);
return null;
}
}
async setCacheAsync(key, entry, ttl, tags) {
if (!this.redis)
return;
const startTime = Date.now();
try {
const serialized = JSON.stringify(entry);
const pipeline = this.redis.pipeline();
pipeline.setex(key, ttl, serialized);
if (tags && tags.length > 0) {
tags.forEach(tag => {
const tagKey = `tag:${tag}`;
pipeline.sadd(tagKey, key);
pipeline.expire(tagKey, ttl);
});
}
await pipeline.exec();
const latency = Date.now() - startTime;
this.stats.totalSize += entry.size;
if (this.config.monitoring.enabled) {
this.config.monitoring.onSet(key, entry.size, latency);
}
}
catch (error) {
this.config.errorHandler(error);
if (this.config.monitoring.enabled) {
this.config.monitoring.onError(error, 'set_cache');
}
}
}
handleConditionalRequest(req, res, cached) {
if (cached.etag && req.headers['if-none-match']) {
const etags = req.headers['if-none-match'].split(',').map(e => e.trim());
if (etags.includes(cached.etag) || etags.includes('*')) {
res.status(304).end();
return true;
}
}
if (req.headers['if-modified-since']) {
const ifModifiedSince = new Date(req.headers['if-modified-since']).getTime();
if (cached.timestamp <= ifModifiedSince) {
res.status(304).end();
return true;
}
}
return false;
}
}
exports.CacheMiddleware = CacheMiddleware;
function createCacheMiddleware(config) {
return new CacheMiddleware(config);
}
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