@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
316 lines • 11.6 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.MiddlewareComposer = void 0;
exports.createComposer = createComposer;
const events_1 = require("events");
class MiddlewareWrapper {
constructor(fn, options = {}) {
this.fn = fn;
this.options = options;
}
get name() {
return this.options.name || this.fn.name || 'anonymous';
}
async executeAsync(req, res, next) {
if (this.options.condition) {
const shouldRun = await this.options.condition(req, res);
if (!shouldRun) {
return next();
}
}
let timeoutId;
if (this.options.timeout) {
timeoutId = setTimeout(() => {
const error = new Error(`Middleware '${this.name}' timed out after ${this.options.timeout}ms`);
error.code = 'MIDDLEWARE_TIMEOUT';
next(error);
}, this.options.timeout);
}
let lastError;
const attempts = this.options.retries ? this.options.retries + 1 : 1;
for (let attempt = 0; attempt < attempts; attempt++) {
try {
if (attempt > 0) {
await new Promise(resolve => setTimeout(resolve, this.options.retryDelay || 100));
}
await new Promise((resolve, reject) => {
const result = this.fn(req, res, (err) => {
if (err)
reject(err);
else
resolve();
});
if (result instanceof Promise) {
result.then(resolve).catch(reject);
}
});
if (timeoutId)
clearTimeout(timeoutId);
return next();
}
catch (error) {
lastError = error;
if (attempt === attempts - 1) {
if (timeoutId)
clearTimeout(timeoutId);
if (this.options.errorHandler) {
return this.options.errorHandler(error, req, res, next);
}
return next(error);
}
}
}
if (timeoutId)
clearTimeout(timeoutId);
next(lastError);
}
}
class MiddlewareComposer extends events_1.EventEmitter {
constructor(options = {}) {
super();
this.middleware = [];
this.metrics = new Map();
this.defaultErrorHandler = (error, req, res, next) => {
console.error('Middleware error:', error);
if (res.headersSent) {
return next(error);
}
res.status(500).json({
error: 'Internal Server Error',
message: error.message,
middleware: error.middleware,
code: error.code
});
};
this.options = {
errorHandler: options.errorHandler || this.defaultErrorHandler,
timeout: options.timeout || 30000,
monitoring: options.monitoring ?? true,
contextKey: options.contextKey || 'context'
};
}
use(fn, options) {
if (Array.isArray(fn)) {
fn.forEach(f => this.use(f, options));
}
else {
const wrapper = new MiddlewareWrapper(fn, options);
this.middleware.push(wrapper);
if (this.options.monitoring) {
this.metrics.set(wrapper.name, {
name: wrapper.name,
executions: 0,
errors: 0,
totalTime: 0,
averageTime: 0,
minTime: Infinity,
maxTime: 0
});
}
}
return this;
}
when(condition, trueBranch, falseBranch) {
const branchMiddleware = async (req, res, next) => {
const result = await condition(req, res);
if (result && trueBranch) {
if (trueBranch instanceof MiddlewareComposer) {
return trueBranch.compose()(req, res, next);
}
else {
return trueBranch(req, res, next);
}
}
else if (!result && falseBranch) {
if (falseBranch instanceof MiddlewareComposer) {
return falseBranch.compose()(req, res, next);
}
else {
return falseBranch(req, res, next);
}
}
else {
next();
}
};
return this.use(branchMiddleware, { name: 'conditional-branch' });
}
parallel(middleware, options) {
const parallelMiddleware = async (req, res, next) => {
const promises = middleware.map(fn => new Promise((resolve, reject) => {
fn(req, res, (err) => {
if (err)
reject(err);
else
resolve(undefined);
});
}));
try {
if (options?.waitForAll) {
await Promise.all(promises);
}
else {
await Promise.race(promises);
}
next();
}
catch (error) {
if (options?.errorHandler) {
options.errorHandler(error, req, res, next);
}
else {
next(error);
}
}
};
return this.use(parallelMiddleware, { name: 'parallel-execution' });
}
group(name) {
const subComposer = new MiddlewareComposer(this.options);
this.use(subComposer.compose(), { name });
return subComposer;
}
compose() {
return async (req, res, next) => {
const composerReq = req;
if (!composerReq[this.options.contextKey]) {
composerReq[this.options.contextKey] = {};
}
composerReq.context = composerReq[this.options.contextKey];
composerReq.startTime = Date.now();
composerReq.middlewareStack = [];
let index = 0;
const executeNext = async (error) => {
if (error) {
return this.options.errorHandler(error, composerReq, res, next);
}
if (index >= this.middleware.length) {
const totalTime = Date.now() - composerReq.startTime;
this.emit('complete', {
request: composerReq,
totalTime,
middlewareStack: composerReq.middlewareStack
});
return next();
}
const wrapper = this.middleware[index++];
const startTime = Date.now();
try {
composerReq.middlewareStack.push(wrapper.name);
await wrapper.executeAsync(composerReq, res, executeNext);
if (this.options.monitoring) {
const duration = Date.now() - startTime;
this.updateMetrics(wrapper.name, duration, false);
}
}
catch (error) {
if (this.options.monitoring) {
const duration = Date.now() - startTime;
this.updateMetrics(wrapper.name, duration, true);
}
this.emit('error', {
middleware: wrapper.name,
error,
request: composerReq
});
executeNext(error);
}
};
executeNext();
};
}
updateMetrics(name, duration, error) {
const metrics = this.metrics.get(name);
if (!metrics)
return;
metrics.executions++;
if (error)
metrics.errors++;
metrics.totalTime += duration;
metrics.averageTime = metrics.totalTime / metrics.executions;
metrics.minTime = Math.min(metrics.minTime, duration);
metrics.maxTime = Math.max(metrics.maxTime, duration);
}
getMetrics() {
return Array.from(this.metrics.values());
}
clear() {
this.middleware = [];
this.metrics.clear();
}
rateLimit(limit, window, keyGenerator) {
const requests = new Map();
return this.use((req, res, next) => {
const key = keyGenerator ? keyGenerator(req) : req.ip || 'anonymous';
const now = Date.now();
const windowStart = now - window;
const timestamps = requests.get(key) || [];
const recentRequests = timestamps.filter(t => t > windowStart);
if (recentRequests.length >= limit) {
res.status(429).json({ error: 'Too many requests' });
return;
}
recentRequests.push(now);
requests.set(key, recentRequests);
next();
}, { name: 'rate-limit' });
}
log(logger) {
return this.use((req, res, next) => {
const start = Date.now();
res.on('finish', () => {
const duration = Date.now() - start;
if (logger) {
logger(req, res, duration);
}
else {
console.log(`${req.method} ${req.url} - ${res.statusCode} - ${duration}ms`);
}
});
next();
}, { name: 'request-logger' });
}
cors(options) {
return this.use((req, res, next) => {
const origin = req.headers.origin;
if (options?.origin) {
if (typeof options.origin === 'function') {
if (origin && options.origin(origin)) {
res.setHeader('Access-Control-Allow-Origin', origin);
}
}
else if (Array.isArray(options.origin)) {
if (origin && options.origin.includes(origin)) {
res.setHeader('Access-Control-Allow-Origin', origin);
}
}
else {
res.setHeader('Access-Control-Allow-Origin', options.origin);
}
}
else {
res.setHeader('Access-Control-Allow-Origin', '*');
}
if (options?.credentials) {
res.setHeader('Access-Control-Allow-Credentials', 'true');
}
if (options?.methods) {
res.setHeader('Access-Control-Allow-Methods', options.methods.join(', '));
}
if (options?.headers) {
res.setHeader('Access-Control-Allow-Headers', options.headers.join(', '));
}
if (req.method === 'OPTIONS') {
res.sendStatus(200);
}
else {
next();
}
}, { name: 'cors' });
}
}
exports.MiddlewareComposer = MiddlewareComposer;
function createComposer(options) {
return new MiddlewareComposer(options);
}
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