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62 lines
2.2 KiB
62 lines
2.2 KiB
module.exports = function (app, db) {
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return function (opts) {
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var middleware = function (req, res, next) {
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if (opts.whitelist && opts.whitelist(req)) return next()
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opts.lookup = Array.isArray(opts.lookup) ? opts.lookup : [opts.lookup]
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opts.onRateLimited = typeof opts.onRateLimited === 'function' ? opts.onRateLimited : function (req, res, next) {
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res.status(429).send('Rate limit exceeded')
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}
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var lookups = opts.lookup.map(function (item) {
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return item + ':' + item.split('.').reduce(function (prev, cur) {
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return prev[cur]
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}, req)
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}).join(':')
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var path = opts.path || req.path
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var method = (opts.method || req.method).toLowerCase()
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var key = 'ratelimit:' + path + ':' + method + ':' + lookups
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db.get(key, function (err, limit) {
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if (err && opts.ignoreErrors) return next()
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var now = Date.now()
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limit = limit ? JSON.parse(limit) : {
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total: opts.total,
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remaining: opts.total,
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reset: now + opts.expire
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}
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if (now > limit.reset) {
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limit.reset = now + opts.expire
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limit.remaining = opts.total
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}
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// do not allow negative remaining
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limit.remaining = Math.max(Number(limit.remaining) - 1, -1)
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db.set(key, JSON.stringify(limit), 'PX', opts.expire, function (e) {
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if (!opts.skipHeaders) {
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res.set('X-RateLimit-Limit', limit.total)
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res.set('X-RateLimit-Reset', Math.ceil(limit.reset / 1000)) // UTC epoch seconds
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res.set('X-RateLimit-Remaining', Math.max(limit.remaining,0))
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}
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if (limit.remaining >= 0) return next()
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var after = (limit.reset - Date.now()) / 1000
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if (!opts.skipHeaders) res.set('Retry-After', after)
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opts.onRateLimited(req, res, next)
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})
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})
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}
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if (typeof(opts.lookup) === 'function') {
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var callableLookup = opts.lookup;
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middleware = function (middleware, req, res, next) {
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return callableLookup(req, res, opts, function () {
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return middleware(req, res, next)
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})
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}.bind(this, middleware)
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}
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if (opts.method && opts.path) app[opts.method](opts.path, middleware)
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return middleware
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}
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}
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