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index.js
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index.js
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'use strict'
const fp = require('fastify-plugin')
const ms = require('ms')
const LocalStore = require('./store/LocalStore')
const RedisStore = require('./store/RedisStore')
const routeRateAdded = Symbol('fastify-rate-limit.routeRateAdded')
async function rateLimitPlugin (fastify, settings, next) {
// create the object that will hold the "main" settings that can be shared during the build
// 'global' will define, if the rate limit should be apply by default on all route. default : true
const globalParams = {
global: (typeof settings.global === 'boolean') ? settings.global : true
}
globalParams.addHeaders = Object.assign({
'x-ratelimit-limit': true,
'x-ratelimit-remaining': true,
'x-ratelimit-reset': true,
'retry-after': true
}, settings.addHeaders)
// define the global maximum of request allowed
globalParams.max = (typeof settings.max === 'number' || typeof settings.max === 'function')
? settings.max
: 1000
// define the global Time Window
globalParams.timeWindow = typeof settings.timeWindow === 'string'
? ms(settings.timeWindow)
: typeof settings.timeWindow === 'number'
? settings.timeWindow
: 1000 * 60
globalParams.allowList = settings.allowList || settings.whitelist || null
globalParams.ban = settings.ban || null
// define the name of the app component. Related to redis, it will be use as a part of the keyname define in redis.
const pluginComponent = {
allowList: globalParams.allowList
}
if (settings.store) {
const Store = settings.store
pluginComponent.store = new Store(globalParams)
} else {
if (settings.redis) {
pluginComponent.store = new RedisStore(settings.redis, 'fastify-rate-limit-', globalParams.timeWindow)
} else {
pluginComponent.store = new LocalStore(globalParams.timeWindow, settings.cache, fastify)
}
}
globalParams.keyGenerator = typeof settings.keyGenerator === 'function'
? settings.keyGenerator
: (req) => req.ip
globalParams.errorResponseBuilder = defaultErrorResponse
globalParams.isCustomErrorMessage = false
// define if error message was overwritten with a custom error response callback
if (typeof settings.errorResponseBuilder === 'function') {
globalParams.errorResponseBuilder = settings.errorResponseBuilder
globalParams.isCustomErrorMessage = true
}
// onRoute add the onRequest rate-limit function if needed
fastify.addHook('onRoute', (routeOptions) => {
if (routeOptions.config && typeof routeOptions.config.rateLimit !== 'undefined') {
if (typeof routeOptions.config.rateLimit === 'object') {
const current = Object.create(pluginComponent)
const mergedRateLimitParams = makeParams(routeOptions.config.rateLimit)
mergedRateLimitParams.routeInfo = routeOptions
current.store = pluginComponent.store.child(mergedRateLimitParams)
// if the current endpoint have a custom rateLimit configuration ...
buildRouteRate(current, mergedRateLimitParams, routeOptions)
} else if (routeOptions.config.rateLimit === false) {
// don't apply any rate-limit
} else {
throw new Error('Unknown value for route rate-limit configuration')
}
} else if (globalParams.global) {
// if the plugin is set globally ( meaning that all the route will be 'rate limited' )
// As the endpoint, does not have a custom rateLimit configuration, use the global one.
buildRouteRate(pluginComponent, globalParams, routeOptions)
}
})
// Merge the parameters of a route with the global ones
function makeParams (routeParams) {
const result = Object.assign({}, globalParams, routeParams)
if (typeof result.timeWindow === 'string') {
result.timeWindow = ms(result.timeWindow)
}
return result
}
next()
}
async function buildRouteRate (pluginComponent, params, routeOptions) {
if (routeOptions[routeRateAdded]) {
return
}
routeOptions[routeRateAdded] = true
const after = ms(params.timeWindow, { long: true })
if (Array.isArray(routeOptions.onRequest)) {
routeOptions.onRequest.push(onRequest)
} else if (typeof routeOptions.onRequest === 'function') {
routeOptions.onRequest = [routeOptions.onRequest, onRequest]
} else {
routeOptions.onRequest = [onRequest]
}
// onRequest function that will be use for current endpoint been processed
function onRequest (req, res, next) {
// We retrieve the key from the generator. (can be the global one, or the one define in the endpoint)
const key = params.keyGenerator(req)
// allowList doesn't apply any rate limit
if (pluginComponent.allowList) {
if (typeof pluginComponent.allowList === 'function') {
if (pluginComponent.allowList(req, key)) {
next()
return
}
} else if (pluginComponent.allowList.indexOf(key) > -1) {
next()
return
}
}
// As the key is not allowList in redis/lru, then we increment the rate-limit of the current request and we call the function "onIncr"
pluginComponent.store.incr(key, onIncr)
async function onIncr (err, { current, ttl }) {
if (err && params.skipOnError === false) {
return next(err)
}
const maximum = await getMax()
if (current <= maximum) {
res.header('x-ratelimit-limit', maximum)
.header('x-ratelimit-remaining', maximum - current)
.header('x-ratelimit-reset', Math.floor(ttl / 1000))
if (typeof params.onExceeding === 'function') {
params.onExceeding(req)
}
next()
} else {
if (typeof params.onExceeded === 'function') {
params.onExceeded(req)
}
if (params.addHeaders['x-ratelimit-limit']) { res.header('x-ratelimit-limit', maximum) }
if (params.addHeaders['x-ratelimit-remaining']) { res.header('x-ratelimit-remaining', 0) }
if (params.addHeaders['x-ratelimit-reset']) { res.header('x-ratelimit-reset', Math.floor(ttl / 1000)) }
if (params.addHeaders['retry-after']) { res.header('retry-after', params.timeWindow) }
const code = params.ban && current - maximum > params.ban ? 403 : 429
res.code(code)
const respCtx = {
statusCode: code,
after,
max: maximum
}
if (code === 403) {
respCtx.ban = true
}
res.send(params.errorResponseBuilder(req, respCtx))
}
async function getMax () {
if (typeof params.max === 'number') {
return params.max
} else {
return await params.max(req, key)
}
}
}
}
}
function defaultErrorResponse (req, context) {
const err = new Error(`Rate limit exceeded, retry in ${context.after}`)
err.statusCode = context.statusCode
return err
}
module.exports = fp(rateLimitPlugin, {
fastify: '2.x - 3.x',
name: 'fastify-rate-limit'
})