superlimiter

Installation

$ npm i superlimiter -S

Example

Use for koa frequency limit

const Koa = require('koa');
const Limiter = require('superlimiter');

const limiter = new Limiter(redis, {
  ttl: 60,
  max: 10,
  hash: (ctx) => {
    if (!ctx.session || !ctx.session.user) {
      return '';
    }
    return ctx.session.user.account;
  },
});

const app = new Koa();

// user session
app.use(session());

app.use(limiter.middleware());

// other middlewares
...

app.listen(8080);

API

constructor

• client The redis client

• options The options for limiter

• options.ttl The ttl for frequency limit, default is 60

• options.max The max count for frequency limit, default is 10

• options.expired The expired for frequency limit, it should be HH:mm. If it's set, the ttl will be ignored

• options.hash The function to get the hash key, default is _.identity, if return '', the limit will be ignore

• options.prefix The prefix for the cache key

• options.err The error will be throw when count max than options.max, default is new Error('Exceeded the limit frequency')

const Redis = require('ioredis');
const Limiter = require('superlimiter');

const redis = new Redis('redis://127.0.0.1:6379');
const limiter = new Limiter(redis, {
  ttl: 10,
});

seter

ttl expired prefix can be reset

const Redis = require('ioredis');
const Limiter = require('superlimiter');

const redis = new Redis('redis://127.0.0.1:6379');
const limiter = new Limiter(redis, {
  ttl: 10,
});
limiter.ttl = 60;
limiter.expired = '23:30';
limiter.prefix = 'my-test-';

getter

client options ttl expired prefix

const Redis = require('ioredis');
const assert = require('assert');
const Limiter = require('superlimiter');

const redis = new Redis('redis://127.0.0.1:6379');
const limiter = new Limiter(redis, {
  ttl: 10,
});
assert.equal(limiter.client, redis);
// {ttl : 10, .. ..}
console.info(limiter.options);
assert.equal(limiter.ttl, 10);
assert.equal(limiter.expired, '');
assert.equal(limiter.prefix, 'super-limiter-');

exec

Inc the count of the key, if the count bigger than max, it will be throw an error, otherwise it will be resolve. If the hash function return '', it will be resolve without any change of count.

• ...args The arguments for the hash function

const Redis = require('ioredis');
const Limiter = require('superlimiter');

const redis = new Redis('redis://127.0.0.1:6379');
const limiter = new Limiter(redis, {
  ttl: 10,
});
limiter.exec('mykey').then(() => {
  console.info('pass');
}).catch(console.error);

getCount

• ...args The arguments for the hash function

const Redis = require('ioredis');
const Limiter = require('superlimiter');

const redis = new Redis('redis://127.0.0.1:6379');
const limiter = new Limiter(redis, {
  ttl: 10,
});
limiter.getCount('mykey').then((count) => {
  console.info(count);
}).catch(console.error);

middleware

• type The middleware's type, it can be koa or express, default is koa.

The middleware for koa and express. For koa, it will use ctx for the hash argument. For express, it will use req, res for the hash argument.

const Koa = require('koa');
const Limiter = require('superlimiter');

const limiter = new Limiter(redis, {
  ttl: 60,
  max: 10,
  hash: (ctx) => {
    if (!ctx.session || !ctx.session.user) {
      return '';
    }
    return ctx.session.user.account;
  },
});

const app = new Koa();

// user session
app.use(session());

app.use(limiter.middleware());

// other middlewares
...

app.listen(8080);

keys

Get the keys of this limiter

• withTTL Get the ttl of key if set true, default is false

const Redis = require('ioredis');
const Limiter = require('superlimiter');

const redis = new Redis('redis://127.0.0.1:6379');
const limiter = new Limiter(redis, {
  ttl: 10,
});

// ["...", "..."]
limiter.keys().then(console.info).catch(console.error);

// [{"key": "...", "ttl": ..}, ...]
limiter.keys(true).then(console.info).catch(console.error);