在节点中使用Redis SCAN [英] Using Redis SCAN in NODE

问题描述

我的 Redis 有很多某种格式的键，我想获得匹配某种模式的键并对它们进行一些操作.我不使用 KEYS 方法，因为它不推荐在生产中使用.使用 SCAN 我想知道用代码编写它的最佳方法是什么.我必须做一些类似 while 循环的事情，但是使用 promises，我当前的解决方案看起来像这样(代码稍微简化了一点):

I have Redis with a lot of keys in some format and I want to get keys that match some pattern and do some operations on them. I don't use KEYS method since it's not recommend in production. Using SCAN I'm wondering what is the best way to write it in code. I have to do something like a while loop but using promises, my current solution looks like this (code is simplified a little):

'use strict'
const Promise = require('bluebird');
const config = require('./config');
const client = require('./clinet');

let iterator = 0;
Promise.coroutine(function* () {
  do {
    iterator = yield clinet.scanAsync(iterator, 'myQuery', 'COUNT', config.scanChunkSize)
      .then(data => {
        let nextIterator = data[0];
        let values = data[1];
        //do some magic with values
        return nextIterator;
      })
  } while (iterator !== '0');
})();

有没有更好的方法来实现我所缺少的?

Is there a better way to do it that I'm missing?

推荐答案

您可以使用递归来保持调用 scan 直到完成.

You can use recursion to keep calling scan until done.

function scanAsync(cursor, pattern, returnSet){

    return redisClient.scanAsync(cursor, "MATCH", pattern, "COUNT", "100").then(
        function (reply) {

            cursor = reply[0];
            var keys = reply[1];
            keys.forEach(function(key,i){
                returnSet.add(key);
            });

            if( cursor === '0' ){
                return Array.from(returnSet);
            }else{
                return scanAsync(cursor, pattern, returnSet)
            }

    });
}

传入 Set() 以确保键不会重复

Pass in a Set() to make sure keys aren't duplicated

myResults = new Set();

scanAsync('0', "NOC-*[^listen]*", myResults).map( 
    function( myResults ){ console.log( myResults); }
);

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