在NODE中使用Redis SCAN [英] Using Redis SCAN in NODE

问题描述

我有一些格式的Redis有很多的键，我想要获得匹配一些模式的键，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。使用扫描我想知道在代码中写什么是最好的方法。我必须做一些像while循环，但使用承诺，我目前的解决方案看起来像这样（代码简化了一点）：

 'use strict'
 const Promise = require（'bluebird'）; 
 const config = require（'./ config'）; 
 const client = require（'./ clinet'）; 
 
让迭代器= 0; 
 Promise.coroutine（function *（）{
 do {
 iterator = yield clinet.scanAsync（iterator，'myQuery'，'COUNT'，config.scanChunkSize）
。 （data => {
 let nextIterator = data [0]; 
 let values = data [1]; 
 //使用值
返回nextIterator; 
}）
} while（iterator！=='0'）; 
}）（）; 
  

有没有更好的方法，我失踪了？

解决方案

您可以使用递归来继续调用扫描，直到完成。

  function scanAsync（cursor，pattern，returnSet）{
 
 return redisClient.scanAsync（cursor， （
 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）
} 
 
} ）; 
} 
  

传入一个Set（）以确保键不重复

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

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');
})();

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

解决方案

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)
            }

    });
}

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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