ioredis通過模式

Question

我使用ioredis與快遞（的NodeJS） 全部刪除鍵我知道有通過模式這樣的刪除鍵的方式：

redis-cli KEYS "sample_pattern:*" | xargs redis-cli DEL 

但是，有沒有辦法做到使用ioredis代替？

Answer 1

我對ioredis沒有太多瞭解。 但我認爲鍵*和for循環可以處理它。

順便說一句，我建議你應該使用掃描和刪除，而不是〜

Answer 2

最直接的方法來刪除通過模式按鍵使用keys命令來獲取匹配模式的鍵，然後刪除它們一個接一個，這與您提供的命令行示例類似。下面是與ioredis實現的一個例子：

var Redis = require('ioredis'); 
var redis = new Redis(); 
redis.keys('sample_pattern:*').then(function (keys) { 
    // Use pipeline instead of sending 
    // one command each time to improve the 
    // performance. 
    var pipeline = redis.pipeline(); 
    keys.forEach(function (key) { 
    pipeline.del(key); 
    }); 
    return pipeline.exec(); 
}); 

然而，當你的數據庫有一個大組鍵（比如說一百萬），keys將阻止數據庫幾秒鐘。在這種情況下，scan更有用。 ioredis有scanStream功能幫助您遍歷輕鬆的數據庫：

var Redis = require('ioredis'); 
var redis = new Redis(); 
// Create a readable stream (object mode) 
var stream = redis.scanStream({ 
    match: 'sample_pattern:*' 
}); 
stream.on('data', function (keys) { 
    // `keys` is an array of strings representing key names 
    if (keys.length) { 
    var pipeline = redis.pipeline(); 
    keys.forEach(function (key) { 
     pipeline.del(key); 
    }); 
    pipeline.exec(); 
    } 
}); 
stream.on('end', function() { 
    console.log('done'); 
}); 

不要忘了有關詳細信息，請查看scan命令的官方文檔：http://redis.io/commands/scan。

Answer 3

試試下面的命令，你可以爲每個前綴創建多個客戶端，支持設置得和明確：

// myredis.js 
const Redis = require('ioredis'); 
const ConnectRedis = require('connect-redis'); 
const config = {}; // your ioredis config 
const clients = {}; 

/** 
* @private create redis client 
* @param {string} name client name 
* @param {boolean} isSession is this the application session client or not 
* @return {Redis|*} 
*/ 
const createClient = (name, isSession = false) => { 
    let client; 
    client = new Redis({...config, "keyPrefix":`${name}:`)}); 
    client.on('error', msg => console.log("Redis Client[" + name + "]: " + msg)); 
    client.on('connect',() => console.log("Redis Client[" + name + "]: Connected")); 
    if (isSession) { 
    const RedisStore = ConnectRedis(isSession); 
    client = new RedisStore({client}); 
    } 
    return client; 
}; 

/** 
* Create or get redis client 
* @param {string} name client name 
* @return {Redis|*} 
*/ 
const getClient = name => { 
    let client = clients[name]; 
    if (!client || !client.connected) { 
    client = clients[name] = createClient(name); 
    } 
    return client; 
}; 

/** 
* get keys only related to this client prefix 
* @param name 
*/ 
const getClientKeys = name => getClient(name).keys(`${name}:*`).then(keys => keys.map(key => key.substr(name.length + 1))); 

/** 
* clear client 
* @param name 
*/ 
const clearClient = name => getClientKeys(name).then(keys => { 
    const client = getClient(name); 
    client && keys.forEach(key => client.del(key)) 
}); 

module.exports = {getClient, clearClient, getClientKeys}; 

使用方法：

const {getClient, clearClient} = require("./myredis"); 
// this will get a client with prefix "marvel:" and if it is not exists it will be created 
const client = getClient("marvel"); 

// set value 
client.set("fav", "ironman"); 

// get the value 
client.get("fav", (error, value) => console.log(value)); 

// clear client 
clearClient("marvel");