NODEJS(15)Platform - memcached

最新推荐文章于 2025-08-11 17:17:42 发布

magic_dreamer

最新推荐文章于 2025-08-11 17:17:42 发布

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分类专栏： Scripts 文章标签： memcached json 操作系统

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本文介绍了一个Node.js客户端驱动程序node-memcached，并详细解释了如何使用它进行缓存操作，包括设置依赖项、定义Memcached实例及使用公共方法。

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NODEJS(15)Platform - memcached

1. memcached Introdution
This is a nodeJS client driver, node-memcached.
It is using consistent hashing, oh, my old days, I use memcached when this algorithm is not implemented, I implemented it myself once.

It is using the ASCII protocol, oh, I used to heard that long time ago, it plans to use binary protocol. But till now, it is not binary, the good things for this is we can see what is send over the wire.

There are punch of options to define a Memcached Instance.
maxKeySize, maxExpiration, maxValue, poolSize, algorithm, reconnect, timeout, retries, failures, retry, failOverServers,
keyCompression, idle

Define the Memcached with option

var memcached = new Memcached(‘localhost:11211’, {retries:10, retry:10000, remove:true, failOverServers:[“localhost:11212”]});

Public Methods
memcached.touch(key,lifetime,callback) lifetime is measured by seconds
memcached.get(key, callback)
memcached.get(‘foo’, function(err, data){
console.log(data);
});
memcached.getMulti(keys, callback)
memcached.getMulti([‘foo’,’bar’], function(err, data){
console.log(data.foo + data.bar);
});

memcached.set(key, value, lifetime, callback)
memcached.set(‘foo’,’bar’,10,function(err){ });

memcached.replace(key, value, lifetime, callback)
memcached.replace(‘foo’, ‘bar’, 10, function(err){ });

memcached.del(key, callback)
memcached.end

2. How I Use It
Add the dependencies
{
     "name": "buglist",
     "version": "0.0.1",
     "private": true,
     "dependencies": {
          "express": "4.2.0",
          "body-parser": "1.2.0",
          "generic-pool": "2.0.4",
          "mongodb": "1.4.5",
          "log4js": "0.6.14",
          "memcached": "0.2.8"
     }
}

Using Memcached
var Memcached = require('memcached');
var memcached = new Memcached({'127.0.0.1:11211': 1, '127.0.0.1:11212': 1 })

memcached.get("bugs", function(err, data){
                  if(data != false){
                       logger.debug("hitting the memached =" + data + "!");
                       res.json(data);
                  }else{
                       logger.debug("missing the memached!");
                       db.collection('bugs').find({}).toArray(function(err, bugs){
                              if (err) res.json(500, err);
                              else {
                                   logger.debug("setting the memached!");
                                   memcached.set("bugs", bugs ,120,function(err){
                                        if(err != undefined) res.json(500, err);
                                   });
                                   res.json(bugs);
                              }
                              pool.release(db);
                         });
                  }
             });

Here is the log, first miss, second hit
[2014-05-30 17:26:15,776] [DEBUG] [M] missing the memached!

[2014-05-30 17:26:15,778] [DEBUG] [M] setting the memached!

[2014-05-30 17:26:15,780] [INFO ] [M] 127.0.0.1 - - "GET /bugs HTTP/1.1" 200 130 "" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/34.0.1847.137 Safari/537.36"

[2014-05-30 17:26:22,356] [DEBUG] [M] hitting the memached =[object Object]! [2014-05-30 17:26:22,358] [INFO ] [M] 127.0.0.1 - - "GET /bugs HTTP/1.1" 200 130 "" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/34.0.1847.137 Safari/537.36"

References:
https://github.com/3rd-Eden/node-memcached

Graceful closing and Process
http://heyrod.com/snippet/s/node-js-process-on-sigint.html
http://nodejs.org/api/process.html

Nodejs request package
https://github.com/mikeal/request