在開始本文之前請確保安裝好 Redis 和 Node.js 以及 Node.js 的 Redis 擴展 ―― node_redis
首先創建一個新文件夾并新建文本文件 app.js 文件內容如下：
var redis = require("redis") , client = redis.createClient(); client.on("error", function (err) { console.log("Error " + err);}); client.on("connect", runSample); function runSample() { // Set a value client.set("string key", "Hello World", function (err, reply) { console.log(reply.toString()); }); // Get a value client.get("string key", function (err, reply) { console.log(reply.toString()); });}
當連接到 Redis 后會調用 runSample 函數并設置一個值，緊接著便讀出該值，運行的結果如下：
OKHello World
我們也可以使用 EXPIRE 命令來設置對象的失效時間，代碼如下：
var redis = require('redis') , client = redis.createClient(); client.on('error', function (err) { console.log('Error ' + err);}); client.on('connect', runSample); function runSample() { // Set a value with an expiration client.set('string key', 'Hello World', redis.print); // Expire in 3 seconds client.expire('string key', 3); // This timer is only to demo the TTL // Runs every second until the timeout // occurs on the value var myTimer = setInterval(function() { client.get('string key', function (err, reply) { if(reply) { console.log('I live: ' + reply.toString()); } else { clearTimeout(myTimer); console.log('I expired'); client.quit(); } }); }, 1000);}
注意: 上述使用的定時器只是為了演示 EXPIRE 命令，你必須在 Node.js 項目中謹慎使用定時器。
運行上述程序的輸出結果是：
Reply: OKI live: Hello WorldI live: Hello WorldI live: Hello WorldI expired
接下來我們檢查一個值在失效之前存留了多長時間：
var redis = require('redis') , client = redis.createClient(); client.on('error', function (err) { console.log('Error ' + err);}); client.on('connect', runSample); function runSample() { // Set a value client.set('string key', 'Hello World', redis.print); // Expire in 3 seconds client.expire('string key', 3); // This timer is only to demo the TTL // Runs every second until the timeout // occurs on the value var myTimer = setInterval(function() { client.get('string key', function (err, reply) { if(reply) { console.log('I live: ' + reply.toString()); client.ttl('string key', writeTTL); } else { clearTimeout(myTimer); console.log('I expired'); client.quit(); } }); }, 1000);} function writeTTL(err, data) { console.log('I live for this long yet: ' + data);}運行結果：
Reply: OKI live: Hello WorldI live for this long yet: 2I live: Hello WorldI live for this long yet: 1I live: Hello WorldI live for this long yet: 0I expired
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