A simple way to read and write Redis databases in node.js applications

This article mainly introduces the Redis database in the Node.js application of the simple method, Redis is a memory-type high-speed database, the need for friends can refer to the

Before you begin this article, be sure to install the Redis extensions for Redis and Node.js and Node.js--node_redis

First create a new folder and new text file app.js the contents of the file are as follows:

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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.to String ()); }); Get a value Client.get ("String Key", function (err, reply) {Console.log (reply.tostring ());}); }

When connected to the Redis, the Runsample function is called and a value is set, followed by a readout of the value, running as follows:

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1 2	OK Hello World

We can also use the EXPIRE command to set the expiration time of an object, as follows:

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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 the Expiration Client.set (' string key ', ' Hello World ', redis.print);//Expire I   N 3 seconds Client.expire (' string key ', 3); This is the ' only ' to Demo ' TTL//runs every second until the timeout//occurs on the value var MyTimer = Setinter Val (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); }

Note: The timer used above is only to demonstrate the EXPIRE command, you must use the timer carefully in the Node.js project.

The output from running the above program is:

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Reply:ok i Live:hello World i live:hello World I live:hello world I expired

Next we check how long a value is persisted before it expires:

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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 are only to demo the TTL//runs every second until the timeout//occurs on the value var MyTimer = s Etinterval (function () {client.get (' string key ', function (err, reply) {if (reply) {Console.log (' I live: ' + Reply.tostri Ng ()); 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); }

Run Result:

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Reply:ok i Live:hello world I live for this long yet:2 I Live:hello World I live for this long yet:1 i live:hello Wo Rld I live for this long yet:0 I expired