noderedis（noderedis v4）

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本文目录一览：

• 1、Nodejs 连接 Redis数据库实例
• 2、nodejs中redis有必要做连接池吗
• 3、nodejs 怎么访问指定的redis据库
• 4、node.js中如何配置redis与连接池？
• 5、在Node.js应用中读写Redis数据库的简单方法

Nodejs 连接 Redis数据库实例

报错：Node连蚂慧接Redis报错 “ClientClosedError: The client is closed”

查询资料才发现：Node Redis版本V4之后，连接语法变了。

Starting from v4 of node-redis library, you need to call client.connect() after initializing a client. See this migration guide.

新语法：

const redis = require('redis');

const client = redis.createClient({ socket: { port: 6379 } });

client.connect();

client.on('connect', () = {

    console.log('connected');

});

You might also want to consider running the client connect method with await in an asynchronous function. So you don't have to worry about event listeners.

const redis = require('redis'闷枯答);

(async () = {

  try {

    const client = redis.createClient({ socket: { port: 6379 } });

    await client.connect();

    console.log('connected');

  } catch (err) {

    console.error(err)

  }

})()

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[Example]:

const redis = require("redis");

(async () = {

  try {

    const client = redis.createClient({

      socket: { port: 6379 },

      legacyMode: true,

    });

    await client.connect();

    console.log("connected");

    await client.v4.set("key4", "value2", {

      NX: true,

    });

    client.set("key3", "value3", "NX", (err, reply) = {});

   败帆 await client.get("key4", function (err, v) {

      console.log("redis get hello err,v", err, v);

    });

    client.set("student1", "Laylaa1", function (err, reply) {

      if (err) {

        console.log(err);

        callback(err, null);

        return;

      }

      console.log(reply);

    });

  } catch (err) {

    console.error(err);

  }

})();

nodejs中redis有必要做连接池吗

木有必要。。因为redis也是单线程处理你的请求的。。保持长连接就好了

[img]

nodejs 怎么访问指定的redis据库

安装redis模块, 该模森野块会默认安装至当前掘春枝目录下的node_modules里边:

npm install redis

然后连接redis, 并进行get-set操判敏作

var redis = require('redis');

var client = redis.createClient('6379', '127.0.0.1');

// redis 链接错误

client.on("error", function(error) {

console.log(error);

});

node.js中如何配置redis与连接池？

node.js中配置连接池可以考虑使用generic-pool模块

官缺厅网：

var poolModule = bbPromise.promisifyAll(require('generic-pool'));

var redispool = poolModule.Pool({

name : 'redis',

create : function(callback) {

var client = Redis.createClient(configs.dbconfig.dbredis.port,

configs.dbconfig.dbredis.host);

callback(null, client);

},

destroy : function(client) { client.quit(); },

max : 10,

// optional. if you set this, make sure to drain() (see step 3)

min : 2,

// specifies how long a resource can stay idle in pool before being removed

idleTimeoutMillis : 30000

// if true, logs via console.log - can also be a function

//log : true

});

function getRedisClient() {

return redispool.acquireAsync().disposer(function(client, promise) {

console.log("redispool.release(client)"旁扮森运亩)

redispool.release(client);

});

}

dbs.redisclient = getRedisClient ;

在Node.js应用中读写Redis数据库的简单方法

在开始本文之前请确保安装好

Redis

和

Node.js

以及

Node.js

的

Redis

扩展

——

node_redis

首先创建一个新文件夹并新建文本文件

app.js

文件内容如下：

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("型侍羡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());

});

}

当连接到

Redis

后会调用

runSample

函数并设置一个值，紧接着便读出该值，运行的结果如下：

OK

Hello

World

我们也可以使用

EXPIRE

命令来设置对象的失效时间，代码如下：

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:

上述使用的定时器只是为了演示

EXPIRE

命令，你必须在

Node.js

项目中谨慎使用定时器。

运行上述程序的输出卜拍结谈皮果是：

Reply:

OK

I

live:

Hello

World

I

live:

Hello

World

I

live:

Hello

World

I

expired

接下来我们检查一个值在失效之前存留了多长时间：

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);

}

运行结果：

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

World

I

live

for

this

long

yet:

I

expired

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