Integrate Redis to a Node.js project

On this article we are going to add caching to our Node.js application using Redis.

We will install the recommended client for node.js as mentioned on the official Redis page.

npm install redis --save

Next we shall create our client connection

var redis = require('redis')

var hostname = '127.0.0.1'
var port = '6379'
var password = 'yourpassword'

var client = redis.createClient(port,hostname,{no_ready_check: true})

client.auth(password)

client.on('connect', function() {
        console.log('Client was connected')
})

The password provided on auth will be stashed and used on every connect.

Let’s see some basic actions

SMEMBERS actions


client.sadd('aset', 2)
client.sadd('aset', 1)
client.sadd('aset', 5)

client.smembers('aset',function(err,reply) {
    console.log(reply)
})

Get and Set actions

client.set('akey', "This is the value")

client.get('akey',function(err,reply) {
    console.log(reply)
})

Hash value actions

client.hset('hashone', 'fieldone', 'some value');
client.hset('hashone', 'fieldtwo', 'another value');

var hash = 'hashone'

client.hkeys(hash, function (err, fields) {

    fields.forEach(function(field,i) {

        console.log('The field is '+field)

        client.hget(hash,field,function (err, value) {
            console.log('The content is '+value)
        })
    })

});

List actions

client.rpush(['mylist', 'firstItem', 'secondItem'], function(err, listsize) {
    console.log(listsize)
});

client.lrange('mylist',0,-1,function(err,values) {
    console.log(values)
})

client.lpop('mylist',function(err,value) {
    console.log('Got '+value)
})

 

Conclusion

The Redis client for Node.js is pretty straightforward and easy to get started.

Keep in mind that one connection is adequate. Redis is single threaded therefore there is no need in opening multiple connections.

You can refer to the github page for more examples and usage showcases.

Integrate Redis to your Spring project

This article shows how to integrate Redis cache to your spring project through annotation configuration.

We will begin with our Gradle configuration. We will use the jedis driver.

group 'com.gkatzioura.spring'
version '1.0-SNAPSHOT'

apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'idea'
apply plugin: 'spring-boot'

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:1.2.5.RELEASE")
    }
}

jar {
    baseName = 'gs-serving-web-content'
    version =  '0.1.0'
}

sourceCompatibility = 1.8

repositories {
    mavenCentral()
}

dependencies {
    compile "org.springframework.boot:spring-boot-starter-thymeleaf"
    compile 'org.slf4j:slf4j-api:1.6.6'
    compile 'ch.qos.logback:logback-classic:1.0.13'
    compile 'redis.clients:jedis:2.7.0'
    compile 'org.springframework.data:spring-data-redis:1.5.0.RELEASE'
    testCompile group: 'junit', name: 'junit', version: '4.11'
}

task wrapper(type: Wrapper) {
    gradleVersion = '2.3'
}

Will proceed with the Redis configuration using spring annotations.

package com.gkatzioura.spring.config;

import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.CachingConfigurerSupport;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;

@Configuration
@EnableCaching
public class RedisConfig extends CachingConfigurerSupport {

    @Bean
    public JedisConnectionFactory redisConnectionFactory() {

        JedisConnectionFactory jedisConnectionFactory = new JedisConnectionFactory();
        jedisConnectionFactory.setUsePool(true);
        return jedisConnectionFactory;
    }

    @Bean
    public RedisSerializer redisStringSerializer() {
        StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();
        return stringRedisSerializer;
    }

    @Bean(name="redisTemplate")
    public RedisTemplate<String, String> redisTemplate(RedisConnectionFactory cf,RedisSerializer redisSerializer) {
        RedisTemplate<String, String> redisTemplate = new RedisTemplate<String, String>();
        redisTemplate.setConnectionFactory(cf);
        redisTemplate.setDefaultSerializer(redisSerializer);
        return redisTemplate;
    }

    @Bean
    public CacheManager cacheManager() {
        return new RedisCacheManager(redisTemplate(redisConnectionFactory(),redisStringSerializer()));
    }

}

Next step is to create our caching interface

package com.gkatzioura.spring.cache;

import java.util.Date;
import java.util.List;

public interface CacheService {

    public void addMessage(String user,String message);

    public List<String> listMessages(String user);

}

A user will add messages and he will be able to retrieve them .
However on our implementation, user related messages will have a time to live of one minute.

Our implementation CacheService using Redis follows.

package com.gkatzioura.spring.cache.impl;

import com.gkatzioura.spring.cache.CacheService;
import org.springframework.data.redis.core.ListOperations;
import org.springframework.data.redis.core.RedisOperations;
import org.springframework.data.redis.core.SetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.time.ZonedDateTime;
import java.time.temporal.ChronoUnit;
import java.util.Date;
import java.util.List;

@Service("cacheService")
public class RedisService implements CacheService {

    @Resource(name = "redisTemplate")
    private ListOperations<String, String> messageList;

    @Resource(name = "redisTemplate")
    private RedisOperations<String,String> latestMessageExpiration;

    @Override
    public void addMessage(String user,String message) {

        messageList.leftPush(user,message);

        ZonedDateTime zonedDateTime = ZonedDateTime.now();
        Date date = Date.from(zonedDateTime.plus(1, ChronoUnit.MINUTES).toInstant());
        latestMessageExpiration.expireAt(user,date);
    }

    @Override
    public List<String> listMessages(String user) {
        return messageList.range(user,0,-1);
    }

}

Our cache mechanism will retain a list of messages sent by each user. To achieve so we will employee the ListOperations interface using the user as a key.
The RedisOperations interface gives us the ability to specify a time to live for a key. In our case it is used for the user key.

Next we create a controller with the cache service injected.

package com.gkatzioura.spring.controller;

import com.gkatzioura.spring.cache.CacheService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
public class MessageController {


    @Autowired
    private CacheService cacheService;

    @RequestMapping(value = "/message",method = RequestMethod.GET)
    @ResponseBody
    public List<String> greeting(String user) {

        List<String> messages = cacheService.listMessages(user);

        return messages;
    }

    @RequestMapping(value = "/message",method = RequestMethod.POST)
    @ResponseBody
    public String saveGreeting(String user,String message) {

        cacheService.addMessage(user,message);

        return "OK";

    }

}

Last but not least our Application class

package com.gkatzioura.spring;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

}

In order to run just issue

gradle bootRun