Basices comands+setUp+connction+api
redis 127.0.0.1:6379> PING PONG redis 127.0.0.1:6379> SET name elad OK redis 127.0.0.1:6379> GET name "elad" redis 127.0.0.1:6379> SET age 26 OK redis 127.0.0.1:6379> Get age "26" redis 127.0.0.1:6379> DEL age (integer) 1 redis 127.0.0.1:6379> Get age (nil) redis 127.0.0.1:6379> EXISTS bru (integer) 0 redis 127.0.0.1:6379> EXISTS name (integer) 1 redis 127.0.0.1:6379> KEYS * 1) "name" 2) "post" redis 127.0.0.1:6379> FLUSHALL OK redis 127.0.0.1:6379> KEYS * (empty list or set) redis 127.0.0.1:6379> SET name elad OK redis 127.0.0.1:6379> GET name "elad"
redis 127.0.0.1:6379> ttl name /*ttl-timeToLive*/ (integer) -1//not have ttl redis 127.0.0.1:6379> expire name 10 //set 10 secto expired (integer) 1 redis 127.0.0.1:6379> ttl name (integer) 6 redis 127.0.0.1:6379> ttl name (integer) 4 redis 127.0.0.1:6379> ttl name (integer) 3 redis 127.0.0.1:6379> ttl name (integer) 1 redis 127.0.0.1:6379> ttl name (integer) -1//it means the key expired redis 127.0.0.1:6379> get name (nil)//now its not exicts /*second way to execute exparation when creating spesifice key*/ redis 127.0.0.1:6379> setex name 10 elad OK redis 127.0.0.1:6379> ttl name (integer) 5 redis 127.0.0.1:6379> ttl name (integer) 3 redis 127.0.0.1:6379> ttl name (integer) 0 redis 127.0.0.1:6379> ttl name (integer) -1 redis 127.0.0.1:6379> ttl name (integer) -1 redis 127.0.0.1:6379> get name (nil)
redis 127.0.0.1:6379> lpush friends ross //create new list name friends and add ross in it (integer) 1 redis 127.0.0.1:6379> lpush friends monika //add monika to thefirst cellof the list (integer) 2 redis 127.0.0.1:6379> lrange friends 0 -1 //show all list rang from 0 to the end of it 1) "monika" 2) "ross" redis 127.0.0.1:6379> rpush friends chendler //add chendler to the last cell of the list (integer) 3 redis 127.0.0.1:6379> lrange friends 0 -1 //show the new list 1) "monika" 2) "ross" 3) "chendler" redis 127.0.0.1:6379> LPOP friends //remove the obj of the first cell that is from the left "monika" redis 127.0.0.1:6379> lrange friends 0 -1 1) "ross" 2) "chendler" redis 127.0.0.1:6379> RPOP friends //remove the obj of the last cell that is from the right "chendler" redis 127.0.0.1:6379> lrange friends 0 -1 1) "ross"
redis 127.0.0.1:6379> SADD hobbies "weight lifting" //add new set called hobbies (integer) 1 redis 127.0.0.1:6379> SMEMBERS hobbies //see all hobbies 1) "weight lifting" redis 127.0.0.1:6379> SREM hobbies "weight lifting" //remove spesific (integer) 1 redis 127.0.0.1:6379> SMEMBERS hobbies (empty list or set)
// code example from: https://www.youtube.com/watch?v=AzQ6_DTcG6c
/*const express =require("express");
const redis = require("redis")
const util=require("util")
const axios = require ("axios");
const redisUrl="redis://127.0.0.1:6379"
const client= redis.createClient(redisUrl)
client.set=util.promisify(client.set)//inorder to be able using pormis with redis
client.get=util.promisify(client.get)
const app =express();
app.use(express.json());
app.post("/",async(req,res)=>{
const{key,value}=req.body;
const response= await client.set(key,value)
res.json(response)
})
app.get("/", async (req,res)=>{
const{key} =req.body;
const value= await client.get(key);
res.json(value)
})
//example 1 :
app.get("/posts/:id",async(req,res)=>{
const {id}=req.params;
//make uniqe key
const cachedPost=await client.get(`post-${id}`)
//check if it alredy found the key name before
if(cachedPost){
return res.json(JSON.parse(cachedPost))
}
//if unique key not found get response from api and set new uniqe key
const response=await axios.get(`https://jsonplaceholder.typicode.com/posts/${id}`)//frome: https://jsonplaceholder.typicode.com/
client.set(`post-${id}`,JSON.stringify(response.data))
return res.json(response)
})
//example 2 :
//update cache using expired- in order to get new data to cach after changes in the api/DB
app.get("/posts/:id",async(req,res)=>{
const {id}=req.params;
const cachedPost=await client.get(`posts-${id}`)
if(cachedPost){
return res.json(JSON.parse(cachedPost))
}
const response=await axios.get(`https://jsonplaceholder.typicode.com/posts/${id}`)
// SET a key that its exparation date will be in 10 sec
client.set(`post-${id}`,JSON.stringify(response.data),"EX",10)
return res.json(response)
})
//setting port
var PORT=8080;
app.listen(PORT,()=>{
console.log(`listen to port ${PORT} !`)
});*/
/******************************** NEW CODE 2 ***************************************************/
//code +readme file basice coomands on redis from : https://www.youtube.com/watch?v=jgpVdJB2sKQ
const express =require("express");
const axios = require ("axios");
const cors =require("cors");
const Redis = require("redis")
//help me get the option to use that var with redis commands
const redisClient=Redis.createClient()
//one Hour
const DEFUALT_EXPERATION=3600
const app =express();
app.use(cors())
// #1 GET req => http://localhost:3000/photos
app.get("/photos",async(req,res)=>{
const albumId=req.query.albumId;
//change key to spesific alboum id👇 while doing param query
RedisClient.get(`photos?albumId=${albumId}`,async(error,photos)=>{//req redis photos collection //19:00
if (error) console.error(error)
if(photos!=null) {//it means that redis still hold the last data it got
console.log('cache hit')
return res.json(JSON.parse(photos))//so return this data
}else{
console.log('cache Miss')
// execute this code below if photos obj expired/not init at first call yet...
const { data } = await axios.get("https://jsonplaceholder.typicode.com/photos",
{params:{albumId}}
)
//use redisClient that i set above and add expration to
//data is coming from axios as an array so i need to make it to string(stringify) in order to sent it to redis
redisClient.setex(`photos?albumId=${albumId}`,DEFUALT_EXPERATION,JSON.stringify(data))
res.json(data)
}
})
})
//#2
app.get('/photos/:id', async(req,res)=>{
const {data } = await axios.get(
`https://jsonplaceholder.typicode.com/photos/${req.params.id}`
)
res.json(data);
});
//#4 write stage #1 in shorter way using function
app.get("/photos",async(req,res)=>{
const photos=await getOrSetCache(`photos?albumId=${albumId}`,async()=>{
const { data } = await axios.get("https://jsonplaceholder.typicode.com/photos",
{params:{albumId}}
)
return data
})
res.json(photos)
})
//#3
//EXTERNAL FUNCTION -do the process of checking key validation and define where to go redis or api
function getOrSetCache(key,cb){
return new Promise((resolve,reject)=>{
//try get key if not return eror else return key data
redisClient.get(key, async(error,data)=>{
if (error) return reject(error);
if (data!=null) return resolve(JSON.parse(data))
const freshData=cb()//the new data in case it is first try getting to DB or last call expired
redisClient,setex(key,DEFUALT_EXPERATION,JSON.stringify(freshData))
resolve(freshData)
})
})
}
console.log("work ")
app.listen(3000);