# Redis

## Redis

1\.

windows下載 <https://github.com/MSOpenTech/redis/releases> <https://github.com/dmajkic/redis/downloads> (下載後點選redis-server.exe 之後點選redis-cli)

Linux

```
sudo apt install redis-server
```

Mac using homebrew

<https://medium.com/@petehouston/install-and-config-redis-on-mac-os-x-via-homebrew-eb8df9a4f298#.su9r2yd8u>

2\.

cd到目錄後執行`redis-server.exe`

3.再開一個terminal一樣cd 到redis路徑 輸入`redis-cli`可產生client端

4\. 試著在client端輸入 `set food noodle`後`get food`

## #使用

基本上使用set 與get 即可用來存儲js相關字串或物件及array，但記得要先轉為string，記得要加上第三個參數callback不然可能無法使用

另外操作的過程不用像mongodb一樣寫在ready裡面

```
const redis = require("redis");
const Redisclient = redis.createClient();

export default () => {

  Redisclient.on("ready", function (err) {
      console.log("Ready");
  });

  Redisclient.on("error", function (err) {
      console.log("Error " + err);
  });
}

exports.Redisclient = Redisclient;
```

```
import { Redisclient } from './redis';
import Redis from './redis';
Redis();

const payload = [{a:12,b:13},{a:12,b:13},{a:12,b:13}];

Redisclient.set("short", JSON.stringify(payload), () => {

});
Redisclient.get("short",function (err, reply) {
    console.log(JSON.parse(reply)); // Will print `OK`
});
```

```
# #使用AWS的Redis ElastiCache

>預設只給EC2做內網連線

有兩種可選一種為Redis，一種為Memcached

我們這裡選擇開Redis

>注意：如果是要免費的記得選擇開啟的機器規格
預設的選項是要付費的，FREE TIRE的免費只有t2 micro的Redis

開完後記得先到`ElastiCache dashboard`上方點選Modify，並選擇和你EC2相同之security group，之後回到`EC2 dashboard`把security group的Inbound加上 6379的PORT

####連線:
ssh到EC2後使用 `telnet`
telnet test.aq9nab.ng.0001.apne1.cache.amazonaws.com 6379
```

```
#開放從電腦本機連線到AWS Redis

利用轉傳規則 ssh -f -N -L6379::6379
```

之後即可本機端和EC2共用同一個Redis 伺服器

再輸入`redis-cli`即可使用

<http://stackoverflow.com/questions/21917661/can-you-connect-to-amazon-elasticache-redis-outside-of-amazon>

## 可用資料結構

```
String (SET GET)
Hash (HSET HGET HDEL HGETALL)
List (LPUSH LPOP RPUSH RPOP)
Set (SADD SPOP)
Sorted Set (ZADD ZRANGE)
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://easonwang.gitbook.io/web_advance/redis.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.