1. Introduction

August 5, 2016 · View on GitHub

Redis Back







1. Introduction

===
  • Redis is an open source (BSD licensed), in-memory data structure store, used as database, cache and message broker.
  • It supports data strucures such as strings(字符串), hashes(哈希), lists(列表), sets(集合), sorted sets(有序集合) with range queries, bitmaps(位圖), hyperloglogs and geospatial indexes with radius queries.
  • 6 strategies(策略) of Redis:
      1. volatile-lru: 從已設置過期的數據集(server.db[i].expires)中挑選最近最少使用的數據淘汰.
      1. volatile-ttl: 從已設置過期的數據集(server.db[i].expires)中挑選將要過期的數據淘汰.
      1. volatile-random: 從已設置過期時間的數據集(server.db[i].expires)中任意選擇數據淘汰.
      1. allkeys-lru: 從數據集(server.db[i].dict)中挑選最近最少使用的數據淘汰.
      1. allkeys-random: 從數據集(server.db[i].dict)中任意選擇數據淘汰.
      1. no-enviction(驅逐): 禁止驅逐數據.






2. Commands

===
2.1 EXISTS key [key ...]

  • Description: To search whether multiple keys are existed.

  • Return:

    • 1: if the key exists.
    • 0: if the key does not exist.
    • The number of keys existing among the ones specified as arguments. Keys mentioned multiple times and existing are counted multiple times. (Since Redis 3.0.3)

  • Example:

redis> SET key1 "Hello" OK redis> EXISTS key1 (integer) 1 redis> EXISTS nosuchkey (integer) 0 redis> SET key2 "World" OK redis> EXISTS key1 key2 nosuchkey (integer) 2 redis>



##### 2.2 APPEND key value

- Description: If key already exists and is a string, this command appends the value at the end of the string. If **key** does not exist it is created and set as an empty string.
- Return: The length of the value.
- Example:

	```redis
redis> EXIST mykey
(integer) 0
redis> APPEND mykey
(integer) 0
redis> APPEND mykey "Hello"
(integer) 5
redis> APPEND mykey " World"
(integer) 11
redis> GET mykey
"Hello World"
redis>
2.3 DEL key [key ...]

  • Description: To delete keys.

  • Return: The number of keys that were removed.

  • Example:

redis> SET key1 "Hello" OK redis> SET key2 "World" OK redis> DEL key1 key2 key3 (integer) 2 redis>


##### 2.4 SET key value [EX seconds] [PX milliseconds] [NX|XX]

- Description: Set key to hold the string value. If key already holds a value, it is overwritten, regardless of its type.
- Options:
	- **EX** (seconds): Set the specified expire time, in seconds.
	- **PX** (milliseconds): Set the specified expire time, in milliseconds.
	- **NX**: Only set the key if it does not already exist.
	- **XX**: Only set the key if it already exist.
- Return: 
	- **OK**: if SET was executed correctly.
	- **(nil)**: a Null Bulk Reply is returned if the SET operation was not performed because the user specified the NX or XX option but the condition was not met.
- Example:

	```redis
redis> SET mykey "Hello"
OK
redis> GET mykey
"Hello"
redis>
2.5 GET key

  • Description: Get the value of key.

  • Return:

    • Value: the value of key.
    • (nil): a Null Bulk Reply is returned if the key does not exist.

  • Example:

redis> GET nonexisting (nil) redis> SET mykey "Hello" OK redis> GET mykey "Hello" redis>


##### 2.6 KEYS pattern

- Description: Returns all keys matching pattern.
- Options: pattern (Use `\` to escape special characters if you want to match them verbatim.)
	- **h?llo**: matches **hello**, **hallo** and **hxllo**.
	- **h\*llo**: matches **hllo**, **hxxxxxxxxxllo**.
	- **h[ae]llo**: matches **hello** and **hallo**, but not **hillo**.
	- **h[^e]llo**: matches **hallo**, **hbllo**, ... but not **hello**.
	- **h[a-c]llo**: matches **hallo**, **hbllo** and **hcllo**.
- Return: list of keys matching pattern.
- Example:

	```redis
redis> GET nonexisting
(nil)
redis> SET mykey "Hello"
OK
redis> GET mykey
"Hello"
redis>
2.7 INCR key

  • Description: Increments the number stored at key by one.

  • Note: This is a string operation because Redis does not have a dedicated integer type. The string stored at the key is interpreted as a base-10 64 bit signed integer to execute the operation.

  • Return: the value of key after the increment.

  • Example:

redis> SET mykey "10" OK redis> INCR mykey (integer) 11 redis> GET mykey "11" redis>


##### 2.8 DECR key

- Description: Decrements the number stored at key by one.
- **Note**: This operation is limited to **64 bit signed integers**.
- Return: the value of key after the decrement.
- Example:

	```redis
redis> SET mykey "10"
OK
redis> DECR mykey
(integer) 9
redis> SET mykey "234293482390480948029348230948"
OK
redis> DECR mykey
ERR value is not an integer or out of range
redis>
2.9 INCRBY key increment

  • Description: Increments the number stored at key by increment.

  • Note: An error is returned if the key contains a value of the wrong type or contains a string that can not be represented as integer.

  • Return: the value of key after the increment.

  • Example:

redis> SET mykey "10" OK redis> INCRBY mykey 5 (integer) 15 redis>


##### 2.10 DECRBY key decrement

- Description: Decrements the number stored at key by decrement.
- **Note**: An error is returned if the key contains a value of the wrong type or contains a string that can not be represented as integer.
- Return: the value of key after the decrement.
- Example:

	```redis
redis> SET mykey "10"
OK
redis> DECRBY mykey 3
(integer) 7
redis>
2.11 More Commands






3. Usages in PHP

===
3.1 Connect

  • Description: Connect to a redis.

  • Return:

    • true: success
    • false: failure

  • Example:

connect('127.0.0.1', 6379); var_dump($result); // bool(true) ?> 

##### 3.2 Set

- Description: set the **value** of a key.
- Return: 
	- **true**: success
	- **false**: failure
- Example:

	```php
<?php  
$redis = new redis();  
$redis->connect('127.0.0.1', 6379);  
$result = $redis->set('test',"11111111111");  
var_dump($result);	// bool(true)
?>
3.3 Get

  • Description: get the value of a key.

  • Return:

    • value: the value of the specific key
    • false: key does not exist

  • Example:

connect('127.0.0.1', 6379); $result = $redis->set('test',"11111111111"); var_dump($result); // string(11) "11111111111" ?> 

##### 3.4 Delete

- Description: to delete the key.
- Options: an array of keys
- Return: 
	- **value**: the number of deleted keys
- Example:

	```php
<?php  
$redis = new redis();  
$redis->connect('127.0.0.1', 6379);  
$redis->set('test',"1111111111111");  
echo $redis->get('test');   // 1111111111111  
$redis->delete('test');  
var_dump($redis->get('test'));  // bool(false)  
?>
3.5 Set, Setnx, Setxx

  • Description: to set the value of a key

  • Return:

    • true: success
    • false: failure

  • Example:

connect('127.0.0.1', 6379); $redis->set('test',"1111111111111"); $redis->setnx('test',"22222222"); echo $redis->get('test'); // 1111111111111 $redis->delete('test'); $redis->setnx('test',"22222222"); echo $redis->get('test'); // 22222222 ?> 

##### 3.6 Exists

- Description: to whether a key is existed
- Return: 
	- **true**: success
	- **false**: failure
- Example:

	```php
<?php  
$redis = new redis();  
$redis->connect('127.0.0.1', 6379);  
$redis->set('test',"1111111111111");  
var_dump($redis->exists('test'));  // bool(true)  
?>
3.7 Incr

  • Description: to increase the value of a key by one.

  • Return: the new value after the increment

  • Example:

connect('127.0.0.1', 6379); $redis->set('test',"123"); var_dump($redis->incr("test")); // int(124) var_dump($redis->incr("test")); // int(125) ?> 

##### 3.8 Decr

- Description: to decrease the value of a key by one.
- Return: the new value after the decrement
- Example:

	```php
<?php  
$redis = new redis();  
$redis->connect('127.0.0.1', 6379);  
$redis->set('test',"123");  
var_dump($redis->decr("test"));  // int(122)  
var_dump($redis->decr("test"));  // int(121)  
?>
3.9 More Usages






4. Usages in Laravel

===
4.1