Redis Back

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• 1. Introduction
• 2. Commands
• 3. Usages in PHP
• 4. Usages in Laravel

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> 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> 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^ello: matches hallo, hbllo, ... but not hello.
  • h[a-c]llo: matches hallo, hbllo and hcllo.
• Return: list of keys matching pattern.

• Example:

  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> 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> 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:

  <?php  
  $redis = new redis();  
  $result = $redis->connect('127.0.0.1', 6379);  
  var_dump($result);    // bool(true)  
  ?>
  

3.2 Set

• Description: set the value of a key.
• Return:
  • true: success
  • false: failure

• Example:

  <?php  
  $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:

  <?php  
  $redis = new redis();  
  $redis->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  
  $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:

  <?php  
  $redis = new redis();  
  $redis->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  
  $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:

  <?php  
  $redis = new redis();  
  $redis->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  
  $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

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