在PHP中的函数之间共享变量，而无需使用全局变量 [英] Share variables between functions in PHP without using globals

问题描述

我有一个用于与Memcache服务器进行交互的类.我具有用于插入，删除和检索数据的不同功能.最初，每个函数都调用memcache_connect()，但这是不必要的，例如:

I have a class for interacting with a memcache server. I have different functions for inserting, deleting and retrieving data. Originally each function made a call to memcache_connect(), however that was unnecessary, e.g.:

mc->insert()  
mc->get()  
mc->delete() 

将建立三个内存缓存连接.我通过为该类创建构造来解决此问题:

would make three memcache connections. I worked around this by creating a construct for the class:

function __construct() {
    $this->mem = memcache_connect( ... );
}

，然后在需要资源的任何地方使用$this->mem，因此三个功能中的每一个都使用相同的memcache_connect资源.

and then using $this->mem wherever the resource was needed, so each of the three functions use the same memcache_connect resource.

没关系，但是如果我在其他类中调用该类，例如:

This is alright, however if I call the class inside other classes, e.g.:

class abc
{
    function __construct() {
        $this->mc = new cache_class;
    }
}    
class def
{
    function __construct() {
        $this->mc = new cache_class;
    }
}

然后，它只需要 一个时，仍会打两个memcache_connect呼叫.

then it is still making two memcache_connect calls, when it only needs one.

我可以对全局变量执行此操作，但是如果不需要，我不希望使用它们.

I can do this with globals but I would prefer not to use them if I don't have to.

示例全局实现:

$resource = memcache_connect( ... );

class cache_class
{
    function insert() {
        global $resource;
        memcache_set( $resource , ... );
    }
    function get() {
        global $resource;
        return memcache_get( $resource , ... );
    }

}

然后，无论该类被调用多少次，都只会对memcache_connect进行一次调用.

Then no matter how many times the class is called there will only be one call to memcache_connect.

有没有办法做到这一点，还是应该只使用全局变量?

Is there a way to do this or should I just use globals?

推荐答案

我将使用单例模式编写另一个类的代码，以获取唯一的内存缓存实例.像这样-

I would code another class using singleton pattern for getting the only instance of memcache. Like this -

class MemCache 
{ 
  private static $instance = false;   
  private function __construct() {}

  public static function getInstance()
  { 
    if(self::$instance === false)
    { 
      self::$instance = memcache_connect(); 
    } 

    return self::$instance; 
  } 
}

和用法-

$mc = MemCache::getInstance();
memcache_get($mc, ...)
...

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