PHP解决Python魔术__getattr __()的方法 [英] PHP approach to python's magic __getattr__()

问题描述

我想知道PHP中是否有某种方法可以复制Python属性/键访问的某些魔术.

I was wondering if there was some way in PHP to duplicate some of the magic of Python attribute/key access.

我使用由史蒂夫·莱西(Steve Lacey)编写的Mongo ORM类，称为val = doc.foo和val = doc['foo']等效.

I use a Mongo ORM class written by Steve Lacey called Minimongo in which he utilizes the __getattr__ and __getitem__ to reroute key and attribute flavored access and preserve the 'document-oriented' nature of Mongo. val = doc.foo and val = doc['foo'] become equivalent.

我想知道PHP中是否有类似的接口，该接口允许更改从其继承的类处理对象访问的方式.我查看了STL，找不到适合的衣服.设置默认值将非常有用.谢谢.

I was wondering if there is a similar interface in PHP that would allow the changing of how object access is handled for a class that inherits from it. I looked through the STL and couldn't find one that filled suit. It would be greatly useful for setting up defaults. Thanks.

推荐答案

看看使用前者，您可以使非公共成员可以访问，就像$obj->foo一样；使用前者，您可以像$obj['foo']一样访问它们.

With the former you can make non-public members accessbile, as in $obj->foo, with the latter you can access them like $obj['foo'].

您可以根据需要在内部对其进行硬接线.

You can hardwire them however you like, internally.

我个人建议您将这些可魔术访问的属性保留在类的单个数组成员中，这样您就不会得到意粉代码了.

Personally I would suggest you keep these magically-accessible properties into one single array member of the class, so you don't end up with spaghetti code.

POC:

 1  <?php
 2  class Magic implements ArrayAccess {
 3  
 4      protected $items = array();
 5  
 6      public function offsetExists($key) {
 7          return isset($this->items[$key]);
 8      }
 9      public function offsetGet($key) {
10          return $this->items[$key];
11      }
12      public function offsetSet($key, $value) {
13          $this->items[$key] = $value;
14      }
15      public function offsetUnset($key) {
16          unset($this->items[$key]);
17      }
18  
19      //do not modify below, this makes sure we have a consistent
20      //implementation only by using ArrayAccess-specific methods
21      public function __get($key) {
22          return $this->offsetGet($key);
23      }
24      public function __set($key, $value) {
25          $this->offsetSet($key, $value);
26      }
27      public function __isset($key) {
28          return $this->offsetExists($key);
29      }
30      public function __unset($key) {
31          $this->offsetUnset($key);
32      }
33  }
34  
35  //demonstrate the rountrip of magic
36  $foo = new Magic;
37  $foo['bar'] = 42;
38  echo $foo->bar, PHP_EOL;//output 42
39  $foo->bar++;
40  echo $foo['bar'];//output 43
41  

Milord的一致性，完全按照您的要求.

Consistency Milord, exactly as you asked.

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