php magic method __sleep __wakeup __toString __debuginfo

__sleep():

When using serialize() for serialization, it will detect whether there is a __sleep() magic method in the class. If so, it will call __sleep() first and return an object containing all the objects that need to be serialized. An array of variable names

<code><span><?php</span><span><span>class</span><span>test</span>{</span><span>public</span><span>$name</span>=<span>'demon'</span>;

    <span>private</span><span>$age</span>=<span>'19'</span>;

    <span>public</span><span><span>function</span><span>__sleep</span><span>()</span>{</span><span>return</span> [<span>'name'</span>];
    }  
}

<span>$test</span> = <span>new</span> test();
<span>echo</span> serialize(<span>$test</span>);
<span>//输出结果：O:4:"test":1:{s:4:"name";s:5:"demon";}</span></code>

__wakeup()

When serializing using serialize(), it will detect whether there is a __wakeup() magic method in the class. If so, it will call __wakeup() first to perform some initialization operations.

<code><span><?php</span><span><span>class</span><span>test</span>{</span><span>public</span><span>$name</span>=<span>'demon'</span>;

    <span>private</span><span>$age</span>=<span>'19'</span>;

    <span>public</span><span><span>function</span><span>say</span><span>()</span>{</span><span>echo</span><span>"反序列化"</span>;
    }

    <span>public</span><span><span>function</span><span>__wakeup</span><span>()</span>{</span><span>$this</span>->say();
    }   
}

<span>$test</span> = <span>new</span> test();
unserialize(serialize(<span>$test</span>));
<span>//输出结果：反序列化</span></span></code>

__toString()

__toString() is used as a response when a class is used as a string. It can only return a string

<code><span><?php</span><span><span>class</span><span>test</span>{</span><span>public</span><span>$name</span>=<span>'demon'</span>;

    <span>private</span><span>$age</span>=<span>'19'</span>;

    <span>public</span><span><span>function</span><span>__toString</span><span>()</span>{</span><span>return</span><span>'test'</span>;
    } 
}

<span>$test</span> = <span>new</span> test();
<span>echo</span><span>$test</span>;
<span>//输出结果：test</span></code>

__debuginfo()

__debuginfo() is a feature added in php5.6, var_dump ()A response to a class, returns an array containing object attributes

<code><span><?php</span><span><span>class</span><span>test</span>{</span><span>public</span><span>$name</span>=<span>'demon'</span>;

    <span>private</span><span>$age</span>=<span>'19'</span>;

    <span>public</span><span><span>function</span><span>__debuginfo</span><span>()</span>{</span><span>return</span> [<span>'name'</span>];
    }

}

<span>$test</span> = <span>new</span> test();
var_dump(<span>$test</span>);
<span>//输出结果：object(test)#1 (1) { [0]=> string(4) "name" }</span></code>

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The above introduces the PHP magic methods __sleep __wakeup __toString __debuginfo, including the relevant content. I hope it will be helpful to friends who are interested in PHP tutorials.