What are the methods of php serialization?

PHP serialization method: 1. Use the serialize() function, the syntax "serialize(value)"; 2. Use the base64_encode() function; 3. Use the var_export() function; 4. Use wddx_serialize_value() function.

The operating environment of this tutorial: Windows 7 system, PHP 7.1 version, DELL G3 computer

Scenario:

Cookie cannot store composite form data, so a multi-dimensional array needs to be serialized and stored in the cookie. However, because the PHP version is too low (5.2), it does not support json_encode

Solution (serialization and Deserialization):

1, serialize and unserialize functions: only support one-dimensional arrays, it is said to have better support for objects, json_encode does not support objects

All values ​​in PHP can be converted into a string that can be stored using the serialize() function, which is serialization. The unserialize() function can change the string back to PHP's original value, which is deserialization.

Take objects as an example. When serializing an object, all variables of the object will be saved, but the methods of the object will not be saved, only the name of the class will be saved. Additionally, in order to be able to deserialize an object, the object's class must have been defined. If you serialize an object of class A, a string related to class A will be returned that contains the values ​​of all variables in the object.

If you want to deserialize an object in another file, the class of the object must be defined before deserialization. This can be achieved by including a file that defines the class or using the function spl_autoload_register() .

The syntax format of the serialize() function is as follows:

serialize(mixed $value)

where $value is the variable to be serialized.

The serialize() function can handle any type except resource. When serializing an object, PHP calls the object's __sleep() member function before the sequence action. This allows any cleanup operations to be done before the object is serialized. Similarly, when an object is deserialized using unserialize(), the __wakeup() member function is called.

After using the serialize() function to serialize the object, you can save the obtained string to a file or database, and then use the unserialize() function to reverse the string where needed. Serialization.

2, base64_encode and base64_decode, the same problem, multi-dimensional is not supported, if used, base64 encoding will increase the length of the string. In order to overcome this problem, you can use it with gzcompress:

function my_serialize( $obj )
{
  return base64_encode(gzcompress(serialize($obj)));
}

//反序列化
function my_unserialize($txt)
{
  return unserialize(gzuncompress(base64_decode($txt)));
}

3. var_export and eval

$look_books = array($aid => array($cid => array('article_name' => $article->articlename, 'chapter_name' => $chapter->chaptername))) + $look_books;
            $look_books = var_export($look_books, true);
            setcookie('look_books', $look_books, $cookieTime, '/', '.dym.com');

support multi-dimensional arrays, but you need to note that single and double quotes will be escaped. character, causing eval to fail, the escape character needs to be removed

stripcslashes() 即可。

4. wddx_serialize_value and wddx deserialize

$a = array('a' => 'Apple' ,'b' => 'banana' , 'c' => 'Coconut');
  
//序列化数组
$s = wddx_serialize_value($a);
echo $s;
  
//输出结果（查看输出字符串的源码）：<wddxPacket version=&#39;1.0&#39;><header/><data><struct><var name=&#39;a&#39;><string>Apple</string></var><var name=&#39;b&#39;><string>banana</string></var><var name=&#39;c&#39;><string>Coconut</string></var></struct></data></wddxPacket>
  
echo &#39;<br /><br />&#39;;
  
//反序列化
$o = wddx_deserialize($s);
print_r($o);
//输出结果：Array ( [a] => Apple [b] => banana 1 => Coconut )

In this way, the xml label itself occupies too many characters. Comparatively takes up memory.

Recommended learning: "PHP Video Tutorial"

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