PHP Tutorial-How to Deserialize

Serialization is the process of converting a variable into a string that can be saved or transmitted, and deserialization is the conversion of the string to the original variable at the appropriate time. Together, these two processes make it easy to store and transfer data, making the program more maintainable. Brother even PHP training (www.lampbrother.net)



1. Serialize and Unserialize functions



These two are common functions for serializing and deserializing data in PHP.

<?php

$a = Array (' a ' = = ' Apple ', ' b ' = ' banana ', ' c ' = ' Coconut ');

Serializing arrays

$s = serialize ($a);

Echo $s;

Output: a:3:{s:1: "a"; S:5: "Apple"; s:1: "B"; S:6: "Banana"; s:1: "C"; s:7: "Coconut";}

Echo ' <br/><br/> ';

Deserialization

$o = Unserialize ($s);

Print_r ($o);

Output Array ([a] + Apple [b] = banana [c] = = Coconut)

?>

Problems can occur when an array value contains characters such as double quotes, single quotes, or colons, which are deserialized. To overcome this problem, a clever trick is to use Base64_encode and Base64_decode.

$obj = Array ();

Serialization of

$s = Base64_encode (serialize ($obj));

Deserialization

$original = Unserialize (Base64_decode ($s));

But base64 encoding will increase the length of the string. To overcome this problem, you can use it with gzcompress.

Defines a function to serialize an object

function My_serialize ($obj)

{

Return Base64_encode (Gzcompress (Serialize ($obj)));

}

Deserialization

function My_unserialize ($txt)

{

Return Unserialize (Gzuncompress (Base64_decode ($txt)));

}

2. Json_encode and Json_decode



Serializing and deserializing using JSON format is a good choice:



Using Json_encode and Json_decode format output is much faster for serialize and unserialize formats.

The JSON format is readable.

The JSON format is smaller than the serialize return data result.

The JSON format is open and portable. It can also be used in other languages.

$a = Array (' a ' = = ' Apple ', ' b ' = ' banana ', ' c ' = ' Coconut ');

Serializing arrays

$s = json_encode ($a);

Echo $s;

Output: {"A": "Apple", "B": "Banana", "C": "Coconut"}

Echo ' <br/><br/> ';

Deserialization

$o = Json_decode ($s);

In the above example, the Json_encode output length is obviously shorter than the serialize output length in the previous example.



3. Var_export and Eval



The Var_export function outputs the variable as a string, and Eval executes the string as PHP code, deserializing the contents of the original variable.



$a = Array (' a ' = = ' Apple ', ' b ' = ' banana ', ' c ' = ' Coconut ');



Serializing arrays



$s = Var_export ($a, true);



Echo $s;



Output: Array (' a ' + = ' Apple ', ' b ' = ' banana ', ' c ' = ' Coconut ',)



Echo ' <br/><br/> ';



Deserialization



Eval (' $my _var= '. $s. ';');



Print_r ($my _var);

4. Wddx_serialize_value and WDDX Deserialize



The Wddx_serialize_value function can serialize array variables and output them as XML strings.



$a = Array (' a ' = = ' Apple ', ' b ' = ' banana ', ' c ' = ' Coconut ');



Serializing arrays

$s = wddx_serialize_value ($a);

Echo $s;



Output (view source of output String): <wddxpacket version= ' 1.0 ' >


Echo ' <br/><br/> ';



Deserialization

$o = Wddx_deserialize ($s);

Print_r ($o);

Output: Array ([a] = Apple [b] = Banana 1 = Coconut)

As you can see, there are more XML tag characters, resulting in a lot of space for serialization of this format.



Summary



All of the above functions perform normally when serializing array variables, but they are different when applied to objects. For example, the Json_encode serialization object fails. When deserializing an object, Unserialize and eval will have different effects.

