PHP multiple serialization and deserialization methods

Serialization is the process of converting a variable to a saved or transmitted string. deserialization is to convert the string to the original variable when appropriate. These two processes can be combined to easily store and transmit data, making the program more maintainability.

Serialization is the process of converting a variable to a saved or transmitted string. deserialization is to convert the string to the original variable when appropriate. These two processes can be combined to easily store and transmit data, making the program more maintainability.

1. serialize and unserialize functions

These two are common functions for serialization and deserialization of PHP Data.

$ A = array ('a' => 'apple', 'B' => 'bana', 'C' => 'coconut '); // serialized array $ s = serialize ($ a); echo $ s; // output result: a: 3: {s: 1: "a"; s: 5: "Apple"; s: 1: "B"; s: 6: "banana"; s: 1: "c"; s: 7: "Coconut ";} echo ''; // deserialization $ o = unserialize ($ s); print_r ($ o ); // output result Array ([a] => Apple [B] => banana [c] => Coconut)?> When array values contain characters such as double quotes, single quotes, or colons, they may be deserialized. To overcome this problem, a clever technique is to use base64_encode and base64_decode. $ Obj = array (); // serialization $ s = base64_encode (serialize ($ obj); // deserialization $ original = unserialize (base64_decode ($ s ));

However, base64 encoding increases the length of the string. To overcome this problem, it can be used with gzcompress.

// Define a function called my_serialize ($ obj) {return base64_encode (gzcompress (serialize ($ obj);} // deserialize function my_unserialize ($ txt) {return unserialize (gzuncompress (base64_decode ($ txt )));}

2. json_encode and json_decode

JSON format serialization and deserialization are a good choice:

The output in json_encode and json_decode formats is much faster than that in serialize and unserialize formats.

The JSON format is readable.

The JSON format is smaller than the data returned by serialize.

JSON format is open and portable. You can also use it in other languages.

$ A = array ('a' => 'apple', 'B' => 'bana', 'C' => 'coconut '); // serialized array $ s = json_encode ($ a); echo $ s; // output result: {"a": "Apple", "B": "banana ", "c": "Coconut"} echo ''; // deserialization $ o = json_decode ($ s); in the preceding example, the json_encode output length is obviously shorter than the serialize output length in the previous example. 3. the var_export and evalvar_export functions output the variable as a string. The eval treats the string as PHP code for execution and deserializes it to get the content of the original variable. $ A = array ('a' => 'apple', 'B' => 'bana', 'C' => 'coconut '); // serialized array $ s = var_export ($ a, true); echo $ s; // output result: array ('a' => 'apple ', 'B' => 'bana', 'C' => 'Coconut',) echo ''; // deserialize eval ('$ my_var = '. $ s. ';'); print_r ($ my_var); 4. the wddx_serialize_value and wddx deserializewddx_serialize_value functions can serialize array variables and output them as XML strings. $ A = array ('a' => 'apple', 'B' => 'bana', 'C' => 'coconut '); // serialized array $ s = wddx_serialize_value ($ a); echo $ s; // output result (view the source code of the output string): applebananaco conutecho ''; // deserialization $ o = wddx_deserialize ($ s); print_r ($ o); // output result: array ([a] => Apple [B] => banana 1 => Coconut)

It can be seen that the serialization of this format still occupies a lot of space due to the large number of XML tag characters.

Summary

All the above functions can be normally executed when serializing array variables, but the objects used are different. For example, json_encode fails to serialize the object. When deserializing an object, unserialize and eval have different effects.