Metadata-Version: 2.4
Name: phpserialize
Version: 1.3
Summary: a port of the serialize and unserialize functions of php to python.
Home-page: http://dev.pocoo.org/hg/phpserialize-main
Author: Armin Ronacher
Author-email: armin.ronacher@active-4.com
Classifier: License :: OSI Approved :: BSD License
Classifier: Programming Language :: PHP
Classifier: Programming Language :: Python
Classifier: Programming Language :: Python :: 3
Dynamic: author
Dynamic: author-email
Dynamic: classifier
Dynamic: description
Dynamic: home-page
Dynamic: summary
phpserialize
~~~~~~~~~~~~
a port of the ``serialize`` and ``unserialize`` functions of
php to python. This module implements the python serialization
interface (eg: provides `dumps`, `loads` and similar functions).
Usage
=====
>>> from phpserialize import *
>>> obj = dumps("Hello World")
>>> loads(obj)
'Hello World'
Due to the fact that PHP doesn't know the concept of lists, lists
are serialized like hash-maps in PHP. As a matter of fact the
reverse value of a serialized list is a dict:
>>> loads(dumps(range(2)))
{0: 0, 1: 1}
If you want to have a list again, you can use the `dict_to_list`
helper function:
>>> dict_to_list(loads(dumps(range(2))))
[0, 1]
It's also possible to convert into a tuple by using the `dict_to_tuple`
function:
>>> dict_to_tuple(loads(dumps((1, 2, 3))))
(1, 2, 3)
Another problem are unicode strings. By default unicode strings are
encoded to 'utf-8' but not decoded on `unserialize`. The reason for
this is that phpserialize can't guess if you have binary or text data
in the strings:
>>> loads(dumps(u'Hello W\xf6rld'))
'Hello W\xc3\xb6rld'
If you know that you have only text data of a known charset in the result
you can decode strings by setting `decode_strings` to True when calling
loads:
>>> loads(dumps(u'Hello W\xf6rld'), decode_strings=True)
u'Hello W\xf6rld'
Dictionary keys are limited to strings and integers. `None` is converted
into an empty string and floats and booleans into integers for PHP
compatibility:
>>> loads(dumps({None: 14, 42.23: 'foo', True: [1, 2, 3]}))
{'': 14, 1: {0: 1, 1: 2, 2: 3}, 42: 'foo'}
It also provides functions to read from file-like objects:
>>> from StringIO import StringIO
>>> stream = StringIO('a:2:{i:0;i:1;i:1;i:2;}')
>>> dict_to_list(load(stream))
[1, 2]
And to write to those:
>>> stream = StringIO()
>>> dump([1, 2], stream)
>>> stream.getvalue()
'a:2:{i:0;i:1;i:1;i:2;}'
Like `pickle` chaining of objects is supported:
>>> stream = StringIO()
>>> dump([1, 2], stream)
>>> dump("foo", stream)
>>> stream.seek(0)
>>> load(stream)
{0: 1, 1: 2}
>>> load(stream)
'foo'
This feature however is not supported in PHP. PHP will only unserialize
the first object.
Array Serialization
===================
Starting with 1.2 you can provide an array hook to the unserialization
functions that are invoked with a list of pairs to return a real array
object. By default `dict` is used as array object which however means
that the information about the order is lost for associative arrays.
For example you can pass the ordered dictionary to the unserilization
functions:
>>> from collections import OrderedDict
>>> loads('a:2:{s:3:"foo";i:1;s:3:"bar";i:2;}',
... array_hook=OrderedDict)
collections.OrderedDict([('foo', 1), ('bar', 2)])
Object Serialization
====================
PHP supports serialization of objects. Starting with 1.2 of phpserialize
it is possible to both serialize and unserialize objects. Because class
names in PHP and Python usually do not map, there is a separate
`object_hook` parameter that is responsible for creating these classes.
For a simple test example the `phpserialize.phpobject` class can be used:
>>> data = 'O:7:"WP_User":1:{s:8:"username";s:5:"admin";}'
>>> user = loads(data, object_hook=phpobject)
>>> user.username
'admin'
>>> user.__name__
'WP_User'
An object hook is a function that takes the name of the class and a dict
with the instance data as arguments. The instance data keys are in PHP
format which usually is not what you want. To convert it into Python
identifiers you can use the `convert_member_dict` function. For more
information about that, have a look at the next section. Here an
example for a simple object hook:
>>> class User(object):
... def __init__(self, username):
... self.username = username
...
>>> def object_hook(name, d):
... cls = {'WP_User': User}[name]
... return cls(**d)
...
>>> user = loads(data, object_hook=object_hook)
>>> user.username
'admin'
To serialize objects you can use the `object_hook` of the dump functions
and return instances of `phpobject`:
>>> def object_hook(obj):
... if isinstance(obj, User):
... return phpobject('WP_User', {'username': obj.username})
... raise LookupError('unknown object')
...
>>> dumps(user, object_hook=object_hook)
'O:7:"WP_User":1:{s:8:"username";s:5:"admin";}'
PHP's Object System
===================
The PHP object system is derived from compiled languages such as Java
and C#. Attributes can be protected from external access by setting
them to `protected` or `private`. This does not only serve the purpose
to encapsulate internals but also to avoid name clashes.
In PHP each class in the inheritance chain can have a private variable
with the same name, without causing clashes. (This is similar to the
Python `__var` name mangling system).
This PHP class::
class WP_UserBase {
protected $username;
public function __construct($username) {
$this->username = $username;
}
}
class WP_User extends WP_UserBase {
private $password;
public $flag;
public function __construct($username, $password) {
parent::__construct($username);
$this->password = $password;
$this->flag = 0;
}
}
Is serialized with a member data dict that looks like this:
>>> data = {
... ' * username': 'the username',
... ' WP_User password': 'the password',
... 'flag': 'the flag'
... }
Because this access system does not exist in Python, the
`convert_member_dict` can convert this dict:
>>> d = convert_member_dict(data)
>>> d['username']
'the username'
>>> d['password']
'the password'
The `phpobject` class does this conversion on the fly. What is
serialized is the special `__php_vars__` dict of the class:
>>> user = phpobject('WP_User', data)
>>> user.username
'the username'
>>> user.username = 'admin'
>>> user.__php_vars__[' * username']
'admin'
As you can see, reassigning attributes on a php object will try
to change a private or protected attribute with the same name.
Setting an unknown one will create a new public attribute:
>>> user.is_admin = True
>>> user.__php_vars__['is_admin']
True
To convert the phpobject into a dict, you can use the `_asdict`
method:
>>> d = user._asdict()
>>> d['username']
'admin'
Python 3 Notes
==============
Because the unicode support in Python 3 no longer transparently
handles bytes and unicode objects we had to change the way the
decoding works. On Python 3 you most likely want to always
decode strings. Because this would totally fail on binary data
phpserialize uses the "surrogateescape" method to not fail on
invalid data. See the documentation in Python 3 for more
information.
Changelog
=========
1.3
- added support for Python 3
1.2
- added support for object serialization
- added support for array hooks
1.1
- added `dict_to_list` and `dict_to_tuple`
- added support for unicode
- allowed chaining of objects like pickle does
|