Serialize object having js-function()

[Val K]

Hi! 

I made mini but useful and universal class to hold json-serializable objects.

Main goal - serialize objects having items-function() as js-objects

from types import MethodType

from gluon.contrib  import simplejson as sj

class Smart_Storage(dict):

    """

    A Smart_Storage object is like a dictionary but:

    - set/get value:

        obj['foo'] == obj.foo

    - set/get attribute:

        # use `._.` or `._['attr_name']`  to set attribute

            obj._.attr = 'I`m attribute but not data!!!'

            obj._['another_attr'] = 'I`m another one'

        # set/update many attributes

            obj._.update(dict(...))

        # use dot only to get attribute

            print obj.attr

        # remember that

            obj['any_attr'] == None

        # but don't forget

            obj.__dict__['any_attr'] == obj.any_attr

    - bind/call method:

        # use `._['@...']` to bind method

            obj._['@my_meth'] = lambda self: 'I`m method of %s' % self

        # nothing new

            obj.my_meth()

    - finally obj.__json__():

        # works recursively

        # for item that is Smart_Storage instance - item.__json__() will be applied

            obj.__json__(only = None, exclude = None, values_only = False)

    - and obj.__formatters__():

        # use __formatters__ to control serialization (note double quote)

            obj.__formatters__['key_name'] = lambda self, k, v: self.check_access(k) and v or '"-access denied-"'

        # or just

            obj.__formatters__['key_name'] = '"key = %(k)s,  value = %(v)s"'

        # serialize web2py helpers

            obj.html = DIV()

            obj.__formatters__['html'] = lambda self, k, v: '"%s"' % v.xml()

        # serialize js-function/object for embedding as script

            obj.name='John'

            obj.surname='Smith'

            obj.who_are_you = "function(){ console.log( 'I`m', this.name, this.surname );}"

            obj.__formatters__['who_are_you'] = '%(v)s' # not '"%(v)s"'

            obj._['@xml'] = lambda self: \

                SCRIPT( '\n'.join([

                                    'var obj = %s;',

                                    'obj.who_are_you();',

                                 ]) % self.__json__()

                        ).xml()

            ...

            # in the view just

                {{ =obj }}

            # that will be

            <script><!--

                var obj = {"who_are_you":function(){ console.log( 'I`m ', this.name, this.surname );},"surname":"Smith","name":"John"};

                obj.who_are_you();

            //--></script>

    """

    __getattr__ = dict.get

    __getitem__ = dict.get

    __delattr__ = dict.__delitem__

    __repr__ = lambda self: '<Smart_Storage %s>' % dict.__repr__(self)

    class Add_Attr:

        def __init__(self, mystor_obj, args=None):

            self.__dict__['mystor_obj'] = mystor_obj

            if args:

                self.update(args)

        def __setattr__(self, k, v):

            if k in self.mystor_obj:

                raise RuntimeError('"%s" is in keys' % k)

            self.mystor_obj.__dict__[k] = v

        def __setitem__(self, k ,v):

            if k[0] in '0123456789&#.%$':

                raise RuntimeError('"%s" is invalid name' % k)

            if k[0]=='@':

                v = MethodType(v, self.mystor_obj)

                k=k[1:]

            self.__setattr__(k ,v)

        def update(self, d):

            [self.__setattr__(k, d[k]) for k in d]

    def __setattr__(self, k, v):

        if k in self.__dict__:

            raise RuntimeError('"%s" is in __dict__' % k)

        dict.__setitem__(self, k, v)

    def __init__(self, *a, **kwargs):

        _ = kwargs.pop('_', None)

        if 0:

            self._ = None

            self.__formatters__ = {}

        dict.__init__(self, *a, **kwargs)

        self.__dict__['_'] = Smart_Storage.Add_Attr(self, _)

        self.__dict__['__formatters__'] = {}

    def __json_pair__(self, k, v):

        formatter = self.__formatters__.get(k, None)

        if formatter is not None:

            if callable( formatter):

                ret = formatter(self, k, v)

            elif isinstance(formatter, basestring):

                ret = formatter % dict(k=k, v=v)

            else:

                raise RuntimeError('Unsupported formatter for  %s : "%s"' % (k, formatter))

        else:

            if isinstance(v, Smart_Storage):

                ret = v.__json__()

            elif isinstance(v, (list, tuple)):

                json_lst= [isinstance(it, Smart_Storage) and it.__json__() or sj.dumps(it) \

                            for it in v]

                ret= '[%s]'% ','.join(json_lst)

            else:

                ret = sj.dumps(v)

        return (k, ret)

    def __json__(self, only = None, exclude = None, values_only = False):

        """

        - only / exclude - filter out keys, 'exclude' applies after 'only', so:

            (only = ['a', 'b', 'c'], exclude = ['b']) == (only = ['a', 'c'])

        - values_only = True - serialize as json list of values

        """

        f_dict = lambda pair: '"%s":%s' % pair

        f_lst = lambda pair: pair[1]

        ret_str, f_str= values_only and ('[%s]' , f_lst) or ('{%s}',f_dict)

        buf = []

        if only or exclude:

            keys = only or self

            if exclude:

                keys = set(keys)-set(exclude)

            for k in keys:

                pair = self.__json_pair__(k, self[k])

                if pair:

                    buf.append(f_str(pair))

        else:

            for k, v in self.iteritems():

                pair = self.__json_pair__(k,v)

                if pair:

                    buf.append(f_str(pair))

        return ret_str % ','.join(buf)

[Manuele Pesenti]

Il 28/04/16 00:26, Val K ha scritto:

Hi! 

I made mini but useful and universal class to hold json-serializable objects.

Main goal - serialize objects having items-function() as js-objects

It looks very interesting to me :)
Thank you for sharing!
I'll notice here if I use it for a little project I have in my mind ;)
Cheers

    Manuele

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