orm.py

'really simple ORM for RethinkDB objects'
import inflect
import re
import rethinkdb as r

p = inflect.engine()

class DocumentMetaClass(type):
    def __new__(meta, classname, bases, attrs):
        if '_table' not in attrs:
            base = re.sub("(.)([A-Z])", r'\1_\2', classname).lower()
            attrs['_table'] = p.plural(base)

        attrs['r'] = r.table(attrs['_table'])

        return type.__new__(meta, classname, bases, attrs)

class Document(dict):
    'wrapper and convenience methods for rethinkdb documents'
    __metaclass__ = DocumentMetaClass
    #_db = None
    _pk = 'id'

    def save(self, conn):
        if self._pk in self:
            return self.update(conn)
        else:
            return self.insert(conn)

    def update(self, conn):
        'update this document'
        if self.pk not in self:
            raise TypeError('Need a PK to update with')

        return self.r.update(self).run(conn)

    def insert(self, conn):
        'insert this document'
        response = self.r.insert(self).run(conn)
        if self._pk not in self:
            self[self._pk] = response['generated_keys'][0]

        return response

    def delete(self, conn):
        'delete this document'
        return self.r.get(self[self._pk]).delete().run(conn)

    def __getattr__(self, attr):
        return self[attr]

    def __setattr__(self, attr, value):
        self[attr] = value

    @classmethod
    def convert(cls, cursor_or_obj):
        return cls(cursor_or_obj)

    @classmethod
    def convert_cursor(cls, cursor):
        for item in cursor:
            yield cls.convert(item)