Python sqlalchemy.ext.declarative.api.DeclarativeMeta() Examples

def from_everything(everything, engine, limit=None):
    """
    Construct a Prettytable from any kinds of sqlalchemy query.
    """
    if isinstance(everything, Table):
        return from_table(everything, engine, limit=limit)

    if type(everything) is DeclarativeMeta:
        return from_object(everything, engine, limit=limit)

    if isinstance(everything, Query):
        return from_query(everything, engine, limit=limit)

    if isinstance(everything, Select):
        return from_sql(everything, engine, limit=limit)

    if isinstance(everything, ResultProxy):
        return from_resultproxy(everything)

    if isinstance(everything, list):
        return from_data(everything) 

def test_base_class(self):
        assert isinstance(Base, DeclarativeMeta) 

def gen_items():
    """
    创建 items
    $ python gen.py gen_items
    字段规则： 去除自增主键，非自增是需要的。
    """
    from models import news

    file_path = os.path.join(BASE_DIR, 'news/items.py')

    model_list = [(k, v) for k, v in news.__dict__.items() if isinstance(v, DeclarativeMeta) and k != 'Base']

    with open(file_path, b'w') as f:
        f.write(b'# -*- coding: utf-8 -*-\n\n')
        f.write(b'# Define here the models for your scraped items\n#\n')
        f.write(b'# See documentation in:\n')
        f.write(b'# http://doc.scrapy.org/en/latest/topics/items.html\n\n')
        f.write(b'import scrapy\n')

        for model_name, model_class in model_list:
            result = model_class().to_dict()
            table_name = model_class().__tablename__
            model_pk = inspect(model_class).primary_key[0].name
            f.write(b'\n\nclass %sItem(scrapy.Item):\n' % model_name)
            f.write(b'    """\n')
            f.write(b'    table_name: %s\n' % table_name)
            f.write(b'    primary_key: %s\n' % model_pk)
            f.write(b'    """\n')
            for field_name in list(result.keys()):
                if field_name in [model_pk, 'create_time', 'update_time']:
                    continue
                f.write(b'    %s = scrapy.Field()\n' % field_name) 

def to_alchemy_obj(
        self
    ) -> Tuple[DeclarativeMeta, Type[DeclarativeMeta]]:
        raise NotImplementedError 

def create_resource(self, model, collection_name=None, expose_fields=None):
        """Produce a set of resource endpoints.

        Arguments:
            model: a model class derived from DeclarativeMeta.

        Keyword Args:
            collection_name: string name of collection. Passed through to
                ``collection_view_factory()``
            expose_fields: set of field names to be exposed. Passed through to
                ``collection_view_factory()``
        """

        # Find the primary key column from the model and use as 'id_col_name'
        try:
            keycols = sqlalchemy.inspect(model).primary_key
        except sqlalchemy.exc.NoInspectionAvailable:
            # Trying to inspect the declarative_base() raises this exception. We
            # don't want to add it to the API.
            return
        # Only deal with one primary key column.
        if len(keycols) > 1:
            raise Exception(
                'Model {} has more than one primary key.'.format(
                    model.__name__
                )
            )

        if not hasattr(model, '__pyramid_jsonapi__'):
            model.__pyramid_jsonapi__ = {}
        if 'id_col_name' not in model.__pyramid_jsonapi__:
            model.__pyramid_jsonapi__['id_col_name'] = keycols[0].name

        # Create a view class for use in the various add_view() calls below.
        view = self.collection_view_factory(model,
                                            collection_name or
                                            getattr(
                                                model, '__pyramid_jsonapi__', {}
                                            ).get('collection_name') or
                                            sqlalchemy.inspect(model).tables[-1].name,
                                            expose_fields=expose_fields)

        self.view_classes[model] = view

        view.default_limit = int(self.settings.paging_default_limit)
        view.max_limit = int(self.settings.paging_max_limit)

        self.endpoint_data.add_routes_views(view)