def filter(cls, **query_args):
"""Finds data entries from storage as list of Model instances
:param: query_args - a dict holding query conditions like {'id': 123}
:returns: list with Model instances or empty list if no match
"""
retval = []
storage = StorageForge()
model_name = cls.get_model_name()
values_list = storage.filter(model_name, **query_args)
for values in values_list:
retval.append(cls(**values))
return retval
def __init__(self, **values):
"""During initialization it is possible to set all Fields
To set Field values during Model initialization time a dict
of field names and values is required in such form:
{<field-name>: <value>}
"""
if values:
for name, value in values.items():
field = getattr(self, name)
# FIXME field value gets overwritten when creating multiple
# instances
field.put_value(value)
self.storage = StorageForge()
class Model(object):
"""Provides Model for storing and managing data
to initiate model one needs to subclass from Model class and use
Field class data-type-methods to define Model. This alows data
validation and control when assigning values to Model instance.
Also this class implements ``sync`` method which synchronises
data schema with actual data storage.
"""
def __new__(cls, **kwargs):
user_model_inst = super(Model, cls).__new__(cls, **kwargs)
return user_model_inst
def __setattr__(self, name, value):
"""Here we define how user values should be assigned
When Field does not exists by name it will be added
:param: name - string name of an Field
:param: value - data value which gets passed to Field
"""
field = self._introspect(name=name)
if field:
field = field[name].put_value(value)
else:
super(Model, self).__setattr__(name, value)
def __init__(self, **values):
"""During initialization it is possible to set all Fields
To set Field values during Model initialization time a dict
of field names and values is required in such form:
{<field-name>: <value>}
"""
if values:
for name, value in values.items():
field = getattr(self, name)
# FIXME field value gets overwritten when creating multiple
# instances
field.put_value(value)
self.storage = StorageForge()
def save(self):
"""Here is where value of Field gets stored in actual storage
All Field values are collected here and passed to storage
back-end where these get saved according to earlier Model
definition which was synced with storage.
"""
values = []
fields = self._introspect()
for name, field in fields.items():
attr = getattr(self, name)
values.append(attr)
model_name = self.get_model_name()
self.storage.save(model_name, values)
@classmethod
def filter(cls, **query_args):
"""Finds data entries from storage as list of Model instances
:param: query_args - a dict holding query conditions like {'id': 123}
:returns: list with Model instances or empty list if no match
"""
retval = []
storage = StorageForge()
model_name = cls.get_model_name()
values_list = storage.filter(model_name, **query_args)
for values in values_list:
retval.append(cls(**values))
return retval
@classmethod
def sync(cls):
"""Synchronizes Model with Storage"""
fields = cls._introspect()
storage = StorageForge()
model_name = cls.get_model_name()
storage.sync(model_name, fields)
@classmethod
def flush(cls):
"""Deletes all Model entries in storage"""
fields = cls._introspect()
storage = StorageForge()
model_name = cls.get_model_name()
storage.flush(model_name)
@classmethod
def _introspect(cls, name=None):
"""Looks for defined Field in the Model definition
:param: name - string name of specific Field (optional)
:returns: dict of {'name': Field,} or first matched Field if ``name`` given
"""
fields = {}
for attr_name in dir(cls):
attr = getattr(cls, attr_name)
if isinstance(attr, Field):
if name is not None:
if attr_name == name:
return {attr_name: attr}
else:
fields[attr_name] = attr
return fields
@classmethod
def get_model_name(cls):
"""Gets name of model in lower case
:returns: name - string name of the model
"""
return cls.__name__.lower()
def flush(cls):
"""Deletes all Model entries in storage"""
fields = cls._introspect()
storage = StorageForge()
model_name = cls.get_model_name()
storage.flush(model_name)
def sync(cls):
"""Synchronizes Model with Storage"""
fields = cls._introspect()
storage = StorageForge()
model_name = cls.get_model_name()
storage.sync(model_name, fields)
