406 lines
11 KiB
Python
406 lines
11 KiB
Python
'''
|
|
Storage
|
|
=======
|
|
|
|
.. versionadded:: 1.7.0
|
|
|
|
.. warning::
|
|
|
|
This module is still experimental, and the API is subject to change in a
|
|
future version.
|
|
|
|
Usage
|
|
-----
|
|
|
|
The idea behind the Storage module is to be able to load/store any number of
|
|
key-value pairs via an indexed key. The default model is abstract so you
|
|
cannot use it directly. We provide some implementations such as:
|
|
|
|
- :class:`kivy.storage.dictstore.DictStore`: use a python dict as a store
|
|
- :class:`kivy.storage.jsonstore.JsonStore`: use a
|
|
`JSON <https://en.wikipedia.org/wiki/JSON>`_ file as a store
|
|
- :class:`kivy.storage.redisstore.RedisStore`: use a `Redis <http://redis.io>`_
|
|
database with `redis-py <https://github.com/andymccurdy/redis-py>`_
|
|
|
|
|
|
Examples
|
|
--------
|
|
|
|
For example, let's use a JsonStore::
|
|
|
|
from kivy.storage.jsonstore import JsonStore
|
|
|
|
store = JsonStore('hello.json')
|
|
|
|
# put some values
|
|
store.put('tito', name='Mathieu', org='kivy')
|
|
store.put('tshirtman', name='Gabriel', age=27)
|
|
|
|
# using the same index key erases all previously added key-value pairs
|
|
store.put('tito', name='Mathieu', age=30)
|
|
|
|
# get a value using a index key and key
|
|
print('tito is', store.get('tito')['age'])
|
|
|
|
# or guess the key/entry for a part of the key
|
|
for item in store.find(name='Gabriel'):
|
|
print('tshirtmans index key is', item[0])
|
|
print('his key value pairs are', str(item[1]))
|
|
|
|
Because the data is persistent, you can check later to see if the key exists::
|
|
|
|
from kivy.storage.jsonstore import JsonStore
|
|
|
|
store = JsonStore('hello.json')
|
|
if store.exists('tito'):
|
|
print('tite exists:', store.get('tito'))
|
|
store.delete('tito')
|
|
|
|
|
|
Synchronous / Asynchronous API
|
|
------------------------------
|
|
|
|
All the standard methods (:meth:`~AbstractStore.get`,
|
|
:meth:`~AbstractStore.put` , :meth:`~AbstractStore.exists`,
|
|
:meth:`~AbstractStore.delete`, :meth:`~AbstractStore.find`) have an
|
|
asynchronous version.
|
|
|
|
For example, the *get* method has a `callback` parameter. If set, the
|
|
`callback` will be used to return the result to the user when available:
|
|
the request will be asynchronous. If the `callback` is None, then the
|
|
request will be synchronous and the result will be returned directly.
|
|
|
|
|
|
Without callback (Synchronous API)::
|
|
|
|
entry = mystore.get('tito')
|
|
print('tito =', entry)
|
|
|
|
With callback (Asynchronous API)::
|
|
|
|
def my_callback(store, key, result):
|
|
print('the key', key, 'has a value of', result)
|
|
mystore.get('plop', callback=my_callback)
|
|
|
|
|
|
The callback signature (for almost all methods) is::
|
|
|
|
def callback(store, key, result):
|
|
"""
|
|
store: the `Store` instance currently used.
|
|
key: the key sought for.
|
|
result: the result of the lookup for the key.
|
|
"""
|
|
|
|
|
|
Synchronous container type
|
|
--------------------------
|
|
|
|
The storage API emulates the container type for the synchronous API::
|
|
|
|
store = JsonStore('hello.json')
|
|
|
|
# original: store.get('tito')
|
|
store['tito']
|
|
|
|
# original: store.put('tito', name='Mathieu')
|
|
store['tito'] = {'name': 'Mathieu'}
|
|
|
|
# original: store.delete('tito')
|
|
del store['tito']
|
|
|
|
# original: store.count()
|
|
len(store)
|
|
|
|
# original: store.exists('tito')
|
|
'tito' in store
|
|
|
|
# original: for key in store.keys()
|
|
for key in store:
|
|
pass
|
|
|
|
'''
|
|
|
|
from kivy.clock import Clock
|
|
from kivy.event import EventDispatcher
|
|
|
|
|
|
class AbstractStore(EventDispatcher):
|
|
'''Abstract class used to implement a Store
|
|
'''
|
|
|
|
def __init__(self, **kwargs):
|
|
super(AbstractStore, self).__init__(**kwargs)
|
|
self.store_load()
|
|
|
|
def exists(self, key):
|
|
'''Check if a key exists in the store.
|
|
'''
|
|
return self.store_exists(key)
|
|
|
|
def async_exists(self, callback, key):
|
|
'''Asynchronous version of :meth:`exists`.
|
|
|
|
:Callback arguments:
|
|
`store`: :class:`AbstractStore` instance
|
|
Store instance
|
|
`key`: string
|
|
Name of the key to search for
|
|
`result`: boo
|
|
Result of the query, None if any error
|
|
'''
|
|
self._schedule(self.store_exists_async,
|
|
key=key, callback=callback)
|
|
|
|
def get(self, key):
|
|
'''Get the key-value pairs stored at `key`. If the key is not found, a
|
|
`KeyError` exception will be thrown.
|
|
'''
|
|
return self.store_get(key)
|
|
|
|
def async_get(self, callback, key):
|
|
'''Asynchronous version of :meth:`get`.
|
|
|
|
:Callback arguments:
|
|
`store`: :class:`AbstractStore` instance
|
|
Store instance
|
|
`key`: string
|
|
Name of the key to search for
|
|
`result`: dict
|
|
Result of the query, None if any error
|
|
'''
|
|
self._schedule(self.store_get_async, key=key, callback=callback)
|
|
|
|
def put(self, key, **values):
|
|
'''Put new key-value pairs (given in *values*) into the storage. Any
|
|
existing key-value pairs will be removed.
|
|
'''
|
|
need_sync = self.store_put(key, values)
|
|
if need_sync:
|
|
self.store_sync()
|
|
return need_sync
|
|
|
|
def async_put(self, callback, key, **values):
|
|
'''Asynchronous version of :meth:`put`.
|
|
|
|
:Callback arguments:
|
|
`store`: :class:`AbstractStore` instance
|
|
Store instance
|
|
`key`: string
|
|
Name of the key to search for
|
|
`result`: bool
|
|
Indicate True if the storage has been updated, or False if
|
|
nothing has been done (no changes). None if any error.
|
|
'''
|
|
self._schedule(self.store_put_async,
|
|
key=key, value=values, callback=callback)
|
|
|
|
def delete(self, key):
|
|
'''Delete a key from the storage. If the key is not found, a `KeyError`
|
|
exception will be thrown.'''
|
|
need_sync = self.store_delete(key)
|
|
if need_sync:
|
|
self.store_sync()
|
|
return need_sync
|
|
|
|
def async_delete(self, callback, key):
|
|
'''Asynchronous version of :meth:`delete`.
|
|
|
|
:Callback arguments:
|
|
`store`: :class:`AbstractStore` instance
|
|
Store instance
|
|
`key`: string
|
|
Name of the key to search for
|
|
`result`: bool
|
|
Indicate True if the storage has been updated, or False if
|
|
nothing has been done (no changes). None if any error.
|
|
'''
|
|
self._schedule(self.store_delete_async, key=key,
|
|
callback=callback)
|
|
|
|
def find(self, **filters):
|
|
'''Return all the entries matching the filters. The entries are
|
|
returned through a generator as a list of (key, entry) pairs
|
|
where *entry* is a dict of key-value pairs ::
|
|
|
|
for key, entry in store.find(name='Mathieu'):
|
|
print('key:', key, ', entry:', entry)
|
|
|
|
Because it's a generator, you cannot directly use it as a list. You can
|
|
do::
|
|
|
|
# get all the (key, entry) availables
|
|
entries = list(store.find(name='Mathieu'))
|
|
# get only the entry from (key, entry)
|
|
entries = list((x[1] for x in store.find(name='Mathieu')))
|
|
'''
|
|
return self.store_find(filters)
|
|
|
|
def async_find(self, callback, **filters):
|
|
'''Asynchronous version of :meth:`find`.
|
|
|
|
The callback will be called for each entry in the result.
|
|
|
|
:Callback arguments:
|
|
`store`: :class:`AbstractStore` instance
|
|
Store instance
|
|
`key`: string
|
|
Name of the key to search for, or None if we reach the end of
|
|
the results
|
|
`result`: bool
|
|
Indicate True if the storage has been updated, or False if
|
|
nothing has been done (no changes). None if any error.
|
|
'''
|
|
self._schedule(self.store_find_async,
|
|
callback=callback, filters=filters)
|
|
|
|
def keys(self):
|
|
'''Return a list of all the keys in the storage.
|
|
'''
|
|
return self.store_keys()
|
|
|
|
def async_keys(self, callback):
|
|
'''Asynchronously return all the keys in the storage.
|
|
'''
|
|
self._schedule(self.store_keys_async, callback=callback)
|
|
|
|
def count(self):
|
|
'''Return the number of entries in the storage.
|
|
'''
|
|
return self.store_count()
|
|
|
|
def async_count(self, callback):
|
|
'''Asynchronously return the number of entries in the storage.
|
|
'''
|
|
self._schedule(self.store_count_async, callback=callback)
|
|
|
|
def clear(self):
|
|
'''Wipe the whole storage.
|
|
'''
|
|
return self.store_clear()
|
|
|
|
def async_clear(self, callback):
|
|
'''Asynchronous version of :meth:`clear`.
|
|
'''
|
|
self._schedule(self.store_clear_async, callback=callback)
|
|
|
|
#
|
|
# Operators
|
|
#
|
|
|
|
def __setitem__(self, key, values):
|
|
if not isinstance(values, dict):
|
|
raise Exception('Only dict are accepted for the store[key] = dict')
|
|
self.put(key, **values)
|
|
|
|
def __getitem__(self, key):
|
|
return self.get(key)
|
|
|
|
def __delitem__(self, key):
|
|
return self.keys()
|
|
|
|
def __contains__(self, key):
|
|
return self.exists(key)
|
|
|
|
def __len__(self):
|
|
return self.count()
|
|
|
|
def __iter__(self):
|
|
for key in self.keys():
|
|
yield key
|
|
|
|
#
|
|
# Used for implementation
|
|
#
|
|
|
|
def store_load(self):
|
|
pass
|
|
|
|
def store_sync(self):
|
|
pass
|
|
|
|
def store_get(self, key):
|
|
raise NotImplementedError
|
|
|
|
def store_put(self, key, value):
|
|
raise NotImplementedError
|
|
|
|
def store_exists(self, key):
|
|
raise NotImplementedError
|
|
|
|
def store_delete(self, key):
|
|
raise NotImplementedError
|
|
|
|
def store_find(self, filters):
|
|
return []
|
|
|
|
def store_keys(self):
|
|
return []
|
|
|
|
def store_count(self):
|
|
return len(self.store_keys())
|
|
|
|
def store_clear(self):
|
|
for key in self.store_keys():
|
|
self.store_delete(key)
|
|
self.store_sync()
|
|
|
|
def store_get_async(self, key, callback):
|
|
try:
|
|
value = self.store_get(key)
|
|
callback(self, key, value)
|
|
except KeyError:
|
|
callback(self, key, None)
|
|
|
|
def store_put_async(self, key, value, callback):
|
|
try:
|
|
value = self.put(key, **value)
|
|
callback(self, key, value)
|
|
except:
|
|
callback(self, key, None)
|
|
|
|
def store_exists_async(self, key, callback):
|
|
try:
|
|
value = self.store_exists(key)
|
|
callback(self, key, value)
|
|
except:
|
|
callback(self, key, None)
|
|
|
|
def store_delete_async(self, key, callback):
|
|
try:
|
|
value = self.delete(key)
|
|
callback(self, key, value)
|
|
except:
|
|
callback(self, key, None)
|
|
|
|
def store_find_async(self, filters, callback):
|
|
for key, entry in self.store_find(filters):
|
|
callback(self, filters, key, entry)
|
|
callback(self, filters, None, None)
|
|
|
|
def store_count_async(self, callback):
|
|
try:
|
|
value = self.store_count()
|
|
callback(self, value)
|
|
except:
|
|
callback(self, 0)
|
|
|
|
def store_keys_async(self, callback):
|
|
try:
|
|
keys = self.store_keys()
|
|
callback(self, keys)
|
|
except:
|
|
callback(self, [])
|
|
|
|
def store_clear_async(self, callback):
|
|
self.store_clear()
|
|
callback(self)
|
|
|
|
#
|
|
# Privates
|
|
#
|
|
|
|
def _schedule(self, cb, **kwargs):
|
|
# XXX not entirely sure about the best value (0 or -1).
|
|
Clock.schedule_once(lambda dt: cb(**kwargs), 0)
|