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Mini Shell
Mini Shell
import operator
import pickle
try:
import simplejson as json
except ImportError:
import json
from peewee import *
from peewee import Node
from playhouse.fields import PickledField
try:
from playhouse.apsw_ext import APSWDatabase
def KeyValueDatabase(db_name, **kwargs):
return APSWDatabase(db_name, **kwargs)
except ImportError:
def KeyValueDatabase(db_name, **kwargs):
return SqliteDatabase(db_name, check_same_thread=False, **kwargs)
Sentinel = type('Sentinel', (object,), {})
key_value_db = KeyValueDatabase(':memory:', threadlocals=False)
class JSONField(TextField):
def db_value(self, value):
return json.dumps(value)
def python_value(self, value):
if value is not None:
return json.loads(value)
class KeyStore(object):
"""
Rich dictionary with support for storing a wide variety of data types.
:param peewee.Field value_type: Field type to use for values.
:param boolean ordered: Whether keys should be returned in sorted order.
:param peewee.Model model: Model class to use for Keys/Values.
"""
def __init__(self, value_field, ordered=False, database=None):
self._value_field = value_field
self._ordered = ordered
self._database = database or key_value_db
self._compiler = self._database.compiler()
self.model = self.create_model()
self.key = self.model.key
self.value = self.model.value
self._database.create_table(self.model, True)
self._native_upsert = isinstance(self._database, SqliteDatabase)
def create_model(self):
class KVModel(Model):
key = CharField(max_length=255, primary_key=True)
value = self._value_field
class Meta:
database = self._database
return KVModel
def query(self, *select):
query = self.model.select(*select).tuples()
if self._ordered:
query = query.order_by(self.key)
return query
def convert_node(self, node):
if not isinstance(node, Node):
return (self.key == node), True
return node, False
def __contains__(self, key):
node, _ = self.convert_node(key)
return self.model.select().where(node).exists()
def __len__(self):
return self.model.select().count()
def __getitem__(self, node):
converted, is_single = self.convert_node(node)
result = self.query(self.value).where(converted)
item_getter = operator.itemgetter(0)
result = [item_getter(val) for val in result]
if len(result) == 0 and is_single:
raise KeyError(node)
elif is_single:
return result[0]
return result
def _upsert(self, key, value):
self.model.insert(**{
self.key.name: key,
self.value.name: value}).upsert().execute()
def __setitem__(self, node, value):
if isinstance(node, Node):
update = {self.value.name: value}
self.model.update(**update).where(node).execute()
elif self._native_upsert:
self._upsert(node, value)
else:
try:
self.model.create(key=node, value=value)
except:
self._database.rollback()
(self.model
.update(**{self.value.name: value})
.where(self.key == node)
.execute())
def __delitem__(self, node):
converted, _ = self.convert_node(node)
self.model.delete().where(converted).execute()
def __iter__(self):
return self.query().execute()
def keys(self):
return map(operator.itemgetter(0), self.query(self.key))
def values(self):
return map(operator.itemgetter(0), self.query(self.value))
def items(self):
return iter(self)
def get(self, k, default=None):
try:
return self[k]
except KeyError:
return default
def pop(self, k, default=Sentinel):
with self._database.transaction():
node, is_single = self.convert_node(k)
try:
res = self[k]
except KeyError:
if default is Sentinel:
raise
return default
del(self[node])
return res
def clear(self):
self.model.delete().execute()
class PickledKeyStore(KeyStore):
def __init__(self, ordered=False, database=None):
super(PickledKeyStore, self).__init__(
PickledField(), ordered, database)
class JSONKeyStore(KeyStore):
def __init__(self, ordered=False, database=None):
field = JSONField(null=True)
super(JSONKeyStore, self).__init__(field, ordered, database)
Zerion Mini Shell 1.0