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Direktori : /opt/alt/python35/lib64/python3.5/site-packages/playhouse/ |
Current File : //opt/alt/python35/lib64/python3.5/site-packages/playhouse/kv.py |
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)