255 lines
8.9 KiB
Python
255 lines
8.9 KiB
Python
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#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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"""
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Developed by niphlod@gmail.com
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License MIT/BSD/GPL
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Redis-backed sessions
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"""
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import logging
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from threading import Lock
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from gluon import current
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from gluon.storage import Storage
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from gluon.contrib.redis_utils import acquire_lock, release_lock
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from gluon.contrib.redis_utils import register_release_lock
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from gluon._compat import to_bytes
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logger = logging.getLogger("web2py.session.redis")
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locker = Lock()
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def RedisSession(redis_conn, session_expiry=False, with_lock=False, db=None):
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"""
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Usage example: put in models::
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from gluon.contrib.redis_utils import RConn
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rconn = RConn()
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from gluon.contrib.redis_session import RedisSession
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sessiondb = RedisSession(redis_conn=rconn, with_lock=True, session_expiry=False)
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session.connect(request, response, db = sessiondb)
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Args:
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redis_conn: a redis-like connection object
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with_lock: prevent concurrent modifications to the same session
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session_expiry: delete automatically sessions after n seconds
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(still need to run sessions2trash.py every 1M sessions
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or so)
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Simple slip-in storage for session
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"""
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locker.acquire()
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try:
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instance_name = 'redis_instance_' + current.request.application
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if not hasattr(RedisSession, instance_name):
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setattr(RedisSession, instance_name,
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RedisClient(redis_conn, session_expiry=session_expiry, with_lock=with_lock))
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return getattr(RedisSession, instance_name)
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finally:
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locker.release()
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class RedisClient(object):
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def __init__(self, redis_conn, session_expiry=False, with_lock=False):
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self.r_server = redis_conn
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self._release_script = register_release_lock(self.r_server)
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self.tablename = None
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self.session_expiry = session_expiry
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self.with_lock = with_lock
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def get(self, what, default):
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return self.tablename
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def Field(self, fieldname, type='string', length=None, default=None,
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required=False, requires=None):
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return None
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def define_table(self, tablename, *fields, **args):
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if not self.tablename:
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self.tablename = MockTable(
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self, self.r_server, tablename, self.session_expiry,
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self.with_lock)
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return self.tablename
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def __getitem__(self, key):
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return self.tablename
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def __call__(self, where=''):
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q = self.tablename.query
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return q
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def commit(self):
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# this is only called by session2trash.py
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pass
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class MockTable(object):
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def __init__(self, db, r_server, tablename, session_expiry, with_lock=False):
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# here self.db is the RedisClient instance
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self.db = db
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self.tablename = tablename
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# set the namespace for sessions of this app
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self.keyprefix = 'w2p:sess:%s' % tablename.replace('web2py_session_', '')
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# fast auto-increment id (needed for session handling)
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self.serial = "%s:serial" % self.keyprefix
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# index of all the session keys of this app
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self.id_idx = "%s:id_idx" % self.keyprefix
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# remember the session_expiry setting
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self.session_expiry = session_expiry
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self.with_lock = with_lock
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def __call__(self, record_id, unique_key=None):
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# Support DAL shortcut query: table(record_id)
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# This will call the __getattr__ below
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# returning a MockQuery
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q = self.id
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# Instructs MockQuery, to behave as db(table.id == record_id)
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q.op = 'eq'
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q.value = record_id
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q.unique_key = unique_key
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row = q.select()
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return row[0] if row else Storage()
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def __getattr__(self, key):
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if key == 'id':
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# return a fake query. We need to query it just by id for normal operations
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self.query = MockQuery(
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field='id', db=self.db,
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prefix=self.keyprefix, session_expiry=self.session_expiry,
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with_lock=self.with_lock, unique_key=self.unique_key
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)
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return self.query
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elif key == '_db':
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# needed because of the calls in sessions2trash.py and globals.py
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return self.db
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def insert(self, **kwargs):
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# usually kwargs would be a Storage with several keys:
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# 'locked', 'client_ip','created_datetime','modified_datetime'
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# 'unique_key', 'session_data'
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# retrieve a new key
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newid = str(self.db.r_server.incr(self.serial))
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key = self.keyprefix + ':' + newid
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if self.with_lock:
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key_lock = key + ':lock'
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acquire_lock(self.db.r_server, key_lock, newid)
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with self.db.r_server.pipeline() as pipe:
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# add it to the index
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pipe.sadd(self.id_idx, key)
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# set a hash key with the Storage
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pipe.hmset(key, kwargs)
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if self.session_expiry:
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pipe.expire(key, self.session_expiry)
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pipe.execute()
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if self.with_lock:
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release_lock(self.db, key_lock, newid)
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return newid
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class MockQuery(object):
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"""a fake Query object that supports querying by id
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and listing all keys. No other operation is supported
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"""
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def __init__(self, field=None, db=None, prefix=None, session_expiry=False,
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with_lock=False, unique_key=None):
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self.field = field
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self.value = None
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self.db = db
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self.keyprefix = prefix
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self.op = None
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self.session_expiry = session_expiry
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self.with_lock = with_lock
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self.unique_key = unique_key
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def __eq__(self, value, op='eq'):
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self.value = value
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self.op = op
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def __gt__(self, value, op='ge'):
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self.value = value
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self.op = op
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def select(self):
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if self.op == 'eq' and self.field == 'id' and self.value:
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# means that someone wants to retrieve the key self.value
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key = self.keyprefix + ':' + str(self.value)
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if self.with_lock:
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acquire_lock(self.db.r_server, key + ':lock', self.value, 2)
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rtn = self.db.r_server.hgetall(key)
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if rtn:
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if self.unique_key:
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# make sure the id and unique_key are correct
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if rtn[b'unique_key'] == to_bytes(self.unique_key):
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rtn[b'update_record'] = self.update # update record support
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else:
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rtn = None
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return [Storage(rtn)] if rtn else []
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elif self.op == 'ge' and self.field == 'id' and self.value == 0:
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# means that someone wants the complete list
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rtn = []
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id_idx = "%s:id_idx" % self.keyprefix
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# find all session keys of this app
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allkeys = self.db.r_server.smembers(id_idx)
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for sess in allkeys:
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val = self.db.r_server.hgetall(sess)
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if not val:
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if self.session_expiry:
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# clean up the idx, because the key expired
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self.db.r_server.srem(id_idx, sess)
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continue
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val = Storage(val)
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# add a delete_record method (necessary for sessions2trash.py)
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val.delete_record = RecordDeleter(
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self.db, sess, self.keyprefix)
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rtn.append(val)
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return rtn
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else:
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raise Exception("Operation not supported")
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def update(self, **kwargs):
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# means that the session has been found and needs an update
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if self.op == 'eq' and self.field == 'id' and self.value:
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key = self.keyprefix + ':' + str(self.value)
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if not self.db.r_server.exists(key):
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return None
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with self.db.r_server.pipeline() as pipe:
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pipe.hmset(key, kwargs)
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if self.session_expiry:
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pipe.expire(key, self.session_expiry)
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rtn = pipe.execute()[0]
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if self.with_lock:
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release_lock(self.db, key + ':lock', self.value)
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return rtn
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def delete(self, **kwargs):
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# means that we want this session to be deleted
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if self.op == 'eq' and self.field == 'id' and self.value:
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id_idx = "%s:id_idx" % self.keyprefix
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key = self.keyprefix + ':' + str(self.value)
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with self.db.r_server.pipeline() as pipe:
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pipe.delete(key)
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pipe.srem(id_idx, key)
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rtn = pipe.execute()
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return rtn[1]
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class RecordDeleter(object):
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"""Dumb record deleter to support sessions2trash.py"""
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def __init__(self, db, key, keyprefix):
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self.db, self.key, self.keyprefix = db, key, keyprefix
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def __call__(self):
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id_idx = "%s:id_idx" % self.keyprefix
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# remove from the index
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self.db.r_server.srem(id_idx, self.key)
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# remove the key itself
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self.db.r_server.delete(self.key)
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