SP/web2py/gluon/contrib/redis_session.py
Saturneic 064f602b1a Add.
2018-10-25 23:33:13 +08:00

255 lines
8.9 KiB
Python

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