dabo Commit
Revision 4930
Date: 2009-01-14 12:55:45 -0800 (Wed, 14 Jan 2009)
Author: Paul
Trac: http://trac.dabodev.com/changeset/4930
Changed:
U trunk/dabo/db/dBackend.py
Log:
Added KeepAliveInterval to dBackend, which by default is None so has the old
behavior. But set it to a number of seconds, if desired, to cause a small
query to the server to be made in order to keep the connection alive. This
is useful to me for a MySQL app I have.
Currently, there's no way to set this other than e.g.:
form.getBizobj()._CurrentCursor.BackendObject.KeepAliveInterval = 3600
Consider this experimental. Because it is set on a backend object and not
a cursor, it doesn't make sense to expose the property in dCursorMixin.
Diff:
Modified: trunk/dabo/db/dBackend.py
===================================================================
--- trunk/dabo/db/dBackend.py 2009-01-12 04:28:00 UTC (rev 4929)
+++ trunk/dabo/db/dBackend.py 2009-01-14 20:55:45 UTC (rev 4930)
@@ -1,7 +1,9 @@
# -*- coding: utf-8 -*-
import sys
+import time
import re
import datetime
+import threading
import dabo
from dabo.dLocalize import _
import dabo.dException as dException
@@ -552,6 +554,38 @@
return clause
###########################################
+ def _applyKeepAlive(self):
+ """Start a thread to keep the connection alive."""
+
+ class WorkerThread(threading.Thread):
+ def __init__(self, backendObj):
+ threading.Thread.__init__(self)
+ self._toStop = False
+ self.backendObj = backendObj
+
+ def run(self):
+ last_hit = time.time()
+ while True:
+ kal = self.backendObj.KeepAliveInterval
+ app = self.backendObj.Application
+ if kal is None or not app or
getattr(app, "_finished", False):
+ self._toStop = True
+ if self._toStop:
+ return
+ if time.time() - last_hit > kal:
+ con =
self.backendObj._connection
+ cur = con.cursor()
+ cur.execute("select 1")
+ last_hit = time.time()
+ time.sleep(0.1)
+
+ existingThread = getattr(self, "_keepAliveThread", None)
+ if existingThread:
+ existingThread._toStop = True
+ if self.KeepAliveInterval is not None:
+ wt = self._keepAliveThread = WorkerThread(self)
+ wt.start()
+
def _setEncoding(self, enc):
""" Set backend encoding. Must be overridden in the subclass
to notify database about proper charset conversion.
@@ -563,5 +597,25 @@
return self._encoding
+ def _getKeepAliveInterval(self):
+ try:
+ ret = self._keepAliveInterval
+ except AttributeError:
+ ret = self._keepAliveInterval = None
+ return ret
+
+ def _setKeepAliveInterval(self, val):
+ self._keepAliveInterval = val
+ self._applyKeepAlive()
+
+
Encoding = property(_getEncoding, _setEncoding, None,
_("Backend encoding (str)"))
+
+ KeepAliveInterval = property(_getKeepAliveInterval,
_setKeepAliveInterval, None,
+ _("""Specifies how often a KeepAlive query should be
sent to the server.
+
+ Defaults to None, meaning we never send a KeepAlive
query. The interval
+ is expressed in seconds.
+ """))
+
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