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| """An ISAPI extension base class implemented using a thread-pool.""" | |
| # $Id$ | |
| import sys | |
| import threading | |
| import time | |
| import traceback | |
| from pywintypes import OVERLAPPED | |
| from win32event import INFINITE | |
| from win32file import ( | |
| CloseHandle, | |
| CreateIoCompletionPort, | |
| GetQueuedCompletionStatus, | |
| PostQueuedCompletionStatus, | |
| ) | |
| from win32security import SetThreadToken | |
| import isapi.simple | |
| from isapi import ExtensionError, isapicon | |
| ISAPI_REQUEST = 1 | |
| ISAPI_SHUTDOWN = 2 | |
| class WorkerThread(threading.Thread): | |
| def __init__(self, extension, io_req_port): | |
| self.running = False | |
| self.io_req_port = io_req_port | |
| self.extension = extension | |
| threading.Thread.__init__(self) | |
| # We wait 15 seconds for a thread to terminate, but if it fails to, | |
| # we don't want the process to hang at exit waiting for it... | |
| self.setDaemon(True) | |
| def run(self): | |
| self.running = True | |
| while self.running: | |
| errCode, bytes, key, overlapped = GetQueuedCompletionStatus( | |
| self.io_req_port, INFINITE | |
| ) | |
| if key == ISAPI_SHUTDOWN and overlapped is None: | |
| break | |
| # Let the parent extension handle the command. | |
| dispatcher = self.extension.dispatch_map.get(key) | |
| if dispatcher is None: | |
| raise RuntimeError("Bad request '%s'" % (key,)) | |
| dispatcher(errCode, bytes, key, overlapped) | |
| def call_handler(self, cblock): | |
| self.extension.Dispatch(cblock) | |
| # A generic thread-pool based extension, using IO Completion Ports. | |
| # Sub-classes can override one method to implement a simple extension, or | |
| # may leverage the CompletionPort to queue their own requests, and implement a | |
| # fully asynch extension. | |
| class ThreadPoolExtension(isapi.simple.SimpleExtension): | |
| "Base class for an ISAPI extension based around a thread-pool" | |
| max_workers = 20 | |
| worker_shutdown_wait = 15000 # 15 seconds for workers to quit... | |
| def __init__(self): | |
| self.workers = [] | |
| # extensible dispatch map, for sub-classes that need to post their | |
| # own requests to the completion port. | |
| # Each of these functions is called with the result of | |
| # GetQueuedCompletionStatus for our port. | |
| self.dispatch_map = { | |
| ISAPI_REQUEST: self.DispatchConnection, | |
| } | |
| def GetExtensionVersion(self, vi): | |
| isapi.simple.SimpleExtension.GetExtensionVersion(self, vi) | |
| # As per Q192800, the CompletionPort should be created with the number | |
| # of processors, even if the number of worker threads is much larger. | |
| # Passing 0 means the system picks the number. | |
| self.io_req_port = CreateIoCompletionPort(-1, None, 0, 0) | |
| # start up the workers | |
| self.workers = [] | |
| for i in range(self.max_workers): | |
| worker = WorkerThread(self, self.io_req_port) | |
| worker.start() | |
| self.workers.append(worker) | |
| def HttpExtensionProc(self, control_block): | |
| overlapped = OVERLAPPED() | |
| overlapped.object = control_block | |
| PostQueuedCompletionStatus(self.io_req_port, 0, ISAPI_REQUEST, overlapped) | |
| return isapicon.HSE_STATUS_PENDING | |
| def TerminateExtension(self, status): | |
| for worker in self.workers: | |
| worker.running = False | |
| for worker in self.workers: | |
| PostQueuedCompletionStatus(self.io_req_port, 0, ISAPI_SHUTDOWN, None) | |
| # wait for them to terminate - pity we aren't using 'native' threads | |
| # as then we could do a smart wait - but now we need to poll.... | |
| end_time = time.time() + self.worker_shutdown_wait / 1000 | |
| alive = self.workers | |
| while alive: | |
| if time.time() > end_time: | |
| # xxx - might be nice to log something here. | |
| break | |
| time.sleep(0.2) | |
| alive = [w for w in alive if w.is_alive()] | |
| self.dispatch_map = {} # break circles | |
| CloseHandle(self.io_req_port) | |
| # This is the one operation the base class supports - a simple | |
| # Connection request. We setup the thread-token, and dispatch to the | |
| # sub-class's 'Dispatch' method. | |
| def DispatchConnection(self, errCode, bytes, key, overlapped): | |
| control_block = overlapped.object | |
| # setup the correct user for this request | |
| hRequestToken = control_block.GetImpersonationToken() | |
| SetThreadToken(None, hRequestToken) | |
| try: | |
| try: | |
| self.Dispatch(control_block) | |
| except: | |
| self.HandleDispatchError(control_block) | |
| finally: | |
| # reset the security context | |
| SetThreadToken(None, None) | |
| def Dispatch(self, ecb): | |
| """Overridden by the sub-class to handle connection requests. | |
| This class creates a thread-pool using a Windows completion port, | |
| and dispatches requests via this port. Sub-classes can generally | |
| implement each connection request using blocking reads and writes, and | |
| the thread-pool will still provide decent response to the end user. | |
| The sub-class can set a max_workers attribute (default is 20). Note | |
| that this generally does *not* mean 20 threads will all be concurrently | |
| running, via the magic of Windows completion ports. | |
| There is no default implementation - sub-classes must implement this. | |
| """ | |
| raise NotImplementedError("sub-classes should override Dispatch") | |
| def HandleDispatchError(self, ecb): | |
| """Handles errors in the Dispatch method. | |
| When a Dispatch method call fails, this method is called to handle | |
| the exception. The default implementation formats the traceback | |
| in the browser. | |
| """ | |
| ecb.HttpStatusCode = isapicon.HSE_STATUS_ERROR | |
| # control_block.LogData = "we failed!" | |
| exc_typ, exc_val, exc_tb = sys.exc_info() | |
| limit = None | |
| try: | |
| try: | |
| import cgi | |
| ecb.SendResponseHeaders( | |
| "200 OK", "Content-type: text/html\r\n\r\n", False | |
| ) | |
| print(file=ecb) | |
| print("<H3>Traceback (most recent call last):</H3>", file=ecb) | |
| list = traceback.format_tb( | |
| exc_tb, limit | |
| ) + traceback.format_exception_only(exc_typ, exc_val) | |
| print( | |
| "<PRE>%s<B>%s</B></PRE>" | |
| % ( | |
| cgi.escape("".join(list[:-1])), | |
| cgi.escape(list[-1]), | |
| ), | |
| file=ecb, | |
| ) | |
| except ExtensionError: | |
| # The client disconnected without reading the error body - | |
| # its probably not a real browser at the other end, ignore it. | |
| pass | |
| except: | |
| print("FAILED to render the error message!") | |
| traceback.print_exc() | |
| print("ORIGINAL extension error:") | |
| traceback.print_exception(exc_typ, exc_val, exc_tb) | |
| finally: | |
| # holding tracebacks in a local of a frame that may itself be | |
| # part of a traceback used to be evil and cause leaks! | |
| exc_tb = None | |
| ecb.DoneWithSession() | |