1 錯誤現象
ThreadingHTTPServer 實現的 http 服務，如果用戶端在伺服器返回前，主動中斷連線，則伺服器端會報 [Errno 32] Broken pipe 錯，並導致處理線程 crash.
下面先看個例子,python 版本: 2.7
範例程式碼
| 代碼如下 |
複製代碼 |
#!/usr/bin/env python
#!coding=utf-8
import os
import time
import socket
import threading
from BaseHTTPServer import HTTPServer ,BaseHTTPRequestHandler
from SocketServer import ThreadingMixIn
class RequestHandler(BaseHTTPRequestHandler):
def do_GET(self):
"""
處理get請求
"""
query=self.path
print "query: %s thread=%s" % (query, str(threading.current_thread()))
#ret_str="<html>" + self.path + "<br>" + str(self.server) + "<br>" + str(self.responses) + "</html>"
ret_str="<html>" + self.path + "<br>" + str(self.server) + "</html>"
time.sleep(5)
try:
self.send_response(200)
self.send_header('Content-type','text/html')
self.end_headers()
self.wfile.write(ret_str)
except socket.error, e:
print "socket.error : Connection broke. Aborting" + str(e)
self.wfile._sock.close() # close socket
self.wfile._sock=None
return False
print "success prod query :%s" % (query)
return True
#多執行緒
class ThreadingHTTPServer(ThreadingMixIn,HTTPServer):
pass
if __name__ == '__main__':
serveraddr = ('',9001)
ser = ThreadingHTTPServer(serveraddr,RequestHandler)
ser.serve_forever()
sys.exit(0) 運行服務
./thread_http_server_error.py |
第1次 curl ，等待返回
| 代碼如下 |
複製代碼 |
[~]$curl -s ‘http://10.232.41.142:9001/hello1′ <html>/hello1<br><__main__.ThreadingHTTPServer instance at 0x37483b0></html>[~]$ 此時伺服器端輸出日誌如下： $./thread_http_server_error.py query: /hello1 thread= search041142.sqa.cm4.tbsite.net – - [15/May/2014 15:02:27] “GET /hello1 HTTP/1.1″ 200 - success prod query :/hello1 |
第2次 curl ，不等待返回，ctrl +C 來類比用戶端斷開
| 代碼如下 |
複製代碼 |
[~]$curl -s ‘http://10.232.41.142:9001/hello2′
[~]$ ctrl+C |
此時伺服器端輸出日誌如下：
query: /hello2 thread=
search041142.sqa.cm4.tbsite.net – - [15/May/2014 15:33:10] “GET /hello2 HTTP/1.1″ 200 -
socket.error : Connection broke. Aborting[Errno 32] Broken pipe
—————————————-
Exception happened during processing of request from (’10.232.41.142′, 48769)
Traceback (most recent call last):
File “/home/wuzhu/tools/python_2_7_1/lib/python2.7/SocketServer.py”, line 582, in process_request_thread
self.finish_request(request, client_address)
File “/home/wuzhu/tools/python_2_7_1/lib/python2.7/SocketServer.py”, line 323, in finish_request
self.RequestHandlerClass(request, client_address, self)
File “/home/wuzhu/tools/python_2_7_1/lib/python2.7/SocketServer.py”, line 639, in __init__
self.handle()
File “/home/wuzhu/tools/python_2_7_1/lib/python2.7/BaseHTTPServer.py”, line 337, in handle
self.handle_one_request()
File “/home/wuzhu/tools/python_2_7_1/lib/python2.7/BaseHTTPServer.py”, line 326, in handle_one_request
self.wfile.flush() #actually send the response if not already done.
File “/home/wuzhu/tools/python_2_7_1/lib/python2.7/socket.py”, line 303, in flush
self._sock.sendall(view[write_offset:write_offset+buffer_size])
AttributeError: ‘NoneType’ object has no attribute ‘sendall’
—————————————-
2 原因分析
“[Errno 32] Broken pipe “ 產生的原因還是比較明確的，由於 client 在伺服器返回前主動中斷連線，所以伺服器在返回時寫 socket 收到SIGPIPE報錯。雖然在我們的程式中也對異常進行了處理，將handler 的 wfile._sock 對象close 掉 ，但python 的庫裡BaseHTTPServer.py中BaseHTTPRequestHandler 類的成員函數handle_one_request還是會直接調用 wfile.flush ，而沒有判斷 wfile 是否已經 close。
| 代碼如下 |
複製代碼 |
def handle_one_request(self):
"""Handle a single HTTP request.
You normally don't need to override this method; see the class
__doc__ string for information on how to handle specific HTTP
commands such as GET and POST.
"""
try:
self.raw_requestline = self.rfile.readline(65537)
if len(self.raw_requestline) > 65536:
self.requestline = ''
self.request_version = ''
self.command = ''
self.send_error(414)
return
if not self.raw_requestline:
self.close_connection = 1
return
if not self.parse_request():
# An error code has been sent, just exit
return
mname = 'do_' + self.command
if not hasattr(self, mname):
self.send_error(501, "Unsupported method (%r)" % self.command)
return
method = getattr(self, mname)
method()
#沒有判斷 wfile 是否已經 close 就直接調用 flush()
self.wfile.flush() #actually send the response if not already done.
except socket.timeout, e:
#a read or a write timed out. Discard this connection
self.log_error("Request timed out: %r", e)
self.close_connection = 1
return |
3 解決辦法
只要在RequestHandler重載其基類BaseHTTPRequestHandler的成員函數handle_one_reques（），在調用 wfile.flush() 前加上 wfile 是否已經 close 即可。
| 代碼如下 |
複製代碼 |
#!/usr/bin/env python
#!coding=utf-8
import os
import time
import socket
import threading
from BaseHTTPServer import HTTPServer ,BaseHTTPRequestHandler
from SocketServer import ThreadingMixIn
class RequestHandler(BaseHTTPRequestHandler):
def handle_one_request(self):
"""Handle a single HTTP request.
You normally don't need to override this method; see the class
__doc__ string for information on how to handle specific HTTP
commands such as GET and POST.
"""
try:
self.raw_requestline = self.rfile.readline(65537)
if len(self.raw_requestline) > 65536:
self.requestline = ''
self.request_version = ''
self.command = ''
self.send_error(414)
return
if not self.raw_requestline:
self.close_connection = 1
return
if not self.parse_request():
# An error code has been sent, just exit
return
mname = 'do_' + self.command
if not hasattr(self, mname):
self.send_error(501, "Unsupported method (%r)" % self.command)
return
method = getattr(self, mname)
print "before call do_Get"
method()
#增加 debug info 及 wfile 判斷是否已經 close
print "after call do_Get"
if not self.wfile.closed:
self.wfile.flush() #actually send the response if not already done.
print "after wfile.flush()"
except socket.timeout, e:
#a read or a write timed out. Discard this connection
self.log_error("Request timed out: %r", e)
self.close_connection = 1
return
def do_GET(self):
"""
處理get請求
"""
query=self.path
print "query: %s thread=%s" % (query, str(threading.current_thread()))
ret_str="<html>" + self.path + "<br>" + str(self.server) + "</html>"
time.sleep(5)
try:
self.send_response(200)
self.send_header('Content-type','text/html')
self.end_headers()
self.wfile.write(ret_str)
except socket.error, e:
print "socket.error : Connection broke. Aborting" + str(e)
self.wfile._sock.close()
self.wfile._sock=None
return False
print "success prod query :%s" % (query)
return True
#多執行緒
class ThreadingHTTPServer(ThreadingMixIn,HTTPServer):
pass
if __name__ == '__main__':
serveraddr = ('',9001)
ser = ThreadingHTTPServer(serveraddr,RequestHandler)
ser.serve_forever()
sys.exit(0) 運行服務
./thread_http_server.py
curl ，不等待返回，ctrl +C 來類比用戶端斷開
[~]$curl -s 'http://10.232.41.142:9001/hello2'
[~]$ ctrl+C |
此時伺服器端輸出日誌如下：
| 代碼如下 |
複製代碼 |
$./thread_http_server.pybefore call do_Get query: /hello2 thread=<Thread(Thread-1, started 1103210816)> search041142.sqa.cm4.tbsite.net - - [15/May/2014 15:54:09] "GET /hello2 HTTP/1.1" 200 - socket.error : Connection broke. Aborting[Errno 32] Broken pipe after call do_Get after wfile.flush() |
