Python提示[Errno 32]Broken pipe导致线程crash错误解决方法

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本文实例讲述了Python提示[Errno 32]Broken pipe导致线程crash错误解决方法。分享给大家供大家参考。具体方法如下：

1. 错误现象
ThreadingHTTPServer 实现的 http 服务，如果客户端在服务器返回前，主动断开连接，则服务器端会报 [Errno 32] Broken pipe 错，并导致处理线程 crash.
下面先看个例子,python 版本: 2.7
示例代码
复制代码代码如下:#!/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):
 """
 处理get请求
 """
 query=self.path
 print "query: %s thread=%s" % (query, str(threading.current_thread()))

 #ret_str="<html>" + self.path + " " + str(self.server) + " " + str(self.responses) + "</html>"
 ret_str="<html>" + self.path + " " + 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

#多线程处理
class ThreadingHTTPServer(ThreadingMixIn,HTTPServer):
 pass

if __name__ == '__main__':
 serveraddr = ('',9001)

 ser = ThreadingHTTPServer(serveraddr,RequestHandler)
 ser.serve_forever()
 sys.exit(0)
运行服务
./thread_http_server_error.py
第1次 curl ，等待返回
复制代码代码如下:[~]$curl -s 'http://10.232.41.142:9001/hello1′
<html>/hello1 <__main__.ThreadingHTTPServer instance at 0x37483b0></html>[~]$
此时服务器端输出日志如下：
$./thread_http_server_error.py
query: /hello1 thread=
search041142.sqa.cm4.tbsite.net – - [15/May/2014 15:02:27] “GET /hello1 HTTP/1.1″ 200 -
success prod query :/hello1
第2次 curl ，不等待返回，ctrl +C 来模拟客户端断开
复制代码代码如下:[~]$curl -s 'http://10.232.41.142:9001/hello2′
[~]$ ctrl+C
此时服务器端输出日志如下：
复制代码代码如下: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 “ 产生的原因还是比较明确的，由于 client 在服务器返回前主动断开连接，所以服务器在返回时写 socket 收到SIGPIPE报错。虽然在我们的程序中也对异常进行了处理，将handler 的 wfile._sock 对象close 掉，但python 的库里BaseHTTPServer.py中BaseHTTPRequestHandler 类的成员函数handle_one_request还是会直接调用 wfile.flush ，而没有判断 wfile 是否已经 close。
复制代码代码如下: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()
        #没有判断 wfile 是否已经 close 就直接调用 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. 解决办法

只要在RequestHandler重载其基类BaseHTTPRequestHandler的成员函数handle_one_reques（），在调用 wfile.flush() 前加上 wfile 是否已经 close 即可。
复制代码代码如下:#!/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 判断是否已经 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):
 """
 处理get请求
 """
 query=self.path
 print "query: %s thread=%s" % (query, str(threading.current_thread()))

 ret_str="<html>" + self.path + " " + 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

#多线程处理
class ThreadingHTTPServer(ThreadingMixIn,HTTPServer):
 pass

if __name__ == '__main__':
 serveraddr = ('',9001)

 ser = ThreadingHTTPServer(serveraddr,RequestHandler)
 ser.serve_forever()
 sys.exit(0)
运行服务
./thread_http_server.py
curl ，不等待返回，ctrl +C 来模拟客户端断开
复制代码代码如下:[~]$curl -s 'http://10.232.41.142:9001/hello2'
[~]$ ctrl+C
此时服务器端输出日志如下：
复制代码代码如下:$./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()
希望本文所述对大家的Python程序设计有所帮助。