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
| 代码如下 | 复制代码 |
|
#!/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 + "<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 |
|
第1次 curl ，等待返回
| 代码如下 | 复制代码 |
|
[~]$curl -s ‘http://10.232.41.142:9001/hello1′ <html>/hello1<br><__main__.ThreadingHTTPServer instance at 0x37483b0></html>[~]$ 此时服务器端输出日志如下： $./thread_http_server_error.py query: /hello1 thread= search041142.sqa.cm4.tbsite.net – - [15/May/2014 15:02:27] “GET /hello1 HTTP/1.1″ 200 - success prod query :/hello1 |
|
第2次 curl ，不等待返回，ctrl +C 来模拟客户端断开
| 代码如下 | 复制代码 |
| [~]$curl -s ‘http://10.232.41.142:9001/hello2′ [~]$ ctrl+C |
|
此时服务器端输出日志如下：
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。
| 代码如下 | 复制代码 |
|
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。
| 代码如下 | 复制代码 |
|
#!/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 + "<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 |
|
此时服务器端输出日志如下：
| 代码如下 | 复制代码 |
|
$./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() |
|