asyncore python挂起
我尝试使用asyncore执行简单的异步http客户端: 此代码工作正常,输出为(fast enought): 但是,我取消了对不存在主机的行的注释:asyncore python挂起,python,asyncore,Python,Asyncore,我尝试使用asyncore执行简单的异步http客户端: 此代码工作正常,输出为(fast enought): 但是,我取消了对不存在主机的行的注释: #c = AsyncHTTP('http://www.no-such-host.ru') #!this line breaks execution! 执行中断、代码挂起一段时间、输出部分数据并挂起,没有最后的数据输出: connection error: [Errno -5] No address associated with hostnam
#c = AsyncHTTP('http://www.no-such-host.ru') #!this line breaks execution!
执行中断、代码挂起一段时间、输出部分数据并挂起,没有最后的数据输出:
connection error: [Errno -5] No address associated with hostname
www.gmail.com : recv http code: 301
www.yandex.ru : recv http code: 200
www.yahoo.com : recv http code: 302
www.com.com : recv http code: 302
www.bom.com : recv http code: 301
www.gravatar.com : recv http code: 302
。。。
一些主机在此丢失,并且在启动时长时间延迟
为什么会发生这种情况以及如何解决
# coding=utf-8
import asyncore
import string, socket
import StringIO
import mimetools, urlparse
class AsyncHTTP(asyncore.dispatcher):
# HTTP requestor
def __init__(self, uri):
asyncore.dispatcher.__init__(self)
self.uri = uri
# turn the uri into a valid request
scheme, host, path, params, query, fragment = urlparse.urlparse(uri)
assert scheme == "http", "only supports HTTP requests"
try:
host, port = string.split(host, ":", 1)
port = int(port)
except (TypeError, ValueError):
port = 80 # default port
if not path:
path = "/"
if params:
path = path + ";" + params
if query:
path = path + "?" + query
self.request = "GET %s HTTP/1.0\r\nHost: %s\r\n\r\n" % (path, host)
self.host = host
self.port = port
self.status = None
self.header = None
self.http_code = None
self.data = ""
# get things going!
self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
#self.connect((host, port))
#return
try:
self.connect((host, port))
except Exception,e:
self.close()
self.handle_connect_expt(e)
def handle_connect(self):
self.send(self.request)
def handle_expt(self):
print "handle_expt error!"
self.close()
def handle_error(self):
print "handle_error error!"
self.close()
def handle_connect_expt(self,expt):
print "connection error:",expt
def handle_code(self):
print self.host," : ","recv http code: ",self.http_code
def handle_read(self):
data = self.recv(2048)
#print data
if not self.header:
self.data = self.data + data
try:
i = string.index(self.data, "\r\n\r\n")
except ValueError:
return # continue
else:
# parse header
fp = StringIO.StringIO(self.data[:i+4])
# status line is "HTTP/version status message"
status = fp.readline()
self.status = string.split(status, " ", 2)
self.http_code = self.status[1]
self.handle_code()
# followed by a rfc822-style message header
self.header = mimetools.Message(fp)
# followed by a newline, and the payload (if any)
data = self.data[i+4:]
self.data = ""
#header recived
#self.close()
def handle_close(self):
self.close()
c = AsyncHTTP('http://www.python.org')
c = AsyncHTTP('http://www.yandex.ru')
c = AsyncHTTP('http://www.google.ru')
c = AsyncHTTP('http://www.gmail.com')
c = AsyncHTTP('http://www.gravatar.com')
c = AsyncHTTP('http://www.yahoo.com')
c = AsyncHTTP('http://www.com.com')
c = AsyncHTTP('http://www.bom.com')
#c = AsyncHTTP('http://www.no-such-host.ru') #!this line breaks execution!
asyncore.loop()
ps:My system Ubuntu11.10+Python2.7.2当您执行
self.connect((主机,端口))
时,您会调用一个阻塞名称解析。结合您的本地DNS配置,这就是为什么您的程序在启动时有很长的延迟
作为asyncore的替代方案,您可以考虑使用Twisted来解决如何自己进行非阻塞名称解析的问题。Twisted的TCP连接设置API(主要是
reactor.connectTCP
或构建在其上的一个API)不会阻塞。因此,简单地使用它将保持适当的异步。在我的linux系统(而不是ubuntu)上尝试了你的脚本,它运行时没有遇到你报告的任何问题。所以你的ubuntu设置可能有问题。@ekhumoro:对不起,我弄错了,即使我试过这段代码,也没有问题:)
# coding=utf-8
import asyncore
import string, socket
import StringIO
import mimetools, urlparse
class AsyncHTTP(asyncore.dispatcher):
# HTTP requestor
def __init__(self, uri):
asyncore.dispatcher.__init__(self)
self.uri = uri
# turn the uri into a valid request
scheme, host, path, params, query, fragment = urlparse.urlparse(uri)
assert scheme == "http", "only supports HTTP requests"
try:
host, port = string.split(host, ":", 1)
port = int(port)
except (TypeError, ValueError):
port = 80 # default port
if not path:
path = "/"
if params:
path = path + ";" + params
if query:
path = path + "?" + query
self.request = "GET %s HTTP/1.0\r\nHost: %s\r\n\r\n" % (path, host)
self.host = host
self.port = port
self.status = None
self.header = None
self.http_code = None
self.data = ""
# get things going!
self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
#self.connect((host, port))
#return
try:
self.connect((host, port))
except Exception,e:
self.close()
self.handle_connect_expt(e)
def handle_connect(self):
self.send(self.request)
def handle_expt(self):
print "handle_expt error!"
self.close()
def handle_error(self):
print "handle_error error!"
self.close()
def handle_connect_expt(self,expt):
print "connection error:",expt
def handle_code(self):
print self.host," : ","recv http code: ",self.http_code
def handle_read(self):
data = self.recv(2048)
#print data
if not self.header:
self.data = self.data + data
try:
i = string.index(self.data, "\r\n\r\n")
except ValueError:
return # continue
else:
# parse header
fp = StringIO.StringIO(self.data[:i+4])
# status line is "HTTP/version status message"
status = fp.readline()
self.status = string.split(status, " ", 2)
self.http_code = self.status[1]
self.handle_code()
# followed by a rfc822-style message header
self.header = mimetools.Message(fp)
# followed by a newline, and the payload (if any)
data = self.data[i+4:]
self.data = ""
#header recived
#self.close()
def handle_close(self):
self.close()
c = AsyncHTTP('http://www.python.org')
c = AsyncHTTP('http://www.yandex.ru')
c = AsyncHTTP('http://www.google.ru')
c = AsyncHTTP('http://www.gmail.com')
c = AsyncHTTP('http://www.gravatar.com')
c = AsyncHTTP('http://www.yahoo.com')
c = AsyncHTTP('http://www.com.com')
c = AsyncHTTP('http://www.bom.com')
#c = AsyncHTTP('http://www.no-such-host.ru') #!this line breaks execution!
asyncore.loop()