Python urllib open-如何控制重试次数

如何控制

opener.open的重试次数

在下面的代码中，在引发异常或代码成功之前，它将发送大约6个
GET
HTTP请求（我在Wireshark嗅探器中看到）

password_mgr = urllib.request.HTTPPasswordMgrWithDefaultRealm()
password_mgr.add_password(None,url, username, password)
handler = urllib.request.HTTPBasicAuthHandler(password_mgr)
opener = urllib.request.build_opener(handler)

try: 
    resp = opener.open(url,None,1)

except urllib.error.URLError as e:
    print ("no success")
else:
    print ("success!")

urllib
使用
httplib
处理HTTP连接。如果您查看
httplib.py
源代码，并分析
HTTPConnection
类，您将看到
connect
方法是如何工作的

def connect(self):
    """Connect to the host and port specified in __init__."""
    msg = "getaddrinfo returns an empty list"
    for res in socket.getaddrinfo(self.host, self.port, 0, socket.SOCK_STREAM):
        af, socktype, proto, canonname, sa = res
        try:
            self.sock = socket.socket(af, socktype, proto)
            if self.debuglevel > 0:
                print "connect: (%s, %s)" % (self.host, self.port)
            self.sock.connect(sa)
        except socket.error, msg:
            if self.debuglevel > 0:
                print 'connect fail:', (self.host, self.port)
            if self.sock:
                self.sock.close()
            self.sock = None
            continue
        break

    if not self.sock:
        raise socket.error, msg

实际上，尝试的次数取决于返回的列表的长度。代码遍历所有可用的套接字选项以设置连接

我怀疑减少尝试次数是否有意义。但您可以按如下方式增加此数字：

maxtries = 3
delay = 3
n = 0
while n < maxtries:
    try: 
        resp = opener.open(url,None,1)
    except e:
        print ("no success")
        n += 1
        sleep(delay)
    else:
        print ("success!")
        break

maxtries=3
延迟=3
n=0
当n
urllib
使用
httplib
处理HTTP连接。如果您查看
httplib.py
源代码，并分析
HTTPConnection
类，您将看到
connect
方法是如何工作的

def connect(self):
    """Connect to the host and port specified in __init__."""
    msg = "getaddrinfo returns an empty list"
    for res in socket.getaddrinfo(self.host, self.port, 0, socket.SOCK_STREAM):
        af, socktype, proto, canonname, sa = res
        try:
            self.sock = socket.socket(af, socktype, proto)
            if self.debuglevel > 0:
                print "connect: (%s, %s)" % (self.host, self.port)
            self.sock.connect(sa)
        except socket.error, msg:
            if self.debuglevel > 0:
                print 'connect fail:', (self.host, self.port)
            if self.sock:
                self.sock.close()
            self.sock = None
            continue
        break

    if not self.sock:
        raise socket.error, msg

实际上，尝试的次数取决于返回的列表的长度。代码遍历所有可用的套接字选项以设置连接

我怀疑减少尝试次数是否有意义。但您可以按如下方式增加此数字：

maxtries = 3
delay = 3
n = 0
while n < maxtries:
    try: 
        resp = opener.open(url,None,1)
    except e:
        print ("no success")
        n += 1
        sleep(delay)
    else:
        print ("success!")
        break

maxtries=3
延迟=3
n=0
当n