Question

我可以在try - catch上看到几个主题，但似乎没有讨论错误，如果有任何来自finally块本身。我发现如果它在finally块中，则不会处理错误。什么是最终管理的理想方式？

例如。下面是邮件功能。如果try块中有任何错误，最后将执行本身未启动的quit方法，因此会发生未处理的错误。那么最好确保finally块中没有错误发生吗？

def send_email(ldap, email_address, password, msg):
    try:
        message = MIMEMultipart('alternative')
        message['To'] = email.utils.formataddr(('Recipient', '%s@abc.com'%email_address))
        message['From'] = email.utils.formataddr(('Author', '%s@abc.com'%email_address))
        message['Subject'] = 'Sample subject'
        text = "%s"%msg
        html = MIMEText('<html><head></head><h2>data</h2><body><p>%s</p></body></html>'%msg,'html')

        message.attach(html)
        server = smtplib.SMTP(host="ip",port=0)
        server.set_debuglevel(True)

        # identify ourselves, prompting server for supported features
        server.ehlo()

        if server.has_extn('STARTTLS'):
            server.starttls()
            server.ehlo() 

        server.login(ldap, password)
        print "%s@abc.com, %s@abc.com, %s "%(email_address,email_address,message.as_string())
        server.sendmail('%s@abc.com'%email_address, "%s@abc.com"%email_address, message.as_string())
    finally:
        server.quit()

Answer 1

不要将一堆代码（做不同的事情）放到一个try / except块中，但是你可以在finally块中轻松添加if / else条件：

def send_email(ldap, email_address, password, msg):
    server = None  #make sure server variable is always defined.
    try:
        ...
        server = smtplib.SMTP(...)
        ...
    finally:
        if server and isinstance(x, smtplib.SMTP):
            server.quit()

Answer 2

由于您的console.debug( variable )块仅用于确保服务器连接正确关闭，显而易见的答案是仅将相关部分包装在finally块中：

try

更好的解决方案是将此代码拆分为不同的函数，每个函数都具有明确定义的责任 - 准备消息，获取与服务器的连接等，即：

def send_email(ldap, email_address, password, msg):
    message = MIMEMultipart('alternative')
    message['To'] = email.utils.formataddr(('Recipient', '%s@abc.com'%email_address))
    message['From'] = email.utils.formataddr(('Author', '%s@abc.com'%email_address))
    message['Subject'] = 'Sample subject'
    text = "%s"%msg
    html = MIMEText('<html><head></head><h2>data</h2><body><p>%s</p></body></html>'%msg,'html')

    message.attach(html)
    server = smtplib.SMTP(host="ip",port=0)

    # now you can start the try block:
    try:
        server.set_debuglevel(True)    
        # identify ourselves, prompting server for supported features
        server.ehlo()
        if server.has_extn('STARTTLS'):
            server.starttls()
            server.ehlo() 
        server.login(ldap, password)
        print "%s@abc.com, %s@abc.com, %s "%(email_address,email_address,message.as_string())
        server.sendmail('%s@abc.com'%email_address, "%s@abc.com"%email_address, message.as_string())
    finally:
        server.quit()

如何在python

2 个答案: