Python 中的套接字编程 - 发送邮件时的 SMTP 服务器

问：

我正在尝试在发送邮件时使用SMTP服务器。

这是我 user.py SMTP 函数：

def smtp():
    conn = SMTP('localhost', int(fdns_query(SMTP_SERVER, 'P')))
    to = []
    while True:
        _to = input('To: ')
        if _to == '':
            break
        to.append(_to)
    subject = input('Subject: ')
    content = input('Content: ')
    msg = MIMEText(content, 'plain', 'utf-8')
    msg['Subject'] = subject
    msg['From'] = args.email
    conn.sendmail(args.email, to, msg.as_string())
    conn.quit()

if __name__ == '__main__':
    while True:
        try:
            cmd = input('[smtp|pop|exit]>>> ')
            if cmd == 'smtp':
                smtp()
            elif cmd == 'pop':
                pop()
            elif cmd == 'exit':
                break
            else:
                print('Invalid command')
        except KeyboardInterrupt:
            break
        except Exception as e:
            print('-ERR in agent.py!!!!!')
            print(repr(e))

这是 server.py：

class SMTPServer(BaseRequestHandler):
    def handle(self):
        conn = self.request
        conn.sendall(b'220 Welcome to the SMTP server\r\n')

        sender = None
        recipients = []

        hostname = socket.gethostname()

        while True:
            data = conn.recv(1024)
            if not data:
                break

            command = data.decode().strip()
            print(command)
            if command.startswith('HELO') or command.startswith('EHLO'):
                #conn.sendall(b'250 Hello\r\n')
                #conn.sendall(b'250 Hello ' + command.split(' ')[1] + b'\r\n')
                #conn.sendall(b'250-localhost Hello\r\n')
                conn.sendall(f'250 Hello {hostname}\r\n'.encode())
            elif command.startswith('MAIL FROM'):
                sender = command.split('<')[1].split('>')[0]
                conn.sendall(b'250 Sender OK\r\n')
            elif command.startswith('RCPT TO'):
                recipient = command.split('<')[1].split('>')[0]
                recipients = ast.literal_eval(recipient)
                conn.sendall(b'250 Recipient OK\r\n')
            elif command == 'DATA':
                conn.sendall(b'354 Start mail input; end with <CRLF>.<CRLF>\r\n')
                mail_content = []

                # line = conn.recv(1024).decode()
                # if line.strip() == '.':
                #     break
                # mail_content.append(line)
                while True:
                    line = conn.recv(1024).decode()
                    if line.strip() == '.':
                        break
                    mail_content.append(line)

                for recipient in recipients:
                    if recipient in MAILBOXES:
                        MAILBOXES[recipient].append(mail_content)
                    else:
                        print(f"Recipient {recipient} not found in MAILBOXES.")
                conn.sendall(b'250 Mail accepted\r\n')
                print(f"Sender: {sender}")
                print(f"Recipients: {', '.join(recipients)}")
                print("Mail Content:")
                print("\n".join(mail_content))
                sender = None
                recipients = []
            elif command == 'QUIT':
                conn.sendall(b'221 Bye\r\n')
                break
            else:
                conn.sendall(b'500 Syntax error\r\n')

我已经通过以下方式打开服务器： python3 server.py -n [服务器]

并在另一个 cmd 中运行以下命令： pyhton3 user.py -e [电子邮件地址] -p [密码]

但是我遇到了以下错误：

[smtp|pop|exit]>>> smtp
To: [email]
To:
Subject: Hiii
Content: I am emailing myself
-ERR in agent.py!!!!!
SMTPHeloError(500, b'Syntax error')

谁能帮我修复分析错误？SMTPServer（BaseRequestHandler）有问题吗？它不断抛出 500，语法错误。谢谢