Python Mailer脚本

Question

对于一个非常简单的python电子邮件脚本，我有一个奇怪的问题。脚本本身运行良好，但是当我在现有代码中(在if语句中)使用脚本时，它似乎将FROM、TO、SUBJECT和文本字段放在电子邮件正文中(而不仅仅是文本字段)

脚本

import smtplib
SERVER = "localhost"
FROM = "test@test.com"
TO = ["myemail@email.com"] # must be a list
SUBJECT = "Test"
TEXT = "This message was sent with Python's smtplib."

message = """\
From: %s
To: %s
Subject: %s

%s
""" % (FROM, ", ".join(TO), SUBJECT, TEXT)

server = smtplib.SMTP(SERVER)
server.sendmail(FROM, TO, message)
server.quit()

当我将它包装在一个If语句中时，它会变得混乱，并将所有内容都放入电子邮件正文中。

if X == 1:
    import smtplib
    SERVER = "localhost"
    FROM = "test@test.com"
    TO = ["myemail@email.com"] # must be a list
    SUBJECT = "Test"
    TEXT = "This message was sent with Python's smtplib."

    message = """\
    From: %s
    To: %s
    Subject: %s

    %s
    """ % (FROM, ", ".join(TO), SUBJECT, TEXT)

    server = smtplib.SMTP(SERVER)
    server.sendmail(FROM, TO, message)
    server.quit()
else:
    continue

这将给我一封如下所示的邮件

From - test@test.com
Subject -
To - undisclosed-recipients

    From: test@test.com
    To: myemail@email.com
    Subject: Hello!

    This message was sent with Python's smtplib.

如前所述，如果我从If语句中删除代码，它就会正常运行，并包含正确的主题行和正文。也许我遗漏了一些明显的东西？

任何帮助都将不胜感激。谢谢我的朋友们。

Answer 1

    message = """\
    From: %s
    To: %s
    Subject: %s

    %s
    """ % (FROM, ", ".join(TO), SUBJECT, TEXT)

此邮件的关键字From、To、Subject等前有空格，因此这些关键字不会被识别为header field names。因此，所有这些都将成为消息正文的一部分。

要解决此问题，请删除文本：

    message = """\
From: %s
To: %s
Subject: %s

%s
""" % (FROM, ", ".join(TO), SUBJECT, TEXT)

或者，为了保持缩进的可读性，

import textwrap
if X == 1:
    message = textwrap.dedent("""\
        From: %s
        To: %s
        Subject: %s
    
        %s
        """ % (FROM, ", ".join(TO), SUBJECT, TEXT))