python SMTP邮件发送

本例使用的时python2.7环境，python3的操作应该也是差不多的。
需要用到smtplib和email两个包。

发送文本类型的邮件

下面看个发送文本邮件的例子（使用网易163的smtp）：

# -*- coding: utf-8 -*-

import smtplib
from email.mime.text import mimetext
from email.header import header
from email.utils import formataddr

# 第三方smtp
mail_host = "smtp.163.com" # smtp服务器
mail_user = "[e-mail]" # 发送者邮箱
mail_pass = "******" # 邮箱的客户端授权码

sender = "[e-mail]" # 邮件的发送者
recivers = ["[e-mail]", "[e-mail]"] # 邮件接收者，可以指定多个

# 三个参数：第一个为文本内容，第二个设置文本格式，第三个设置字符编码
message = mimetext('python邮件发送测试', 'plain', 'utf-8')
message['from'] = sender;
# == message['from'] = formataddr(['sender', sender])
message['to'] = ", ".join(recivers)
# == message['to] = formataddr(['ok', ', '.join(recivers)])
subject = 'python 邮件测试'
message['subject'] = header(subject, 'utf-8')

try:
    smtpobj = smtplib.smtp()
    smtpobj.connect(mali_host， 25) # 连接smtp，端口为25
    smtpobj.set_debuglevel(1)
    smtpobj.login(mail_user, mail_pass)
    smtpobj.sendmail(sender, recivers,message.as_string())
    print "emails send successfully"
except smtplib.smtpexception:
    print "error:cannot send emails"
smtpobj.quit() # 关闭连接

好像网易的smtp有坑，message['from']和message['to']都要和sender和recivers一致才可以，还有标题和内容尽量不要有敏感词，否则会被服务器判为垃圾邮件而发不出去，我第一次就因为subject带有“smtp”而被拦截（滑稽.gif）。
如果邮件发送失败，可以查看set_debuglevel()函数返回的状态码来判定什么原因。

发送html格式的邮件

与发送文本不同的地方就是将mimetext中的_subtype设为html，发送带图片的html还要创建mimemultipart()实例。

# -*- coding: utf-8 -*-

import smtplib
from email.header import header
from email.mime.text import mimetext
from email.mime.multipart import mimemultipart
from email.mime.image import mimeimage

# 第三方smtp
mail_host = "smtp.163.com" # smtp服务器
mail_user = "[e-mail]" # 发送者邮箱
mail_pass = "******" # 邮箱的客户端授权码

sender = "[e-mail]"
recivers = ["[e-mail]", "[e-mail]"]  # 接收邮件

msg = mimemultipart('related')
msg['from'] = sender
msg['to'] = ", ".join(recivers)
subject = 'html 1m4g3'
msg['subject'] = header(subject, 'utf-8')
mail_msg = """
<h1>html image测试</h1>
<p><a href="http://www.baidu.com">learn more</a></p>
<p><img src="cid:image1"></p>
"""
msgalternative = mimemultipart('alternative')
msg.attach(msgalternative)
msgalternative.attach(mimetext(mail_msg, 'html', 'utf-8'))

# 指定当前目录的图片
fp = open('test1.gif', 'rb')
msgimage = mimeimage(fp.read())
fp.close()

# 定义图片id，在html中引用
msgimage.add_header('content-id', '<image1>')
msg.attach(msgimage)

try:
    smtpobj = smtplib.smtp()
    smtpobj.connect(mail_host, 25)  # 25 smtp port
    smtpobj.set_debuglevel(1)
    smtpobj.login(mail_user, mail_pass)
    smtpobj.sendmail(sender, recivers, msg.as_string())
    print "emails send sucessfully"

except smtplib.smtpexception:
    print "error:cannot send emails"
smtpobj.quit()    

发送带附件的邮件

# -*- coding: utf-8 -*-

import smtplib
from email.header import header
from email.mime.text import mimetext
from email.mime.multipart import mimemultipart
from email.mime.image import mimeimage

# 第三方smtp
mail_host = "smtp.163.com"  # 设置服务器
mail_user = "[e-mail]"
mail_pass = "******"

sender = "[e-mail]"
recivers = ["[e-mail]", "[e-mail]"]  # 接收邮件

# 创建附件实例
msg = mimemultipart()
msg['from'] = sender
msg['to'] = ", ".join(recivers)
subject = '邮件附件'
msg['subject'] = header(subject, 'utf-8')
# 邮件正文：
mimetext('邮件正文如下', 'html', 'utf-8')

# 构造附件，传送当前目录下的txt文件：
att1 = mimetext(open('test1.txt', 'rb').read(), 'base64', 'utf-8')
att1["content-type"] = 'application/octet-stream'
# 这里的filename可以任意命名，成为邮件中显示的文件名
att1["content-disposition"] = 'attachment;filename="test_1.txt"'
msg.attach(att1)

try:
    smtpobj = smtplib.smtp()
    smtpobj.connect(mail_host, 25)  # 25 smtp port
    smtpobj.set_debuglevel(1)
    smtpobj.login(mail_user, mail_pass)
    smtpobj.sendmail(sender, recivers, msg.as_string())
    print "emails send sucessfully"

except smtplib.smtpexception:
    print "error:cannot send emails"

smtpobj.quit()

发送正常的就会返回250状态码：

发送失败返回的554：

总结

搞这些操作一是想弄明白智能合约ctf里怎么实现用邮箱发来flag的，再一个就是想补补编程（你打代码像蔡徐坤.gif）。
总之在里面遇到很多坑，而且大部分都是返回的554（可能被判为垃圾邮件而拦截掉了），这里的原因大概率是因为subject有些文字不符（像“test"这种都会被拦截）。还有在批量发送时，recivers是一个list，那么message['to']中需要用逗号和join()函数转成字符串。
over!