Python邮件附件自动转发到指定邮箱 imaplib+smtplib

用imaplib读取邮件、把附件原样打包，再用smtplib自动转发到指定邮箱，适合把客户邮件自动抄送归档到公司邮箱，附完整可运行代码。

场景痛点

客户邮件发到个人QQ邮箱，公司要求所有客户沟通归档到企业邮箱。手动每封转发一次，一天几十封，还容易漏。让脚本自动读邮箱里来自客户的邮件，把正文和附件原样转发到企业邮箱，发完标记已读，整个流程不用人管。

用到的库

# imaplib、smtplib、email都是标准库，无需安装

完整代码

# -*- coding: utf-8 -*-
import imaplib
import smtplib
import email
from email.header import decode_header, make_header
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText

IMAP_SERVER = "imap.qq.com"
IMAP_PORT = 993
SMTP_SERVER = "smtp.qq.com"
SMTP_PORT = 465

ACCOUNT = "your_account@qq.com"
AUTH_CODE = "your_imap_smtp_auth_code"
FORWARD_TO = "archive@company.com"

# 只转发这些发件人发来的邮件
FORWARD_SENDERS = ["client@a.com", "sales@b.com"]


def decode_str(s):
if not s:
return ""
return str(make_header(decode_header(s)))


def build_forward_msg(original):
"""把原邮件重组成一封新邮件，正文+附件都带上"""
fwd = MIMEMultipart()
fwd["From"] = ACCOUNT
fwd["To"] = FORWARD_TO
orig_subj = decode_str(original.get("Subject") or "")
fwd["Subject"] = f"[自动转发] {orig_subj}"

orig_from = decode_str(original.get("From") or "")
body = f"以下是自动转发的邮件：\n原发件人：{orig_from}\n原主题：{orig_subj}\n\n"
fwd.attach(MIMEText(body, "plain", "utf-8"))

# 把原邮件的每个部分（正文/附件）原样搬过来
for part in original.walk():
if part.is_multipart():
continue
filename = part.get_filename()
payload = part.get_payload(decode=True)
if payload is None:
continue
if filename:
# 附件：保留文件名和内容类型
ct = part.get_content_type()
maintype, subtype = ct.split("/", 1) if "/" in ct else ("application", "octet-stream")
from email.mime.base import MIMEBase
from email import encoders
att = MIMEBase(maintype, subtype)
att.set_payload(payload)
encoders.encode_base64(att)
fname = decode_str(filename)
att.add_header("Content-Disposition", "attachment",
filename=("utf-8", "", fname))
fwd.attach(att)
else:
# 纯文本/HTML正文片段，跳过（上面已经写了转发说明）
pass
return fwd


def forward_inbox():
mail = imaplib.IMAP4_SSL(IMAP_SERVER, IMAP_PORT)
mail.login(ACCOUNT, AUTH_CODE)
mail.select("INBOX")

# 先按未读拉出来，本地再按发件人过滤
_, msgs = mail.search(None, "UNSEEN")
ids = msgs[0].split() if msgs[0] else []
print(f"未读邮件 {len(ids)} 封")

sent = 0
# 连接SMTP发信
smtp = smtplib.SMTP_SSL(SMTP_SERVER, SMTP_PORT)
smtp.login(ACCOUNT, AUTH_CODE)

for mid in ids:
_, data = mail.fetch(mid, "(RFC822)")
orig = email.message_from_bytes(data[0][1])
sender = decode_str(orig.get("From") or "")
if not any(s in sender for s in FORWARD_SENDERS):
continue

new_msg = build_forward_msg(orig)
smtp.sendmail(ACCOUNT, [FORWARD_TO], new_msg.as_string())
sent += 1
print(f"已转发：{decode_str(orig.get('Subject'))}")
# 转发完标记已读
mail.store(mid, "+FLAGS", "\\Seen")

smtp.quit()
mail.logout()
print(f"完成，转发 {sent} 封到 {FORWARD_TO}")


if __name__ == "__main__":
forward_inbox()

代码讲解

组合使用两个协议：imaplib负责读邮件（收），smtplib负责发邮件（转）。账号和授权码通常是同一个，QQ邮箱在IMAP/SMTP设置里开一次就行。
build_forward_msg：把原邮件重新打包成MIMEMultipart，正文写一段转发说明，附件通过walk()原样提取再attach回去，文件名用UTF-8编码避免乱码。
转发不是真的"原封不动转发"，而是新建一封邮件，From变成自己账号，主题加[自动转发]前缀。收件人在To看到的是你，原发件人写在正文里。
发完+FLAGS \Seen：标记已读，下次跑不会重复转发。这是闭环的关键。
发件人过滤：因为是本地过滤，把FORWARD_SENDERS列表扩一下就行。想在服务器端过滤，把search条件换成FROM即可。