使用Python下载邮件（pop/imap）

最近实现了一个使用Python自带的poplib和imaplib库下载邮件的程序，本文将对这个程序进行介绍。详细的模块介绍参见Python的官方文档（poplib，imaplib）。

1. 程序源码

本程序的实现流程：

1. 设置邮箱地址、密码、邮件服务器、传输协议（pop/imap）、是否使用SSL及输出目录，并对其进行解析。（为方便起见，上述设置本文使用了硬编码的方式，请根据自己的需求修改输入来源）
2. 根据邮箱地址创建输出目录。
3. 根据传输协议选择pop/imap对应的执行函数，读取邮件信息，解码并保存。
4. 如果目录为空或异常退出，删除输出目录。

#! /usr/bin/env python
# -*- coding: utf-8 -*-

import os
import re
import time
import email
import poplib
import imaplib
import cStringIO
from hashlib import md5


# Configuration
# -------------

# Email address
MAILADDR = "username@163.com"

# Email password
PASSWORD = "password"

# Mail Server (pop/imap)
SERVER = "pop.163.com"

# Transfer protocol (pop3/imap4)
PROTOCOL = "pop3"

# Use SSL? (True/False)
USE_SSL = True

# Main output direcotory
OUTDIR = "result"


# Static variable
# ---------------

# Default port of each protocol
DEFAULT_PORT = {
    "pop3": {False: 110, True: 995},
    "imap4": {False: 143, True: 993},
}


# Function
# --------

def exit_script(reason, e=""):
    """Print error reason and exit this script
    
    :param reason: exit error reason
    :param e: exception
    """
    # Print exit string
    exit_str = "[-] {0}".format(reason)
    if e:
        exit_str += " ({0})".format(e)
    print(exit_str)
    
    # Remove result path
    remove_dir(result_path)
    
    # Exit script
    print("[-] Fetch email failed!")
    exit(-1)

def parse_protocol(protocol):
    """Parse transfer protocol
    
    :param protocol: transfer protocol
    :return: handled protocol
    """
    if protocol in ["pop", "pop3"]:
        return "pop3"
    elif protocol in ["imap", "imap4"]:
        return "imap4"
    else:
        exit_script("Parse protocol failed: {0}".format(protocol))

def parse_server(server, use_ssl, protocol):
    """Change server to host and port. If no port specified, use default value
    
    :param server: mail server (host, host:port)
    :param use_ssl: True if use SSL else False
    :param protocol: transfer protocol (pop3/imap4)
    :return: host and port
    """
    if not server:
        exit_script("No available server")
    
    server_item = server.split(":")
    server_item_len = len(server_item)
    
    if server_item_len > 2:
        exit_script("Too many colons in server: {0}".format(server))
    
    try:
        host = server_item[0]
        port = DEFAULT_PORT[protocol][use_ssl] if server_item_len == 1 else int(server_item[1])
    except BaseException as e:
        exit_script("Parse server format failed: {0}".format(server), e)
    return host, port

def create_dir(result_path):
    """Create output directory if not exist
    
    :param result_path: main result path
    """
    try:
        if not os.path.exists(result_path):
            os.mkdir(result_path)
            print("[*] Create directory {0} successfully".format(result_path))
        else:
            if os.path.isfile(result_path):
                exit_script("{0} is file".format(result_path))
            else:
                print("[*] Directory {0} has already existed".format(result_path))
    except BaseException as e:
        exit_script("Create directory {0} failed".format(result_path), e)

def remove_dir(result_path):
    """Remove output directory if no file in this directory
    
    :param result_path: main result path
    """
    try:
        if os.path.isdir(result_path):
            if len(os.listdir(result_path)) == 0:
                os.rmdir(result_path)
                print("[*] Remove directory {0} successfully".format(result_path))
            else:
                print("[*] Directory {0} is not empty, no need remove".format(result_path))
        else:
            print("[*] No directory {0}".format(result_path))
    except BaseException as e:
        print("[-] Remove directory {0} failed: {1}".format(result_path, e))

def protocol_manager(protocol, host, port, usr, pwd, use_ssl):
    """Choose handle function according to transfer protocol
    
    :param protocol: transfer protocol (pop3/imap4)
    :param host: host
    :param port: port
    :param usr: username
    :param pwd: password
    :param use_ssl: True if use ssl else False
    """
    import __main__
    if hasattr(__main__, protocol):
        getattr(__main__, protocol)(host, port, usr, pwd, use_ssl)
    else:
        exit_script("Wrong protocol: {0}".format(protocol))

def pop3(host, port, usr, pwd, use_ssl):
    """Pop3 handler
    
    :param host: host
    :param port: port
    :param usr: username
    :param pwd: password
    :param use_ssl: True if use SSL else False
    """
    # Connect to mail server
    try:
        conn = poplib.POP3_SSL(host, port) if use_ssl else poplib.POP3(host, port)
        conn.user(usr)
        conn.pass_(pwd)
        print("[+] Connect to {0}:{1} successfully".format(host, port))
    except BaseException as e:
        exit_script("Connect to {0}:{1} failed".format(host, port), e)
    
    # Get email message number
    try:
        msg_num = len(conn.list()[1])
        print("[*] {0} emails found in {1}".format(msg_num, usr))
    except BaseException as e:
        exit_script("Can't get email number", e)

    # Get email content and attachments
    for i in range(1, msg_num+1):
        print("[*] Downloading email {0}/{1}".format(i, msg_num))
        
        # Retrieve email message lines, and write to buffer
        try:
            msg_lines = conn.retr(i)[1]
            
            buf = cStringIO.StringIO()
            for line in msg_lines:
                print >> buf, line
            buf.seek(0)
        except BaseException as e:
            print "[-] Retrieve email {0} failed: {1}".format(i, e)
            continue
        
        # Read buffer
        try:
            msg = email.message_from_file(buf)
        except BaseException as e:
            print "[-] Read buffer of email {0} failed: {1}".format(i, e)
            continue
        
        # Parse and save email content/attachments
        try:
            parse_email(msg, i)
        except BaseException as e:
            print("[-] Parse email {0} failed: {1}".format(i, e))
    
    # Quit mail server
    conn.quit()
    
def imap4(host, port, usr, pwd, use_ssl):
    """Imap4 handler
    
    :param host: host
    :param port: port
    :param usr: username
    :param pwd: password
    :param use_ssl: True if use SSL else False
    """
    # Connect to mail server
    try:
        conn = imaplib.IMAP4_SSL(host, port) if use_ssl else imaplib.IMAP4(host, port)
        conn.login(usr, pwd)
        print("[+] Connect to {0}:{1} successfully".format(host, port))
    except BaseException as e:
        exit_script("Connect to {0}:{1} failed".format(host, port), e)
    
    # Initial some variable
    list_pattern = re.compile(r'\((?P<flags>.*?)\) "(?P<delimiter>.*)" (?P<name>.*)')
    download_num = 0
    download_hash = []
    
    # Get all folders
    try:
        type_, folders = conn.list()
    except BaseException as e:
        exit_script("Get folder list failed", e)
    
    for folder in folders:
        # Parse folder info and get folder name
        try:
            flags, delimiter, folder_name = list_pattern.match(folder).groups()
            folder_name = folder_name.strip('"')
            print "[*] Handling folder: {0}".format(folder_name)
        except BaseException as e:
            print "[-] Parse folder {0} failed: {1}".format(folder, e)
            continue
        
        # Select and search folder
        try:
            conn.select(folder_name, readonly=True)
            type_, data = conn.search(None, "ALL")
        except BaseException as e:
            print "[-] Search folder {0} failed: {1}".format(folder_name, e)
            continue
        
        # Get email number of this folder
        try:
            msg_id_list = [int(i) for i in data[0].split()]
            msg_num = len(msg_id_list)
            print "[*] {0} emails found in {1} ({2})".format(msg_num, usr, folder_name)
        except BaseException as e:
            print "[-] Can't get email number of {0}: {1}".format(folder_name, e)
            continue
        
        # Get email content and attachments
        for i in msg_id_list:
            print "[*] Downloading email {0}/{1}".format(i, msg_num)
            
            # Get email message
            try:
                type_, data = conn.fetch(i, "(RFC822)")
                msg = email.message_from_string(data[0][1])
            except BaseException as e:
                print "[-] Retrieve email {0} failed: {1}".format(i, e)
                continue
            
            # If message already exist, skip this message
            try:
                msg_md5 = md5(data[0][1]).hexdigest()
                if msg_md5 in download_hash:
                    print "[-] This email has been downloaded in other folder"
                    continue
                else:
                    download_hash.append(msg_md5)
                    download_num += 1
            except BaseException as e:
                print "[-] Parse message md5 failed: {0}".format(e)
                continue
            
            # Parse and save email content/attachments
            try:
                parse_email(msg, download_num)
            except BaseException as e:
                print "[-] Parse email {0} failed: {1}".format(i, e)
    
    # Logout this account
    conn.logout()
        
def parse_email(msg, i):
    """Parse email message and save content & attachments to file
    
    :param msg: mail message
    :param i: ordinal number
    """
    global result_file
    
    # Parse and save email content and attachments
    for part in msg.walk():
        if not part.is_multipart():
            filename = part.get_filename()
            content = part.get_payload(decode=True)
            
            if filename:  # Attachment
                # Decode filename
                h = email.Header.Header(filename)
                dh = email.Header.decode_header(h)
                filename = dh[0][0]
                
                result_file = os.path.join(result_path, "mail{0}_attach_{1}".format(i, filename))
            else:  # Main content
                result_file = os.path.join(result_path, "mail{0}_text".format(i))
            
            try:
                with open(result_file, "wb") as f:
                    f.write(content)
            except BaseException as e:
                print("[-] Write file of email {0} failed: {1}".format(i, e))


if __name__ == "__main__":
    print("[*] Start download email script")
    start_time = time.time()
    
    mailaddr = MAILADDR
    password = PASSWORD
    server = SERVER
    protocol = PROTOCOL
    use_ssl = USE_SSL
    outdir = OUTDIR
    
    result_path = os.path.join(OUTDIR, mailaddr)
    protocol = parse_protocol(protocol)
    host, port = parse_server(server, use_ssl, protocol)
    
    create_dir(result_path)
    protocol_manager(protocol, host, port, mailaddr, password, use_ssl)
    remove_dir(result_path)
    
    end_time = time.time()
    exec_time = end_time - start_time
    print("[*] Finish download email of {0} in {1:.2f}s".format(mailaddr, exec_time))

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#! /usr/bin/env python

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

import os

import re

import time

import email

import poplib

import imaplib

import cStringIO

from hashlib import md5

# Configuration

# -------------

# Email address

MAILADDR = "username@163.com"

# Email password

PASSWORD = "password"

# Mail Server (pop/imap)

SERVER = "pop.163.com"

# Transfer protocol (pop3/imap4)

PROTOCOL = "pop3"

# Use SSL? (True/False)

USE_SSL = True

# Main output direcotory

OUTDIR = "result"

# Static variable

# ---------------

# Default port of each protocol

DEFAULT_PORT = {

"pop3": {False: 110, True: 995},

"imap4": {False: 143, True: 993},

}

# Function

# --------

def exit_script(reason, e=""):

"""Print error reason and exit this script

:param reason: exit error reason

:param e: exception

"""

# Print exit string

exit_str = "[-] {0}".format(reason)

if e:

exit_str += " ({0})".format(e)

print(exit_str)

# Remove result path

remove_dir(result_path)

# Exit script

print("[-] Fetch email failed!")

exit(-1)

def parse_protocol(protocol):

"""Parse transfer protocol

:param protocol: transfer protocol

:return: handled protocol

"""

if protocol in ["pop", "pop3"]:

return "pop3"

elif protocol in ["imap", "imap4"]:

return "imap4"

else:

exit_script("Parse protocol failed: {0}".format(protocol))

def parse_server(server, use_ssl, protocol):

"""Change server to host and port. If no port specified, use default value

:param server: mail server (host, host:port)

:param use_ssl: True if use SSL else False

:param protocol: transfer protocol (pop3/imap4)

:return: host and port

"""

if not server:

exit_script("No available server")

server_item = server.split(":")

server_item_len = len(server_item)

if server_item_len > 2:

exit_script("Too many colons in server: {0}".format(server))

try:

host = server_item[0]

port = DEFAULT_PORT[protocol][use_ssl] if server_item_len == 1 else int(server_item[1])

except BaseException as e:

exit_script("Parse server format failed: {0}".format(server), e)

return host, port

def create_dir(result_path):

"""Create output directory if not exist

:param result_path: main result path

"""

try:

if not os.path.exists(result_path):

os.mkdir(result_path)

print("[*] Create directory {0} successfully".format(result_path))

else:

if os.path.isfile(result_path):

exit_script("{0} is file".format(result_path))

else:

print("[*] Directory {0} has already existed".format(result_path))

except BaseException as e:

exit_script("Create directory {0} failed".format(result_path), e)

def remove_dir(result_path):

"""Remove output directory if no file in this directory

:param result_path: main result path

"""

try:

if os.path.isdir(result_path):

if len(os.listdir(result_path)) == 0:

os.rmdir(result_path)

print("[*] Remove directory {0} successfully".format(result_path))

else:

print("[*] Directory {0} is not empty, no need remove".format(result_path))

else:

print("[*] No directory {0}".format(result_path))

except BaseException as e:

print("[-] Remove directory {0} failed: {1}".format(result_path, e))

def protocol_manager(protocol, host, port, usr, pwd, use_ssl):

"""Choose handle function according to transfer protocol

:param protocol: transfer protocol (pop3/imap4)

:param host: host

:param port: port

:param usr: username

:param pwd: password

:param use_ssl: True if use ssl else False

"""

import __main__

if hasattr(__main__, protocol):

getattr(__main__, protocol)(host, port, usr, pwd, use_ssl)

else:

exit_script("Wrong protocol: {0}".format(protocol))

def pop3(host, port, usr, pwd, use_ssl):

"""Pop3 handler

:param host: host

:param port: port

:param usr: username

:param pwd: password

:param use_ssl: True if use SSL else False

"""

# Connect to mail server

try:

conn = poplib.POP3_SSL(host, port) if use_ssl else poplib.POP3(host, port)

conn.user(usr)

conn.pass_(pwd)

print("[+] Connect to {0}:{1} successfully".format(host, port))

except BaseException as e:

exit_script("Connect to {0}:{1} failed".format(host, port), e)

# Get email message number

try:

msg_num = len(conn.list()[1])

print("[*] {0} emails found in {1}".format(msg_num, usr))

except BaseException as e:

exit_script("Can't get email number", e)

# Get email content and attachments

for i in range(1, msg_num+1):

print("[*] Downloading email {0}/{1}".format(i, msg_num))

# Retrieve email message lines, and write to buffer

try:

msg_lines = conn.retr(i)[1]

buf = cStringIO.StringIO()

for line in msg_lines:

print >> buf, line

buf.seek(0)

except BaseException as e:

print "[-] Retrieve email {0} failed: {1}".format(i, e)

continue

# Read buffer

try:

msg = email.message_from_file(buf)

except BaseException as e:

print "[-] Read buffer of email {0} failed: {1}".format(i, e)

continue

# Parse and save email content/attachments

try:

parse_email(msg, i)

except BaseException as e:

print("[-] Parse email {0} failed: {1}".format(i, e))

# Quit mail server

conn.quit()

def imap4(host, port, usr, pwd, use_ssl):

"""Imap4 handler

:param host: host

:param port: port

:param usr: username

:param pwd: password

:param use_ssl: True if use SSL else False

"""

# Connect to mail server

try:

conn = imaplib.IMAP4_SSL(host, port) if use_ssl else imaplib.IMAP4(host, port)

conn.login(usr, pwd)

print("[+] Connect to {0}:{1} successfully".format(host, port))

except BaseException as e:

exit_script("Connect to {0}:{1} failed".format(host, port), e)

# Initial some variable

list_pattern = re.compile(r'\((?P<flags>.*?)\) "(?P<delimiter>.*)" (?P<name>.*)')

download_num = 0

download_hash = []

# Get all folders

try:

type_, folders = conn.list()

except BaseException as e:

exit_script("Get folder list failed", e)

for folder in folders:

# Parse folder info and get folder name

try:

flags, delimiter, folder_name = list_pattern.match(folder).groups()

folder_name = folder_name.strip('"')

print "[*] Handling folder: {0}".format(folder_name)

except BaseException as e:

print "[-] Parse folder {0} failed: {1}".format(folder, e)

continue

# Select and search folder

try:

conn.select(folder_name, readonly=True)

type_, data = conn.search(None, "ALL")

except BaseException as e:

print "[-] Search folder {0} failed: {1}".format(folder_name, e)

continue

# Get email number of this folder

try:

msg_id_list = [int(i) for i in data[0].split()]

msg_num = len(msg_id_list)

print "[*] {0} emails found in {1} ({2})".format(msg_num, usr, folder_name)

except BaseException as e:

print "[-] Can't get email number of {0}: {1}".format(folder_name, e)

continue

# Get email content and attachments

for i in msg_id_list:

print "[*] Downloading email {0}/{1}".format(i, msg_num)

# Get email message

try:

type_, data = conn.fetch(i, "(RFC822)")

msg = email.message_from_string(data[0][1])

except BaseException as e:

print "[-] Retrieve email {0} failed: {1}".format(i, e)

continue

# If message already exist, skip this message

try:

msg_md5 = md5(data[0][1]).hexdigest()

if msg_md5 in download_hash:

print "[-] This email has been downloaded in other folder"

continue

else:

download_hash.append(msg_md5)

download_num += 1

except BaseException as e:

print "[-] Parse message md5 failed: {0}".format(e)

continue

# Parse and save email content/attachments

try:

parse_email(msg, download_num)

except BaseException as e:

print "[-] Parse email {0} failed: {1}".format(i, e)

# Logout this account

conn.logout()

def parse_email(msg, i):

"""Parse email message and save content & attachments to file

:param msg: mail message

:param i: ordinal number

"""

global result_file

# Parse and save email content and attachments

for part in msg.walk():

if not part.is_multipart():

filename = part.get_filename()

content = part.get_payload(decode=True)

if filename: # Attachment

# Decode filename

h = email.Header.Header(filename)

dh = email.Header.decode_header(h)

filename = dh[0][0]

result_file = os.path.join(result_path, "mail{0}_attach_{1}".format(i, filename))

else: # Main content

result_file = os.path.join(result_path, "mail{0}_text".format(i))

try:

with open(result_file, "wb") as f:

f.write(content)

except BaseException as e:

print("[-] Write file of email {0} failed: {1}".format(i, e))

if __name__ == "__main__":

print("[*] Start download email script")

start_time = time.time()

mailaddr = MAILADDR

password = PASSWORD

server = SERVER

protocol = PROTOCOL

use_ssl = USE_SSL

outdir = OUTDIR

result_path = os.path.join(OUTDIR, mailaddr)

protocol = parse_protocol(protocol)

host, port = parse_server(server, use_ssl, protocol)

create_dir(result_path)

protocol_manager(protocol, host, port, mailaddr, password, use_ssl)

remove_dir(result_path)

end_time = time.time()

exec_time = end_time - start_time

print("[*] Finish download email of {0} in {1:.2f}s".format(mailaddr, exec_time))

下面将对其中的核心函数（pop3、imap4、parse_email）进行详细讲解。

2. 核心函数讲解

2.1 pop3

poplib.POP3_SSL(host, port)和poplib.POP3(host, port)：连接pop3服务器。
conn.user(usr)：设置用户名。
conn.pass_(pwd)：设置密码。
len(conn.list()[1])：取得邮箱中邮件的个数。
conn.retr(i)[1]：获取邮件内容。

2.2 imap4

imaplib.IMAP4_SSL(host, port)和imaplib.IMAP4(host, port)：连接imap4服务器。
conn.login(usr, pwd)：用户登录。
conn.list()：取得邮箱中所有文件夹的信息。每行信息包含标识、分隔符、文件夹名称三项，文件夹名称为UTF-7编码（如需转码请自行查找实现方法，如：某实现）。
conn.select(folder_name, readonly=True)：选择文件夹，其中readonly选项表示只读。如果不指定文件夹名称，则默认为INBOX。
conn.search(None, "ALL")：查询选定文件夹下的邮件。第一个参数为字符集，一般设为None。第二个参数“ALL”为查询条件，其详细用法可参见这篇文章。其返回值是邮件的编号。
conn.fetch(i, "(RFC822)")：使用RFC822协议获取编号为i的邮件的内容。

注意：在本实现中，每次下载邮件时会计算md5值，如果重复（不同文件夹均有该邮件）则不再下载该邮件。

2.3 parse_email

msg.walk()：遍历该邮件的每个子部分。
part.get_filename()：获取该部分的文件名（有则为附件，否则为邮件正文）。
part.get_payload(decode=True)：获取邮件内容，并解码。
email.Header.Header(filename)：获取邮件附件的头信息。
email.Header.decode_header(h)：对头信息进行解码，获得解码后的文件名。

本文内容遵从CC3.0版权协议，转载请注明：转自Pythoner

本文链接地址：使用Python下载邮件（pop/imap）

- 上海SEO博客
- 2015/05/09 5:32下午
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貌似代码挺长，略复杂。。
- 收163时报错
- 2015/10/28 4:47下午
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() “/” “INBOX”
(‘OK’, [‘() “/” “INBOX”‘, ‘(\\Drafts) “/” “&g0l6P3ux-“‘, ‘(\\Sent) “/” “&XfJT0ZAB-“‘, ‘(\\Trash) “/” “&XfJSIJZk-“‘, ‘(\\Junk) “/” “&V4NXPpCuTvY-“‘, ‘() “/” “&Xn9USpCuTvY-“‘, ‘() “/” “&i6KWBZCuTvY-“‘])
[*] Handling folder: INBOX
333
[-] Search folder INBOX failed: command SEARCH illegal in state AUTH, only allowed in states SELECTED
有人怀疑163只能用邮箱大师收，不能用其他客户端收。
163 邮箱今天屏蔽了所有 “未知” 客户端的邮件收发功能
http://www.v2ex.com/t/152504
- - 刀刀亮
  - 2015/12/22 5:56下午
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  不是这样的，你是需要在邮箱客户端里面进行设置的。我的163邮箱进行设置后就能收发邮件了
- helscn
- 2016/10/29 5:00下午
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端口定义中IMAP的键名写错了，应该为imap4：

DEFAULT_PORT = {
“pop3”: {False: 110, True: 995},
“imap3”: {False: 143, True: 993},
}

源代码中为imap3，使用imap收取邮件会报错的．
- - alioth310
  - 2016/10/29 6:42下午
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  谢谢，确实是
- 落落
- 2016/12/14 10:20上午
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有没有更高效的方式验证已下载的邮件，例如用邮件的唯一性标识，而不是抓取邮件类容用md5来验证，
- - alioth310
  - 2016/12/15 11:05上午
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  可以看下IMAP4.uid方法（https://docs.python.org/2/library/imaplib.html#imaplib.IMAP4.uid）
- cyd
- 2020/05/13 5:25下午
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正文有图片怎么处理？