如何按主题关键词和指定日期从Gmail下载附件

问题描述 #

日常工作需要每天从Gmail下载CSV格式的数据文件，目前能通过代码的fetch()方法按邮件ID下载附件，但希望实现按主题中的特定关键词以及**指定日期（当日或其他日期）**筛选并下载附件，不清楚如何在现有代码中添加这两个筛选功能，附上当前代码：

import imaplib
import email
import os

attachment_dir = 'file/directory'

# account credentials
user = 'email_adress@gmail.com'
password = 'password'
imap_url = 'imap.gmail.com'

def get_body(msg):
    if msg.is_multipart():
        return get_body(msg.get_payload(0))
    else:
        return msg.get_payload(None, True)  # decode

def search(key, value, connection):
    result, data = connection.search(None, key, '"{}"'.format(value))
    return data

def get_emails(result_bytes):
    msgs = []  # all the email data are pushed inside an array
    for num in result_bytes[0].split():
        typ, data = connection.fetch(num, '(RFC822)')
        msgs.append(data)

    return msgs # it will return an array of bytes separating each email

def get_attachment(msg):
    for part in msg.walk():
        if part.get_content_maintype() == 'multipart':
            continue
        if part.get('Content-Disposition') is None:
            continue
        fileName = part.get_filename()

        if bool(fileName):
            filePath = os.path.join(attachment_dir, fileName)
            if not os.path.isfile(filePath) :
                fp = open(filePath, 'wb')
                fp.write(part.get_payload(decode=True))
                fp.close()

connection = imaplib.IMAP4_SSL(imap_url)
connection.login(user, password)
connection.select('INBOX')

result, data = connection.fetch(b'91', '(RFC822)') # fetch the email body (RFC822) for the given ID, b'91' is the id of the email, you can get it from the search function
raw = email.message_from_bytes(data[0][1])
print(get_body(raw)) # prints the raw text of the whole email

print(search('FROM', 'email.source@gmail.com',connection)) # search and return uids instead

print(get_attachment(raw)) # pass the email to the function

修改后的完整代码 #

以下代码实现了主题关键词筛选、指定日期筛选，并且只下载CSV格式的附件：

import imaplib
import email
import os
from datetime import datetime

# 配置项
attachment_dir = 'file/directory'
user = 'email_adress@gmail.com'
password = 'password'
imap_url = 'imap.gmail.com'
# 筛选条件
target_subject_keyword = '每日数据报表'  # 替换成你要找的主题关键词
target_date = datetime.today().strftime('%d-%b-%Y')  # 当日日期，格式DD-Mon-YYYY，比如05-Jun-2024
# 如需指定其他日期，直接替换成字符串，比如 target_date = '01-Jun-2024'

def create_attachment_dir():
    # 确保附件目录存在
    if not os.path.exists(attachment_dir):
        os.makedirs(attachment_dir)

def search_emails(connection, subject_keyword, target_date):
    # 组合筛选条件：主题包含关键词 + 日期为指定日期
    # IMAP查询语法：AND (SUBJECT "关键词") (ON "日期")
    search_query = f'(AND (SUBJECT "{subject_keyword}") (ON "{target_date}"))'
    result, data = connection.search(None, search_query)
    return data

def fetch_email(connection, email_id):
    # 获取单封邮件的完整内容
    typ, data = connection.fetch(email_id, '(RFC822)')
    return email.message_from_bytes(data[0][1])

def download_csv_attachments(msg):
    # 只下载CSV格式的附件
    for part in msg.walk():
        if part.get_content_maintype() == 'multipart':
            continue
        if part.get('Content-Disposition') is None:
            continue
        
        filename = part.get_filename()
        if filename and filename.lower().endswith('.csv'):
            file_path = os.path.join(attachment_dir, filename)
            # 避免重复下载（可选，如需覆盖可删除判断）
            if not os.path.isfile(file_path):
                with open(file_path, 'wb') as fp:
                    fp.write(part.get_payload(decode=True))
                print(f"已下载附件: {filename}")

if __name__ == "__main__":
    create_attachment_dir()
    
    # 连接Gmail IMAP服务器
    connection = imaplib.IMAP4_SSL(imap_url)
    connection.login(user, password)
    connection.select('INBOX')
    
    # 搜索符合条件的邮件
    email_ids = search_emails(connection, target_subject_keyword, target_date)
    
    if email_ids[0]:
        # 遍历每一封符合条件的邮件
        for email_id in email_ids[0].split():
            msg = fetch_email(connection, email_id)
            download_csv_attachments(msg)
    else:
        print("未找到符合条件的邮件")
    
    # 关闭连接
    connection.close()
    connection.logout()

关键功能说明 #

1. 日期筛选：使用IMAP的ON参数指定精确日期，格式必须为DD-Mon-YYYY（月份为英文缩写），可以用datetime模块自动生成当日日期，也可以手动指定固定日期
2. 主题关键词筛选：使用SUBJECT参数匹配主题中的关键词，支持模糊匹配（只要主题包含该关键词即可）
3. 组合筛选：通过AND将多个筛选条件组合，确保同时满足主题和日期要求
4. CSV附件过滤：在下载逻辑中判断文件名后缀为.csv，避免下载其他格式的附件
5. 目录自动创建：添加了目录检查逻辑，确保附件存储目录存在

内容的提问来源于stack exchange，提问作者user20350073