### 实现监控 Python 网站更新并发送通知 对于监控特定网站上的新内容发布并向用户发送通知这一需求，可以通过编写一个Python脚本来完成。该脚本会定期访问目标网页获取最新数据，并通过对比历史记录判断是否有新的条目被加入。一旦发现新增加的内容，则触发邮件提醒机制。 #### 使用 `requests` 库抓取页面信息 为了能够自动化的从网络上获取HTML文档，可以利用Python中的第三方库——`requests`来进行HTTP GET请求操作从而获得所需网址对应的响应体即HTML源码[^2]。 ```python import requests url = "https://example.com/python-section" response = requests.get(url) if response.status_code == 200: html_content = response.text else: print(f"Failed to retrieve the webpage, status code: {response.status_code}") ``` #### 解析 HTML 文档提取有用的信息 得到完整的HTML字符串之后，还需要进一步解析它以便于定位到具体的元素位置。这里推荐采用BeautifulSoup库作为辅助工具处理复杂的DOM结构： ```python from bs4 import BeautifulSoup soup = BeautifulSoup(html_content, 'html.parser') new_posts = soup.find_all('div', class_='post') # 假设每篇文章都包裹在一个具有class="post"属性的<div>标签内 ``` #### 存储已知的文章列表用于比较差异 初次执行程序时应该先保存当前所有的帖子链接至本地文件或其他持久化存储介质；后续再次爬虫过程中只需要读取旧版本的数据集并与之对照即可得知是否存在未见过的新文章。 ```python known_links_file = './known_python_articles.txt' try: with open(known_links_file, mode='r+', encoding='utf8') as f: known_links = set(line.strip() for line in f.readlines()) except FileNotFoundError: known_links = set() # 更新现有链接集合 for post in new_posts: link = post.a['href'] if not any(link.endswith(ext) for ext in ['.pdf', '.zip']): known_links.add(link) with open(known_links_file, mode='w', newline='\n', encoding='utf8') as f: for item in sorted(list(known_links)): f.write("%s\n" % item) ``` #### 配置SMTP服务准备发送警报消息 最后一步就是配置好SMTP服务器参数并通过`smtplib`调用sendmail方法向预定义好的收件箱地址群发提示信函告知他们有关站点变动的消息了。 ```python import smtplib from email.mime.multipart import MIMEMultipart from email.mime.text import MIMEText def send_email(subject, body): sender_address = 'your-email@example.com' receiver_addresses = ['recipient1@example.com'] msg = MIMEMultipart() msg['From'] = sender_address msg['To'] = ", ".join(receiver_addresses) msg['Subject'] = subject msg.attach(MIMEText(body, 'plain')) try: server = smtplib.SMTP('smtp.example.com', 587) server.starttls() server.login(sender_address, 'password') text = msg.as_string() server.sendmail(sender_address, receiver_addresses, text) server.quit() print("Email sent successfully.") except Exception as e: print(f"Error occurred while sending email: {e}") # 如果存在未知链接则发出警告 unknown_links = [] for post in new_posts: link = post.a['href'] if link not in known_links and not any(link.endswith(ext) for ext in ['.pdf', '.zip']): unknown_links.append(post.h2.string + ': ' + link) if unknown_links: message_body = "\n".join(unknown_links) send_email("[Notice] New Articles on Python Website", message_body) ```