一、前言

在当今的Web开发和测试领域，自动化技术已经成为提高效率的必备工具。本文将介绍如何使用Playwright这一强大的自动化测试工具，实现一个完整的网站登录流程。我们将从环境配置开始，逐步深入到代码实现，最终完成一个可复用的自动化登录脚本。

二、准备阶段

在开始之前，我们需要确保开发环境已经准备就绪：

Python环境：建议使用Python 3.7及以上版本

Playwright安装：

pip install playwright
playwright install

浏览器驱动：Playwright支持Chromium、Firefox和WebKit，本文以Chromium为例

三、代码解析

3.1、基础配置

python
import os
import logging
from playwright.sync_api import sync_playwright, TimeoutError as PlaywrightTimeoutError

# 配置日志
logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s [%(levelname)s] %(message)s",
    handlers=[logging.StreamHandler()]
)

日志配置：使用Python内置的logging模块记录操作日志，便于调试和问题追踪
异常处理：特别处理Playwright的超时异常，确保脚本的健壮性

3.2、核心类设计

python
class PlaywrightAutomation:
    def __init__(self, headless=True):
        self.playwright = None
        self.browser = None
        self.page = None
        self.headless = headless
        self._install_browser()

headless模式：默认为True表示无头模式，适合服务器环境；开发时可设为False便于观察
自动安装浏览器：在初始化时自动检查并安装必要的浏览器组件

3.3、浏览器初始化

python
def init_browser(self):
    try:
        self.playwright = sync_playwright().start()
        self.browser = self.playwright.chromium.launch(headless=self.headless)
        self.page = self.browser.new_page()
        logging.info("浏览器初始化成功")
        return True
    except Exception as e:
        logging.error(f"浏览器初始化失败: {str(e)}")
        return False

使用Chromium作为默认浏览器
完善的异常处理确保初始化失败时程序不会崩溃

3.4、元素等待机制

python
def _wait_for_element(self, selector, timeout=10000, clickable=False):
    try:
        if clickable:
            self.page.wait_for_selector(selector, state="attached", timeout=timeout)
            return self.page.wait_for_selector(selector, state="visible", timeout=timeout)
        return self.page.wait_for_selector(selector, timeout=timeout)
    except PlaywrightTimeoutError:
        logging.error(f"元素定位超时: {selector}")
        raise

支持两种等待模式：普通等待和可点击等待
默认10秒超时时间，可根据实际网络状况调整
详细的错误日志帮助快速定位问题

3.5、登录功能实现

python
def login(self, login_url):
    if not self.init_browser():
        return False

    try:
        username = os.getenv("YOUUSER")
        password = os.getenv("YOUPWD")

        self.page.goto(login_url)
        self.page.set_viewport_size({"width": 1920, "height": 1080})
        
        # 元素定位器
        user_selector = "input[type='text'][placeholder='登录名或手机号']"
        pwd_selector = "input[type='password']"
        login_btn_selector = "[class*='loginButton'] button"
        checkbox_selector = "input[type='checkbox']"

        # 填写表单
        username_field = self._wait_for_element(user_selector)
        password_field = self._wait_for_element(pwd_selector)
        checkbox_field = self._wait_for_element(checkbox_selector)

        username_field.fill("")
        username_field.fill(username)
        password_field.fill("")
        password_field.fill(password)

        if not checkbox_field.is_checked():
            checkbox_field.click()

        # 截图保存
        self.page.screenshot(path="login_user_pwd.png")

        # 提交登录
        login_button = self._wait_for_element(login_btn_selector, clickable=True)
        login_button.click()

        return True
    except Exception as e:
        # 错误处理和截图
        self.page.screenshot(path="login_error.png")
        return False

从环境变量获取敏感信息，避免硬编码
自动调整视口大小确保页面元素正常显示
关键步骤截图保存，便于后续分析
全面的异常处理和日志记录

3.6、资源清理

python
def close(self):
    if self.browser:
        self.browser.close()
    if self.playwright:
        self.playwright.stop()
    logging.info("浏览器已关闭")

确保浏览器和Playwright实例被正确关闭
防止资源泄漏

3.7、完整代码示例

#!/usr/bin/python
# -*- coding: utf-8 -*-
# @Users: LiMu
# @Files：login_playwright.py
# @Times: 2025/6/25
# @Software：PyCharm

import os
import logging
from playwright.sync_api import sync_playwright, TimeoutError as PlaywrightTimeoutError

# 配置日志
logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s [%(levelname)s] %(message)s",
    handlers=[logging.StreamHandler()]
)

class PlaywrightAutomation:
    def __init__(self, headless=True):
        self.playwright = None
        self.browser = None
        self.page = None
        self.headless = headless
        self._install_browser()

    def _install_browser(self):
        """安装必要的浏览器"""
        os.system("playwright install chromium")
        os.system("playwright install --dry-run")

    def init_browser(self):
        """初始化浏览器和页面"""
        try:
            self.playwright = sync_playwright().start()
            self.browser = self.playwright.chromium.launch(headless=self.headless)
            self.page = self.browser.new_page()
            logging.info("浏览器初始化成功")
            return True
        except Exception as e:
            logging.error(f"浏览器初始化失败: {str(e)}")
            return False

    def _wait_for_element(self, selector, timeout=10000, clickable=False):
        """
        等待元素出现或可点击
        :param selector: 选择器
        :param timeout: 超时时间(毫秒)
        :param clickable: 是否要求元素可点击
        :return: ElementHandle
        """
        try:
            if clickable:
                self.page.wait_for_selector(selector, state="attached", timeout=timeout)
                return self.page.wait_for_selector(selector, state="visible", timeout=timeout)
            return self.page.wait_for_selector(selector, timeout=timeout)
        except PlaywrightTimeoutError:
            logging.error(f"元素定位超时: {selector}")
            raise
        except Exception as e:
            logging.error(f"等待元素时发生错误: {str(e)}")
            raise

    def login(self, login_url):
        """执行登录操作"""
        if not self.init_browser():
            return False

        try:
            username = os.getenv("YOUUSER")
            password = os.getenv("YOUPWD")

            self.page.goto(login_url)
            self.page.set_viewport_size({"width": 1920, "height": 1080})
            logging.info("已打开登录页面")

            # 定位元素选择器
            user_selector = "input[type='text'][placeholder='登录名或手机号']"
            pwd_selector = "input[type='password']"
            login_btn_selector = "[class*='loginButton'] button"
            checkbox_selector = "input[type='checkbox']"

            # 等待元素并操作
            username_field = self._wait_for_element(user_selector)
            password_field = self._wait_for_element(pwd_selector)
            checkbox_field = self._wait_for_element(checkbox_selector)

            # 清空并输入用户名密码
            username_field.fill("")
            username_field.fill(username)
            password_field.fill("")
            password_field.fill(password)

            # 判断并勾选复选框
            if not checkbox_field.is_checked():
                checkbox_field.click()

            logging.info("已填写用户名和密码")
            self.page.screenshot(path="login_user_pwd.png")

            # 点击登录按钮
            login_button = self._wait_for_element(login_btn_selector, clickable=True)
            login_button.click()

            logging.info("登录请求已提交")
            return True

        except PlaywrightTimeoutError as e:
            logging.error(f"登录超时: {str(e)}")
            self.page.screenshot(path="login_timeout.png")
            return False
        except Exception as e:
            logging.error(f"登录过程中出错: {str(e)}")
            self.page.screenshot(path="login_error.png")
            return False

    def close(self):
        """关闭浏览器"""
        if self.browser:
            self.browser.close()
        if self.playwright:
            self.playwright.stop()
        logging.info("浏览器已关闭")

if __name__ == "__main__":
    automation = PlaywrightAutomation(headless=False)  # 设置为False可以看到浏览器操作
    try:
        automation.login("https://sh.***xt.com/account/login")
    finally:
        input("按回车键退出浏览器...")
        automation.close()

四、最佳实践建议

4.1、选择器策略：

优先使用属性选择器而非类名，因为类名可能经常变化
对于动态内容，考虑使用XPath或文本匹配

4.2、等待优化：

根据实际网络状况调整超时时间
对于AJAX加载的内容，可以使用page.wait_for_function

4.3、安全考虑：

敏感信息如密码应通过环境变量传递
考虑使用dotenv加载本地.env文件

4.4、扩展功能：

添加验证码识别模块（如需要）
实现多账号轮换登录
添加登录成功后的跳转验证

4.5、常见问题解决

4.5.1、元素定位失败：

检查页面是否完全加载
验证选择器是否正确
尝试增加等待时间

4.5.2、浏览器无法启动：

确认Playwright浏览器已正确安装
检查防火墙设置是否阻止了浏览器启动

4.5.3、登录失败：

检查账号密码是否正确
查看网络请求是否被拦截
分析保存的错误截图

五、结语

本文详细介绍了如何使用Playwright实现自动化登录功能。通过合理的代码结构和完善的错误处理，我们构建了一个健壮、可维护的自动化脚本。这种技术不仅可以应用于登录功能，还可以扩展到各种Web自动化场景，如数据抓取、表单填写、功能测试等。

Playwright实现自动化