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.env

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+COURSE_LIST_URL="https://v18.teachermate.cn/wechat-pro-ssr/student/coursewareinfo?courseid=1426436&openid=6147b5f556d2cf7afe0dcc6da35f8af9"
+COURSE_BUTTON_LOCATOR_XPATH="//*[@class='aK9HC-ZsTCNapKFaNj5fN']/button"

downloader.py

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+import os
+import time
+import requests
+import random
+from urllib.parse import urlparse, unquote, quote
+from dotenv import load_dotenv # <--- 新增导入
+
+from selenium import webdriver
+from selenium.webdriver.common.by import By
+from selenium.webdriver.chrome.service import Service
+from selenium.webdriver.support.ui import WebDriverWait
+from selenium.webdriver.support import expected_conditions as EC
+from webdriver_manager.chrome import ChromeDriverManager
+from selenium.common.exceptions import TimeoutException, NoSuchElementException
+
+# --- 从 .env 文件加载环境变量 ---
+load_dotenv()
+
+# --- 从环境变量中读取配置 ---
+COURSE_LIST_URL = os.getenv("COURSE_LIST_URL")
+COURSE_BUTTON_LOCATOR_XPATH = os.getenv("COURSE_BUTTON_LOCATOR_XPATH")
+
+# 检查环境变量是否成功加载
+if not COURSE_LIST_URL or not COURSE_BUTTON_LOCATOR_XPATH:
+    print("错误：请确保 .env 文件存在于脚本相同目录下，")
+    print("并且其中包含 COURSE_LIST_URL 和 COURSE_BUTTON_LOCATOR_XPATH 变量。")
+    exit()
+
+# --- 主程序 ---
+
+def setup_driver():
+    """初始化并返回一个Chrome WebDriver实例"""
+    print("正在设置浏览器驱动...")
+    service = Service(ChromeDriverManager().install())
+    driver = webdriver.Chrome(service=service)
+    driver.implicitly_wait(5)
+    return driver
+
+def try_fix_url(url, expected_filename):
+    """尝试根据期望的文件名修复URL中的文件名部分，并正确处理URL编码
+    
+    Args:
+        url: 原始URL（可能已被错误解码）
+        expected_filename: 期望的文件名
+    
+    Returns:
+        修复后的URL（正确编码）
+    """
+    if not expected_filename:
+        return url
+    
+    # 从URL中提取基础部分和文件名部分
+    # 例如: https://app.teachermate.com.cn/9cdLn-1693370741604-Chapter One From C to C .ppt
+    # 分解为: https://app.teachermate.com.cn/ + 9cdLn-1693370741604- + Chapter One From C to C .ppt
+    
+    try:
+        # 找到最后一个 '-' 之前的部分
+        last_dash_idx = url.rfind('-')
+        if last_dash_idx > 0:
+            # 获取URL的前缀部分（包含ID）
+            prefix = url[:last_dash_idx + 1]
+            
+            # 从期望文件名中提取实际文件名（去掉前面的K编号）
+            # 例如: K0002-1-1 Chapter One From C to C++.ppt -> Chapter One From C to C++.ppt
+            filename_parts = expected_filename.split()
+            actual_filename = None
+            for i, part in enumerate(filename_parts):
+                if not part.startswith('K') or i > 0:
+                    actual_filename = ' '.join(filename_parts[i:])
+                    break
+            
+            if actual_filename:
+                # 正确编码文件名：
+                # 1. 先对整个文件名进行URL编码（+会变成%2B）
+                # 2. 然后将%20替换为+（这是URL中空格的标准表示）
+                encoded_filename = quote(actual_filename, safe='.')
+                # 将空格的编码%20替换为+
+                encoded_filename = encoded_filename.replace('%20', '+')
+                
+                # 构建新的URL
+                fixed_url = prefix + encoded_filename
+                return fixed_url
+    except Exception as e:
+        print(f"    URL修复失败: {e}")
+    
+    return url
+
+def download_file(session, url, headers, directory=".", expected_filename=None):
+    """使用requests库下载文件
+    
+    Args:
+        session: requests会话对象
+        url: 下载链接
+        headers: 请求头
+        directory: 保存目录
+        expected_filename: 期望的文件名（从课件名称中提取），如果提供则优先使用
+    """
+    try:
+        # 如果提供了期望的文件名，使用它；否则从URL中提取
+        if expected_filename:
+            meaningful_name = expected_filename
+            print(f"准备下载文件: {meaningful_name} (使用课件原始名称)")
+        else:
+            path = urlparse(url).path
+            filename = unquote(os.path.basename(path))
+            clean_filename = filename.split('?')[0]
+            
+            try:
+                meaningful_name = clean_filename.split('-')[-1]
+            except:
+                meaningful_name = clean_filename
+            
+            print(f"准备下载文件: {meaningful_name}")
+        
+        response = session.get(url, stream=True, headers=headers)
+        response.raise_for_status()
+
+        filepath = os.path.join(directory, meaningful_name)
+        with open(filepath, 'wb') as f:
+            for chunk in response.iter_content(chunk_size=8192):
+                f.write(chunk)
+        print(f"成功下载并保存文件到: {filepath}\n")
+        return True
+    except requests.exceptions.RequestException as e:
+        # 特别处理403和404错误，重新抛出以便上层捕获
+        if e.response is not None and e.response.status_code in [403, 404]:
+            raise e # 重新抛出异常
+        print(f"下载文件时出错: {e}\n")
+        return False
+    except Exception as e:
+        print(f"处理文件时发生未知错误: {e}\n")
+        return False
+
+def main():
+    driver = setup_driver()
+    
+    try:
+        print(f"正在访问页面: {COURSE_LIST_URL}")
+        driver.get(COURSE_LIST_URL)
+        
+        # --- 使用从 .env 文件读取的定位符 ---
+        course_button_locator = (By.XPATH, COURSE_BUTTON_LOCATOR_XPATH)
+        
+        WebDriverWait(driver, 20).until(
+            EC.presence_of_element_located(course_button_locator)
+        )
+        
+        user_agent = driver.execute_script("return navigator.userAgent;")
+        
+        course_buttons = driver.find_elements(*course_button_locator)
+        num_courses = len(course_buttons)
+        print(f"检测到 {num_courses} 个课件，准备开始处理...")
+
+        session = requests.Session()
+        for cookie in driver.get_cookies():
+            session.cookies.set(cookie['name'], cookie['value'])
+
+        for i in range(num_courses):
+            course_buttons = WebDriverWait(driver, 10).until(
+                EC.presence_of_all_elements_located(course_button_locator)
+            )
+            button = course_buttons[i]
+            
+            course_name = button.text.strip().replace('\n', ' ') if button.text.strip() else f"课件 {i+1}"
+            print(f"--- 正在处理第 {i+1}/{num_courses} 个课件: {course_name} ---")
+            
+            # 从课件名称中提取实际文件名（去掉前面的ID和状态标记）
+            # 例如："K0002-1-1 Chapter One From C to C++.ppt 已读 Chapter One From C to C++.ppt"
+            # 提取最后一个部分作为文件名
+            parts = course_name.split()
+            # 找到文件扩展名的位置
+            expected_filename = None
+            for idx, part in enumerate(parts):
+                if part.lower().endswith(('.ppt', '.pptx', '.pdf', '.doc', '.docx', '.xls', '.xlsx')):
+                    # 从这个位置开始往前找，直到遇到"已读"或"未读"
+                    start_idx = 0
+                    for j in range(idx, -1, -1):
+                        if parts[j] in ['已读', '未读']:
+                            start_idx = j + 1
+                            break
+                    expected_filename = ' '.join(parts[start_idx:idx+1])
+                    break
+            
+            print(f"提取的文件名: {expected_filename}")
+
+            try:
+                driver.execute_script("arguments[0].click();", button)
+                print("已点击课件按钮，等待操作菜单弹出...")
+
+                preview_button_locator = (By.XPATH, "//span[text()='预览课件']")
+                preview_button = WebDriverWait(driver, 10).until(
+                    EC.element_to_be_clickable(preview_button_locator)
+                )
+                
+                driver.execute_script("arguments[0].click();", preview_button)
+                print("已点击“预览课件”选项。")
+                
+                print("正在当前页面寻找预览iframe...")
+                iframe_locator = (By.XPATH, "//iframe[contains(@src, 'ow365.cn')]")
+                iframe_element = WebDriverWait(driver, 20).until(
+                    EC.presence_of_element_located(iframe_locator)
+                )
+                
+                ow365_url = iframe_element.get_attribute('src')
+                print("成功找到预览URL。")
+
+                modified_url = ow365_url.replace("ssl=1", "ssl=0")
+                print("修改URL并正在访问...")
+                driver.get(modified_url)
+                
+                print("正在从页面文本中提取最终下载链接...")
+                url_div_locator = (By.CSS_SELECTOR, "div[style='color:red']")
+                url_element = WebDriverWait(driver, 20).until(
+                    EC.presence_of_element_located(url_div_locator)
+                )
+                
+                full_download_link = url_element.text.strip()
+                
+                headers = { 'User-Agent': user_agent, 'Referer': modified_url }
+                
+                # ==================================================================
+                # vv 最终决定性测试 vv
+                # ==================================================================
+                
+                # 1. 优先尝试直链（删除参数）
+                clean_url = full_download_link.split('?')[0]
+                print("\n>>> 正在尝试直链（删除参数）下载...")
+                print(f"    将要访问的URL: {clean_url}")
+                
+                try:
+                    # 尝试使用无参数的URL下载，并传入期望的文件名
+                    download_succeeded = download_file(session, clean_url, headers, expected_filename=expected_filename)
+                    if not download_succeeded:
+                         # 如果下载失败但不是403，也打印一下信息
+                         print("    您指定的方法下载失败，但错误不是403。")
+
+                except requests.exceptions.RequestException as e:
+                    # 如果是因为403错误而失败，证明此路不通
+                    if e.response is not None and e.response.status_code == 403:
+                        print(">>> 正在自动切换到备用方案（保留参数）进行重试...")
+                        
+                        # 2. 备用方案：使用完整的带有签名参数的URL重试
+                        try:
+                            download_file(session, full_download_link, headers, expected_filename=expected_filename)
+                        except Exception as retry_error:
+                            print(f"    备用方案也失败了: {retry_error}")
+                    elif e.response is not None and e.response.status_code == 404:
+                        # 404错误，尝试修复URL
+                        print(">>> 检测到404错误，尝试修复URL...")
+                        fixed_url = try_fix_url(clean_url, expected_filename)
+                        if fixed_url != clean_url:
+                            print(f"    修复后的URL: {fixed_url}")
+                            try:
+                                download_file(session, fixed_url, headers, expected_filename=expected_filename)
+                            except Exception as fix_error:
+                                print(f"    修复后的URL仍然无法下载: {fix_error}")
+                                print(f"    跳过此文件。")
+                        else:
+                            print("    无法修复URL，跳过此文件。")
+                    else:
+                        # 如果是其他网络错误
+                        print(f"    您指定的方法下载时遇到未知网络错误: {e}")
+
+
+            except (TimeoutException, NoSuchElementException) as e:
+                print(f"处理课件 '{course_name}' 时出错: {e}")
+                print("跳过此课件，继续下一个...")
+            
+            finally:
+                print("正在返回课程列表页面...")
+                driver.get(COURSE_LIST_URL)
+                
+                sleep_time = random.uniform(1, 2)
+                print(f"暂停 {sleep_time:.2f} 秒...")
+                time.sleep(sleep_time)
+
+    finally:
+        print("所有任务已完成，即将关闭浏览器。")
+        time.sleep(5)
+        driver.quit()
+
+if __name__ == "__main__":
+    main()
+