diff --git a/.env b/.env new file mode 100644 index 0000000..1923151 --- /dev/null +++ b/.env @@ -0,0 +1,2 @@ +COURSE_LIST_URL="https://v18.teachermate.cn/wechat-pro-ssr/student/coursewareinfo?courseid=1426436&openid=6147b5f556d2cf7afe0dcc6da35f8af9" +COURSE_BUTTON_LOCATOR_XPATH="//*[@class='aK9HC-ZsTCNapKFaNj5fN']/button" \ No newline at end of file diff --git a/downloader.py b/downloader.py new file mode 100644 index 0000000..4fbb052 --- /dev/null +++ b/downloader.py @@ -0,0 +1,284 @@ +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() +