使用硒显式等待python等待页面加载

Question

我是一个使用python3 for windows的初学者。 我的问题是我试图从 youtube 播放列表中抓取标题和投票（喜欢/不喜欢），并且似乎无法让我的脚本等待下一页加载，然后再对下一页进行投票，直到播放列表结束。

相反，它只取标题，并且在复制所有内容后，第一页的投票重复此操作并仅单击下一页一次。

我用谷歌搜索并查看了其他帖子，认为可能需要调用显式等待，但它似乎仍然不起作用。

当前脚本：

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

browser = webdriver.Firefox()
browser.get(
    'https://www.youtube.com/watch?v=2bnMiScBRfQ&list=PLx1Dr6w7DLoLfPixTug9c8xrTkGUsyhkQ&index=')

videosInPlaylist = []

for x in range(1, 4):
    wait = WebDriverWait(browser, 10)
    title = wait.until(EC.visibility_of_element_located((By.CSS_SELECTOR, 'h1.title'))).text

    positiveVotes = wait.until(EC.visibility_of_element_located(
        (By.CSS_SELECTOR, 'ytd-toggle-button-renderer.style-text:nth-child(1) > a:nth-child(1) > yt-formatted-string:nth-child(2)'))).text

    negativeVotes = wait.until(EC.visibility_of_element_located(
        (By.CSS_SELECTOR, 'ytd-toggle-button-renderer.style-text:nth-child(2) > a:nth-child(1) > yt-formatted-string:nth-child(2)'))).text

    currentVideo = [title, positiveVotes, negativeVotes]

    nextVideo = wait.until(EC.element_to_be_clickable(
        (By.CSS_SELECTOR, 'ytd-playlist-panel-video-renderer.style-scope:nth-child(3) > a:nth-child(1) > div:nth-child(1) > div:nth-child(3)')))

    videosInPlaylist.append(currentVideo)
    nextVideo.click()
print(videosInPlaylist)

请帮忙。

Answer 1

您必须等到视频标题已更改。请参阅下面的代码。我创建了一个自定义等待类来比较新标题和旧标题。 但是，您可能会遇到会阻止 nextVideo.click() 的广告视频，您需要处理它以使此代码完全正常工作。

class element_text_changed(object):
    def __init__(self, locator, oldTitle):
        self.locator = locator
        self.oldTitle = oldTitle

    def __call__(self, browser):
        wait = WebDriverWait(browser, 10)
        titleElement = wait.until(EC.visibility_of_element_located(self.locator))
        newTitle = titleElement.text.strip()
        print("OLD: " + self.oldTitle + ", NEW: " + newTitle)
        if len(self.oldTitle)==0 or (self.oldTitle!=newTitle):
            return titleElement
        else:
            return False

oldTitle = ''
for x in range(1, 7):
    wait = WebDriverWait(browser, 20)
    title = wait.until(element_text_changed((By.CSS_SELECTOR, 'h1.title'), oldTitle)).text
    print(title)
    oldTitle = title

    wait = WebDriverWait(browser, 10)
    positiveVotes = wait.until(EC.visibility_of_element_located(
        (By.CSS_SELECTOR, 'ytd-toggle-button-renderer.style-text:nth-child(1) > a:nth-child(1) > yt-formatted-string:nth-child(2)'))).text
    ...