较少的图像找到元素<input id =“ smb” class =“ ksb” type =“ button”>无法在视图中滚动

Question

我有一个python代码，我正在使用selenium和geckodriver来抓取Google图片。但是我遇到这样的错误：找不到的图像更少，并且按钮无法在视图中滚动。

from selenium import webdriver
from selenium.webdriver.common.keys import Keys
import os
import json
from urllib.request import *
import sys
import time

os.environ["PATH"] += os.pathsep + os.getcwd()
download_path = "dataset/"


def main():
    searchtext = sys.argv[1]
    num_requested = int(sys.argv[2])
    number_of_scrolls = num_requested / 400 + 1
    # number_of_scrolls * 400 images will be opened in the browser

    if not os.path.exists(download_path + searchtext.replace(" ", "_")):
        os.makedirs(download_path + searchtext.replace(" ", "_"))

    url = "https://www.google.co.in/search?q=" + searchtext + "&source=lnms&tbm=isch"
    driver = webdriver.Firefox()
    driver.get(url)

    headers = {}
    headers[
        'User-Agent'] = "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2228.0 Safari/537.36"
    extensions = {"jpg", "jpeg", "png", "gif"}
    img_count = 0
    downloaded_img_count = 0

    for _ in range(int(number_of_scrolls)):
        for __ in range(120):
            # multiple scrolls needed to show all 400 images
            driver.execute_script("window.scrollBy(0, 1000000)")
            time.sleep(0.2)
        # to load next 400 images
        time.sleep(0.5)
        try:
            driver.find_element_by_xpath("//input[@value='Show more results']").click()
        except Exception as e:
            print("Less images found: {}".format(e))
            break

    imges = driver.find_elements_by_xpath('//div[contains(@class,"rg_meta")]')
    print("Total images: {}\n".format(len(imges)))
    for img in imges:
        img_count += 1
        img_url = json.loads(img.get_attribute('innerHTML'))["ou"]
        img_type = json.loads(img.get_attribute('innerHTML'))["ity"]
        print("Downloading image {}:{}".format(img_count, img_url))
        try:
            if img_type not in extensions:
                img_type = "jpg"
            req = Request(img_url, headers=headers)
            raw_img = urlopen(req).read()
            f = open(download_path + searchtext.replace(" ", "_") + "/" + str(downloaded_img_count) + "." + img_type,
                     "wb")
            f.write(raw_img)
            f.close()
            downloaded_img_count += 1
        except Exception as e:
            print("Download failed: {}".format(e))
        finally:
            print
        if downloaded_img_count >= num_requested:
            break

    print("Total downloaded: {}/{}".format(downloaded_img_count, img_count))
    driver.quit()

我认为嵌套循环有作用！当我尝试更改图像的内部循环次数时，值会有所不同。