实现思路
原理非常简单，就是利用selenium去操作浏览器，获取到想要的链接，然后进行图片的下载，和一般的爬虫无异。
用到的技术：multiprocessing，selenium，xpath，requests
以下按照代码执行的顺序进行讲解。
首先导入需要的包
# coding=utf-8
import base64
import hashlib
import os
import re
import shutil
import time
from multiprocessing import Pool, cpu_count
import requests
import tqdm
from colorama import Fore
from selenium import webdriver
from selenium.common.exceptions import (ElementNotVisibleException,
StaleElementReferenceException)
from selenium.webdriver.common.by import By
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.wait import WebDriverWait
定义一个 run()函数，作为入口。这里使用多进程技术，同时打开多个浏览器进行图片爬取。
def run():
num_process = cpu_count() # 进程数设置为cpu核心数
pool = Pool(num_process) # 建立一个进程池
filelist = []
upload = r"./upload" # 需要进行上传的图片文件夹
getfilelist(upload, filelist) # 递归查找文件夹里面所有的图片文件
result = partition(filelist, num_process) # 将图片文件列表平均分为几个list，每个进程跑一部分
pool.map_async(download_task, result) # 下载任务丢进进程池
pool.close() # 不再允许加入进程池
pool.join() # 等待进程完成
其中 getfilelist()函数是递归查找，工作中用得很多了。
EXTEND = [".bmp", ".jpg", ".jpeg", ".tif", ".tiff",
".jfif", ".png", ".gif", ".iff", ".ilbm"]
def is_img(img_path):
# 根据后缀判断是否为图片
ext = os.path.splitext(img_path)[1]
if ext in EXTEND:
return True
else:
return False
def getfilelist(path, filelist):
file = os.listdir(path)
for im_name in file:
if os.path.isdir(os.path.join(path, im_name)):
getfilelist(os.path.join(path, im_name), filelist)
else:
if is_img(im_name):
name = os.path.join(path, im_name)
filelist.append(name)
partition()函数用于将一个列表均分为几份，以便实现多进程。
def partition(ls, size):
num_per_list = len(ls)//size
result = []
if num_per_list*size == len(ls):
for i in range(size):
result.append(ls[num_per_list*i:num_per_list*(i+1)])
else:
for i in range(size-1):
result.append(ls[num_per_list*i:num_per_list*(i+1)])
result.append(ls[num_per_list*(size-1):])
return result
download_task()为具体的下载任务，一个task实例化一个GoogleSearcher类，遍历自己的图片列表进行以图搜图。
def download_task(filelist):
searcher = GoogleSearcher(
download=r"./download")
for file in filelist:
searcher.simple_file_run(file) # 上传单张图并进行以图搜图
GoogleSearcher类比较长，在注释中进行讲解。
USERNAME = os.environ['USERNAME']
class GoogleSearcher:
def __init__(self, download="download", sleep_time=1):
super().__init__()
self._download = download # 下载文件夹
self.sleep_time = sleep_time # 下载页面时等待时间
self.header = {
"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.163 Safari/537.36"}
os.makedirs(self._download, exist_ok=True) # 创建下载文件夹
self.option = webdriver.ChromeOptions()
# self.option.add_argument("--user-data-dir=" + f"C:/Users/{USERNAME}/AppData/Local/Google/Chrome/User Data/")
# self.option.add_argument("headless") # if use headless, may failed.
self.option.add_argument("disable-gpu")
self.driver = webdriver.Chrome(options=self.option) # 以上为浏览器对象创建
def upload_img_get_html(self, file):
# 上传图片并转到图片列表页面
print(
f"{Fore.GREEN} Begin to upload image {os.path.split(file)[1]} {Fore.RESET}")
self.driver.get("https://www.google.com/imghp")
# 等待相机按钮出现
condition_1 = EC.visibility_of_element_located(
(By.CLASS_NAME, "LM8x9c"))
WebDriverWait(self.driver, timeout=20,
poll_frequency=0.5).until(condition_1)
# 相机按钮出现后点击
image_button = self.driver.find_element_by_class_name("LM8x9c")
image_button.send_keys(Keys.ENTER)
# 等待出现上传图片字样
condition_2 = EC.visibility_of_element_located(
(By.ID, "dRSWfb"))
WebDriverWait(self.driver, timeout=20, poll_frequency=0.5).until(
condition_2)
# 点击上传图片
upload = self.driver.find_element_by_xpath('//*[@id="dRSWfb"]/div/a')
upload.send_keys(Keys.ENTER)
# 找到上传图片的控件
condition_3 = EC.visibility_of_element_located(
(By.ID, 'awyMjb'))
WebDriverWait(self.driver, timeout=10, poll_frequency=0.5).until(
condition_3)
input_ = self.driver.find_element_by_id('awyMjb')
# 因为上传图片的控件是一个input,直接将文件send就行
input_.send_keys(file)
print(f"{Fore.GREEN} uploaded {Fore.RESET}")
# 页面转向另一页
condition_4 = EC.visibility_of_element_located(
(By.XPATH, '//*[@id="top_nav"]'))
WebDriverWait(self.driver, timeout=20,
poll_frequency=0.5).until(condition_4)
# 等待片刻
time.sleep(self.sleep_time)
# print(driver.current_url)
# print(driver.page_source)
print(f"{Fore.GREEN} Finish download source code{Fore.RESET}")
return self.driver.page_source
def highlight(self, element):
self.driver.execute_script(
"arguments[0].setAttribute('style', arguments[1]);", element, "background: yellow; border: 2px solid red;")
def wait_and_click(self, xpath):
# Sometimes click fails unreasonably. So tries to click at all cost.
try:
w = WebDriverWait(self.driver, 15)
elem = w.until(EC.element_to_be_clickable((By.XPATH, xpath)))
elem.click()
self.highlight(elem)
except Exception as e:
print('Click time out - {}'.format(xpath))
print('Refreshing browser...')
self.browser.refresh()
time.sleep(2)
return self.wait_and_click(xpath)
return elem
def get_extension_from_link(self, link, default='jpg'):
# 获取文件后缀
splits = str(link).split('.')
if len(splits) == 0:
return default
ext = splits[-1].lower()
if ext == 'jpg' or ext == 'jpeg':
return 'jpg'
elif ext == 'gif':
return 'gif'
elif ext == 'png':
return 'png'
else:
return default
def base64_to_object(self, src):
# base64 解码
header, encoded = str(src).split(',', 1)
data = base64.decodebytes(bytes(encoded, encoding='utf-8'))
return data
def download_images(self, links, download_dir):
# 下载图片
total = len(links)
for index, link in enumerate(links):
try:
if len(link) < 100:
print('Downloading {} : {} / {}'.format(link, index + 1, total))
else:
print(
'Downloading {} : {} / {}'.format(link[:100], index + 1, total))
# 链接过长，只打印部分
if str(link).startswith('data:image/jpeg;base64'):
# base64编码的jpg图片
response = self.base64_to_object(src=link)
ext = 'jpg'
is_base64 = True
elif str(link).startswith('data:image/png;base64'):
# base64编码的png图片
response = self.base64_to_object(src=link)
ext = 'png'
is_base64 = True
else:
# 图片超链接
response = requests.get(link, stream=True, timeout=5)
ext = self.get_extension_from_link(link=link)
is_base64 = False
path = os.path.join(download_dir, str(index).zfill(4)+"."+ext)
try:
with open(path, "wb") as f:
# base64图片和超链接图片两种保存方法
if is_base64:
f.write(response)
else:
shutil.copyfileobj(response.raw, f)
except Exception as e:
print('Save failed - {}'.format(e))
del response
except Exception as e:
print('Download failed - ', e)
continue
def get_full_resolution_links(self):
print('[Full Resolution Mode]')
time.sleep(1)
elem = self.driver.find_element_by_tag_name("body")
print('Scraping links')
self.wait_and_click('//div[@data-ri="0"]')
time.sleep(1)
links = []
count = 1
last_scroll = 0
scroll_patience = 0
while True:
try:
xpath = '//div[@id="islsp"]//div[@class="v4dQwb"]'
div_box = self.driver.find_element(By.XPATH, xpath)
self.highlight(div_box)
xpath = '//img[@class="n3VNCb"]'
img = div_box.find_element(By.XPATH, xpath)
self.highlight(img)
xpath = '//div[@class="k7O2sd"]'
loading_bar = div_box.find_element(By.XPATH, xpath)
# 等待图片加载，如果加载不完，获取到的是 base64 编码的图片
while str(loading_bar.get_attribute('style')) != 'display: none;':
time.sleep(0.1)
src = img.get_attribute('src')
if src is not None:
links.append(src)
if len(src) < 100:
print('%d: %s' % (count, src))
else:
print('%d: %s' % (count, src[:100])) # 如果太长，只打印一部分
count += 1
except StaleElementReferenceException:
pass
except Exception as e:
print(
'[Exception occurred while collecting links from google_full] {}'.format(e))
scroll = self.driver.execute_script("return window.pageYOffset;") # 页面滚动的位置
if scroll == last_scroll:
# 页面滚动1
scroll_patience += 1
else:
scroll_patience = 0
last_scroll = scroll
if scroll_patience >= 30:
#页面滚动30，停止
break
elem.send_keys(Keys.RIGHT)
links = list(dict.fromkeys(links)) # 链接去重
print('Collect links done. Total: {}'.format(len(links)))
return links
def simple_file_run(self, img):
# 上传图片并进行搜索
img_name = os.path.splitext(os.path.split(img)[1])[0] # 图片名
parent_name = os.path.split(os.path.split(img)[0])[-1] # 图片的父级名字，用来区分图片的类别
print("--> Processing image: {} ".format(img_name))
download_dir = os.path.join(self._download, parent_name, img_name)
os.makedirs(download_dir, exist_ok=True)
html_source = self.upload_img_get_html(img) # 上传图片，到搜索结果页
similar_img_href = self.driver.find_element_by_xpath(
'//div[@class="e2BEnf U7izfe"]/h3/a')
similar_img_href.click() # 查找“类似图片”的链接并点击，进入图片列表页
links = self.get_full_resolution_links() # 将所有图片的大图链接进行收集
self.download_images(links, download_dir) # 下载这些大图
print("{}Image {} finished
{}".format(
Fore.GREEN, img_name, Fore.RESET))
整个流程就跟打开浏览器进行操作一样，难点在于如何控制速度，不被谷歌反爬，不然出现谷歌验证码，破解是不可能的，就要帮它免费打码了。
有何用途
当你需要训练一个图片分类的模型，手头上图片有限，那就可以用这个方法，每一张图都找跟它相似的，轻轻松松就把训练集扩大了几十倍（理想情况，不被反爬的话）。