使用多进程对街拍图片进行下载,并将图片相关信息保存到mongodb数据库中。
import requests, re, json, pymongo
from multiprocessing import Pool
from urllib.parse import urlencode
from hashlib import md5
class JiePaiSpider(object):
# 进程池无法序列化pymongo对象,因为pymongo数据库中含有线程锁。
# TypeError: can't pickle _thread.lock objects
# 建立pymongo的链接
client = pymongo.MongoClient('localhost')
db = client['jiepai']
def __init__(self):
self.headers = {
'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.12 Safari/537.36'
}
def get_list_json(self, offset):
"""
请求列表页的json接口,获取列表页中的图片信息。
:param offset: 请求接口时的偏移量参数。(0, 20, 40....)
:return:
"""
# https://www.toutiao.com/search_content/?offset=0&format=json&keyword=%E8%A1%97%E6%8B%8D&autoload=true&count=20&cur_tab=1&from=search_tab&pd=synthesis
# 准备接口参数
params = {
'offset': offset,
'format': 'json',
'keyword': '街拍',
'autoload': 'true',
'count': '20',
'cur_tab': '1',
'from': 'search_tab',
'pd': 'synthesis'
}
api_url = 'https://www.toutiao.com/search_content/?' + urlencode(params)
try:
response = requests.get(api_url, headers=self.headers)
if response.status_code == 200:
# 响应状态码是200,说明GET请求成功
return response.text
else:
print('请求异常:url={}, status_code={}'.format(api_url, response.status_code))
return None
except Exception as e:
print('请求异常:url={}, error={}'.format(api_url, e))
return None
def parse_list_json(self, json_str):
"""
解析列表页json数据
:param json_str:
:return:
"""
json_dict = json.loads(json_str)
if 'data' in json_dict.keys():
# 判断字典json_dict的所有键中是否包含'data',如果有,可以解析,如果没有,可能没有数据或者发生异常了。
data_list = json_dict.get('data', None)
if data_list and len(data_list) > 0:
# 说明还有数据,可以解析
urls = []
for item in data_list:
if 'single_mode' not in item and 'cell_type' not in item:
article_url = item['article_url']
urls.append(article_url)
return urls
def get_detail_page(self, detail_url):
try:
response = requests.get(detail_url, headers=self.headers)
if response.status_code == 200:
# 响应状态码是200,说明GET请求成功
return response.text
else:
print('请求异常:url={}, status_code={}'.format(detail_url, response.status_code))
return None
except Exception as e:
print('请求异常:url={}, error={}'.format(detail_url, e))
return None
def parse_detail_page(self, detail_html):
# \(:表示对正则表达式中的(进行转义,转化为一个普通的字符。
js_json_str = re.findall(re.compile(r'gallery: JSON\.parse\((.*?)\),', re.S), detail_html)[0].replace('\\', '').strip('"')
# 数据保存到Mongo中
data_dict = json.loads(js_json_str)
self.save_dict_to_db(data_dict)
# 解析Json,取出图片的url地址,下载图片到本地。
for item_dict in data_dict['sub_images']:
img_url = item_dict['url']
# 根据图片url地址,下载图片
self.download_image(img_url)
def download_image(self, img_url):
response = requests.get(img_url, headers=self.headers)
if response.status_code == 200:
# response.text: 获取的是文本资源;(json字符串、网页源代码)
# 但是图片属于二进制资源,图片数据的传输是以二进制流的形式传输的,不再是字符串了。
content = response.content
# md5()函数的参数需要是一个bytes字节码,不能是str类型的字符串。
# hexdigest(): 获取md5加密后的结果。
img_name = md5(img_url.encode('utf-8')).hexdigest()
# 'w': 写入普通文本;'wb': 专门用于写入二进制数据(图片、音频、视频)
f = open('imgs/{}.jpg'.format(img_name), 'wb')
f.write(content)
f.close()
else:
print('图片请求失败:{}'.format(img_url))
def save_dict_to_db(self, dic):
self.db['img'].insert_one(dic)
def start_spider(self, offset):
print('正在请求偏移量为{}的图片'.format(offset))
json_str = self.get_list_json(offset)
if json_str:
urls = self.parse_list_json(json_str)
for detail_url in urls:
detail_html = self.get_detail_page(detail_url)
if detail_html:
self.parse_detail_page(detail_html)
if __name__ == '__main__':
jp = JiePaiSpider()
pool = Pool(3)
pool.map(jp.start_spider, [x for x in range(0, 101) if x % 20 == 0])
# jp.start_spider(0)
pool.close()
pool.join()