会员购项目面试题解析：高效数据抓取与异常处理

会员购项目

亮点

日志记录信息
协程异步抓取数据，大大提高抓取速度
捕获异常，并添加重试机制

源码

python">import logging
import timeimport requests
import asyncio
import aiohttp
from aiohttp import ContentTypeError
import csv# 配置日志
logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(levelname)s : %(message)s')# 解析数据
def parse_data(data):if data:for meeting in data:project_id = meeting['project_id']project_name = meeting['project_name']start_time = meeting['start_time']venue_name = meeting['venue_name']price_low = meeting['price_low'] / 100price_high = meeting['price_high'] / 100yield {'project_id': project_id,'project_name': project_name,'start_time': start_time,'venue_name': venue_name,'price_low': price_low,'price_high': price_high}# 保存至csv文件中
def save_file(city_info, city_id):if city_info:with open(f'{city_id}.csv', 'a+', newline='', encoding='utf-8') as f:writer = csv.writer(f)writer.writerow([f'{city_info["project_id"]}', f'{city_info["project_name"]}', f'{city_info["start_time"]}',f'{city_info["venue_name"]}', f'{city_info["price_low"]}', f'{city_info["price_high"]}'])class Myspider(object):types_list = ['演出', '展览', '本地生活']cities_id_list = []failed_urls = []CONCURRENTCY = 4RETRY_LIMIT = 3def __init__(self):self.session = Noneself.semaphore = asyncio.Semaphore(Myspider.CONCURRENTCY)# 获取城市编号并设置类属性@staticmethoddef set_cities_id():headers = {'user-agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36 Edg/127.0.0.0'}cities_data = requests.get("https://show.bilibili.com/api/ticket/city/list?channel=4", headers=headers).json()['data']developed_cities_id = [city['id'] for city in cities_data['list']]developing_cities_id = [city['id'] for part in cities_data['more'] for city in part['list']]Myspider.cities_id_list = developed_cities_id + developing_cities_idreturn None# 解决单个任务,爬取相关信息async def get_every_page_info(self, url):async with self.semaphore:logging.info(f"scraping {url}")for attempt in range(Myspider.RETRY_LIMIT):try:async with self.session.get(url) as response:data = await response.json()return data["data"]["result"]except ContentTypeError:logging.info(f"error ocurred when scraping {url}", exc_info=True)except aiohttp.ClientError as e:logging.error(f"ClientError on {url}: {e}", exc_info=True)if attempt < Myspider.RETRY_LIMIT - 1:await asyncio.sleep(2 ** attempt)  # Exponential backoffcontinueexcept aiohttp.ServerDisconnectedError:logging.error(f"Server disconnected: {url}", exc_info=True)if attempt < Myspider.RETRY_LIMIT - 1:await asyncio.sleep(2 ** attempt)continueMyspider.failed_urls.append(url)return None  # Return None if all retry attempts fail# 获取 此分类下 此城市下 最大页数def get_max_page(self, url):headers = {'user-agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36 Edg/127.0.0.0'}response = requests.get(url, headers=headers)data = response.json()return data["data"]["numPages"]# 主方法, 获取任务列表, 开4个协程去抓async def main(self):headers = {'user-agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36 Edg/127.0.0.0'}# 初始化session（主要加header头信息以及代理，cookie等头信息）async with aiohttp.ClientSession(headers=headers) as session:self.session = sessionfor type in Myspider.types_list:for city_id in Myspider.cities_id_list:begin_url = "https://show.bilibili.com/api/ticket/project/listV2?version=134&page=1&pagesize=16&area={}&filter=&platform=web&p_type={}".format(city_id, type)max_page = self.get_max_page(begin_url)# 生成任务列表scrapy_tasks = [self.get_every_page_info("https://show.bilibili.com/api/ticket/project/listV2?version=134&page={}&pagesize=16&area={}&filter=&platform=web&p_type={}".format(page, city_id, type)) for page in range(1, max_page + 1)]# 并发执行任务,获取执行结果scrapy_results = await asyncio.gather(*scrapy_tasks)# 解析结果数据for result in scrapy_results:data = parse_data(result)for city_info in data:print(city_info)save_file(city_info, city_id)# 关闭连接await self.session.close()if __name__ == '__main__':# 开始时间start_time = time.time()# 获取城市编号,设置类属性cities_id_listMyspider.set_cities_id()# 初始化Myspiderspider = Myspider()# 创建事件循环池loop = asyncio.get_event_loop()# 注册loop.run_until_complete(spider.main())# 结束事件end_time = time.time()logging.info(f"total_time: {end_time - start_time}")# print(spider.get_max_page('https://show.bilibili.com/api/ticket/project/listV2?version=134&page=1&pagesize=16&area=110100&filter=&platform=web&p_type=%E5%85%A8%E9%83%A8%E7%B1%BB%E5%9E%8B'))