import requests
import parsel
import redis

from urllib.parse import urljoin

# 建立Redis 链接
r = redis.Redis(host='localhost', port=6379, db=0)
# 提前设立待爬取队列和已爬取队列的名称
wait_key_name = "waits"
down_key_name = "downs"

# 进入栏目页
category = requests.get("https://www.bilibili.com/v/popular/rank")
category_html = parsel.Selector(category.text)
category_url = category_html.css("div.rank-list-wrap li a::attr('href')").extract()

# 拼接 URL 并逐条放入待爬队列中(Redis)
for half_url in category_url:
    url = "https:" + half_url
    r.sadd(wait_key_name, url)
print("{:^30}\t\t{:^40}\t\t{:^50}".format( '标题', '播放量/十万','弹幕数/k'))#输出顶端标题
while True:
    # 从待爬队列中弹出一条URL
    if not r.spop(wait_key_name):
        pass
    else:
        target = str(r.spop(wait_key_name), encoding="utf-8")
        resp = requests.get(target)
         # 将请求过的URL放入已爬队列
        r.sadd(down_key_name, target)
        # 使用 parsel 库解析相应正文
        html = parsel.Selector(resp.text)
        # # 判断用于区分列表页和详情页
        if "video" not in target:
            # 从列表页中提取详情页的URL
            detail_url = html.css("div.img a::attr(href)").extract()
            print(detail_url)
            for detail in detail_url:
                # 循环拼接详情页URL，并添加到待爬队列
                d = "https:" + detail
                r.sadd(wait_key_name, d)
        else:
            # 如果请求的详情页，那么直接提取数据
            title = html.css("div.video-info span.tit::text").extract_first()
            view = html.css("div.video-data span.view::text").extract_first()
            danmu = html.css("div.video-data span.dm::text").extract_first()
            if title==None :
                pass
            else:
                print("{:^30}\t\t{:^40}\t\t{:^50}".format(title,view,danmu))#输出