Srapy 爬取知乎用户信息

今天用scrapy框架爬取一下所有知乎用户的信息。道理很简单，找一个知乎大V（就是粉丝和关注量都很多的那种），找到他的粉丝和他关注的人的信息，然后分别再找这些人的粉丝和关注的人的信息，层层递进，这样下来，只要有关注的人或者有粉丝的账号，几乎都能被爬下来。话不多说，进入正题。

1、首先按照上篇博客的介绍，先建立项目，然后建一个spider文件，scrapy  genspider  zhihu  www.zhihu.com.

进入settings.py，修改内容 ROBOTSTXT_OBEY = False，意思是知乎网页中禁止爬取的内容也可以爬的到。

再添加一个User_agent，因为知乎是通过浏览器识别的，否则知乎会禁止爬取

DEFAULT_REQUEST_HEADERS = {
  'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
  'Accept-Language': 'en',
  'User-agent':'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36'
}

2、进入知乎网页页面，搜索一个大V，这里我用的是vczh，这个账号的关注量和粉丝都特别多。

　 改写zhihu.py的内容如下：

from scrapy import Request,Spider

class ZhihuSpider(Spider):
    name = 'zhihu'
    allowed_domains = ['www.zhihu.com']
    start_urls = ['http://www.zhihu.com/']

    def start_requests(self):        # zhihu.py 会先调用 start_requests 函数
        url = 'https://www.zhihu.com/api/v4/members/ji-he-61-7?include=allow_message%2Cis_followed%2Cis_following%2Cis_org%2Cis_blocking%2Cemployments%2Canswer_count%2Cfollower_count%2Carticles_count%2Cgender%2Cbadge%5B%3F(type%3Dbest_answerer)%5D.topics'
        yield Request(url,callback=self.parse)

    def parse(self, response):
        print(response.text)

随便找一个vczh关注的人，把他的Request URL拿过来请求一下，发现正常输出了结果，说明是能够获取 vczh 自己的信息的。

将URL换成 followees（vczh关注的人） 的Request URL，同样输出了正确的结果，说明 vczh 关注的人的信息也能正常输出。

经过观察发现，每个用户详细信息的 URL 只有 url_token 不同，因此分别构造 user_url 和 follows_url：

class ZhihuSpider(Spider):
    name = 'zhihu'
    allowed_domains = ['www.zhihu.com']
    start_urls = ['http://www.zhihu.com/']

    start_user = 'excited-vczh'

    user_url = 'https://www.zhihu.com/api/v4/members/{user}?include={include}'
    user_query = 'allow_message,is_followed,is_following,is_org,is_blocking,employments,answer_count,follower_count,articles_count,gender,badge[?(type=best_answerer)].topics'

    follows_url = 'https://www.zhihu.com/api/v4/members/{user}/followees?include={include}&offset={offset}&limit={limit}'
    follows_query = 'data[*].answer_count,articles_count,gender,follower_count,is_followed,is_following,badge[?(type=best_answerer)].topics'

    def start_requests(self):
        yield Request(self.user_url.format(user=self.start_user, include=self.user_query),callback=self.parse_user)
        yield Request(self.follows_url.format(user=self.start_user, include=self.follows_query, offset=0, limit=20),callback=self.parse_follows)

    def parse_user(self, response):
        result = json.loads(response.text)
        item = Zhihu3Item()
        for field in item.fields:
            if field in result.keys():
                item[field] = result.get(field)
        yield item

    def parse_follows(self, response):
        results = json.loads(response.text)
        if 'data' in results.keys():
            for result in results.get('data'):
                yield Request(self.user_url.format(user=result.get('url_token'), include=self.user_query),
                              self.parse_user)

        if 'paging' in results.keys() and results.get('paging').get('is_end') == False:  # 如果当前页不是最后一页
            next_page_str = results.get('paging').get('next')
            next_page = next_page_str.replace('https://www.zhihu.com/', 'https://www.zhihu.com/api/v4/')
            # next_page = next_page_str[0:22] + 'api/v4/' + next_page_str[22:len(next_page_str)]  # 这种写法也行
            yield Request(next_page, self.parse_follows)

结果正确输出了 vczh 和 他所关注的用户的详细信息。

3、接下来，把 vczh 关注的用户 所 关注的用户的信息输出来：

在  def parse_user(self, response): 函数后添加一句

yield Request(self.follows_url.format(user=result.get('url_token'), include=self.follows_query, offset=0, limit=20),self.parse_follows) 就好了。

4、除了获取用户关注的人以外，还要获取用户的粉丝信息。经观察，发现粉丝信息的 URL 与关注的人的 URL 类似，改写以后的最终版本如下：

class ZhihuSpider(Spider):
    name = 'zhihu'
    allowed_domains = ['www.zhihu.com']
    start_urls = ['http://www.zhihu.com/']

    start_user = 'excited-vczh'

    user_url = 'https://www.zhihu.com/api/v4/members/{user}?include={include}'
    user_query = 'allow_message,is_followed,is_following,is_org,is_blocking,employments,answer_count,follower_count,articles_count,gender,badge[?(type=best_answerer)].topics'

    follows_url = 'https://www.zhihu.com/api/v4/members/{user}/followees?include={include}&offset={offset}&limit={limit}'
    follows_query = 'data[*].answer_count,articles_count,gender,follower_count,is_followed,is_following,badge[?(type=best_answerer)].topics'

    followers_url = 'https://www.zhihu.com/api/v4/members/{user}/followers?include={include}&offset={offset}&limit={limit}'
    followers_query = 'data[*].answer_count,articles_count,gender,follower_count,is_followed,is_following,badge[?(type=best_answerer)].topics'

    def start_requests(self):
        yield Request(self.user_url.format(user=self.start_user, include=self.user_query),callback=self.parse_user)
        yield Request(self.follows_url.format(user=self.start_user, include=self.follows_query, offset=0, limit=20),callback=self.parse_follows)
        yield Request(self.followers_url.format(user=self.start_user, include=self.followers_query, offset=0, limit=20),callback=self.parse_followers)

    def parse_user(self, response):
        result = json.loads(response.text)
        item = Zhihu3Item()
        for field in item.fields:
            if field in result.keys():
                item[field] = result.get(field)
        yield item

        yield Request(self.follows_url.format(user=result.get('url_token'), include=self.follows_query, offset=0, limit=20),self.parse_follows)
        yield Request(self.followers_url.format(user=result.get('url_token'), include=self.followers_query, offset=0, limit=20),self.parse_followers)

    def parse_follows(self, response):
        results = json.loads(response.text)
        if 'data' in results.keys():
            for result in results.get('data'):
                yield Request(self.user_url.format(user=result.get('url_token'), include=self.user_query),
                              self.parse_user)

        if 'paging' in results.keys() and results.get('paging').get('is_end') == False:  # 如果当前页不是最后一页
            next_page_str = results.get('paging').get('next')
            next_page = next_page_str.replace('https://www.zhihu.com/', 'https://www.zhihu.com/api/v4/')
            # next_page = next_page_str[0:22] + 'api/v4/' + next_page_str[22:len(next_page_str)]  # 这种写法也行
            yield Request(next_page, self.parse_follows)

    def parse_followers(self, response):
        results = json.loads(response.text)
        if 'data' in results.keys():
            for result in results.get('data'):
                yield Request(self.user_url.format(user=result.get('url_token'), include=self.user_query),
                              self.parse_user)

        if 'paging' in results.keys() and results.get('paging').get('is_end') == False:  # 如果当前页不是最后一页
            next_page_str = results.get('paging').get('next')
            next_page = next_page_str.replace('https://www.zhihu.com/', 'https://www.zhihu.com/api/v4/')
            # next_page = next_page_str[0:22] + 'api/v4/' + next_page_str[22:len(next_page_str)]  # 这种写法也行
            yield Request(next_page, self.parse_followers)

5、将输出的内容保存到MongoDb中

跟上一篇博文类似，在pipeline.py中写入一下内容，直接上代码：

import pymongo

class MongoPipeline(object):
    def __init__(self, mongo_uri, mongo_db):
        self.mongo_uri = mongo_uri
        self.mongo_db = mongo_db

    @classmethod
    def from_crawler(cls, crawler):
        return cls(
            mongo_uri=crawler.settings.get('MONGO_URI'),
            mongo_db=crawler.settings.get('MONGO_DB')
        )

    def open_spider(self, spider):
        self.client = pymongo.MongoClient(self.mongo_uri)
        self.db = self.client[self.mongo_db]

    def process_item(self, item, spider):
        self.db['information'].update({'url_token':item['url_token']},{'$set':item},True)
        return item    # 根据'url_token'去重，True 表示如果重复就执行刷新操作，如果不重复就执行插入操作

    def close_spider(self, spider):
        self.client.close()

在settings.py中写入以下代码：

ITEM_PIPELINES = {
   'zhihu_3.pipelines.MongoPipeline': 300
}
MONGO_URI='localhost'
MONGO_DB = 'zhihu_3'

运行即可，成功保存到MongoDB中