spider【第八篇】Scrapy突破反爬虫的限制

setting文件

为什么项目中需要配置文件
    在配置文件中存放一些公共变量，在后续的项目中便便修改，注意其中的变量名一般全部大写

配置文件中的变量使用方法
    导入即可使用
    
settings.py中的重点字段和内涵
    USER_AGENT 设置ua
    ROBOTSTXT_OBEY 是否遵守robots协议，默认是遵守
    CONCURRENT_REQUESTS 设置并发请求的数量，默认是16个
    DOWNLOAD_DELAY 下载延迟，默认无延迟
    COOKIES_ENABLED 是否开启cookie，即每次请求带上前一次的cookie，默认是开启的
    DEFAULT_REQUEST_HEADERS 设置默认请求头
    SPIDER_MIDDLEWARES 爬虫中间件，设置过程和管道相同
    DOWNLOADER_MIDDLEWARES 下载中间件

随机更换user-agent

每次url请求更换一次user-agent

pip install fake-useragent

settings

DOWNLOADER_MIDDLEWARES = {
   # 'ArticleSpider.middlewares.MyCustomDownloaderMiddleware': 543,
      'ArticleSpider.middlewares.RandomUserAgentMiddleware': 400,
}

middlewares 

from fake_useragent import UserAgent

class RandomUserAgentMiddleware(object):
    def __init__(self, crawler):
        super(RandomUserAgentMiddleware, self).__init__()

        self.ua = UserAgent()
		# 若settings中没有设置RANDOM_UA_TYPE的值默认值为random，
		# 从settings中获取RANDOM_UA_TYPE变量，值可以是 random ie chrome firefox safari opera msie
        self.ua_type = crawler.settings.get('RANDOM_UA_TYPE', 'random')  

    @classmethod
    def from_crawler(cls, crawler):
        return cls(crawler)

    def process_request(self, request, spider):
        def get_ua():
            '''根据settings的RANDOM_UA_TYPE变量设置每次请求的User-Agent'''
            return getattr(self.ua, self.ua_type)

		ua = get_ua()
		request.headers.setdefault('User-Agent', get_ua())

ip代理

方案一：免费版

自定义函数获取网上的一些免费代理ip

settings

DOWNLOADER_MIDDLEWARES = {
      'ArticleSpider.middlewares.RandomProxyMiddleware': 400,
}

middlewares 

class RandomProxyMiddleware(object):
    #动态设置ip代理
    def process_request(self, request, spider):
        request.meta["proxy"] = get_random_ip() # 这个自定义函数返回一个随机代理ip：port

方案二：收费版

github上scrapy-proxies等等

在线打码

 编码识别：由于验证码识别难度大，而且易更新，所以编码识别验证码(不推荐)

 在线打码：调用已经开发好的在线验证码识别软件接口识别验证码。识别率在90%以上，并且效率高(推荐)

 人工打码：识别率近100%，但是成本高（用于复杂的）

cookie

1.一些网站会跟踪cookie，如果不需要登陆的网站，可禁用cookie，降低被ban概率，scrapy默认开启cookie

COOKIES_ENABLED = False

2.配合其他程序使用，比如其使用selenium把登陆之后的cookie获取到保存到本地，scrapy发送请求之前先读取本地cookie

import scrapy
import re

class RenrenSpider(scrapy.Spider):
    name = 'renren'
    allowed_domains = ['renren.com']
    start_urls = ['http://www.renren.com/941954027/profile']

    def start_requests(self):
        cookie_str = "cookie_str"
        cookie_dict = {i.split("=")[0]:i.split("=")[1] for i in cookie_str.split("; ")}
        yield scrapy.Request(
            self.start_urls[0],
            callback=self.parse,
            cookies=cookie_dict,
            # headers={"Cookie":cookie_str}
        )

    def parse(self, response):
        ret = re.findall("新用户287",response.text)
        print(ret)
        yield scrapy.Request(
            "http://www.renren.com/941954027/profile?v=info_timeline",
            callback=self.parse_detail
        )

    def parse_detail(self,response):
        ret = re.findall("新用户287",response.text)
        print(ret)

自动限速

 

调整某些参数，如

AUTOTHROTTLE_ENABLED = True
DOWNLOAD_DELAY = 3

selenium　

官方文档　http://selenium-python-docs-zh.readthedocs.io/zh_CN/latest/

作用：浏览器操控

安装selenium

pip install selenium

下载对应浏览器的驱动　　

http://selenium-python.readthedocs.io/installation.html

第三方(微博)登录知乎

import time
from selenium import webdriver
from scrapy.selector import Selector

browser = webdriver.Chrome(executable_path="D:/Package/chromedriver.exe")
time.sleep(2)  # 延时为了让页面加载完

browser.get("https://www.zhihu.com/#signin")
browser.find_element_by_css_selector(".qrcode-signin-cut-button").click()
browser.find_element_by_css_selector(".signup-social-buttons").click()
browser.find_element_by_css_selector(".js-bindweibo").click()
#browser.switch_to.window(browser.window_handles[-1])
browser.find_element_by_css_selector(".WB_iptxt").send_keys("xxx")
browser.find_element_by_css_selector("input[node-type='passwd']").send_keys("xxx")
browser.find_element_by_css_selector("a[node-type='submit']").click()
time.sleep(2) # 延时为了让页面加载完
browser.find_element_by_css_selector("a[node-type='submit']").click()

第三方(QQ)登录知乎

代码维护 https://github.com/ecithy/selenium-QQ

# -*- coding: utf-8 -*-
__author__ = 'hy'
import time
from selenium import webdriver
from scrapy.selector import Selector
 
browser = webdriver.Firefox(executable_path="D:/Package/geckodriver.exe")
#
browser.get("https://www.zhihu.com/#signin")
time.sleep(2)
 
# 点击QQ
browser.find_element_by_css_selector(".qrcode-signin-cut-button").click()
browser.find_element_by_css_selector(".signup-social-buttons").click()
time.sleep(2)
browser.find_element_by_css_selector(".js-bindqq").click()
time.sleep(5)
 
browser.switch_to.window(browser.window_handles[-1])
browser.switch_to.frame("ptlogin_iframe")  # iframe必须逐级切入
 
# 用户名 密码

# 隐藏初始界面
browser.execute_script('document.getElementById("qlogin").style="display: none;"')
browser.execute_script('document.getElementsByClassName("authLogin").style="display: none;"')
# 显示用户、密码输入界面
browser.execute_script('document.getElementById("web_qr_login").style="display: block;"')
# browser.evaluate_script('document.getElementById("batch_quto").contentEditable = true')
time.sleep(5)
 
# 输入用户、密码
elem_user = browser.find_element_by_name("u").send_keys("xxx")
elem_pwd = browser.find_element_by_name("p").send_keys("xxx")
elem_but = browser.find_element_by_id("login_button").click()
time.sleep(5)

scrapy集成selenium　　

为什么集成selenium

selenium取代下载器，编码难度大的操作交给selenium

优点：反爬虫难度大

缺点：同步selenium效率低，需要结合Twisted成异步

middleware方式

方式一

settings

DOWNLOADER_MIDDLEWARES = {
      'ArticleSpider.middlewares.JSPageMiddleware':1,
}

middlewares 　　

from selenium import webdriver
from scrapy.http import HtmlResponse
import time


class JSPageMiddleware(object):
    def __init__(self): # 使用同一个self，保证只打开一个浏览器，所有spider使用一个浏览器
        self.browser = webdriver.Chrome(executable_path="D:/Package/chromedriver.exe")
        super(JSPageMiddleware, self).__init__()

    # 通过chrome请求动态网页
    def process_request(self, request, spider):
        if spider.name == "jobbole":
            # self.browser = webdriver.Chrome(executable_path="D:/Package/chromedriver.exe")
            self.browser.get(request.url)
            time.sleep(1)
            print("访问:{0}".format(request.url))
            # browser.quit()
            return HtmlResponse(url=self.browser.current_url, body=self.browser.page_source, 
                                encoding="utf-8", request=request)

方式二

middlewares 

from scrapy.http import HtmlResponse
import time

class JSPageMiddleware(object):
    # 通过chrome请求动态网页
    def process_request(self, request, spider):
        if spider.name == "jobbole":
            # self.browser = webdriver.Chrome(executable_path="D:/Package/chromedriver.exe")
            spider.browser.get(request.url)
            time.sleep(1)
            print("访问:{0}".format(request.url))
            # browser.quit()
            return HtmlResponse(url=spider.browser.current_url, body=spider.browser.page_source,
                                encoding="utf-8", request=request)

spider

from selenium import webdriver
from scrapy.xlib.pydispatch import dispatcher
from scrapy import signals

class JobboleSpider(scrapy.Spider):
    name = 'jobbole'
    allowed_domains = ['blog.jobbole.com']
    start_urls = ['http://blog.jobbole.com/all-posts/']

    def __init__(self): # 使用同一个self，每个spider使用一个浏览器
        self.browser = webdriver.Chrome(executable_path="D:/Package/chromedriver.exe")
        super(JobboleSpider, self).__init__()
        dispatcher.connect(self.spider_closed, signals.spider_closed)  # 爬虫关闭后

    def spider_closed(self, spider):
        self.browser.quit()

scrapy集成selenium/phthomjs模拟登录

为什么不直接用selenium替代原生下载器？

selenium是同步的方式，如果每个页面采用selenium则导致爬虫效率极低，目前并没有scrapy中的Twisted结合selenium的异步方案，因此selenium不推荐替代原生下载器

scrapy集成selenium能做什么？

 由于模拟登录是编码很难解决的问题 ，因此采用selenium解决；其它页面继续用原生下载器的异步下载方案

# -*- coding: utf-8 -*-
import re
import datetime
 
try:
    import urlparse as parse
except:
    from urllib import parse
 
import scrapy
from selenium import webdriver
import time
 
class ZhihuSpider(scrapy.Spider):
    name = "zhihu"
    allowed_domains = ["www.zhihu.com"]
    start_urls = ['https://www.zhihu.com/']
    login_cookies = []

    headers = {
        "HOST": "www.zhihu.com",
        "Referer": "https://www.zhizhu.com",
        'User-Agent': "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:51.0) Gecko/20100101 Firefox/51.0"
    }
 
    # selenium登录保存cookies
    def get_cookies(self):
        browser = webdriver.Chrome(executable_path="D:/Package/chromedriver.exe")
        time.sleep(2)  # 延时为了让页面加载完
 
        browser.get("https://www.zhihu.com/#signin")
        browser.find_element_by_css_selector(".qrcode-signin-cut-button").click()
        browser.find_element_by_css_selector(".signup-social-buttons").click()
        browser.find_element_by_css_selector(".js-bindweibo").click()
        # browser.switch_to.window(browser.window_handles[-1])
        browser.find_element_by_css_selector(".WB_iptxt").send_keys("xxx")
        browser.find_element_by_css_selector("input[node-type='passwd']").send_keys("xxx")
        browser.find_element_by_css_selector("a[node-type='submit']").click()
        time.sleep(2)  # 延时为了让页面加载完
        browser.find_element_by_css_selector("a[node-type='submit']").click()
        login_cookies = browser.get_cookies()
        browser.close()
 
    # 第一步:先于parse方法执行，处理登陆逻辑。可以猜测，start_requests携带的cookie会给后续所有的访问自动带上
    def start_requests(self):
        return [scrapy.Request('https://www.zhihu.com/#signin', headers=self.headers, cookies=self.login_cookies,
                               callback=self.parse)]
 
    # 第二步:处理登陆后的逻辑
    def parse(self, response):
        my_url= 'https://www.zhihu.com/people/edit'  # 该页面是个人中心页，只有登录后才能访问
        yield scrapy.Request(my_url, headers=self.headers)

爬取知乎文章和问答　　

scrapy shell调试　　

scrapy shell -s USER_AGENT="Mozilla/5.0 (Windows NT 6.1; WOW64; rv:51.0) Gecko/20100101 Firefox/51.0" 
https://www.zhihu.com/question/56320032

 页面分析　　

chrome安装jsonview插件

xhr页面查看json数据，这样获取数据更轻松

 

表设计

为了避免可能解析不到的字段或无法插入的情况，需要给字段设置默认值

 

 

ITEM_PIPELINES = {
    'ArticleSpider.pipelines.MysqlTwistedPipline': 1,
}

MYSQL_HOST = "127.0.0.1"
MYSQL_DBNAME = "article_spider"
MYSQL_USER = "root"
MYSQL_PASSWORD = "root"


SQL_DATETIME_FORMAT = "%Y-%m-%d %H:%M:%S"
SQL_DATE_FORMAT = "%Y-%m-%d"

ES_HOST = "127.0.0.1"

import datetime
import re

import scrapy
from scrapy.loader import ItemLoader
from scrapy.loader.processors import MapCompose, TakeFirst, Join

from .utils.common import extract_num
from .settings import SQL_DATETIME_FORMAT, SQL_DATE_FORMAT
from w3lib.html import remove_tags

class ZhihuQuestionItem(scrapy.Item):
    #知乎的问题 item
    zhihu_id = scrapy.Field()
    topics = scrapy.Field()
    url = scrapy.Field()
    title = scrapy.Field()
    content = scrapy.Field()
    answer_num = scrapy.Field()
    comments_num = scrapy.Field()
    watch_user_num = scrapy.Field()
    click_num = scrapy.Field()
    crawl_time = scrapy.Field()

    def get_insert_sql(self):
        #插入知乎question表的sql语句
        insert_sql = """
            insert into zhihu_question(zhihu_id, topics, url, title, content, answer_num, comments_num,
              watch_user_num, click_num, crawl_time
              )
            VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s)
            ON DUPLICATE KEY UPDATE content=VALUES(content), answer_num=VALUES(answer_num), comments_num=VALUES(comments_num),
              watch_user_num=VALUES(watch_user_num), click_num=VALUES(click_num)
        """
        # 方式二：将item loader的item数组形式在这里处理
        zhihu_id = self["zhihu_id"][0]
        topics = ",".join(self["topics"])
        url = self["url"][0]
        title = "".join(self["title"])
        content = "".join(self["content"])
        answer_num = extract_num("".join(self["answer_num"]))
        comments_num = extract_num("".join(self["comments_num"]))

        if len(self["watch_user_num"]) == 2:
            watch_user_num = int(self["watch_user_num"][0])
            click_num = int(self["watch_user_num"][1])
        else:
            watch_user_num = int(self["watch_user_num"][0])
            click_num = 0

        crawl_time = datetime.datetime.now().strftime(SQL_DATETIME_FORMAT)

        params = (zhihu_id, topics, url, title, content, answer_num, comments_num,
                  watch_user_num, click_num, crawl_time)

        return insert_sql, params


class ZhihuAnswerItem(scrapy.Item):
    #知乎的问题回答item
    zhihu_id = scrapy.Field()
    url = scrapy.Field()
    question_id = scrapy.Field()
    author_id = scrapy.Field()
    content = scrapy.Field()
    parise_num = scrapy.Field()
    comments_num = scrapy.Field()
    create_time = scrapy.Field()
    update_time = scrapy.Field()
    crawl_time = scrapy.Field()

    def get_insert_sql(self):
        #插入知乎question表的sql语句
        insert_sql = """
            insert into zhihu_answer(zhihu_id, url, question_id, author_id, content, parise_num, comments_num,
              create_time, update_time, crawl_time
              ) VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s)
              ON DUPLICATE KEY UPDATE content=VALUES(content), comments_num=VALUES(comments_num), parise_num=VALUES(parise_num),
              update_time=VALUES(update_time)
        """

        create_time = datetime.datetime.fromtimestamp(self["create_time"]).strftime(SQL_DATETIME_FORMAT)
        update_time = datetime.datetime.fromtimestamp(self["update_time"]).strftime(SQL_DATETIME_FORMAT)
        params = (
            self["zhihu_id"], self["url"], self["question_id"],
            self["author_id"], self["content"], self["parise_num"],
            self["comments_num"], create_time, update_time,
            self["crawl_time"].strftime(SQL_DATETIME_FORMAT),
        )

        return insert_sql, params

class MysqlTwistedPipline(object):
    def __init__(self, dbpool):
        self.dbpool = dbpool

    @classmethod
    def from_settings(cls, settings):
        dbparms = dict(
            host=settings["MYSQL_HOST"],
            db=settings["MYSQL_DBNAME"],
            user=settings["MYSQL_USER"],
            passwd=settings["MYSQL_PASSWORD"],
            charset='utf8',
            cursorclass=MySQLdb.cursors.DictCursor,
            use_unicode=True,
        )
        dbpool = adbapi.ConnectionPool("MySQLdb", **dbparms)

        return cls(dbpool)

    def process_item(self, item, spider):
        # 使用twisted将mysql插入变成异步执行
        query = self.dbpool.runInteraction(self.do_insert, item)
        query.addErrback(self.handle_error, item, spider)  # 处理异常

    def handle_error(self, failure, item, spider):
        # 处理异步插入的异常
        print(failure)

    def do_insert(self, cursor, item):
        # 执行具体的插入
        # 根据不同的item 构建不同的sql语句并插入到mysql中
        insert_sql, params = item.get_insert_sql()
        print(insert_sql, params)
        cursor.execute(insert_sql, params)

# -*- coding: utf-8 -*-
import re
import json
import datetime

try:
    import urlparse as parse
except:
    from urllib import parse

import scrapy
from scrapy.loader import ItemLoader
from ArticleSpider.items import ZhihuQuestionItem, ZhihuAnswerItem
from selenium import webdriver
import time


class ZhihuSpider(scrapy.Spider):
    name = "zhihu"
    allowed_domains = ["www.zhihu.com"]
    start_urls = ['https://www.zhihu.com/']
    # question的第一页answer的请求url
    start_answer_url = "https://www.zhihu.com/api/v4/questions/{0}/answers?sort_by=default&include=data%5B%2A%5D.is_normal%2Cis_sticky%2Ccollapsed_by%2Csuggest_edit%2Ccomment_count%2Ccollapsed_counts%2Creviewing_comments_count%2Ccan_comment%2Ccontent%2Ceditable_content%2Cvoteup_count%2Creshipment_settings%2Ccomment_permission%2Cmark_infos%2Ccreated_time%2Cupdated_time%2Crelationship.is_author%2Cvoting%2Cis_thanked%2Cis_nothelp%2Cupvoted_followees%3Bdata%5B%2A%5D.author.is_blocking%2Cis_blocked%2Cis_followed%2Cvoteup_count%2Cmessage_thread_token%2Cbadge%5B%3F%28type%3Dbest_answerer%29%5D.topics&limit={1}&offset={2}"
    login_cookies = []

    headers = {
        "HOST": "www.zhihu.com",
        "Referer": "https://www.zhizhu.com",
        'User-Agent': "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:51.0) Gecko/20100101 Firefox/51.0"
    }

    # selenium登录保存cookies
    def get_cookies(self):
        browser = webdriver.Chrome(executable_path="D:/Package/chromedriver.exe")
        time.sleep(2)  # 延时为了让页面加载完

        browser.get("https://www.zhihu.com/#signin")
        browser.find_element_by_css_selector(".qrcode-signin-cut-button").click()
        browser.find_element_by_css_selector(".signup-social-buttons").click()
        browser.find_element_by_css_selector(".js-bindweibo").click()
        # browser.switch_to.window(browser.window_handles[-1])
        browser.find_element_by_css_selector(".WB_iptxt").send_keys("liyao198705@sina.com")
        browser.find_element_by_css_selector("input[node-type='passwd']").send_keys("da_ge_da")
        browser.find_element_by_css_selector("a[node-type='submit']").click()
        time.sleep(2)  # 延时为了让页面加载完
        browser.find_element_by_css_selector("a[node-type='submit']").click()
        login_cookies = browser.get_cookies()
        browser.close()

    # 第一步:先于parse方法执行，处理登陆逻辑
    def start_requests(self):
        return [scrapy.Request('https://www.zhihu.com/#signin', headers=self.headers, cookies=self.login_cookies,
                               callback=self.parse)]

    # 第二步:处理登陆后的逻辑
    def parse(self, response):
        """
        爬取策略：深度优先（
        提取出html登陆后页面中的所有url 并跟踪这些url进行一步爬取）
        如果提取的url中格式为 /question/xxx 就下载之后直接进入解析函数
        """

        all_urls = response.css("a::attr(href)").extract()
        all_urls = [parse.urljoin(response.url, url) for url in all_urls]
        all_urls = filter(lambda x: True if x.startswith("https") else False, all_urls)
        for url in all_urls:
            match_obj = re.match("(.*zhihu.com/question/(\d+))(/|$).*", url)
            if match_obj:
                # 如果提取到question相关的页面则下载后交由提取函数进行提取
                request_url = match_obj.group(1)
                yield scrapy.Request(request_url, headers=self.headers,  callback=self.parse_question)
            else:
                # 如果不是question页面则直接进一步跟踪
                yield scrapy.Request(url, headers=self.headers,  callback=self.parse)

    def parse_question(self, response):
        # 处理question页面， 从页面中提取出具体的question item
        if "QuestionHeader-title" in response.text:
            # 处理新版本
            match_obj = re.match("(.*zhihu.com/question/(\d+))(/|$).*", response.url)
            if match_obj:
                question_id = int(match_obj.group(2))

            item_loader = ItemLoader(item=ZhihuQuestionItem(), response=response)
            item_loader.add_css("title", "h1.QuestionHeader-title::text")
            item_loader.add_css("content", ".QuestionHeader-detail")
            item_loader.add_value("url", response.url)
            item_loader.add_value("zhihu_id", question_id)
            item_loader.add_css("answer_num", ".List-headerText span::text")
            item_loader.add_css("comments_num", ".QuestionHeader-actions button::text")
            item_loader.add_css("watch_user_num", ".NumberBoard-value::text")
            item_loader.add_css("topics", ".QuestionHeader-topics .Popover div::text")

            question_item = item_loader.load_item()
        else:
            # 处理老版本页面的item提取
            match_obj = re.match("(.*zhihu.com/question/(\d+))(/|$).*", response.url)
            if match_obj:
                question_id = int(match_obj.group(2))

            # item没有函数处理可使用默认ItemLoader
            item_loader = ItemLoader(item=ZhihuQuestionItem(), response=response)
            # item_loader.add_css("title", ".zh-question-title h2 a::text")
            item_loader.add_xpath("title",
                                  "//*[@id='zh-question-title']/h2/a/text()|//*[@id='zh-question-title']/h2/span/text()")
            item_loader.add_css("content", "#zh-question-detail")
            item_loader.add_value("url", response.url)
            item_loader.add_value("zhihu_id", question_id)
            item_loader.add_css("answer_num", "#zh-question-answer-num::text")
            item_loader.add_css("comments_num", "#zh-question-meta-wrap a[name='addcomment']::text")
            # item_loader.add_css("watch_user_num", "#zh-question-side-header-wrap::text")
            item_loader.add_xpath("watch_user_num",
                                  "//*[@id='zh-question-side-header-wrap']/text()|//*[@class='zh-question-followers-sidebar']/div/a/strong/text()")
            item_loader.add_css("topics", ".zm-tag-editor-labels a::text")

            question_item = item_loader.load_item()

        yield scrapy.Request(self.start_answer_url.format(question_id, 20, 0), headers=self.headers,
                             callback=self.parse_answer)
        yield question_item

    def parse_answer(self, reponse):
        # 处理question的answer
        ans_json = json.loads(reponse.text)
        is_end = ans_json["paging"]["is_end"]
        next_url = ans_json["paging"]["next"]

        # 提取answer的具体字段
        for answer in ans_json["data"]:
            answer_item = ZhihuAnswerItem()
            answer_item["zhihu_id"] = answer["id"]
            answer_item["url"] = answer["url"]
            answer_item["question_id"] = answer["question"]["id"]
            answer_item["author_id"] = answer["author"]["id"] if "id" in answer["author"] else None
            answer_item["content"] = answer["content"] if "content" in answer else None
            answer_item["parise_num"] = answer["voteup_count"]
            answer_item["comments_num"] = answer["comment_count"]
            answer_item["create_time"] = answer["created_time"]
            answer_item["update_time"] = answer["updated_time"]
            answer_item["crawl_time"] = datetime.datetime.now()

            yield answer_item

        if not is_end:
            yield scrapy.Request(next_url, headers=self.headers, callback=self.parse_answer)