Question

我正在学习抓取技巧，我想做如下：

登录特定网页（已完成）
转到包含我需要的链接的页面
对于该页面中的每个链接，抓取其内容。

问题是我已经为单个链接测试了我的代码，它工作正常，但是当我尝试它用于多级作业时。它以我无法理解的方式失败：它只能抓取每个链接的某些部分。我想知道我的代码中是否存在某些逻辑错误，请帮忙。以下是代码

import scrapy
from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.wait import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
import time

class BaiduSpider(scrapy.Spider):
    name = 'baidu'
    allowed_domains = ['baidu.com']
    start_urls = ['http://tieba.baidu.com']
    main_url = 'http://tieba.baidu.com/f?kw=%E5%B4%94%E6%B0%B8%E5%85%83&ie=utf-8'
    username = ""
    password = ""

def __init__(self, username=username, password=password):
    #options = webdriver.ChromeOptions()
    #options.add_argument('headless')
    #options.add_argument('window-size=1200x600')
    self.driver = webdriver.Chrome()#chrome_options=options)
    self.username = username
    self.password = password
# checked
def logIn(self):
    elem = self.driver.find_element_by_css_selector('#com_userbar > ul > li.u_login > div > a')
    elem.click()
    wait = WebDriverWait(self.driver,10).until(EC.presence_of_element_located((By.CSS_SELECTOR,'#TANGRAM__PSP_10__footerULoginBtn')))
    elem = self.driver.find_element_by_css_selector('#TANGRAM__PSP_10__footerULoginBtn')
    elem.click()
    elem = self.driver.find_element_by_css_selector('#TANGRAM__PSP_10__userName')
    elem.send_keys(self.username)
    elem = self.driver.find_element_by_css_selector('#TANGRAM__PSP_10__password')
    elem.send_keys(self.password)
    self.driver.find_element_by_css_selector('#TANGRAM__PSP_10__submit').click()
# basic checked
def parse(self, response):
    self.driver.get(response.url)
    self.logIn()
    # wait for hand input verify code
    time.sleep(20)
    self.driver.get('http://tieba.baidu.com/f?kw=%E5%B4%94%E6%B0%B8%E5%85%83&ie=utf-8')
    # try first page first
    for url in self.driver.find_elements_by_css_selector('a.j_th_tit'):
        #new_url = response.urljoin(url)
        new_url = url.get_attribute("href")
        yield scrapy.Request(url=new_url, callback=self.parse_sub)

# checked
def pageScroll(self, url):
    self.log('I am scrolling' + url)
    self.driver.get(url)
    SCROLL_PAUSE_TIME = 0.5
    SCROLL_LENGTH = 1200
    page_height = int(self.driver.execute_script("return document.body.scrollHeight"))
    scrollPosition = 0
    while scrollPosition < page_height:
        scrollPosition = scrollPosition + SCROLL_LENGTH
        self.driver.execute_script("window.scrollTo(0, " + str(scrollPosition) + ");")
        time.sleep(SCROLL_PAUSE_TIME)
    time.sleep(1.2)

def parse_sub(self, response):
    self.log('I visited ' + response.url)
    self.pageScroll(response.url)

    for sel in self.driver.find_elements_by_css_selector('div.l_post.j_l_post.l_post_bright'):
        name = sel.find_element_by_css_selector('.d_name').text
        try:
            content = sel.find_element_by_css_selector('.j_d_post_content').text
        except: content = ''
        replys = []
        for i in sel.find_elements_by_xpath('.//div[@class="lzl_cnt"]'):
            user1 = i.find_element_by_xpath('.//a[@username]')
            user1 = self.driver.execute_script("return arguments[0].firstChild.textContent", user1)
            try:
                user2 = i.find_element_by_xpath('.//span[@class="lzl_content_main"]/a[@username]')
                user2 = self.driver.execute_script("return arguments[0].firstChild.textContent", user2)
            except: user2 = name
            span = i.find_element_by_xpath('.//span[@class="lzl_content_main"]')
            reply = self.driver.execute_script('return arguments[0].lastChild.textContent;', span)

            replys.append(tuple(user1, user2, reply))
        yield {"topic": response.css(".core_title_txt::text").extract(), "name":name, "content":content, "replys":replys}

    #follow to next page

    #next_sel = self.driver.find_element_by_css_selector('#thread_theme_7 a:nth-child(3)')
    #next_url_name = next_sel.text

    #if next_sel and next_url_name == '下一页':
    #    next_url = next_sel.get_attribute('href')

    #    yield scrapy.Request(url=next_url, callback=self.parse_sub)

Answer 1

好像你正在使用硬编码的容器而不是通用链接，因此只能在

中找回一个链接

for url in self.driver.find_elements_by_css_selector('a.j_th_tit')

这 - j_th_tit - 似乎是动态生成的类名，并且对于所有锚（a）标记可能不一样。

你可以尝试

 for url in self.driver.find_elements_by_css_selector('a')

获取页面的所有链接。

如何在处理多级网页抓取时使scrapy爬虫正常工作

1 个答案: