- 爬取Google真實的搜索表單
- 爬取依賴JavaScript的網站Facebook
- 爬取典型在線商店Gap
- 爬取擁有地圖接口的寶馬官網
#1.爬Google搜索引擎
# -*- coding: utf-8 -*-
import sys
import urllib
import urlparse
import lxml.html
from downloader import Downloader
def search(keyword):
D = Downloader()
url = 'https://www.google.com/search?q=' + urllib.quote_plus(keyword)
html = D(url)
tree = lxml.html.fromstring(html)
links = []
for result in tree.cssselect('h3.r a'):
link = result.get('href')
qs = urlparse.urlparse(link).query
links.extend(urlparse.parse_qs(qs).get('q', []))
return links
if __name__ == '__main__':
try:
keyword = sys.argv[1]
except IndexError:
keyword = 'test'
print search(keyword)
注意:提取Google搜索結果時注意爬取延時問題,否則下載速度過快會出現驗證碼處理。
#2.爬Facebook和Linkein
查看Packt出版本的Facebook頁面源代碼時,可以找到最開始的幾篇日誌,但後面的日誌只有瀏覽器滾動時纔會通過AJAX加載。
2.1自動化登錄Facebook
這些AJAX的數據無法簡化提取,雖然這些AJAX事件可以被臥逆向工程,但是不同類型的Facebook頁面使用了不用的AJAX調用。所以下面用Selenium渲染實現自動化登錄Facebook。
# -*- coding: utf-8 -*-
import sys
from selenium import webdriver
def facebook(username, password, url):
driver = webdriver.Firefox()
driver.get('https://www.facebook.com')
driver.find_element_by_id('email').send_keys(username)
driver.find_element_by_id('pass').send_keys(password)
driver.find_element_by_id('login_form').submit()
driver.implicitly_wait(30)
# wait until the search box is available,
# which means have succrssfully logged in
search = driver.find_element_by_id('q')
# now are logged in so can navigate to the page of interest
driver.get(url)
# add code to scrape data of interest here
#driver.close()
if __name__ == '__main__':
try:
username = sys.argv[1]
password = sys.argv[2]
url = sys.argv[3]
except IndexError:
print 'Usage: %s <username> <password> <url>' % sys.argv[0]
else:
facebook(username, password, url)
##2.2提取Facebook的API數據
Facebook提供了一些API數據,如果允許訪問這些數據,下面就提取Packt出版社頁面的數據。
# -*- coding: utf-8 -*-
import sys
import json
import pprint
from downloader import Downloader
def graph(page_id):
D = Downloader()
html = D('http://graph.facebook.com/' + page_id)
return json.loads(html)
if __name__ == '__main__':
try:
page_id = sys.argv[1]
except IndexError:
page_id = 'PacktPub'
pprint.pprint(graph(page_id))
Facebook開發者文檔:https://developers.facebook.com/docs/graph-api 這些API調用多數是設計給已授權的facebook用戶交互的facebook應用的,要想提取比如用戶日誌等更加詳細的信息,仍然需要爬蟲。
2.3自動化登錄Linkedin
# -*- coding: utf-8 -*-
import sys
from selenium import webdriver
def search(username, password, keyword):
driver = webdriver.Firefox()
driver.get('https://www.linkedin.com/')
driver.find_element_by_id('session_key-login').send_keys(username)
driver.find_element_by_id('session_password-login').send_keys(password)
driver.find_element_by_id('signin').click()
driver.implicitly_wait(30)
driver.find_element_by_id('main-search-box').send_keys(keyword)
driver.find_element_by_class_name('search-button').click()
driver.find_element_by_css_selector('ol#results li a').click()
# Add code to scrape data of interest from LinkedIn page here
#driver.close()
if __name__ == '__main__':
try:
username = sys.argv[1]
password = sys.argv[2]
keyword = sys.argv[3]
except IndexError:
print 'Usage: %s <username> <password> <keyword>' % sys.argv[0]
else:
search(username, password, keyword)
#3.爬在線商店Gap
Gap擁有一個結構化良好的網站,通過Sitemap可以幫助網絡爬蟲定位到最新的內容。從http://www.gap.com/robots.txt 中可以發現網站地圖Sitemap: http://www.gap.com/products/sitemap_index.html
This XML file does not appear to have any style information associated with it. The document tree is shown below.
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
<sitemap>
<loc>http://www.gap.com/products/sitemap_1.xml</loc>
<lastmod>2017-01-30</lastmod>
</sitemap>
<sitemap>
<loc>http://www.gap.com/products/sitemap_2.xml</loc>
<lastmod>2017-01-30</lastmod>
</sitemap>
</sitemapindex>
如上網站地圖冊鏈接的內容僅僅是索引,其索引的網站地圖纔是數千種產品類目的鏈接,比如:http://www.gap.com/products/blue-long-sleeve-shirts-for-men.jsp 。由於這裏有大量要爬取的內容,因此我們將使用第4篇開發的多線和爬蟲,並支持一人可選的回調參數。
# -*- coding: utf-8 -*-
from lxml import etree
from threaded_crawler import threaded_crawler
def scrape_callback(url, html):
if url.endswith('.xml'):
# Parse the sitemap XML file
tree = etree.fromstring(html)
links = [e[0].text for e in tree]
return links
else:
# Add scraping code here
pass
def main():
sitemap = 'http://www.gap.com/products/sitemap_index.xml'
threaded_crawler(sitemap, scrape_callback=scrape_callback)
if __name__ == '__main__':
main()
該回調函數首先下載到的URL擴展名。如果擴展名是.xml,則用lxml的etree模塊解析XML文件並從中提取鏈接。否則,認爲這是一個類目URL(這例沒有實現提取類目的功能)。
#4.爬寶馬官網
寶馬官方網站中有一個查詢本地經銷商的搜索工具,其網址爲https://www.bmw.de/de/home.html?entryType=dlo
該工具將地理位置作爲輸入參數,然後在地圖上顯示附近的經銷商地點,比如輸入Berlin
按Look For
。
我們使用開發者工具會發現搜索觸發了AJAX請求:
https://c2b-services.bmw.com/c2b-localsearch/services/api/v3/clients/BMWDIGITAL_DLO/DE/pois?country=DE&category=BM&maxResults=99&language=en&lat=52.507537768880056&lng=13.425269635701511
maxResults
默認設爲99,我們可以增大該值。AJAX請求提供了JSONP格式的數據,其中JSONP是指填充模式的JSON(JSON with padding)。這裏的填充通常是指要調用的函數,而函數的參數則爲純JSON數據。本例調用的是callback
函數,要想使用Pythonr的json模塊解析該數據,首先需要將填充的部分截取掉。
# -*- coding: utf-8 -*-
import json
import csv
from downloader import Downloader
def main():
D = Downloader()
url = 'https://c2b-services.bmw.com/c2b-localsearch/services/api/v3/clients/BMWDIGITAL_DLO/DE/pois?country=DE&category=BM&maxResults=%d&language=en&lat=52.507537768880056&lng=13.425269635701511'
jsonp = D(url % 1000) ###callback({"status:{...}"})
pure_json = jsonp[jsonp.index('(') + 1 : jsonp.rindex(')')]
dealers = json.loads(pure_json) ###
with open('bmw.csv', 'w') as fp:
writer = csv.writer(fp)
writer.writerow(['Name', 'Latitude', 'Longitude'])
for dealer in dealers['data']['pois']:
name = dealer['name'].encode('utf-8')
lat, lng = dealer['lat'], dealer['lng']
writer.writerow([name, lat, lng])
if __name__ == '__main__':
main()
>>> dealers.keys() #[u'status',u'count',u'data',...]
>>> dealers['count'] #顯示個數
>>> dealers['data']['pois'][0] #第一個經銷商數據
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【Python爬蟲系列】《【Python爬蟲9】Python網絡爬蟲實例實戰》http://blog.csdn.net/u014134180/article/details/55508272
Python爬蟲系列的GitHub代碼文件:https://github.com/1040003585/WebScrapingWithPython