Codes

Web Crawler for Images

Python Codes:

# coding:utf-8
import os
import re
import urllib
import json
import socket
import urllib.request
import urllib.parse
import urllib.error
import time

timeout = 5
socket.setdefaulttimeout(timeout)

class Crawler:
    __time_sleep = 0.1      # sleeping time
    __amount = 0
    __start_amount = 0
    __counter = 0
    headers = {'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20100101 Firefox/23.0'}       
    # get the url imformation of pirctures
    def __init__(self, t=0.1):
        self.time_sleep = t     # download intervals
    # get suffix name of the pictures
    def get_suffix(self, name):     
        m = re.search(r'\.[^\.]*$', name)
        if m.group(0) and len(m.group(0)) <= 5:
            return m.group(0)
        else:
            return '.jpg'
    # get and generate referrer
    def get_referrer(self, url):        
        par = urllib.parse.urlparse(url)
        if par.scheme:
            return par.scheme + '://' + par.netloc
        else:
            return par.netloc
    def save_image(self, rsp_data, word):        # save images
        if not os.path.exists("./" + word):
            os.mkdir("./" + word)
        self.__counter = len(os.listdir('./' + word)) + 1
        for image_info in rsp_data['imgs']:
            try:
                time.sleep(self.time_sleep)
                suffix = self.get_suffix(image_info['objURL'])            
                refer = self.get_referrer(image_info['objURL'])  # reduce 403 error
                opener = urllib.request.build_opener()
                opener.addheaders = [('User-agent', 'Mozilla/5.0 (Windows NT 10.0; WOW64; rv:55.0) Gecko/20100101 Firefox/55.0'),('Referer', refer)]
                urllib.request.install_opener(opener)
                urllib.request.urlretrieve(image_info['objURL'], './' + word + '/' + str(self.__counter) + str(suffix))
            except urllib.error.HTTPError as urllib_err:
                print(urllib_err)
                continue
            except Exception as err:
                time.sleep(1)
                print(err)
                print("unknown error, cancel operations")
                continue
            else:
                print("figure+1, there is already" + str(self.__counter) + "figures")
                self.__counter += 1
        return
    def get_images(self, word='beautiful girls'):
        search = urllib.parse.quote(word)
        pn = self.__start_amount    
        while pn < self.__amount:
            url = 'http://image.baidu.com/search/avatarjson?tn=resultjsonavatarnew&ie=utf-8&word=' + search + '&cg=girl&pn=' + str(
                pn) + '&rn=60&itg=0&z=0&fr=&width=&height=&lm=-1&ic=0&s=0&st=-1&gsm=1e0000001e'
            try:
                time.sleep(self.time_sleep)
                req = urllib.request.Request(url=url, headers=self.headers)
                page = urllib.request.urlopen(req)
                rsp = page.read().decode('unicode_escape')
                page.close()
            except UnicodeDecodeError as e:
                print(e)
                print('-----UnicodeDecodeErrorurl:', url)
            except urllib.error.URLError as e:
                print(e)
                print("-----urlErrorurl:", url)
            except socket.timeout as e:
                print(e)
                print("-----socket timout:", url)
            else:                
                rsp_data = json.loads(rsp)  
                self.save_image(rsp_data, word)
                print("download the next page")
                pn += 60
            finally:
                page.close()
        print("Finished")
        return
    def start(self, word, spider_page_num=1, start_page=1):
        """
        web crawl entrance
        :param word: key words
        :param spider_page_num: the pages for catching pictures; the total picture number is page_num x 60
        :param start_page: start page
        :return:
        """
        self.__start_amount = (start_page - 1) * 60
        self.__amount = spider_page_num * 60 + self.__start_amount
        self.get_images(word)

if __name__ == '__main__':
    crawler = Crawler(0.05)  # delay time: 0.05
    # crawler.start('beautiful girls', 10, 2)  # key word: "beautiful girls", 10 pages (totally 10x60=600 pictures), the start papge is page 2
    # crawler.start("actors", 5, 3)  # key word: "actors", 5 pages (totally 5x60=300 pictures), the start papge is page 1

Kathleen Li

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