python实现爬取千万淘宝商品的方法

import time
import leveldb
from urllib.parse import quote_plus 
import re
import json
import itertools
import sys
import requests
from queue import Queue
from threading import Thread
URL_BASE = 'http://s.m.taobao.com/search?q={}&n=200&m=api4h5&style=list&page={}'
def url_get(url):
 # print('GET ' + url)
 header = dict()
 header['Accept'] = 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8'
 header['Accept-Encoding'] = 'gzip,deflate,sdch'
 header['Accept-Language'] = 'en-US,en;q=0.8'
 header['Connection'] = 'keep-alive'
 header['DNT'] = '1'
 #header['User-Agent'] = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/28.0.1500.71 Safari/537.36'
 header['User-Agent'] = 'Mozilla/12.0 (compatible; MSIE 8.0; Windows NT)'
 return requests.get(url, timeout = 5, headers = header).text
def item_thread(cate_queue, db_cate, db_item):
 while True:
 try:
 cate = cate_queue.get()
 post_exist = True
 try:
 state = db_cate.Get(cate.encode('utf-8'))
 if state != b'OK': post_exist = False
 except:
 post_exist = False
 if post_exist == True:
 print('cate-{}: {} already exists ... Ignore'.format(cate, title))
 continue
 db_cate.Put(cate.encode('utf-8'), b'crawling')
 for item_page in itertools.count(1):
 url = URL_BASE.format(quote_plus(cate), item_page)
 for tr in range(5):
 try:
 items_obj = json.loads(url_get(url))
 break
 except KeyboardInterrupt:
 quit()
 except Exception as e:
 if tr == 4: raise e
 if len(items_obj['listItem']) == 0: break
 for item in items_obj['listItem']:
 item_obj = dict(
 _id = int(item['itemNumId']),
 name = item['name'],
 price = float(item['price']),
 query = cate,
 category = int(item['category']) if item['category'] != '' else 0,
 nick = item['nick'],
 area = item['area'])
 db_item.Put(str(item_obj['_id']).encode('utf-8'),
 json.dumps(item_obj, ensure_ascii = False).encode('utf-8'))
 print('Get {} items from {}: {}'.format(len(items_obj['listItem']), cate, item_page))
 if 'nav' in items_obj:
 for na in items_obj['nav']['navCatList']:
 try:
 db_cate.Get(na['name'].encode('utf-8'))
 except:
 db_cate.Put(na['name'].encode('utf-8'), b'waiting')
 db_cate.Put(cate.encode('utf-8'), b'OK')
 print(cate, 'OK')
 except KeyboardInterrupt:
 break
 except Exception as e:
 print('An {} exception occured'.format(e))
def cate_thread(cate_queue, db_cate):
 while True:
 try:
 for key, value in db_cate.RangeIter():
 if value != b'OK':
 print('CateThread: put {} into queue'.format(key.decode('utf-8')))
 cate_queue.put(key.decode('utf-8'))
 time.sleep(10)
 except KeyboardInterrupt:
 break
 except Exception as e:
 print('CateThread: {}'.format(e))
if __name__ == '__main__':
 db_cate = leveldb.LevelDB('./taobao-cate')
 db_item = leveldb.LevelDB('./taobao-item')
 orig_cate = '正装'
 try:
 db_cate.Get(orig_cate.encode('utf-8'))
 except:
 db_cate.Put(orig_cate.encode('utf-8'), b'waiting')
 cate_queue = Queue(maxsize = 1000)
 cate_th = Thread(target = cate_thread, args = (cate_queue, db_cate))
 cate_th.start()
 item_th = [Thread(target = item_thread, args = (cate_queue, db_cate, db_item)) for _ in range(5)]
 for item_t in item_th:
 item_t.start()
 cate_th.join()