Question

大家好！我写过小网页抓取功能。但我是多线程的新手，我无法优化它。我的代码是：

alreadySeenURLs = dict() #the dictionary of already seen crawlers
candidates = set() #the set of URL candidates to crawl

def initializeCandidates(url):

    #gets page with urllib2
    page = getPage(url)

    #parses page with BeautifulSoup
    parsedPage = getParsedPage(page)

    #function which return all links from parsed page as set
    initialURLsFromRoot = getLinksFromParsedPage(parsedPage)

    return initialURLsFromRoot 

def updateCandidates(oldCandidates, newCandidates):
    return oldCandidates.union(newCandidates)

candidates = initializeCandidates(rootURL)

for url in candidates:

    print len(candidates)

    #fingerprint of URL
    fp = hashlib.sha1(url).hexdigest()

    #checking whether url is in alreadySeenURLs
    if fp in alreadySeenURLs:
        continue

    alreadySeenURLs[fp] = url

    #do some processing
    print url

    page = getPage(url)
    parsedPage = getParsedPage(page, fix=True)
    newCandidates = getLinksFromParsedPage(parsedPage)

    candidates = updateCandidates(candidates, newCandidates)

有人可以看到，这里需要一个特定时间候选人的网址。我想以这样的方式使这个脚本多线程，它可以从候选人那里获得至少N个url并完成这项工作。谁能指导我？提供任何链接或建议？

Answer 1

您可以从这两个链接开始：

Python中线程的基本参考 http://docs.python.org/library/threading.html
他们在python中实际实现多线程URL爬虫的教程 http://www.ibm.com/developerworks/aix/library/au-threadingpython/

此外，您已经拥有了python的爬虫：http://scrapy.org/

使用多线程优化python脚本

1 个答案: