Python 全局变量重置在Google应用程序引擎中不起作用

我正在从GAE中的处理程序调用一个web爬行函数，它检索一些图像，然后显示它们。它在第一次调用时工作正常，但下一次它显示所有相同的图像时，爬虫程序将从上次调用的位置启动。我认为这是我的全局变量没有正确重置的问题

每次我重新部署应用程序时，它都会在第一次正确运行，但问题开始了

这是我的代码，请让我知道，如果你需要我澄清它，但我认为它应该是有意义的

这里是刮刀功能

visited_pages = []
visit_queue = deque([])
collected_pages = []
collected_pics = []
count = 0
pic_count = 0

def scrape_pages(url, root_url, keywords=[], recurse=True):
    #variables
    max_count = 16
    pic_num = 100

    global count
    global pic_count
    global collected_pics
    global collected_pages

    print 'the keywords and url are'
    print keywords
    print url

    #this is all of the links that have been scraped
    the_links = []

    soup = soupify_url(url)

    #only add new pages onto the queue if the recursion argument is true    
    if recurse:
        #find all the links on the page
        try:
            for tag in soup.findAll('a'):
                the_links.append(tag.get('href'))
        except AttributeError:
            return

        try:
            external_links, internal_links, root_links, primary_links = categorize_links(the_links, url, root_url)
        except TypeError:
            return


        #change it so this depends on the input
        links_to_visit = external_links + internal_links + root_links

        #build the queue
        for link in links_to_visit:
            if link not in visited_pages and link not in visit_queue:
                visit_queue.append(link)

    visited_pages.append(url)
    count = count + 1
#    print 'number of pages visited'
#    print count

    #add pages to collected_pages depending on the criteria given if any keywords are given
    if keywords:
        page_to_add = find_pages(url, soup, keywords)

#        print 'page to add'
#        print page_to_add
        if page_to_add and page_to_add not in collected_pages:
            collected_pages.append(page_to_add)


    pics_to_add = add_pics(url, soup)
#    print 'pics to add'
#    print pics_to_add
    if pics_to_add:
        collected_pics.extend(pics_to_add)

    #here is where the actual recursion happens by finishing the queue
    while visit_queue:
        if count >= max_count:
            return

        if pic_count > pic_num:
            return

        link = visit_queue.popleft()
#        print link
        scrape_pages(link, root_url, keywords)

#    print '***done***'
    ###done with the recursive scraping function here

#here I just get a list of links from Bing, add them to the queue and go through them then reset all the global variables
def scrape_bing_src(keywords):
    visit_queue, the_url = scrape_bing.get_links(keywords, a_list = False)
    scrape_pages(visit_queue.popleft(), the_url, keywords, recurse=True)

    global collected_pics
    global pic_count
    global count
    global visited_pages
    global visit_queue

    pic_count = 0
    count = 0
    visited_pages = []
    visit_queue = deque([])

    pics_to_return = collected_pics
    collected_pics = []
    return pics_to_return

#this just simply displays the images
class Try(BlogHandler):
    def get(self, keyword):
        keyword = str(keyword)
        keyword_list = keyword.split()
        img_list = scraper.scrape_bing_src(keyword_list)

        for img in img_list:
            self.response.write("""<br><img src='""" + img + """'>""")

        self.response.write('we are done here')

下面是调用scraper函数的处理程序

visited_pages = []
visit_queue = deque([])
collected_pages = []
collected_pics = []
count = 0
pic_count = 0

def scrape_pages(url, root_url, keywords=[], recurse=True):
    #variables
    max_count = 16
    pic_num = 100

    global count
    global pic_count
    global collected_pics
    global collected_pages

    print 'the keywords and url are'
    print keywords
    print url

    #this is all of the links that have been scraped
    the_links = []

    soup = soupify_url(url)

    #only add new pages onto the queue if the recursion argument is true    
    if recurse:
        #find all the links on the page
        try:
            for tag in soup.findAll('a'):
                the_links.append(tag.get('href'))
        except AttributeError:
            return

        try:
            external_links, internal_links, root_links, primary_links = categorize_links(the_links, url, root_url)
        except TypeError:
            return


        #change it so this depends on the input
        links_to_visit = external_links + internal_links + root_links

        #build the queue
        for link in links_to_visit:
            if link not in visited_pages and link not in visit_queue:
                visit_queue.append(link)

    visited_pages.append(url)
    count = count + 1
#    print 'number of pages visited'
#    print count

    #add pages to collected_pages depending on the criteria given if any keywords are given
    if keywords:
        page_to_add = find_pages(url, soup, keywords)

#        print 'page to add'
#        print page_to_add
        if page_to_add and page_to_add not in collected_pages:
            collected_pages.append(page_to_add)


    pics_to_add = add_pics(url, soup)
#    print 'pics to add'
#    print pics_to_add
    if pics_to_add:
        collected_pics.extend(pics_to_add)

    #here is where the actual recursion happens by finishing the queue
    while visit_queue:
        if count >= max_count:
            return

        if pic_count > pic_num:
            return

        link = visit_queue.popleft()
#        print link
        scrape_pages(link, root_url, keywords)

#    print '***done***'
    ###done with the recursive scraping function here

#here I just get a list of links from Bing, add them to the queue and go through them then reset all the global variables
def scrape_bing_src(keywords):
    visit_queue, the_url = scrape_bing.get_links(keywords, a_list = False)
    scrape_pages(visit_queue.popleft(), the_url, keywords, recurse=True)

    global collected_pics
    global pic_count
    global count
    global visited_pages
    global visit_queue

    pic_count = 0
    count = 0
    visited_pages = []
    visit_queue = deque([])

    pics_to_return = collected_pics
    collected_pics = []
    return pics_to_return

#this just simply displays the images
class Try(BlogHandler):
    def get(self, keyword):
        keyword = str(keyword)
        keyword_list = keyword.split()
        img_list = scraper.scrape_bing_src(keyword_list)

        for img in img_list:
            self.response.write("""<br><img src='""" + img + """'>""")

        self.response.write('we are done here')

#这只是简单地显示图像
类Try（BlogHandler）：
def get（自我，关键字）：
关键字=str（关键字）
关键字列表=关键字.split（）
img\u list=scraper.scrape\u bing\u src（关键字列表）
对于img_列表中的img：
self.response.write（“
”）
self.response.write（'我们到此结束'）

您的代码并不是只在一个“服务器”和一个实例中运行，您可能已经注意到管理控制台中的“实例”选项卡。所以，即使在两次调用之间，您也有可能切换到不同的服务器，或者进程将“重新启动”（您可以读取更多）。在预热过程中，应用程序将从磁盘读取到内存中，然后开始处理请求。因此，每次您使用自己的全局变量值获取新的预缓存python实例时

---

在您的情况下，最好使用。

可能重复伟大的资源，但似乎有相当多的信息，其中一些相互冲突。您认为最好将这些变量设置为None，还是将调用它的函数设置在原始类之外并让它返回它？没有两种方法：在函数定义中使用

keywords=None

。不，我不希望全局变量停留在实例之间。我想我只需要改变它，不再使用全局变量。全局变量不会“停留”在实例之间。然而，一旦你的应用程序被加载到一个实例上，程序就会一直运行直到关闭——这意味着在你的处理程序处理完一个请求后，全局变量是活动的。听起来你肯定不想要这里的全局数据。