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996635
V2EX  ›  Python

尝试用 Flask 调用 scrapy 的 commandline 来执行爬虫,报 signal only works in main thread

  •  
  •   996635 · 2016-12-28 13:32:33 +08:00 · 7695 次点击
    这是一个创建于 2102 天前的主题,其中的信息可能已经有所发展或是发生改变。

    报错我能理解,但是这种情况怎么解决呢? 本人才开始玩 python,各种没头绪啊 traceback 如下:

        Traceback (most recent call last):
          File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1994, in __call__
            return self.wsgi_app(environ, start_response)
          File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1985, in wsgi_app
            response = self.handle_exception(e)
          File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1540, in handle_exception
            reraise(exc_type, exc_value, tb)
          File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1982, in wsgi_app
            response = self.full_dispatch_request()
          File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1614, in full_dispatch_request
            rv = self.handle_user_exception(e)
          File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1517, in handle_user_exception
            reraise(exc_type, exc_value, tb)
          File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1612, in full_dispatch_request
            rv = self.dispatch_request()
          File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1598, in dispatch_request
            return self.view_functions[rule.endpoint](**req.view_args)
          File "/Users/chenchen/code/flask_scrapy/webapp/run.py", line 91, in run
            crawler = CrawlerProcess(settings)
          File "/usr/local/lib/python2.7/site-packages/scrapy/crawler.py", line 239, in __init__
            install_shutdown_handlers(self._signal_shutdown)
          File "/usr/local/lib/python2.7/site-packages/scrapy/utils/ossignal.py", line 21, in install_shutdown_handlers
            reactor._handleSignals()
          File "/usr/local/lib/python2.7/site-packages/twisted/internet/posixbase.py", line 295, in _handleSignals
            _SignalReactorMixin._handleSignals(self)
          File "/usr/local/lib/python2.7/site-packages/twisted/internet/base.py", line 1154, in _handleSignals
            signal.signal(signal.SIGINT, self.sigInt)
        ValueError: signal only works in main thread
    

    附上核心代码

    @app.route('/run')
    def run():
        project = dict()
        project['name'] = 'test'
        project['mod'] = 'debug'
        project['script'] = """
    # -*- coding: utf-8 -*-
    
    import scrapy
    
    
    class TiebaCategorySpider(scrapy.Spider):
        name = "tieba_category"
    
        start_url = 'http://tieba.baidu.com/f/index/forumclass'
    
        def start_requests(self):
            yield scrapy.Request(self.start_url)
    
        def parse(self, response):
            try:
                links = response.xpath('//ul[@class="item-list-ul clearfix"]/li/a')
                for i in links:
                    a = i.xpath('@href').extract_first()
                    name = i.xpath('text()').extract_first()
                    yield scrapy.Request(self.repair_url(a), callback=self.parse_category, meta={'sub_category': name})
            except Exception as e:
                print e
                return
    
        def parse_category(self, response):
            a_list = response.xpath('//a[@class="ba_href clearfix"]')
            category = response.xpath('//div[@class="ba_class_title"]/text()').extract_first()
            for i in a_list:
                item = CategoryItem()
    
                item['img'] = i.xpath('img[@class="ba_pic"]/@src').extract_first()
                item['name'] = i.xpath('div[@class="ba_content"]/p[@class="ba_name"]/text()').extract_first()
                item['member_count'] = i.xpath('div[@class="ba_content"]//span[@class="ba_m_num"]/text()').extract_first()
                item['post_count'] = i.xpath('div[@class="ba_content"]//span[@class="ba_p_num"]/text()').extract_first()
                item['sub_category'] = response.meta.get('sub_category')
                item['desc'] = i.xpath('div[@class="ba_content"]//p[@class="ba_desc"]/text()').extract_first()
                item['category'] = category
    
                yield item
    
            next_url = response.xpath('//div[@class="pagination"]/a[@class="next"]/@href').extract_first()
            if next_url:
                yield scrapy.Request(self.repair_url(next_url), callback=self.parse_category,
                                     meta={'sub_category': response.meta.get('sub_category')})
    
        @staticmethod
        def repair_url(url):
            if url.startswith('http'):
                pass
            else:
                url = ''. join(['http://tieba.baidu.com', url])
            return url
    
        """
        loader = ProjectLoader(project)
        module = loader.load_module('test_spider')
        a = module.__dict__
        for each in list(six.itervalues(module.__dict__)):
            if inspect.isclass(each) and issubclass(each, scrapy.Spider):
                module.__dict__['__handler_cls__'] = each
        _class = module.__dict__.get('__handler_cls__')
        assert _class is not None, "need BaseHandler in project module"
    
        spider = _class()
    
        settings = get_project_settings()
        crawler = CrawlerProcess(settings)
        crawler.crawl(spider)
        # crawler.start()
        return repr(module.__dict__)
    
    2 条回复    2016-12-28 14:34:15 +08:00
    wwqgtxx
        1
    wwqgtxx  
       2016-12-28 13:55:25 +08:00
    意思就是你这一样必须在主线程执行
    crawler = CrawlerProcess(settings)
    onlyice
        2
    onlyice  
       2016-12-28 14:34:15 +08:00
    Scrapy 依赖 twisted ,应该是 twisted 的异步网络模型的要求
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