Scrapy：如何手动从spider_idle事件回调插入请求？

class FooSpider(baseSpider):    def __init__(self, *args, **kwargs):        super(FooSpider, self).__init__(*args, **kwargs)        dispatcher.connect(self.dont_close_me, signals.spider_idle)    def dont_close_me(self, spider):        if spider != self: return        self.crawler.engine.crawl(self.create_request(), spider)        raise DontCloseSpider("..I prefer live spiders.")

2016年更新：

class FooSpider(baseSpider):    yet = False    @classmethod    def from_crawler(cls, crawler, *args, **kwargs):        from_crawler = super(FooSpider, cls).from_crawler        spider = from_crawler(crawler, *args, **kwargs)        crawler.signals.connect(spider.idle, signal=scrapy.signals.spider_idle)        return spider    def idle(self):        if not self.yet: self.crawler.engine.crawl(self.create_request(), self) self.yet = True