Python scraper.Scraper類代碼示例

 def configure(self, spider_closed_callback):
     """
     Configure execution engine with the given scheduling policy and downloader.
     """
     self.scheduler = load_object(settings['SCHEDULER'])()
     self.downloader = Downloader()
     self.scraper = Scraper(self)
     self.configured = True
     self._spider_closed_callback = spider_closed_callback

 def configure(self):
     """
     Configure execution engine with the given scheduling policy and downloader.
     """
     self.scheduler = load_object(settings['SCHEDULER'])()
     self.spider_scheduler = load_object(settings['SPIDER_SCHEDULER'])()
     self.downloader = Downloader()
     self.scraper = Scraper(self)
     self.configured = True

 def __init__(self, crawler, spider_closed_callback):
     self.settings = crawler.settings
     self.slots = {}
     self.running = False
     self.paused = False
     self.scheduler_cls = load_object(self.settings['SCHEDULER'])
     self.downloader = Downloader(crawler)
     self.scraper = Scraper(crawler)
     self._concurrent_spiders = self.settings.getint('CONCURRENT_SPIDERS')
     self._spider_closed_callback = spider_closed_callback

 def __init__(self, settings, spider_closed_callback):
     self.settings = settings
     self.slots = {}
     self.running = False
     self.paused = False
     self._next_request_calls = {}
     self.scheduler = load_object(settings['SCHEDULER'])()
     self.downloader = Downloader()
     self.scraper = Scraper(self, self.settings)
     self._spider_closed_callback = spider_closed_callback

 def __init__(self, settings, spider_closed_callback):
     self.settings = settings
     self.closing = {} # dict (spider -> reason) of spiders being closed
     self.closing_dfds = {} # dict (spider -> deferred) of spiders being closed
     self.running = False
     self.paused = False
     self._next_request_calls = {}
     self.scheduler = load_object(settings['SCHEDULER'])()
     self.downloader = Downloader()
     self.scraper = Scraper(self, self.settings)
     self._spider_closed_callback = spider_closed_callback

 def __init__(self, crawler, spider_closed_callback):
     self.crawler = crawler
     self.settings = crawler.settings
     self.signals = crawler.signals
     self.logformatter = crawler.logformatter
     self.slot = None
     self.spider = None
     self.running = False
     self.paused = False
     self.scheduler_cls = load_object(self.settings['SCHEDULER'])
     downloader_cls = load_object(self.settings['DOWNLOADER'])
     self.downloader = downloader_cls(crawler)
     self.scraper = Scraper(crawler)
     self._spider_closed_callback = spider_closed_callback

 def __init__(self, crawler, spider_closed_callback):
     self.settings = crawler.settings
     self.slots = {}
     self.running = False
     self.paused = False
     self.scheduler_cls = load_object(self.settings["SCHEDULER"])
     self.downloader = Downloader(crawler)
     self.scraper = Scraper(crawler)
     self._concurrent_spiders = self.settings.getint("CONCURRENT_SPIDERS", 1)
     if self._concurrent_spiders != 1:
         warnings.warn(
             "CONCURRENT_SPIDERS settings is deprecated, use " "Scrapyd max_proc config instead",
             ScrapyDeprecationWarning,
         )
     self._spider_closed_callback = spider_closed_callback

 def __init__(self, crawler, spider_closed_callback):
     self.crawler = crawler
     self.settings = crawler.settings
     self.signals = crawler.signals
     self.logformatter = crawler.logformatter
     self.slot = None
     self.spider = None
     self.running = False
     self.paused = False
     self.scheduler_cls = load_object(self.settings['SCHEDULER'])
     self.downloader = Downloader(crawler)
     self.scraper = Scraper(crawler)
     self._concurrent_spiders = self.settings.getint('CONCURRENT_SPIDERS', 1)
     if self._concurrent_spiders != 1:
         warnings.warn("CONCURRENT_SPIDERS settings is deprecated, use " \
             "Scrapyd max_proc config instead", ScrapyDeprecationWarning)
     self._spider_closed_callback = spider_closed_callback

    def __init__(self, crawler, spider_closed_callback):
        self.crawler = crawler
        self.settings = crawler.settings
        self.signals = crawler.signals
        self.logformatter = crawler.logformatter
        self.slot = None
        self.spider = None
        self.running = False
        self.paused = False
        self.scheduler_cls = load_object(self.settings['SCHEDULER'])
	#在這裏獲取了scheduler類
	#默認是'scrapy.core.scheduler.Scheduler'

        downloader_cls = load_object(self.settings['DOWNLOADER'])
        #這裏獲取downloader
        #默認是'scrapy.core.downloader.Downloader'
        self.downloader = downloader_cls(crawler)
	#下載器實例化

        self.scraper = Scraper(crawler)
        self._spider_closed_callback = spider_closed_callback

class ExecutionEngine(object):

    def __init__(self, crawler, spider_closed_callback):
        self.settings = crawler.settings
        self.slots = {}
        self.running = False
        self.paused = False
        self.scheduler_cls = load_object(self.settings['SCHEDULER'])
        self.downloader = Downloader(crawler)
        self.scraper = Scraper(crawler)
        self._concurrent_spiders = self.settings.getint('CONCURRENT_SPIDERS')
        self._spider_closed_callback = spider_closed_callback

    @defer.inlineCallbacks
    def start(self):
        """Start the execution engine"""
        assert not self.running, "Engine already running"
        self.start_time = time()
        yield send_catch_log_deferred(signal=signals.engine_started)
        self.running = True

    def stop(self):
        """Stop the execution engine gracefully"""
        assert self.running, "Engine not running"
        self.running = False
        dfd = self._close_all_spiders()
        return dfd.addBoth(lambda _: self._finish_stopping_engine())

    def pause(self):
        """Pause the execution engine"""
        self.paused = True

    def unpause(self):
        """Resume the execution engine"""
        self.paused = False

    def _next_request(self, spider):
        try:
            slot = self.slots[spider]
        except KeyError:
            return

        if self.paused:
            slot.nextcall.schedule(5)
            return

        while not self._needs_backout(spider):
            if not self._next_request_from_scheduler(spider):
                break

        if slot.start_requests and not self._needs_backout(spider):
            try:
                request = slot.start_requests.next()
                self.crawl(request, spider)
            except StopIteration:
                slot.start_requests = None

        if self.spider_is_idle(spider) and slot.close_if_idle:
            self._spider_idle(spider)

    def _needs_backout(self, spider):
        slot = self.slots[spider]
        return not self.running \
            or slot.closing \
            or self.downloader.needs_backout() \
            or self.scraper.slots[spider].needs_backout()

    def _next_request_from_scheduler(self, spider):
        slot = self.slots[spider]
        request = slot.scheduler.next_request()
        if not request:
            return
        d = self._download(request, spider)
        d.addBoth(self._handle_downloader_output, request, spider)
        d.addErrback(log.msg, spider=spider)
        d.addBoth(lambda _: slot.remove_request(request))
        d.addErrback(log.msg, spider=spider)
        d.addBoth(lambda _: slot.nextcall.schedule())
        d.addErrback(log.msg, spider=spider)
        return d

    def _handle_downloader_output(self, response, request, spider):
        assert isinstance(response, (Request, Response, Failure)), response
        # downloader middleware can return requests (for example, redirects)
        if isinstance(response, Request):
            self.crawl(response, spider)
            return
        # response is a Response or Failure
        d = self.scraper.enqueue_scrape(response, request, spider)
        d.addErrback(log.err, spider=spider)
        return d

    def spider_is_idle(self, spider):
        scraper_idle = spider in self.scraper.slots \
            and self.scraper.slots[spider].is_idle()
        pending = self.slots[spider].scheduler.has_pending_requests()
        downloading = bool(self.downloader.slots)
        idle = scraper_idle and not (pending or downloading)
        return idle

#.........這裏部分代碼省略.........

class ExecutionEngine(object):

    def __init__(self, crawler, spider_closed_callback):
        self.crawler = crawler
        self.settings = crawler.settings
        self.signals = crawler.signals
        self.logformatter = crawler.logformatter
        self.slot = None
        self.spider = None
        self.running = False
        self.paused = False
        self.scheduler_cls = load_object(self.settings['SCHEDULER'])
        downloader_cls = load_object(self.settings['DOWNLOADER'])
        self.downloader = downloader_cls(crawler)
        self.scraper = Scraper(crawler)
        self._spider_closed_callback = spider_closed_callback

    @defer.inlineCallbacks
    def start(self):
        """Start the execution engine"""
        assert not self.running, "Engine already running"
        self.start_time = time()
        yield self.signals.send_catch_log_deferred(signal=signals.engine_started)
        self.running = True
        self._closewait = defer.Deferred()
        yield self._closewait

    def stop(self):
        """Stop the execution engine gracefully"""
        assert self.running, "Engine not running"
        self.running = False
        dfd = self._close_all_spiders()
        return dfd.addBoth(lambda _: self._finish_stopping_engine())

    def close(self):
        """Close the execution engine gracefully.

        If it has already been started, stop it. In all cases, close all spiders
        and the downloader.
        """
        if self.running:
            # Will also close spiders and downloader
            return self.stop()
        elif self.open_spiders:
            # Will also close downloader
            return self._close_all_spiders()
        else:
            return defer.succeed(self.downloader.close())

    def pause(self):
        """Pause the execution engine"""
        self.paused = True

    def unpause(self):
        """Resume the execution engine"""
        self.paused = False

    def _next_request(self, spider):
        slot = self.slot
        if not slot:
            return

        if self.paused:
            return

        while not self._needs_backout(spider):
            if not self._next_request_from_scheduler(spider):
                break

        if slot.start_requests and not self._needs_backout(spider):
            try:
                request = next(slot.start_requests)
            except StopIteration:
                slot.start_requests = None
            except Exception:
                slot.start_requests = None
                logger.error('Error while obtaining start requests',
                             exc_info=True, extra={'spider': spider})
            else:
                self.crawl(request, spider)

        if self.spider_is_idle(spider) and slot.close_if_idle:
            self._spider_idle(spider)

    def _needs_backout(self, spider):
        slot = self.slot
        return not self.running \
            or slot.closing \
            or self.downloader.needs_backout() \
            or self.scraper.slot.needs_backout()

    def _next_request_from_scheduler(self, spider):
        slot = self.slot
        request = slot.scheduler.next_request()
        if not request:
            return
        d = self._download(request, spider)
        d.addBoth(self._handle_downloader_output, request, spider)
        d.addErrback(lambda f: logger.info('Error while handling downloader output',
                                           exc_info=failure_to_exc_info(f),
#.........這裏部分代碼省略.........

class ExecutionEngine(object):

    def __init__(self, crawler, spider_closed_callback):
        self.crawler = crawler
        self.settings = crawler.settings
        self.signals = crawler.signals
        self.logformatter = crawler.logformatter
        self.slot = None
        self.spider = None
        self.running = False
        self.paused = False
        self.scheduler_cls = load_object(self.settings['SCHEDULER'])
        self.downloader = Downloader(crawler)
        self.scraper = Scraper(crawler)
        self._concurrent_spiders = self.settings.getint('CONCURRENT_SPIDERS', 1)
        if self._concurrent_spiders != 1:
            warnings.warn("CONCURRENT_SPIDERS settings is deprecated, use " \
                "Scrapyd max_proc config instead", ScrapyDeprecationWarning)
        self._spider_closed_callback = spider_closed_callback

    @defer.inlineCallbacks
    def start(self):
        """Start the execution engine"""
        assert not self.running, "Engine already running"
        self.start_time = time()
        yield self.signals.send_catch_log_deferred(signal=signals.engine_started)
        self.running = True
        self._closewait = defer.Deferred()
        yield self._closewait

    def stop(self):
        """Stop the execution engine gracefully"""
        assert self.running, "Engine not running"
        self.running = False
        dfd = self._close_all_spiders()
        return dfd.addBoth(lambda _: self._finish_stopping_engine())

    def pause(self):
        """Pause the execution engine"""
        self.paused = True

    def unpause(self):
        """Resume the execution engine"""
        self.paused = False

    def _next_request(self, spider):
        slot = self.slot
        if not slot:
            return

        if self.paused:
            slot.nextcall.schedule(5)
            return

        while not self._needs_backout(spider):
            if not self._next_request_from_scheduler(spider):
                break

        if slot.start_requests and not self._needs_backout(spider):
            try:
                request = next(slot.start_requests)
            except StopIteration:
                slot.start_requests = None
            except Exception as exc:
                log.err(None, 'Obtaining request from start requests', \
                        spider=spider)
            else:
                self.crawl(request, spider)

        if self.spider_is_idle(spider) and slot.close_if_idle:
            self._spider_idle(spider)

    def _needs_backout(self, spider):
        slot = self.slot
        return not self.running \
            or slot.closing \
            or self.downloader.needs_backout() \
            or self.scraper.slot.needs_backout()

    def _next_request_from_scheduler(self, spider):
        slot = self.slot
        request = slot.scheduler.next_request()
        if not request:
            return
        d = self._download(request, spider)
        d.addBoth(self._handle_downloader_output, request, spider)
        d.addErrback(log.msg, spider=spider)
        d.addBoth(lambda _: slot.remove_request(request))
        d.addErrback(log.msg, spider=spider)
        d.addBoth(lambda _: slot.nextcall.schedule())
        d.addErrback(log.msg, spider=spider)
        return d

    def _handle_downloader_output(self, response, request, spider):
        assert isinstance(response, (Request, Response, Failure)), response
        # downloader middleware can return requests (for example, redirects)
        if isinstance(response, Request):
            self.crawl(response, spider)
            return
        # response is a Response or Failure
#.........這裏部分代碼省略.........

class ExecutionEngine(object):

    def __init__(self, settings, spider_closed_callback):
        self.settings = settings
        self.closing = {} # dict (spider -> reason) of spiders being closed
        self.closing_dfds = {} # dict (spider -> deferred) of spiders being closed
        self.running = False
        self.paused = False
        self._next_request_calls = {}
        self.scheduler = load_object(settings['SCHEDULER'])()
        self.downloader = Downloader()
        self.scraper = Scraper(self, self.settings)
        self._spider_closed_callback = spider_closed_callback

    @defer.inlineCallbacks
    def start(self):
        """Start the execution engine"""
        assert not self.running, "Engine already running"
        self.start_time = time()
        yield send_catch_log_deferred(signal=signals.engine_started)
        self.running = True

    def stop(self):
        """Stop the execution engine gracefully"""
        assert self.running, "Engine not running"
        self.running = False
        dfd = self._close_all_spiders()
        return dfd.addBoth(lambda _: self._finish_stopping_engine())

    def pause(self):
        """Pause the execution engine"""
        self.paused = True

    def unpause(self):
        """Resume the execution engine"""
        self.paused = False

    def is_idle(self):
        return self.scheduler.is_idle() and self.downloader.is_idle() and \
            self.scraper.is_idle()

    def next_request(self, spider, now=False):
        """Scrape the next request for the spider passed.

        The next request to be scraped is retrieved from the scheduler and
        requested from the downloader.

        The spider is closed if there are no more pages to scrape.
        """
        if now:
            self._next_request_calls.pop(spider, None)
        elif spider not in self._next_request_calls:
            call = reactor.callLater(0, self.next_request, spider, now=True)
            self._next_request_calls[spider] = call
            return call
        else:
            return

        if self.paused:
            return reactor.callLater(5, self.next_request, spider)

        while not self._needs_backout(spider):
            if not self._next_request(spider):
                break

        if self.spider_is_idle(spider):
            self._spider_idle(spider)

    def _needs_backout(self, spider):
        return not self.running \
            or self.spider_is_closed(spider) \
            or self.downloader.sites[spider].needs_backout() \
            or self.scraper.sites[spider].needs_backout()

    def _next_request(self, spider):
        # Next pending request from scheduler
        request, deferred = self.scheduler.next_request(spider)
        if request:
            dwld = mustbe_deferred(self.download, request, spider)
            dwld.chainDeferred(deferred).addBoth(lambda _: deferred)
            dwld.addErrback(log.err, "Unhandled error on engine._next_request()",
                spider=spider)
            return dwld

    def spider_is_idle(self, spider):
        scraper_idle = spider in self.scraper.sites \
            and self.scraper.sites[spider].is_idle()
        pending = self.scheduler.spider_has_pending_requests(spider)
        downloading = spider in self.downloader.sites \
            and self.downloader.sites[spider].active
        return scraper_idle and not (pending or downloading)

    def spider_is_closed(self, spider):
        """Return True if the spider is fully closed (ie. not even in the
        closing stage)"""
        return spider not in self.downloader.sites

    def spider_is_open(self, spider):
        """Return True if the spider is fully opened (ie. not in closing
        stage)"""
#.........這裏部分代碼省略.........

class ExecutionEngine(object):

    def __init__(self):
        self.configured = False
        self.closing = {} # dict (spider -> reason) of spiders being closed
        self.running = False
        self.killed = False
        self.paused = False
        self._next_request_calls = {}
        self._crawled_logline = load_object(settings['LOG_FORMATTER_CRAWLED'])

    def configure(self, spider_closed_callback):
        """
        Configure execution engine with the given scheduling policy and downloader.
        """
        self.scheduler = load_object(settings['SCHEDULER'])()
        self.downloader = Downloader()
        self.scraper = Scraper(self)
        self.configured = True
        self._spider_closed_callback = spider_closed_callback

    def start(self):
        """Start the execution engine"""
        assert not self.running, "Engine already running"
        self.start_time = time()
        send_catch_log(signal=signals.engine_started, sender=self.__class__)
        self.running = True

    def stop(self):
        """Stop the execution engine gracefully"""
        assert self.running, "Engine not running"
        self.running = False
        dfd = self._close_all_spiders()
        return dfd.addBoth(lambda _: self._finish_stopping_engine())

    def kill(self):
        """Forces shutdown without waiting for pending transfers to finish.
        stop() must have been called first
        """
        assert not self.running, "Call engine.stop() before engine.kill()"
        self.killed = True

    def pause(self):
        """Pause the execution engine"""
        self.paused = True

    def unpause(self):
        """Resume the execution engine"""
        self.paused = False

    def is_idle(self):
        return self.scheduler.is_idle() and self.downloader.is_idle() and \
            self.scraper.is_idle()

    def next_request(self, spider, now=False):
        """Scrape the next request for the spider passed.

        The next request to be scraped is retrieved from the scheduler and
        requested from the downloader.

        The spider is closed if there are no more pages to scrape.
        """
        if now:
            self._next_request_calls.pop(spider, None)
        elif spider not in self._next_request_calls:
            call = reactor.callLater(0, self.next_request, spider, now=True)
            self._next_request_calls[spider] = call
            return call
        else:
            return

        if self.paused:
            return reactor.callLater(5, self.next_request, spider)

        while not self._needs_backout(spider):
            if not self._next_request(spider):
                break

        if self.spider_is_idle(spider):
            self._spider_idle(spider)

    def _needs_backout(self, spider):
        return not self.running \
            or self.spider_is_closed(spider) \
            or self.downloader.sites[spider].needs_backout() \
            or self.scraper.sites[spider].needs_backout()

    def _next_request(self, spider):
        # Next pending request from scheduler
        request, deferred = self.scheduler.next_request(spider)
        if request:
            dwld = mustbe_deferred(self.download, request, spider)
            dwld.chainDeferred(deferred).addBoth(lambda _: deferred)
            dwld.addErrback(log.err, "Unhandled error on engine._next_request()",
                spider=spider)
            return dwld

    def spider_is_idle(self, spider):
        scraper_idle = spider in self.scraper.sites \
            and self.scraper.sites[spider].is_idle()
#.........這裏部分代碼省略.........

class ExecutionEngine(object):

    def __init__(self, settings, spider_closed_callback):
        self.settings = settings
        self.slots = {}
        self.running = False
        self.paused = False
        self._next_request_calls = {}
        self.scheduler = load_object(settings['SCHEDULER'])()
        self.downloader = Downloader()
        self.scraper = Scraper(self, self.settings)
        self._spider_closed_callback = spider_closed_callback

    @defer.inlineCallbacks
    def start(self):
        """Start the execution engine"""
        assert not self.running, "Engine already running"
        self.start_time = time()
        yield send_catch_log_deferred(signal=signals.engine_started)
        self.running = True

    def stop(self):
        """Stop the execution engine gracefully"""
        assert self.running, "Engine not running"
        self.running = False
        dfd = self._close_all_spiders()
        return dfd.addBoth(lambda _: self._finish_stopping_engine())

    def pause(self):
        """Pause the execution engine"""
        self.paused = True

    def unpause(self):
        """Resume the execution engine"""
        self.paused = False

    def is_idle(self):
        return self.scheduler.is_idle() and self.downloader.is_idle() and \
            self.scraper.is_idle()

    def next_request(self, spider, now=False):
        """Scrape the next request for the spider passed.

        The next request to be scraped is retrieved from the scheduler and
        requested from the downloader.

        The spider is closed if there are no more pages to scrape.
        """
        if now:
            self._next_request_calls.pop(spider, None)
        elif spider not in self._next_request_calls:
            call = reactor.callLater(0, self.next_request, spider, now=True)
            self._next_request_calls[spider] = call
            return call
        else:
            return

        if self.paused:
            return reactor.callLater(5, self.next_request, spider)

        while not self._needs_backout(spider):
            if not self._next_request(spider):
                break

        if self.spider_is_idle(spider):
            self._spider_idle(spider)

    def _needs_backout(self, spider):
        slot = self.slots[spider]
        return not self.running \
            or slot.closing \
            or self.spider_is_closed(spider) \
            or self.downloader.sites[spider].needs_backout() \
            or self.scraper.sites[spider].needs_backout()

    def _next_request(self, spider):
        request = self.scheduler.next_request(spider)
        if not request:
            return
        d = self._download(request, spider)
        d.addBoth(self._handle_downloader_output, request, spider)
        d.addErrback(log.msg, spider=spider)
        slot = self.slots[spider]
        d.addBoth(lambda _: slot.remove_request(request))
        d.addErrback(log.msg, spider=spider)
        d.addBoth(lambda _: self.next_request(spider))
        return d

    def _handle_downloader_output(self, response, request, spider):
        assert isinstance(response, (Request, Response, Failure)), response
        # downloader middleware can return requests (for example, redirects)
        if isinstance(response, Request):
            self.crawl(response, spider)
            return
        # response is a Response or Failure
        d = defer.Deferred()
        d.addBoth(self.scraper.enqueue_scrape, request, spider)
        d.addErrback(log.err, spider=spider)
        if isinstance(response, Failure):
            d.errback(response)
#.........這裏部分代碼省略.........