python scrapy框架基如何实现多线程_Python实现在线程里运行scrapy的方法

本文实例讲述了Python实现在线程里运行scrapy的方法。分享给大家供大家参考。具体如下：

如果你希望在一个写好的程序里调用scrapy，就可以通过下面的代码，让scrapy运行在一个线程里。

"""

Code to run Scrapy crawler in a thread - works on Scrapy 0.8

"""

import threading, Queue

from twisted.internet import reactor

from scrapy.xlib.pydispatch import dispatcher

from scrapy.core.manager import scrapymanager

from scrapy.core.engine import scrapyengine

from scrapy.core import signals

class CrawlerThread(threading.Thread):

def __init__(self):

threading.Thread.__init__(self)

self.running = False

def run(self):

self.running = True

scrapymanager.configure(control_reactor=False)

scrapymanager.start()

reactor.run(installSignalHandlers=False)

def crawl(self, *args):

if not self.running:

raise RuntimeError("CrawlerThread not running")

self._call_and_block_until_signal(signals.spider_closed,

scrapymanager.crawl, *args)

def stop(self):

reactor.callFromThread(scrapyengine.stop)

def _call_and_block_until_signal(self, signal, f, *a, **kw):

q = Queue.Queue()

def unblock():

q.put(None)

dispatcher.connect(unblock, signal=signal)

reactor.callFromThread(f, *a, **kw)

q.get()

# Usage example below:

import os

os.environ.setdefault('SCRAPY_SETTINGS_MODULE', 'myproject.settings')

from scrapy.xlib.pydispatch import dispatcher

from scrapy.core import signals

from scrapy.conf import settings

from scrapy.crawler import CrawlerThread

settings.overrides['LOG_ENABLED'] = False # avoid log noise

def item_passed(item):

print "Just scraped item:", item

dispatcher.connect(item_passed, signal=signals.item_passed)

crawler = CrawlerThread()

print "Starting crawler thread..."

crawler.start()

print "Crawling somedomain.com...."

crawler.crawl('somedomain.com) # blocking call

print "Crawling anotherdomain.com..."

crawler.crawl('anotherdomain.com') # blocking call

print "Stopping crawler thread..."

crawler.stop()

希望本文所述对大家的Python程序设计有所帮助。

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