Python implements the method of running scrapy in a thread
- 2020-05-05 11:28:38
- OfStack
This article illustrates how the Python implementation runs scrapy in a thread. Share with you for your reference. The details are as follows:
If you want to call scrapy in a written program, you can make scrapy run in a thread with the following code.
"""
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()
I hope this article has been helpful to your Python programming.