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這篇文章給大家介紹怎么在scrapy中利用phantomJS實現異步爬取，內容非常詳細，感興趣的小伙伴們可以參考借鑒，希望對大家能有所幫助。
使用時需要PhantomJSDownloadHandler添加到配置文件的DOWNLOADER中。
# encoding: utf-8
from __future__ import unicode_literals
from scrapy import signals
from scrapy.signalmanager import SignalManager
from scrapy.responsetypes import responsetypes
from scrapy.xlib.pydispatch import dispatcher
from selenium import webdriver
from six.moves import queue
from twisted.internet import defer, threads
from twisted.python.failure import Failure
class PhantomJSDownloadHandler(object):
def __init__(self, settings):
self.options = settings.get('PHANTOMJS_OPTIONS', {})
max_run = settings.get('PHANTOMJS_MAXRUN', 10)
self.sem = defer.DeferredSemaphore(max_run)
self.queue = queue.LifoQueue(max_run)
SignalManager(dispatcher.Any).connect(self._close, signal=signals.spider_closed)
def download_request(self, request, spider):
"""use semaphore to guard a phantomjs pool"""
return self.sem.run(self._wait_request, request, spider)
def _wait_request(self, request, spider):
try:
driver = self.queue.get_nowait()
except queue.Empty:
driver = webdriver.PhantomJS(**self.options)
driver.get(request.url)
# ghostdriver won't response when switch window until page is loaded
dfd = threads.deferToThread(lambda: driver.switch_to.window(driver.current_window_handle))
dfd.addCallback(self._response, driver, spider)
return dfd
def _response(self, _, driver, spider):
body = driver.execute_script("return document.documentElement.innerHTML")
if body.startswith("<head></head>"): # cannot access response header in Selenium
body = driver.execute_script("return document.documentElement.textContent")
url = driver.current_url
respcls = responsetypes.from_args(url=url, body=body[:100].encode('utf8'))
resp = respcls(url=url, body=body, encoding="utf-8")
response_failed = getattr(spider, "response_failed", None)
if response_failed and callable(response_failed) and response_failed(resp, driver):
driver.close()
return defer.fail(Failure())
else:
self.queue.put(driver)
return defer.succeed(resp)
def _close(self):
while not self.queue.empty():
driver = self.queue.get_nowait()
driver.close()關于怎么在scrapy中利用phantomJS實現異步爬取就分享到這里了，希望以上內容可以對大家有一定的幫助，可以學到更多知識。如果覺得文章不錯，可以把它分享出去讓更多的人看到。
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