Selepy with Selenium，W​​ebdriver无法实例化 [英] Scrapy with selenium, webdriver failing to instantiate

问题描述

我正尝试使用selenium/phantomjs，而且出现了很多错误.例如，使用以下代码段:

I am trying to use selenium/phantomjs with scrapy and I'm riddled with errors. For example, take the following code snippet:

def parse(self, resposne):

    while True:
        try:
            driver = webdriver.PhantomJS()
            # do some stuff
            driver.quit()
            break
        except (WebDriverException, TimeoutException):
            try:
                driver.quit()
            except UnboundLocalError:
                print "Driver failed to instantiate"
            time.sleep(3)
            continue

很多时候，驱动程序似乎都无法实例化(因此driver是未绑定的，因此是例外)，我得到了blurb(以及我输入的打印消息)

A lot of the times the driver it seems it has failed to instantiate (so the driver is unbound, hence the exception), and I get the blurb (along with the print message I put in)

Exception AttributeError: "'Service' object has no attribute 'process'" in <bound method Service.__del__ of <selenium.webdriver.phantomjs.service.Service object at 0x7fbb28dc17d0>> ignored

谷歌搜索，似乎每个人都建议更新我拥有的phantomjs(从源代码构建的1.9.8).有人知道还会导致此问题和适当的诊断吗?

Googling around, it seems everyone suggests updating phantomjs, which I have (1.9.8 built from source). Would anyone know what else could be causing this problem and a suitable diagnosis?

推荐答案

此行为的原因是PhantomJS驱动程序的

The reason for this behavior is how the PhantomJS driver's Service class is implemented.

定义了一个__del__方法，该方法调用self.stop()方法:

There is a __del__ method defined that calls self.stop() method:

def __del__(self):
    # subprocess.Popen doesn't send signal on __del__;
    # we have to try to stop the launched process.
    self.stop()

并且，self.stop()假定服务实例仍在尝试访问其属性时仍然存在:

And, self.stop() is assuming the service instance is still alive trying to access it's attributes:

def stop(self):
    """
    Cleans up the process
    """
    if self._log:
        self._log.close()
        self._log = None
    #If its dead dont worry
    if self.process is None:
        return

    ...

此线程完全描述了相同的确切问题:

The same exact problem is perfectly described in this thread:

• __del__上的Python attributeError

您应该做的是静默忽略退出驱动程序实例时出现的AttributeError:

What you should do is to silently ignore AttributeError occurring while quitting the driver instance:

try:
    driver.quit()
except AttributeError:
    pass

此问题是由修订版引入的.这意味着降级为2.40.0也会有所帮助.

The problem was introduced by this revision. Which means that downgrading to 2.40.0 would also help.

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