[英]how can i use multi-threading for web-crawling in selenium web-driver python
i have scenario where i go to a webpage and open each link in a new window and check for specific documents but its taking enormous time to go through each link so is there a way to increase performance using multi-threading 我有一个场景,我要转到网页并在新窗口中打开每个链接并检查特定文档,但是花大量时间浏览每个链接,所以有没有办法使用多线程来提高性能
known problem 已知问题
selenium is not thread safe 硒不是线程安全的
but i can create multiple instances of driver for each thread which takes care of this problem 但是我可以为每个线程创建驱动程序的多个实例,以解决此问题
current code which i am using 我正在使用的当前代码
for tag in self.driver.find_elements_by_xpath('//body//a[@href]'):
current_window = self.driver.current_window_handle
if href:
self.driver.execute_script('window.open(arguments[0]);', href)
time.sleep(10)
new_window = [window for window in self.driver.window_handles if window != current_window][0]
self.driver.switch_to.window(new_window)
# Execute required operations
func_url=self.driver.current_url
self.driver.close()
self.driver.switch_to.window(current_window)
if not func_url:
continue
if re.search('\.(?:pdf|png|jpg|doc|ppt|zip)',func_url):
cat=fd.findCat(func_url)
fd.findDate(func_url)
time.sleep(10)
If you want to win time, first of all you have to use WebDriverWait: 如果您想赢得时间,首先必须使用WebDriverWait:
This is an EXAMPLE 这是一个例子
def exec_sync(driver, script, waitTime, scriptName):
global contador
print scriptName
driver.execute_script(script)
WebDriverWait(driver, waitTime).until(
EC.presence_of_element_located(
(By.ID, 'uniqueIdentifier' + str(contador))
)
#driver.find_element_by_id(cadena)
)
contador += 1
print 'Success'
Second, WebDriver is not for multithreading as you have said, so you HAVE TO use SEMAPHORE 其次,WebDriver不像您所说的那样用于多线程,因此您必须使用SEMAPHORE
https://docs.python.org/2/library/threading.html#semaphore-objects https://www.tutorialspoint.com/python/python_multithreading.htm https://docs.python.org/2/library/threading.html#semaphore-objects https://www.tutorialspoint.com/python/python_multithreading.htm
It's the only way for multithreading 这是多线程的唯一方法
MT + Wait.until is what you need to save time MT + Wait.until是节省时间所需的
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