Script Suddenly Stops Crawling Without Error or Ex

2019-06-15 14:32发布

站内文章 / Python
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问题:

I'm not sure why, but my script always stops crawling once it hits page 9. There are no errors, exceptions, or warnings, so I'm kind of at a loss.

Can somebody help me out?

P.S. Here is the full script in case anybody wants to test it for themselves!

def initiate_crawl():
    def refresh_page(url):
        ff = create_webdriver_instance()
        ff.get(url)
        ff.find_element(By.XPATH, '//*[@id="FilterItemView_sortOrder_dropdown"]/div/span[2]/span/span/span/span').click()
        ff.find_element(By.XPATH, '//a[contains(text(), "Discount - High to Low")]').click()
        items = WebDriverWait(ff, 15).until(
            EC.visibility_of_all_elements_located((By.XPATH, '//div[contains(@id, "100_dealView_")]'))
        )
        print(len(items))
        for count, item in enumerate(items):
            slashed_price = item.find_elements(By.XPATH, './/span[contains(@class, "a-text-strike")]')
            active_deals = item.find_elements(By.XPATH, './/*[contains(text(), "Add to Cart")]')
            if len(slashed_price) > 0 and len(active_deals) > 0:
                product_title = item.find_element(By.ID, 'dealTitle').text
                if product_title not in already_scraped_product_titles:
                    already_scraped_product_titles.append(product_title)
                    url = ff.current_url
                    ff.quit()
                    refresh_page(url)
                    break
            if count+1 is len(items):
                try:
                    next_button = WebDriverWait(ff, 15).until(
                        EC.text_to_be_present_in_element((By.PARTIAL_LINK_TEXT, 'Next→'), 'Next→')
                    )
                    ff.find_element(By.PARTIAL_LINK_TEXT, 'Next→').click()
                    url = ff.current_url
                    ff.quit()
                    refresh_page(url)
                except Exception as error:
                    print(error)
                    ff.quit()

    refresh_page('https://www.amazon.ca/gp/goldbox/ref=gbps_ftr_s-3_4bc8_dct_10-?gb_f_c2xvdC0z=sortOrder:BY_SCORE,discountRanges:10-25%252C25-50%252C50-70%252C70-&pf_rd_p=f5836aee-0969-4c39-9720-4f0cacf64bc8&pf_rd_s=slot-3&pf_rd_t=701&pf_rd_i=gb_main&pf_rd_m=A3DWYIK6Y9EEQB&pf_rd_r=CQ7KBNXT36G95190QJB1&ie=UTF8')

initiate_crawl()

Printing the length of items invokes some strange behaviour too. Instead of it always returning 32, which would correspond to the number of items on each page, it prints 32 for the first page, 64 for the second, 96 for the third, so on and so forth. I fixed this by using //div[contains(@id, "100_dealView_")]/div[contains(@class, "dealContainer")] instead of //div[contains(@id, "100_dealView_")] as the XPath for the items variable. I'm hoping this is the reason why it runs into issues on page 9. I'm running tests right now. Update: It is now scraping page 10 and beyond, so the issue is resolved.

回答1:

As per your 10th revision of this question the error message...

HTTPConnectionPool(host='127.0.0.1', port=58992): Max retries exceeded with url: /session/e8beed9b-4faa-4e91-a659-56761cb604d7/element (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x0000022D31378A58>: Failed to establish a new connection: [WinError 10061] No connection could be made because the target machine actively refused it'))

...implies that the get() method failed raising HTTPConnectionPool error with a message Max retries exceeded.

A couple of things:

  • As per the discussion max-retries-exceeded exceptions are confusing the traceback is somewhat misleading. Requests wraps the exception for the users convenience. The original exception is part of the message displayed.

  • Requests never retries (it sets the retries=0 for urllib3's HTTPConnectionPool), so the error would have been much more canonical without the MaxRetryError and HTTPConnectionPool keywords. So an ideal Traceback would have been:

    NewConnectionError(<class 'socket.error'>: [Errno 10061] No connection could be made because the target machine actively refused it)

  • You will find a detailed explaination in MaxRetryError: HTTPConnectionPool: Max retries exceeded (Caused by ProtocolError('Connection aborted.', error(111, 'Connection refused')))

Solution

As per the Release Notes of Selenium 3.14.1:

* Fix ability to set timeout for urllib3 (#6286)

The Merge is: repair urllib3 can't set timeout!

Conclusion

Once you upgrade to Selenium 3.14.1 you will be able to set the timeout and see canonical Tracebacks and would be able to take required action.

References

A couple of relevent references:

  • Adding max_retries as an argument
  • Removed the bundled charade and urllib3.
  • Third party libraries committed verbatim

This usecase

I have taken your full script from codepen.io - A PEN BY Anthony. I had to make a few tweaks to your existing code as follows:

  • As you have used:

    ua_string = random.choice(ua_strings)

    You have to mandatorily import random as:

    import random

  • You have created the variable next_button but haven't used it. I have clubbed up the following four lines:

    next_button = WebDriverWait(ff, 15).until(
                EC.text_to_be_present_in_element((By.PARTIAL_LINK_TEXT, 'Next→'), 'Next→')
            )
ff.find_element(By.PARTIAL_LINK_TEXT, 'Next→').click()

    As:

    WebDriverWait(ff, 15).until(EC.text_to_be_present_in_element((By.PARTIAL_LINK_TEXT, 'Next→'), 'Next→'))
ff.find_element(By.PARTIAL_LINK_TEXT, 'Next→').click()

  • Your modified code block will be:

    # -*- coding: utf-8 -*-
from selenium import webdriver
from selenium.webdriver.firefox.options import Options
from selenium.webdriver.common.by import By
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.ui import WebDriverWait
import time
import random


""" Set Global Variables
"""
ua_strings = ['Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36']
already_scraped_product_titles = []



""" Create Instances of WebDriver
"""
def create_webdriver_instance():
    ua_string = random.choice(ua_strings)
    profile = webdriver.FirefoxProfile()
    profile.set_preference('general.useragent.override', ua_string)
    options = Options()
    options.add_argument('--headless')
    return webdriver.Firefox(profile)



""" Construct List of UA Strings
"""
def fetch_ua_strings():
    ff = create_webdriver_instance()
    ff.get('https://techblog.willshouse.com/2012/01/03/most-common-user-agents/')
    ua_strings_ff_eles = ff.find_elements_by_xpath('//td[@class="useragent"]')
    for ua_string in ua_strings_ff_eles:
        if 'mobile' not in ua_string.text and 'Trident' not in ua_string.text:
            ua_strings.append(ua_string.text)
    ff.quit()



""" Log in to Amazon to Use SiteStripe in order to Generate Affiliate Links
"""
def log_in(ff):
    ff.find_element(By.XPATH, '//a[@id="nav-link-yourAccount"] | //a[@id="nav-link-accountList"]').click()
    ff.find_element(By.ID, 'ap_email').send_keys('anthony_falez@hotmail.com')
    ff.find_element(By.ID, 'continue').click()
    ff.find_element(By.ID, 'ap_password').send_keys('lo0kyLoOkYig0t4h')
    ff.find_element(By.NAME, 'rememberMe').click()
    ff.find_element(By.ID, 'signInSubmit').click()



""" Build Lists of Product Page URLs
"""
def initiate_crawl():
    def refresh_page(url):
    ff = create_webdriver_instance()
    ff.get(url)
    ff.find_element(By.XPATH, '//*[@id="FilterItemView_sortOrder_dropdown"]/div/span[2]/span/span/span/span').click()
    ff.find_element(By.XPATH, '//a[contains(text(), "Discount - High to Low")]').click()
    items = WebDriverWait(ff, 15).until(
        EC.visibility_of_all_elements_located((By.XPATH, '//div[contains(@id, "100_dealView_")]'))
    )
    for count, item in enumerate(items):
        slashed_price = item.find_elements(By.XPATH, './/span[contains(@class, "a-text-strike")]')
        active_deals = item.find_elements(By.XPATH, './/*[contains(text(), "Add to Cart")]')
        # For Groups of Items on Sale
        # active_deals = //*[contains(text(), "Add to Cart") or contains(text(), "View Deal")]
        if len(slashed_price) > 0 and len(active_deals) > 0:
            product_title = item.find_element(By.ID, 'dealTitle').text
            if product_title not in already_scraped_product_titles:
                already_scraped_product_titles.append(product_title)
                url = ff.current_url
                # Scrape Details of Each Deal
                #extract(ff, item.find_element(By.ID, 'dealImage').get_attribute('href'))
                print(product_title[:10])
                ff.quit()
                refresh_page(url)
                break
        if count+1 is len(items):
            try:
                print('')
                print('new page')
                WebDriverWait(ff, 15).until(EC.text_to_be_present_in_element((By.PARTIAL_LINK_TEXT, 'Next→'), 'Next→'))
                ff.find_element(By.PARTIAL_LINK_TEXT, 'Next→').click()
                time.sleep(10)
                url = ff.current_url
                print(url)
                print('')
                ff.quit()
                refresh_page(url)
            except Exception as error:
                """
                ff.find_element(By.XPATH, '//*[@id="pagination-both-004143081429407891"]/ul/li[9]/a').click()
                url = ff.current_url
                ff.quit()
                refresh_page(url)
                """
                print('cannot find ff.find_element(By.PARTIAL_LINK_TEXT, "Next?")')
                print('Because of... {}'.format(error))
                ff.quit()

    refresh_page('https://www.amazon.ca/gp/goldbox/ref=gbps_ftr_s-3_4bc8_dct_10-?gb_f_c2xvdC0z=sortOrder:BY_SCORE,discountRanges:10-25%252C25-50%252C50-70%252C70-&pf_rd_p=f5836aee-0969-4c39-9720-4f0cacf64bc8&pf_rd_s=slot-3&pf_rd_t=701&pf_rd_i=gb_main&pf_rd_m=A3DWYIK6Y9EEQB&pf_rd_r=CQ7KBNXT36G95190QJB1&ie=UTF8')

#def extract_info(ff, url):
fetch_ua_strings()
initiate_crawl()

  • Console Output: With Selenium v3.14.0 and Firefox Quantum v62.0.3, I can extract the following output on the console:

    J.Rosée Si
B.Catcher 
Bluetooth4
FRAM G4164
Major Crim
20% off Oh
True Blood
Prime-Line
Marathon 3
True Blood
B.Catcher 
4 Film Fav
True Blood
Texture Pa
Westinghou
True Blood
ThermoPro 
...
...
...

Note: I could have optimized your code and performed the same web scrapping operations initializing the Firefox Browser Client only once and traverse through various products and their details. But to preserve your logic and innovation I have suggested the minimal changes required to get you through.



回答2:

I slightly adjusted the code and it seems to work. Changes:

import random statement because it is used and would not run without it.

Inside product_title loop these lines are removed:

ff.quit(), refresh_page(url) and break

The ff.quit() statement would cause a fatal (connection) error causing the script to break.

Also is changed to == for if count + 1 == len(item):

# -*- coding: utf-8 -*-
from selenium import webdriver
from selenium.webdriver import Firefox
from selenium.webdriver.firefox.options import Options
from selenium.webdriver.common.by import By
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.ui import WebDriverWait
import time
import random



""" Set Global Variables
"""
ua_strings = ['Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36']
already_scraped_product_titles = []



""" Create Instances of WebDriver
"""
def create_webdriver_instance():
    ua_string = random.choice(ua_strings)
    profile = webdriver.FirefoxProfile()
    profile.set_preference('general.useragent.override', ua_string)
    options = Options()
    options.add_argument('--headless')
    return webdriver.Firefox(profile)

""" Construct List of UA Strings
"""
def fetch_ua_strings():
    ff = create_webdriver_instance()
    ff.get('https://techblog.willshouse.com/2012/01/03/most-common-user-agents/')
    ua_strings_ff_eles = ff.find_elements_by_xpath('//td[@class="useragent"]')
    for ua_string in ua_strings_ff_eles:
        if 'mobile' not in ua_string.text and 'Trident' not in ua_string.text:
            ua_strings.append(ua_string.text)
    ff.quit()

""" Build Lists of Product Page URLs
"""
def initiate_crawl():
    def refresh_page(url):
        ff = create_webdriver_instance()
        ff.get(url)
        ff.find_element(By.XPATH, '//*[@id="FilterItemView_sortOrder_dropdown"]/div/span[2]/span/span/span/span').click()
        ff.find_element(By.XPATH, '//a[contains(text(), "Discount - High to Low")]').click()
        items = WebDriverWait(ff, 15).until(
            EC.visibility_of_all_elements_located((By.XPATH, '//div[contains(@id, "100_dealView_")]'))
        )
        print(items)
        for count, item in enumerate(items):
            slashed_price = item.find_elements(By.XPATH, './/span[contains(@class, "a-text-strike")]')
            active_deals = item.find_elements(By.XPATH, './/*[contains(text(), "Add to Cart")]')
            # For Groups of Items on Sale
            # active_deals = //*[contains(text(), "Add to Cart") or contains(text(), "View Deal")]
            if len(slashed_price) > 0 and len(active_deals) > 0:
                product_title = item.find_element(By.ID, 'dealTitle').text
                if product_title not in already_scraped_product_titles:
                    already_scraped_product_titles.append(product_title)
                    url = ff.current_url
                    # Scrape Details of Each Deal
                    #extract(ff, item.find_element(By.ID, 'dealImage').get_attribute('href'))
                    print(product_title[:10])
                    # This ff.quit()-line breaks connection which breaks things.:
                    #ff.quit()
                    # And why 
                    #refresh_page(url)
                    #break
            # 'is' tests for object equality; == tests for value equality:
            if count+1 == len(items):
                try:
                    print('')
                    print('new page')
                    next_button = WebDriverWait(ff, 15).until(
                        EC.text_to_be_present_in_element((By.PARTIAL_LINK_TEXT, 'Next→'), 'Next→')
                    )
                    ff.find_element(By.PARTIAL_LINK_TEXT, 'Next→').click()                    
                    time.sleep(3)
                    url = ff.current_url
                    print(url)
                    print('')
                    ff.quit()
                    refresh_page(url)
                except Exception as error:
                    """
                    ff.find_element(By.XPATH, '//*[@id="pagination-both-004143081429407891"]/ul/li[9]/a').click()
                    url = ff.current_url
                    ff.quit()
                    refresh_page(url)
                    """
                    print('cannot find ff.find_element(By.PARTIAL_LINK_TEXT, "Next→")')
                    print('Because of... {}'.format(error))
                    ff.quit()

    refresh_page('https://www.amazon.ca/gp/goldbox/ref=gbps_ftr_s-3_4bc8_dct_10-?gb_f_c2xvdC0z=sortOrder:BY_SCORE,discountRanges:10-25%252C25-50%252C50-70%252C70-&pf_rd_p=f5836aee-0969-4c39-9720-4f0cacf64bc8&pf_rd_s=slot-3&pf_rd_t=701&pf_rd_i=gb_main&pf_rd_m=A3DWYIK6Y9EEQB&pf_rd_r=CQ7KBNXT36G95190QJB1&ie=UTF8')

#def extract_info(ff, url):
fetch_ua_strings()
initiate_crawl()


标签： python selenium python-requests geckodriver urllib3
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