Python Selenium：如何循环刷新页面直至找到指定元素？

Hey there! Let's fix your issue with refreshing the page until the target element shows up and handling the BOM replacement. Here are two reliable approaches using Selenium with ChromeDriver:

Basic Loop with Exception Handling #

This straightforward approach uses a loop to repeatedly check for the element, refresh the page if it's missing, and stop once we find it (or hit a max attempt limit to avoid infinite loops):

from selenium import webdriver
from selenium.common.exceptions import NoSuchElementException
import time

# Initialize ChromeDriver
driver = webdriver.Chrome()
driver.get("YOUR_TARGET_PAGE_URL")

# Set a maximum number of refresh attempts to prevent infinite loops
max_refresh_attempts = 20
current_attempt = 0

while current_attempt < max_refresh_attempts:
    try:
        # Locate the element by its class name
        target_element = driver.find_element_by_class_name("YOUR_TARGET_CLASS_NAME")
        
        # Remove BOM (common UTF-8 BOM is \ufeff; adjust if your BOM is different)
        cleaned_text = target_element.text.replace("\ufeff", "")
        print("Cleaned text without BOM:", cleaned_text)
        
        # Exit the loop once we successfully find and process the element
        break
    
    except NoSuchElementException:
        print(f"Attempt {current_attempt + 1}: Element not found, refreshing page...")
        driver.refresh()
        current_attempt += 1
        time.sleep(2)  # Wait 2 seconds after refresh to let the page load

# If we exit the loop without breaking, we hit the max attempts
else:
    print(f"Failed to find element after {max_refresh_attempts} refresh attempts.")

# Clean up the driver
driver.quit()

Elegant Approach with WebDriverWait #

For a more Selenium-idiomatic solution, use WebDriverWait with a custom condition. This handles the polling and waiting logic for you, and we'll add automatic refreshes when the element is missing:

from selenium import webdriver
from selenium.webdriver.support.ui import WebDriverWait
from selenium.common.exceptions import NoSuchElementException, TimeoutException

driver = webdriver.Chrome()
driver.get("YOUR_TARGET_PAGE_URL")

def check_for_element_and_refresh(driver):
    """Custom condition: return the element if found, else refresh and return False"""
    try:
        return driver.find_element_by_class_name("YOUR_TARGET_CLASS_NAME")
    except NoSuchElementException:
        driver.refresh()
        return False

try:
    # Wait up to 30 seconds, check every 2 seconds
    target_element = WebDriverWait(driver, 30, poll_frequency=2).until(check_for_element_and_refresh)
    
    # Remove BOM from the element's text
    cleaned_text = target_element.text.replace("\ufeff", "")
    print("Cleaned text without BOM:", cleaned_text)

except TimeoutException:
    print("Timed out waiting for the element to appear after multiple refreshes.")

driver.quit()

Key Notes to Troubleshoot Further #

• Verify your class name: Double-check that the class name you're using is exactly correct (no typos, and it's the class of the element you want—find_element_by_class_name returns the first matching element).
• Identify the correct BOM character: If \ufeff doesn't work, print the raw text representation to see hidden characters:

  print(repr(target_element.text))
  

  This will show you the exact BOM character (e.g., \ufffe for UTF-16 BOM) to replace.
• Why find_element_by_partial_link_text failed: This method only works for <a> (link) elements. If your target element isn't a link, or its text is dynamically rendered/contains hidden characters, this method won't work—using class name is a solid alternative here.

内容的提问来源于stack exchange，提问作者Nudam