使用 selenium 的函数我做错了什么？

Question

from selenium import webdriver
from selenium.webdriver.common.keys import Keys
import time

# define path of driver
driver = webdriver.Chrome()

def mainloop():
    driver.get("https://www.nitrotype.com/login")
    login(username, password)

# LOGGING IN

def login(username, password):
    time.sleep(2)
    username = driver.find_element_by_id('username')
    username.send_keys(username)
    time.sleep(1)
    password = driver.find_element_by_id('password')
    username.send_keys(username)
    time.sleep(1)
    password.send_keys(password, Keys.RETURN)


mainloop()

when I run this, it shows me

Traceback (most recent call last):
  File "/home/stevek/Projects/Python/nitrotype-bot/main.py", line 25, in <module>
    mainloop()
  File "/home/stevek/Projects/Python/nitrotype-bot/main.py", line 10, in mainloop
    login(username, password)
  File "/home/stevek/Projects/Python/nitrotype-bot/main.py", line 17, in login
    username.send_keys(username)
  File "/home/stevek/.local/lib/python3.9/site-packages/selenium/webdriver/remote/webelement.py", line 478, in send_keys
    {'text': "".join(keys_to_typing(value)),
  File "/home/stevek/.local/lib/python3.9/site-packages/selenium/webdriver/common/utils.py", line 150, in keys_to_typing
    for i in range(len(val)):
TypeError: object of type 'WebElement' has no len()

I'm so confused. I didn't use any XPaths.

from selenium import webdriver
from selenium.webdriver.common.keys import Keys

driver = webdriver.Chrome()
driver.get("https://www.nitrotype.com/login")
username = driver.find_element_by_id('username')
password = driver.find_element_by_id('password')
username.send_keys(username)
password.send_keys(password, Keys.RETURN)

When I didn't use functions, like this, it runs as expected. It logins. No functions. What's wrong? Also, note that I replaced all username with variables.

Answer 1

You are passing variable names into login() that have the same name as the variables you are defining for the web elements within that function. You can't do that.

Change them to something different, like below user and pw

def mainloop():
    driver.get("https://www.nitrotype.com/login")
    login("test", "testPW")

# LOGGING IN

def login(user, pw):
    time.sleep(2)
    username = driver.find_element_by_id('username')
    username.send_keys(user)
    time.sleep(1)
    password = driver.find_element_by_id('password')
    time.sleep(1)
    password.send_keys(pw, Keys.RETURN)


mainloop()

I also removed the duplicate username.send_keys(user) in the function

Answer 2

The problem is that you are overwriting the username parameter passed into the method with a WebElement then passing that to .send_keys() which is expecting a string.

def login(username, password):
          ^ username parameter is a string
    username = driver.find_element_by_id('username')
    ^ username is overwritten with a WebElement here

In your method, you don't need to assign the elements to a variable. The whole method can be simplified down to two lines,

def login(username, password):
    driver.find_element_by_id('username').send_keys(username)
    driver.find_element_by_id('password').send_keys(username, Keys.RETURN)

I also removed all of the sleeps because they likely aren't needed. Best practice when you need a wait is to use WebDriverWait .

Also, your final code with no method wouldn't work either because of the same reason.

username = driver.find_element_by_id('username')
^ this is a WebElement
username.send_keys(username)
^ this is a WebElement
                   ^ this is a WebElement but should be a string.

You likely hardcoded the .send_keys() string but replaced it when you "replaced all username with variables."