I am trying to read the file with tkinter button basically when button press the function will read the files if the files doesn't exists it will show an error if its exits than it will continue, but it throws me an error

expected str, bytes or os.PathLike object, not NoneType

Here are the codes:

def ffr(driver,filename):
    f = open(filename, "r")
    lines = f.readlines()
    f= []
    for i in lines:
        f.append(i[:-1])
    wait = webdriver(driver, 10)
    for i in f:
        url = "https://www.instagram.com/" i "/"
        driver.get(url)
        time.sleep(1)

def follow_file():
    try:
        open('reading.txt')
    except FileNotFoundError:
        Error_box_follow_file_not_found()

The Button:

ff= Button(root,text="read file", command=lambda:ffr(driver,follow_file()))
ff.grid(column=1,row=19)

Error box

def Error_box_follow_file_not_found():
messagebox.showerror('insa', "Error: Please add file 'readline.txt' into path!")
messagebox.CANCEL

CodePudding user response：

Main problem: follow_file() has to return filename which will get ffr(driver,filename)

def follow_file():
    try:
        open('reading.txt')
        return 'reading.txt'  # <---
    except FileNotFoundError:
        Error_box_follow_file_not_found()

But this still have other problem.

If file doesn't exists then it run Error_box_follow_file_not_found() but later it exits this function with return None and it runs ffr(driver, None) and it will raise error. It would have to check filename is not None at start and skip rest of code.

def ffr(driver, filename):

    if filename:  # if filename is not None:
        f = open(filename)
        lines = f.read().split("\n")
        f.close()

        wait = webdriver(driver, 10)

        for i in lines:
            url = "https://www.instagram.com/" i "/"
            driver.get(url)
            time.sleep(1)

Frankly, I would do all in one function

def ffr(driver):

    try:
        f = open('reading.txt')
        lines = f.read().split("\n")
        f.close()
    except FileNotFoundError:
        Error_box_follow_file_not_found()
        return

    wait = webdriver(driver, 10)

    for i in lines:
        url = "https://www.instagram.com/" i "/"
        driver.get(url)
        time.sleep(1)

EDIT:

Minimal working code

import tkinter as tk
from tkinter import messagebox
from selenium import webdriver

# --- functions ---  # PEP8: `lower_case_names`

def error_box_follow_file_not_found():
    messagebox.showerror('insa', "Error: Please add file 'readline.txt' into path!")

def ffr(driver):

    try:
        f = open('reading.txt')
        lines = f.read().split("\n")
        f.close()
    except FileNotFoundError:
        error_box_follow_file_not_found()
        return

    wait = webdriver(driver, 10)

    for i in lines:
        url = f"https://www.instagram.com/{i}/"
        driver.get(url)
        time.sleep(1)

# --- main ---

driver = webdriver.Firefox()

root = tk.Tk()

ff = tk.Button(root, text="Read file", command=lambda:ffr(driver))
ff.grid(column=1, row=19)

root.mainloop()