How to receive the size of the file that the user wants to retrieve using urllib in python

Question

I am basically a newbie in python and I am building this downloader program in python using tkinter and urllib.request and it is quite done but as a final touch I wanted to add a progress bar to show how much the file is downloaded. I found out that I can add a progress bar using TQDM but first I should have gotten the size of the file that the user wants to downloaded to show how much the program has downloaded it and I didn't find anything! Can anyone help me out? My code(BTW if you have any idea how to make my code better I would appreciate it):

from tkinter import *
from tkinter import font as tkFont
import random
import urllib.request


def printsth():
    print("Yay it works! ")


def main_menu():
    root = Tk()
    # the top menu
    num = IntVar()
    var = IntVar()
    menu = Menu(root)
    root.config(menu=menu)
    submenu = Menu(menu)
    menu.add_cascade(label="File", menu=submenu)
    submenu.add_command(label="New project...", command=printsth)
    submenu.add_command(label="New ", command=printsth)
    submenu.add_separator()
    submenu.add_command(label="Exit", command=root.destroy)

    # the edit menu
    editmenu = Menu(menu)
    menu.add_cascade(label="Edit", menu=editmenu)
    editmenu.add_command(label="Redo...", command=printsth)

    # the tool bar
    toolbar = Frame(root, bg="light gray")
    insert_button = Button(toolbar, text="Insert an image", command=printsth)
    insert_button.pack(side=LEFT, padx=2, pady=2)
    print_button = Button(toolbar, text="Print", command=printsth)
    print_button.pack(side=LEFT, padx=2, pady=2)
    toolbar.pack(side=TOP, fill=X)

    # the status bar
    status_bar = Label(root, text="This is only an example...", bd=1, relief=SUNKEN, anchor=W)
    status_bar.pack(side=BOTTOM, fill=X)

    # the download frame
    def download_image():
        global formatname
        if num.get() == 1:
            name = random.randrange(1, 10000)
        else:
            name = str(name_entry.get())
        formatname = str(format_entry.get())
        '''if var.get() == 1:
            operator = str(url_entry.get())
            formatname = '.' + operator[-3] + operator[-2] + operator[-1]
        else:
            pass'''
        fullname = str(name) + formatname
        url = str(url_entry.get())
        urllib.request.urlretrieve(url, fullname)
    body_frame = Frame(root, bg="light blue")
    download_button = Button(body_frame, text="Download! ", command=download_image, border=3, width=20, height=5)
    download_design = tkFont.Font(size=12, slant='italic')
    download_button['font'] = download_design
    download_button.pack(side=LEFT, pady=5, padx=5)
    body_frame.pack(side=LEFT, fill=Y)
    # the main interaction menu
    inter_frame = Frame(root)
    url_entry = Entry(inter_frame)
    label = Label(inter_frame, text="Enter the image URL: ")
    file_format = Label(inter_frame, text="Choose your file format: ")
    format_entry = Entry(inter_frame)
    file_name = Label(inter_frame, text="File's name: ")
    name_entry = Entry(inter_frame)
    check_name = Checkbutton(inter_frame, text="Give a random name", variable=num)
    check_format = Checkbutton(inter_frame, text="Download with default format", variable=var)
    file_name.pack(anchor=CENTER, expand=1)
    name_entry.pack(anchor=CENTER, expand=1)
    check_name.pack(anchor=CENTER, expand=1)
    label.pack(anchor=CENTER, expand=1)
    url_entry.pack(anchor=CENTER, expand=1)
    file_format.pack(anchor=CENTER, expand=1)
    format_entry.pack(anchor=CENTER, expand=1)
    # check_format.pack(anchor=CENTER)
    inter_frame.pack(expand=1)
    root.mainloop()

    # the end!
main_menu()

Answer 1

To get the size do a HEAD requests:

file_size = int(requests.head('https://www.cs.cmu.edu/~./enron/enron_mail_20150507.tar.gz', headers={'accept-encoding': ''}).headers['Content-Length'])

Or a GET requests (may be incorrect):

file size = int(requests.get('https://www.cs.cmu.edu/~./enron/enron_mail_20150507.tar.gz').headers['Content-Length'])