Tkinter entry returns ValueError: invalid literal for int() with base 10: ''

Question

So today I've been working on a new GUI with tkinter and came across and issue with parsing a string from an entry into an int and I get this error.

Traceback (most recent call last):
  File "/Users/g.shiner21/Desktop/Python/P2PFile/P2PFileServer.py", line 47, in <module>
    bStartServer = Button(f1, text="Start Server", command=startServer(host))
  File "/Users/g.shiner21/Desktop/Python/P2PFile/P2PFileServer.py", line 28, in startServer
    intport = int(port)
ValueError: invalid literal for int() with base 10: ''

Here is the function,

def startServer(host):
    port = ePort.get()
    intport = int(port)
    s = socket.socket()
    s.bind((host, intport))
    s.listen(4)

The most confusing part is that when I test something like this,

strTest = "10000"
intTest = int(strTest)

I get no errors. So I don't think I'm doing my parsing wrong. But at this point I'm not too sure. Any help would be greatly appreciated! :)

Edit: For those that it helps here is the full program(or at least what I have so far. I commented out the second part of it while I was building the GUI because I didn't want to have to deal with any interferences.

# server.py

import socket                   # Import socket module
import sys
from tkinter import *
from tkinter import ttk

port = 0                  # Reserve a port for your service.
s = socket.socket()             # Create a socket object
host = "0.0.0.0" 

root=Tk()
root.title("Test Window")

c = '#ececec'

n = ttk.Notebook(root)  #Create notebook
f1 = ttk.Frame(n)   #Create frames for notebook
f2 = ttk.Frame(n)
f3 = ttk.Frame(n)
n.add(f1, text='Server')    #Add frames to notebook
n.add(f2, text='File')
n.add(f3, text='Playback')
n.pack(expand=1, fill='both')   #Pack notebook

def startServer(host):
    port = ePort.get()
    intport = int(port)
    s = socket.socket()
    s.bind((host, intport))
    s.listen(4)

lservType = Label(f1, text="Select Server Type: ", bg=c)
lservType.grid(columnspan=2, row=0)

R1 = Radiobutton(f1, text="Local Host", variable=host, value="localhost", bg=c)
R1.grid(row=1, column=0)
R2 = Radiobutton(f1, text="Wireless Host", variable=host, value="0.0.0.0", bg=c)
R2.grid(row=1, column=1)

lPort = Label(f1, text="Port: ", bg=c)
ePort = Entry(f1)

lPort.grid(row=2, column=0, sticky='e')
ePort.grid(row=2, column=1)

bStartServer = Button(f1, text="Start Server", command=startServer(host))
bStartServer.grid(row=3, columnspan=2)

"""
port = 60000                    # Reserve a port for your service.
s = socket.socket()             # Create a socket object
host = "0.0.0.0"                # Get local machine name
s.bind((host, port))            # Bind to the port
s.listen(4)                     # Now wait for client connection.
#print("Your IP address is: " + socket.gethostbyname(socket.gethostname()))

print ('Server listening....')

while True:
    conn, addr = s.accept()     # Establish connection with client.
`    print ('Got connection from', addr)
    input ('Press the enter key to send')

    filename = 'send.mov'
    print ('File Assigned')
    f = open(filename,'rb')
    print ('File Oppened')
    l = f.read(131072)
    print ('Reading')
    while (l):
        conn.send(l)
        print('Sent ',repr(l))
        l = f.read(131072)
        print ('Reading')
    f.close()

    print('Done sending')
    conn.close()
#sys.exit()
"""
root.mainloop()

Answer 1

You get this error when the python can't cast the variable to int. make sure "port" is an integer and the try casting that to int. the second example works fine because your hard coding the value of input and it's an integer. You can update your function as follows:

def startServer(host):
    try:
        port = ePort.get()
        intport = int(port)
        s = socket.socket()
        s.bind((host, intport))
        s.listen(4)
    except BaseException:
        print('wrong entry')