base64编码图像； binascii.Error: 无效的 base64 编码

Question

as a project for a course, I'm developing an image coder/decoder using python, but it seems I got a little stuck and I would really apreciate getting some help

The error I'm getting is:

runfile('D:/Documentos/Python/Proyecto_Final/Main.py', wdir='D:/Documentos/Python/Proyecto_Final')
Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\...\anaconda3\lib\tkinter\__init__.py", line 1705, in __call__
    return self.func(*args)
  File "D:\Documentos\Python\Proyecto_Final\Main.py", line 32, in decode64
    imagen.write(base64.decodebytes(baset.encode()))
  File "C:\...\anaconda3\lib\base64.py", line 546, in decodebytes
    return binascii.a2b_base64(s)
binascii.Error: Invalid base64-encoded string: number of data characters (1) cannot be 1 more than a multiple of 4

My code is:

from tkinter import *
import os
import base64

def browseBtn():
    filename = filedialog.askopenfilename()
    texto.insert(0, filename)

def convbase64():
    path = str(texto.get())
    imagen = open(path, 'rb')
    leeimg = imagen.read()
    codigo64 = base64.encodebytes(leeimg)
    texto2.insert("1.0", codigo64)

def decode64():
    myFormats = [('JPEG / JFIF','*.jpg'),\
                     ('Portable Network Graphics','*.png'),\
                     ('Windows Bitmap','*.bmp'),('CompuServer GIF','*.gif'),]
    baset = texto2.get(1.0)
    filepath = filedialog.asksaveasfilename(filetypes=myFormats)
    imagen = open(filepath, 'wb')
    imagen.write(base64.decodebytes(baset.encode()))
    imagen.close()

ventana = Tk()
ventana.title("Convertidor imagen a Base64")
ventana.geometry("800x480")
letrero = Label(ventana, text = "Imagen:")
texto = Entry(ventana, width = 100)
buscarImg = Button(ventana, text = "Elegir", command=browseBtn)
letrero2 = Label(ventana, text = "codigo base64:")
texto2 = Text(width = 75, height = 1)
btnconvertir = Button(ventana, text = "Codificar", command=convbase64)
btndecodificar = Button(ventana, text = "decodificar", command=decode64)
letrero.place(x = 32, y = 32)
letrero2.place(x = 16, y = 64)
texto.place(x = 114, y = 35)
texto2.place(x = 114, y = 69)
buscarImg.place(x = 724, y = 32)
btnconvertir.place(x = 724, y = 64)
btndecodificar.place (x = 724, y = 96)

ventana.mainloop()

I'm using anaconda's Spyder 3.7

Answer 1

When using Text.get to get more than one character, you need to give it an end position. You can use the special string "end" for this, but ignoring the last newline character that tkinter adds with "end-1c" :

baset = texto2.get("1.0", "end-1c")

See this answer for more information