Cannot encode object: pymongo

Question

I'm fairly new to programming and basically I have no idea what I'm doing.

I'm trying to make a write simple UI that that can take an input and write it to a mongodb.

import pymongo
from tkinter import *
from tkinter import ttk

class Input:

    def __init__(self, root,):

        self.myclient = pymongo.MongoClient("mongodb://localhost:27017/")

        self.mydb = self.myclient["mydatabase"]

        self.mycol = self.mydb["input"]

        title_label = Label(root, text="input")

        title_label.grid(row=0, column=0, padx=10, pady=10, sticky=W)

        self.input_value = StringVar(root, value="")

        self.input = ttk.Entry(root, textvariable=self.input_value)

        self.input.grid(row=0, column=1, padx=10, pady=10, sticky=W)

        self.submit_button = ttk.Button(root,
                                        text="Submit",
                                        command=self.submit())
        self.submit_button.grid(row=1, column=0,
                                padx=10, pady=10, sticky=W)

    def submit(self):
        entry = {"input": self.input_value}
        self.mycol.insert(entry)


root = Tk()

In = Input(root)

root.mainloop()

When trying to run this I get

bson.errors.InvalidDocument: Cannot encode object: <tkinter.StringVar object at 0x000001EC62343908>

I tried converting input_value to 'normal' string

self.input_value = str(StringVar(root, value=""))

By doing that I get the program to run but whatever I input into the entry field it writes 'PY_VAR0' to the database.

What am I doing wrong?

Other way around. Rather than "assign a simple string" you need to coerce `self.input_value` to a "simple string", or at least a valid type for the BSON serializer. So `{ "input": str(self.input_value) }` — Neil Lunn, Mar 25 '19 at 07:45
Doing that still results in "PY_VAR0" being written to the database. — DracoTomes, Mar 25 '19 at 07:52
[Get contents of a Tkinter Entry widget](https://stackoverflow.com/questions/9815063/get-contents-of-a-tkinter-entry-widget) then? Possibly returns a dict from which you might need to further extract specific fields. — Neil Lunn, Mar 25 '19 at 08:00

score 1 · Accepted Answer · answered Mar 25 '19 at 08:36

Thanks Neil Lunn.

entry = {"input": self.input_value.get()}

is now working using the get method.

Another problem I found is that I wrote

self.submit_button = ttk.Button(root,
                                text="Submit",
                                command=self.submit())

It actually needs to be

self.submit_button = ttk.Button(root,
                                text="Submit",
                                command=self.submit)

Without the parenthesis on self.submit. Those caused the funktion to be executed at the start of the programm so it wrote empty strings even when using the get method.

Cannot encode object: pymongo

1 Answers1