How to encode/decode string using django.utils.http

Using Django Forms & APIs
1

Hi there,

I am trying to pass a user ID (primary key) to url as base 64 encoded. I am using django.utils.http.urlsafe_base64_encode to encode the user ID as the following:

from django.utils.http import urlsafe_base64_encode

user_id_base_64 = urlsafe_base64_encode(str(user.pk).encode('utf-8'))

This works fine and I get the desired 64 base byte of user id. The url pattern to hold this user id 64 base is:

path("password-reset/<uidb64>/, views.dashboard())

But I need to decode the same in the view which is accessed by the above url.

I try to do that with the following:

from django.utils.http import urlsafe_base64_decode

.
.
.
user_id = urlsafe_base64_decode(uidb64)

This does not give me the correct result, i.e. a numeric string or an integer.

Can someone help me how do I decode it properly to get the correct value?

2

Most obvious to me is the mistake here. Unless you’re doing something really unusual here, the definition would be:
path("password-reset/<uidb64>/", views.dashboard)

Beyond that, it would be helpful if you showed an example of one of the keys, what that translates to for the url, and what you’re seeing in the view.

3

Actually it was just a typo here in this post. In reality I have the same definition of path as you told in my code.

Well, the I have the following output when I print user.key:

>>> from .models import User
>>> user = User.objects.get(pk=1)
>>> print(user.pk)
1

and when I get the following output of encoding:

>>> from django.utils.http import urlsafe_base64_encode
>>> user_id_base_64 = urlsafe_base64_encode(str(user.pk).encode('utf-8'))
>>> print(user_id_base_64)
MQ

Now when I try to decode, I get the following output:

>>> from django.utils.http import urlsafe_base64_decode
>>> user_key = urlsafe_base64_decode(user_id_base_64)
>>> print(user_key)
b'1'

So, you can see instead of getting back 1 either in form of str or int, I am getting b'1'.

4

It’s decoding as a bytes object; you can then decode it as a string.

5

Doing the following:

user_key = urlsafe_base64_decode(user_id_base_64.decode('str'))

gives me the following error:

Traceback (most recent call last):
  File "<string>", line 6, in <module>
AttributeError: 'bytes' object has no attribute 'encode'
6

It’s the output of urlsafe_base64_decode that is returning the bytes object, what you are printing as user_key - that is what you want to decode as a string.

7

Upon doing the following

user_key = urlsafe_base64_decode(user_key_base_64).decode('str')

I get the following error:

Traceback (most recent call last):
  File "<string>", line 6, in <module>
LookupError: unknown encoding: str
8

@KenWhitesell any solution to this problem?

9

What do you think that error message is telling you?

10

Its saying that it does not recognize str encoding. So what should I do to make it recognize or what’s the alternative method?

11

Did you read the documentation I referenced? It shows what all the valid encodings are.

2 Likes
12

OK, I got it, I changed 'str' to 'ascii' and I got the original string back, now just needed to convert it to integer using int() method. Thanks a lot.

1 Like