Encoding for Bcrypt in custom login tutorial

Anvil Q&A
1

Good afternoon ladies and gents,

I am trying to replicate the custom sign-up flow tutorial and there is a specific server function that is not working.

Specifically:

@anvil.server.callable
def _do_signup(email, name, password):
  if name is None or name.strip() == "":
    return "Must supply a name"

  pwhash = bcrypt.hashpw(password, bcrypt.gensalt())

In the above last line where pwhash is being created, I get an error:

TypeError: Unicode-objects must be encoded before hashing at

I tried turning password into password.encode(‘utf-8’) or ‘latin-1’

but it then gives me a different error that is more cryptic:

anvil.server.ExecutionTerminatedError: Server code exited unexpectedly: 53c2d8dc17

2

Hey,

What you should have got is:

TypeError: Object of type 'bytes' is not JSON serializable

My guess is that you returned pwhash from the server function as raw bytes, rather than as a string, which Anvil doesn’t support. (If you want to send raw bytes around, put them into a BlobMedia. In this case, a bcrypt hash is an ASCII string anyway, so try just decode()ing it before returning it :slight_smile: )

I’m looking at our error reporting system now, to see why that error didn’t come out as you’d expect…

1 Like
3

likewise trying to implement the custom sign-up flow tutorial + some admin abilities like changing the password on an account, i started off with the administrative change password functionality and i was able to get this code to work for setting a password administratively:

user[‘password_hash’] = bcrypt.hashpw(password.encode(‘utf-8’), bcrypt.gensalt())

but after i make the change, when i try to log in with the new password, i get an InternalError: Internal server error: 7985e2c3953a

i have about 850 active users, will i have to move to the complete custom sign-up flow and force everyone to reset their passwords or does the custom sign-up flow tutorial use the same methodology as the Users service?

the only way to get an account working again after i set the password using the code above is to find it in the Users service and reset it there.

4

For anyone that stumbles on this looking for the answer, it’s answered over at Custom Signup Flow Error on Sign Up.

The working code is:

user[‘password_hash’] = bcrypt.hashpw(password.encode(), bcrypt.gensalt())

instead of:

user[‘password_hash’] = bcrypt.hashpw(password.encode(‘utf-8’), bcrypt.gensalt())
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