TypeError: hash must be unicode or bytes, not None


I am working on Flask project works with mongoengine. Register code hashed to password with passlib.hash when user registered. When I try to read password in login authentication I’ve got this error.

TypeError: hash must be unicode or bytes, not None

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TypeError: hash must be unicode or bytes, not appname.models.User

Traceback (most recent call last)

File "/*/**/***/***/appname/env/lib/python2.7/site-packages/flask/app.py", line 1836, in __call__
return self.wsgi_app(environ, start_response)

File "/*/**/***/***/appname/env/lib/python2.7/site-packages/flask/app.py", line 1820, in wsgi_app
response = self.make_response(self.handle_exception(e))

File "/*/**/***/***/appname/env/lib/python2.7/site-packages/flask/app.py", line 1403, in handle_exception
reraise(exc_type, exc_value, tb)

File "/*/**/***/***/appname/env/lib/python2.7/site-packages/flask/app.py", line 1817, in wsgi_app
response = self.full_dispatch_request()

File "/*/**/***/***/appname/env/lib/python2.7/site-packages/flask/app.py", line 1477, in full_dispatch_request
rv = self.handle_user_exception(e)

File "/*/**/***/***/appname/env/lib/python2.7/site-packages/flask/app.py", line 1381, in handle_user_exception
reraise(exc_type, exc_value, tb)

File "/*/**/***/***/appname/env/lib/python2.7/site-packages/flask/app.py", line 1475, in full_dispatch_request
rv = self.dispatch_request()

File "/*/**/***/***/appname/env/lib/python2.7/site-packages/flask/app.py", line 1461, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)

File "/*/**/***/***/appname/views.py", line 207, in login
if sha256_crypt.verify(u''+ passW,user):

File "/*/**/***/***/appname/env/lib/python2.7/site-packages/passlib/utils/handlers.py", line 567, in verify
self = cls.from_string(hash, **context)

File "/*/**/***/***/appname/env/lib/python2.7/site-packages/passlib/handlers/sha2_crypt.py", line 285, in from_string
hash = to_unicode(hash, "ascii", "hash")

File "/*/**/***/***/appname/env/lib/python2.7/site-packages/passlib/utils/__init__.py", line 617, in to_unicode
raise ExpectedStringError(source, param)

TypeError: hash must be unicode or bytes, not appname.models.User
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Here is my views.py codes:

@app.route("/login", methods=['GET','POST'])
def login():
    if current_user.is_authenticated:
        flash("You're already registered", "info")
        return redirect(url_for('profile')+('/'+current_user.slug))

    form = LoginForm()
    passW = form.password.data

    if request.method == 'POST':
        form = LoginForm()

        if form.validate_on_submit():
            user = User.objects(email=form.email.data, password=str(passW)).first()
            if sha256_crypt.verify(passW, user):
                login_user(user, form.remember_me.data)
                slug = slugify(user.name)

                flash('We are glad you came {}.'.format(user.name),'success')
                return redirect(request.args.get('next') or url_for('profile', slug=slug))

                flash('Wrong username or password.','danger')
                return render_template("login.html", form=form, title="Cp-Login")
    return render_template("login.html", form=form, title="Cp-Login")

Any help will be appreciated.


I guess the problem is here:

user = User.objects(email=form.email.data, password=str(passW)).first()

If your database can’t find any match user, user will be none. So you’d better use if else to tell if the user exist first.


From the doc in Passlib,

>>> # import the hash algorithm
>>> from passlib.hash import sha256_crypt

>>> # generate new salt, and hash a password
>>> hash = sha256_crypt.encrypt("toomanysecrets")
>>> hash

>>> # verifying the password
>>> sha256_crypt.verify("toomanysecrets", hash)
>>> sha256_crypt.verify("joshua", hash)

Your code

if sha256_crypt.verify(passW, user):

should be

if sha256_crypt.verify(passW, user.password):

if you store user’s password use Passlib. But usually you should use django build-in authenticating to do something like this.

Answered By – Windsooon

This Answer collected from stackoverflow, is licensed under cc by-sa 2.5 , cc by-sa 3.0 and cc by-sa 4.0

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