Python: NoneType erreur - "coercing à Unicode: chaîne de besoin ou tampon, NoneType trouvé"

Question

Je travaille avec Google App Engine et en utilisant le magasin de données pour créer une table pour les utilisateurs contenant le nom d'utilisateur des entités, le hash du mot de passe, email et la date jointe. Mais lorsque j'exécute une fonction pour enregistrer un utilisateur, la fonction qui hache les mots de passe renvoie l'erreur NoneType.

J'ai essayé de rechercher l'erreur, mais le formulaire affiche les valeurs et je peux les récupérer dans les en-têtes.

C'est le morceau de code qui gère l'enregistrement

def make_salt(): 
chars = string.ascii_uppercase + string.ascii_lowercase + string.ascii_digits 
return ''.join(random.choice(chars) for x in range(5)) 

def make_pw_h(name, pw, salt = None): 
    if salt: 
     salt = make_salt() 
return "%s,%s" % (salt, hashlib.sha256(name + pw + salt).hexdigest()) 

def check_pw_h(name, pw, h): 
    h = h.split(',')[1] 
    return h == make_pw_h(name, pw, h) 

class Users(db.Model): 
    username = db.StringProperty(required = True) 
    pw_hash = db.StringProperty(required = True) 
    emai = db.StringProperty() 
    user_since = db.DateTimeProperty(auto_now_add = True) 

@classmethod 
def by_id(cls, uid): 
    return Users.get_by_id(uid) 

@classmethod 
def by_name(cls, name): 
    user = Users.all().filter('name = ', name).get() 
    return user 

@classmethod 
def register(cls, name, pw, email = None): 
    pw_h = make_pw_h(name, pw) 
    return Users(username = name, 
       pw_hash = pw_h, 
       email = email) 

@classmethod 
def login(cls, name, pw): 
    u = cls.by_name(name) 
    if u and check_pw(pw): 
     return u   

def make_secure_val(s): 
    return '%s|%s' % (val, hmac.new(secret, val).hexdigest()) 

def check_secure_val(sec_val): 
    val = val.split('|')[0] 
    if sec_val == make_secure_val(val): 
     return val 

class BaseHandler(webapp2.RequestHandler): 

#this function uses the render_str funcion to display the html form in the browser 
def render(self, template, **kw): 
    self.response.out.write(render_str(template, **kw)) 

#this funcion is a simple function using the template engine to write out the required data with 
#any extra parameters 
def write(self, *a, **kw): 
    self.response.out.write(*a, **kw) 

def set_sec_coki(self, name, val): 
    sec_val = make_secure_val(val) 
    self.response.headers.add_cookie('Set-Cookie', "%s=%s; Path=/" % (name, sec_val)) 

def read_sec_coki(self, name): 
    coki_val = self.request.cookies.get(name) 
    return coki_val and check_secure_val(coki_val) 

def Initialize(self, *a, **kw): 
    webapp2.RequestHandler.Initialize(self, *a, **kw) 
    uid = self.read_sec_coki('user-id') 
    self.user = uid and Users.by_id(int(uid)) 


class Signup(BaseHandler): 
def get(self): 
    self.render("signup-form.html") 

def post(self): 
    have_error = False 
    self.username = self.request.get('username') 
    self.password = self.request.get('password') 
    self.verify = self.request.get('verify') 
    self.email = self.request.get('email') 

    params = dict(username = self.username, 
        email = self.email) 

    if not valid_username(self.username): 
     params['error_username'] = "That's not a valid username." 
     have_error = True 

    if not valid_password(self.password): 
     params['error_password'] = "That wasn't a valid password." 
     have_error = True 
    elif self.password != self.verify: 
     params['error_verify'] = "Your passwords didn't match." 
     have_error = True 

    if not valid_email(self.email): 
     params['error_email'] = "That's not a valid email." 
     have_error = True 

    if have_error: 
     self.render('signup-form.html', **params) 
    else: 
     u = Users.by_name(self.username) 
     if u: 
      msg = "User already exists" 
      self.render('signup-form.html', error_username = msg) 
     else: 
      sing_user = Users.register(self.username, self.password, self.email) 
      sing_user.put() 

      self.login(sing_user) 


      self.set_sec_coki('user-id', sing_user.key().id()) 

      self.redirect('/welcome') 


class WelcomePage(BaseHandler): 
def get(self): 
    coki_val = read_sec_coki('user-id') 
    u_id = coki_val.check_secure_val(coki_val) 
    part_usr = u_id.by_id(int(u_id)) 
    name = part_usr.username 
    self.render("welcome.html", username = name) 

Et ceci est la pile d'erreur que je reçois lorsque je tente d'enregistrer un nouvel utilisateur via le formulaire

Traceback (most recent call last): 
File "/home/bigb/google_projects/google_appengine/lib/webapp2/webapp2.py", line 1536, in  __call__ 
rv = self.handle_exception(request, response, e) 
File "/home/bigb/google_projects/google_appengine/lib/webapp2/webapp2.py", line 1530, in __call__ 
rv = self.router.dispatch(request, response) 
File "/home/bigb/google_projects/google_appengine/lib/webapp2/webapp2.py", line 1278, in default_dispatcher 
return route.handler_adapter(request, response) 
File "/home/bigb/google_projects/google_appengine/lib/webapp2/webapp2.py", line 1102, in __call__ 
return handler.dispatch() 
File "/home/bigb/google_projects/google_appengine/lib/webapp2/webapp2.py", line 572, in dispatch 
return self.handle_exception(e, self.app.debug) 
File "/home/bigb/google_projects/google_appengine/lib/webapp2/webapp2.py", line 570, in dispatch 
return method(*args, **kwargs) 
File "/home/bigb/google_projects/my-ramblings/blog.py", line 197, in post 
sing_user = Users.register(self.username, self.password, self.email) 
File "/home/bigb/google_projects/my-ramblings/blog.py", line 55, in register 
pw_h = make_pw_h(name, pw) 
File "/home/bigb/google_projects/my-ramblings/blog.py", line 32, in make_pw_h 
return "%s,%s" % (salt, hashlib.sha256(name + pw + salt).hexdigest()) 
TypeError: coercing to Unicode: need string or buffer, NoneType found 

Answer 1

Vous appelez make_pw_h() avec seulement deux arguments, name et pw. Vous laissez salt à la valeur par défaut, None:

def make_pw_h(name, pw, salt = None): 
    if salt: 
     salt = make_salt() 
    return "%s,%s" % (salt, hashlib.sha256(name + pw + salt).hexdigest()) 

Cela signifie que le test if salt: est False et vous vous retrouvez avec le passage None-hashlib.sha256.

Peut-être que vous avez voulu tester si salt est pas ensemble:

def make_pw_h(name, pw, salt=None): 
    if salt is None: 
     salt = make_salt() 
    return "%s,%s" % (salt, hashlib.sha256(name + pw + salt).hexdigest())