All,
I am in the process of learning Google App Engine / Webapp2 and i'm having trouble saving an object to the datastore, redirecting to another page/handler, then fetching that object from the datastore. Forgive me if there is an easy answer to this question. The following is a description of the code I have.
I have a base handler:
class BaseHandler(webapp2.RequestHandler):
def set_secure_cookie(self, name, val):
cookie_val = make_secure_val(val)
self.response.headers.add_header(
'Set-Cookie',
'%s=%s; Path=/' % (name, cookie_val))
def get_secure_cookie(self, name):
cookie_val = self.request.cookies.get(name)
return cookie_val and check_secure_val(cookie_val)
def login(self, user):
self.set_secure_cookie('user', str(user.name))
# Called before every request and stores user object
def initialize(self, *a, **kw):
webapp2.RequestHandler.initialize(self, *a, **kw)
username = self.get_secure_cookie('user')
self.user = username and User.by_name(str(username))
I have a Signup page which inherits from BaseHandler:
class Signup(BaseHandler):
def get(self):
# Get the page
def post(self):
has_error = False
# Extract and validate the input
if has_error:
#Re-render the form
else:
new_user = User.register(self.username, self.password, self.email)
new_user.put()
self.login(new_user)
self.redirect("/blog/welcome")
If the user is a new user, the User db.Model object is created, the user is stored to the datastore, a user cookie is set and we are redirected to the Welcome handler:
class Welcome(BaseHandler):
def get(self):
if self.user:
self.render('welcome.html', username = self.user.name)
else:
self.redirect('/blog/signup')
The intent here is that upon redirect, BaseHandler.initialize() would get called and would set self.user of the new user I just created.
Here is what I know:
- When signing up a new user, I am redirected back to the signup page.
- If I then manually navigate to /blog/welcome, the page loads correctly with the new username populated.
If I add the following logging statements into Welcome.get():
username = self.get_secure_cookie('user')
logging.info("Cookie %r obtained inside of Welcome.get().", username)
logging.info("Found user %r", User.by_name(str(username)))
The cookie is obtained for the new username but no User object is found. Again, if I navigate directly to /blog/welcome, the logs report that the cookie is obtained and the User object is found for the new user.
The User object looks like so:
def users_key(group = 'default'):
return db.Key.from_path('users', group)
class User(db.Model):
name = db.StringProperty(required = True)
password = db.StringProperty(required = True)
email = db.StringProperty()
@classmethod
def by_name(cls, name):
u = User.all().filter('name =', name).get()
return u
@classmethod
def register(cls, name, password, email = None):
return User(parent = users_key(),
name = name,
password = password,
email = email)
Is there something about the datastore that is causing this first query to get the new user to return nothing? How should I proceed in debugging this? Is there additional reading I should do? (I have tried to provide all necessary code snippets but I can provide additional code if required.)