All,
I am desktop developer in the process of learning Google App Engine and
Webapp2. I am 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):
...
def post(self):
logging.info("Inside Signup.post()")
has_error = False
self.username = self.request.get('username')
self.password = self.request.get('password')
self.email = self.request.get('email')
# Validate the input
if has_error:
self.render('signup-form.html', **signup_params)
else:
# Ensure user does not exist
u = User.by_name(str(self.username))
if u is not None:
msg = "User already exists."
self.render('signup-form.html', username_error = msg)
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():
class Welcome(BaseHandler):
def get(self):
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)))
if self.user:
self.render('welcome.html', username = self.user.name)
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()
created = db.DateTimeProperty(auto_now_add = True)
updated = db.DateTimeProperty(auto_now = True)
@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.)
Thanks,
Charlie
--
You received this message because you are subscribed to the Google Groups
"Google App Engine" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/google-appengine.
For more options, visit https://groups.google.com/groups/opt_out.
