Re: How to Retrieve Session User?
Re: How to Retrieve Session User?
- Subject: Re: How to Retrieve Session User?
- From: Fred Shurtleff <email@hidden>
- Date: Wed, 04 Apr 2007 20:34:01 -0400
Gino, Mark, Chuck, Mike,
I have tried all of your 'best practice' suggestions (not Chuck's yet),
and STILL have no luck. To recap, this is my setup:
Session.java (declare a user)-
protected EOEnterpriseObject user;
Main.java (fetch/authenticate, & set the user in session)-
// fetch the user
EOEnterpriseObject user =
EOUtilities.objectMatchingKeyAndValue(session().defaultEditingContext(),
"User", "name", username);
// set the session.user
((Session) session()).takeValueForKey(user, "user");
Post.java (get the user for inserting transaction)=
EOEnterpriseObject user = (EOEnterpriseObject) ((Session)
session()).valueForKey("user");
At this point (using the debug mode) the user is null!! This seems so...
basic, yet I cannot see the problem. So if you see something awry,
please shout again.
Now what I think Chuck & Mike is saying is the above approach is 'taking
a short cut' so-to-speak(using built-in KVC settor/gettors), and is
lacking for reasons mentioned. A better practice is to code explicit
java methods to message (get/set) objects - a la OO Programming style.
I appreciate all your help & suggestions - Fred
Chuck Hill wrote:
Adding onto Mark's comments... KVC is for when you can't use
statically compiled Java. Using KVC instead of statically compiled Java:
- reduces the chance of having the compiler catch your mistakes
- makes the code harder to read
- makes it harder to make naming changes
- makes you a bad person ;-)
In your session you should have:
private User loggedInUser;
public void setUser(User user) {
loggedInUser = user;
}
public User user() {
return loggedInUser;
}
And your code sample should read:
// set the session user
((Session)session()).setUser(user);
...
EOEnterpriseObject user = ((Session)session()).user();
And if it still evaluates to null, then your code is probably
creating more sessions than you realize.
Chuck
On Apr 4, 2007, at 3:58 PM, Mark Morris wrote:
Hi Fred,
KVC is certainly an integral part of WO, but much of that is a bit
behind the scenes. For instance, if you create the user() and
setUser() methods in your Session class, WO's KVC implementation is
what lets you bind session.user to a WOString in a component. So you
get the advantages, while still getting the benefits of proper
methods that Mike was mentioning (such as some compiler error
checking, easier maintainability/internal documentation, and the
ability to put some logic in the accessor methods).
Regards,
Mark
On Apr 4, 2007, at 5:22 PM, Fred Shurtleff wrote:
Chuck,
I would welcome your comments on my KVC usage.
I was actually surprised by Mike's statement re: KVC 'funnybusiness'
as I was led to believe from my readings that KVC was a very
integral part of WO. And the KVC concept seems very straight-forward
to me - what can be simpler than takeValueForKey( value, key)? Also
this is the technique I have learned from a number of tutorials.
But then I am unable to put/get a user into the session - so there
must be something I am missing. Actually I have tried so many ways
to retrieve the user, I now think I never got the user into the
session to begin with. :-)
Chuck Hill wrote:
Listen to Mike. I was just about to write and make the same
complaint of your code. Abusing KVC is NOT your friend.
Chuck
On Apr 4, 2007, at 1:45 PM, Mike Schrag wrote:
PERSONALLY, I'd stop all this KVC funnybusiness. It has its place
and it's really powerful, but you're making your life way
obnoxious. Let Java do its job and just call methods on things --
there are LOTS of benefits of this. Define a proper user field on
your Session class and do setUser(..) and user() to retrieve it.
On Apr 4, 2007, at 4:40 PM, Fred Shurtleff wrote:
Mark - I understand where you are coming from, and did try your
suggestion. But I still am NOT getting a user EO instance (I get
null per the debugger).
Actually I checked the WO docs and both valueForKeyPath AND
valueForKey are valid methods of the Session class. Problem is
what is the correct syntax. The docs say
object.valueForKey(string), and your suggestion provided the
object part (ie session()) (I also tried your input +
valueForKeyPath but Eclipse complained about 'no such key =
session')
So I still am at a loss on how to retrieve a user EO from the
session. :-(
But thanks for your help/input!
Mark Morris wrote:
Hi Fred,
On Apr 4, 2007, at 3:10 PM, Fred Shurtleff wrote:
Hello,
I have a basic question on how to access the logged in user for
later use in updates. After authenticating a user I enter him
into the session, but when I later try to retrieve this user in
another page, it fails(returns null).
So in my main page I record the user as follows:
if (_password.equals(password)) {
EOEnterpriseObject user =
EOUtilities.objectMatchingKeyAndValue(session().defaultEditingContext(),
"User", "name", username);
// set the
session.user
session().takeValueForKey(user, "user");
And on another page to add a new transaction which needs the
user relation attribute(as a foreign key):
EOEnterpriseObject user = (EOEnterpriseObject)
valueForKeyPath("session.user"); // user evals to null???
Try changing this to:
EOEnterpriseObject user =
(EOEnterpriseObject)session().valueForKey("user");
valueForKeyPath is useful, but I don't think it can do what
you're asking of it here.
purchase.addObjectToBothSidesOfRelationshipWithKey(user, "user");
The save fails because user is a required attribute. And I'm
not sure if I am not properly storing the user in the session,
or not properly retrieving the user from the session.
Can anyone see what I am doing wrong or suggest another approach?
TIA
Personally, I usually make currentUser an actual variable in
Session. (Private, with public accessor methods, of course! ;-)
Regards,
Mark
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overall knowledge of WebObjects or who are trying to solve specific
problems.
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