Web Single Sign Out–Part II
Following up on previous post, there were 2 questions:
Where do these green checks images come from? There are nowhere in a-Order or in a-Expense… you would spend hours looking for the PNG, or JPG or GIF and you will never find it, because it is very well concealed. Can you guess where it comes from?
I was referring to the green checks displayed here:
The src for these is a rather cryptic src=http://localhost/a-Order/?wa=signoutcleanup1.0
And the answer is: it’s coming from within WIF (the FAM more specifically). If you explore the FAM with Reflector you will see a byte array embedded in the code. That byte array is the GIF for the green check. Exercise to the reader: is this the only behaviour? Can the FAM do something else? under which circumstances?
The second question was:
Bonus question: how does the IdP know all the applications the user accessed to?
No WIF magic here. The issuer will have to keep a list of all the RP. In our sample (that we expect to release really soon) we use exactly the technique described in Vittorio’s book. We have a small helper class “SingleSignonManager” that keeps track of RPs in cookies:
Then, when the signout request is received, we simply iterate over the list and return the right markup:
The SingleSignoutManager class is mentioned in Vittorio’s book but not available there, so we included it in the sample.