Object Caching in XP SP2 RC2

[Rade Todorovic]

Our Web applications use a custom COM class serving as an "object
cache": it can consume an object (and return a random "ticket"), and
can later retrieve the object (assuming the "ticket" is provided). Any
instance of this class accesses a global cache of objects (on the
level of the in-proc server). The main reason is to allow different
Web pages to reuse the same objects, under condition that they can
communicate the "tickets" to each other (i.e. we don't want to
circumvent any security model inherent to IE).

We have noted that, if an object is put into the cache on one Web
page, and then retrieved on another, the "permission denied" exception
is thrown upon the first usage of the retrieved object on the second
page. This behavior has been detected with XP SP2 build 2026 (with
JScript code). The object being put is some custom COM object (not
related to the browser). Setting FEATURE_OBJECT_CACHING to zero in
Registry solves this problem. However, the same problem does not even
arise in XP SP2 build 2149 (i.e., our object caching normally works
and permission is not denied).

Any explanations? Also, what will be the behavior of the final SP2
release (like build 2026? like build 2149? something else?)?

 

[Roger Abell]

You should take this to the SP2 prerelease newsgroups.
It is not surprising that you are seeing these differences
between the early and the recent build, as both IE and
in your case especially DCOM/COM behaviors have
been adjusted.

 

[Rade Todorovic]

You should take this to the SP2 prerelease newsgroups.

I already did, and I hope for answers from both sources.

It is not surprising that you are seeing these differences
between the early and the recent build, as both IE and
in your case especially DCOM/COM behaviors have
been adjusted.

Certainly. I am not surprised... Obviously Microsoft had implemented
two different mechanisms to prevent using objects (created on one
page) by a different page. One of them prevented our cached objects
(from our custom "object cache") working, while the other didn't.

As a bottom line, I am interested whether Microsoft is going to keep
the latter mechanism in the final SP2 release. However, I am also
interested in the internals of this mechanism (i.e. which particular
function is governed by this FEATURE_OBJECT_CACHING flag). I can make
my own assumptions, but until Microsoft issues an official explanation
(KB article ???), I won't be able to tell if I am right, and whether a
particular piece of code will work or not.

Therefore, this post can be regarded as an appeal to Microsoft, to
issue (at least an unofficial) detailed explanation of this "object
caching" feature in SP2.

Rade