I had posted this question to four different Java fora over four days and gotten zero replies, when it occurred to me how stupid not to ask the community that wrote Tomcat. I was just going to post this, which is a summary that describes what I've found so far: -- QUOTE -- In the interest of informing the community, I'm publishing the results of four days of testing and debugging of XMLHttpRequests and attributes. This has led me to the conclusion that servlets invoked with an XMLHttpRequest do not have the same access to server-side objects (actually, attributes) as those invoked via the normal URL mechanism. I don't know why, because if I insert a filter, the filter gets executed, albeit the first time with the wrong session ID.
I began this odyssey when a filter in place to check if a user's session had timed out would fail the first time when invoked with an XMLHttpRequest, but would work each time thereafter. What I discovered there was that there were two JSESSIONID cookies stored and being sent in the browser and the jsp and other servlets were requesting the correct one. The xml request was not, it was requesting the (old? I don't know) invalid JSESSIONID. One would think, "OK, I'll just read the cookies in my servlet, check each ID with request.isRequestedSessionIdValid(), and force the right one". Wrong. All of the http session APIs that allow one to manipulate the session ID and force a good one are deprecated, according to Sun's web site, so the programmer isn't allowed to find & use a good session ID. In order to progress while I waited vainly for a reply, I just removed the filter from the servlet's path so it didn't invoke it. I want the filter to check, but decided to move on in the meantime. That's when I discovered that, evidently, the servlet does not get a valid session ID either. I had the following line in my XMLHttpRequest servlet: [code] HttpSession sess= req.getSession(); [/code] This seemed to execute and work fine, until I needed to access session-scoped attributes I had defined in other pages or servlets. The were repeatedly null. When I changed the above line to this: [code] HttpSession sess= req.getSession(false); [/code] the reason was apparent: the servlet was generating a brand new session for me. So, for some reason, XMLHttpRequests don't get the same treatment that normal servlets get. I'm going to have to go and modify a lot of code to pass stuff around as query parameters in URLs, which I really don't want to do for both aesthetic & security reasons, but see no alternative. Hopefully, there really is someone out there that knows more about this than I do and can explain to the community & me what's going on. -- END QUOTE -- 1. So the last paragraph has my main question in it: why can't I access attributes in a servlet invoked via an XMLHttpRequest? However, I have a another important question and a couple of ancillary ones as well: 2. What is the difference in the servlet invocation between a regular URL invocation & an XMLHttpInvocation? 3. How can I get my filter to work? I. e., get it the correct session ID? 4. WHY are all the session manipulation APIs deprecated, and, at least according to Sun's web site, not being replaced? It seems unusual to be removing control from the programmer/software engineer instead of trying to give him more control over his environment. With those APIs I could have fixed this (well, kludged it up, anyway). If you need me to post any code, I'll be glad to, but it's really pretty straightforward. In fact, when I started this adventure, the servlet was empty except for print statements, and the filter has been in place & working for months. Thanks!! anw --------------------------------------------------------------------- To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
