Displaying a (really) variable variable on an otherwise cached page

patricka

Tough questions! While pondering the answer, my roommate stumbled upon the following bit of code in the wmpcommunityedition xslStyleSheet.jspf:

<c:forEach var="presentation" items="${website.presentations}">
    <c:if test="${presentation.scopes[0] == 'WebSite' &&
              fn:startsWith(presentation.identifier,'xslStyleSheetWCB')}">
        <wm:render presentationName="${presentation.identifier}" />
    </c:if>
</c:forEach>

A hook!

This means that if you start the name of your presentation with "xslStyleSheetWCB" and give it scope "WebSite", it will be picked up and rendered in the general stylesheet.

See, personalization is all about getting the expressions in the XSL stylesheet. This hook will allow you to create a presentation and have it embedded in the XSL stylesheet. E.g. like below:

<!-- chtulhuLovesUserid.xml -->
<presentation>
    <name>xslStyleSheetWCB Cthulhu Loves Userid</name>
    <display-name>Cthulhu Loves Userid</display-name>
    <scope>WebSite</scope>
</presentation>

and

<xsl:template match="wm-cthulhu-loves-userid">
    <xsl:value-of select="/root/system/user/userid"/>
</xsl:template>

And elsehwere you would put that tag to good use in your favorite .jspf.

As for the second question: I don't think there is a better way to determine the userid, because your code will probably not be called at all because of caching. If you want to execute code and be sure of the userid, use personalization to determine it and use that id in either a server side include (SSI) or an AJAX call.

Greetings,

Patrick

Displaying a (really) variable variable on an otherwise cached page

Cthulhu

Yeah, that looks like it'll do what I'm looking for. Just a few more questions, bear with me ^^.

* Is it possible to add this personalization through a WCB's code? You know, so the WCB will work out of the box.

* Is there (again, in code) a neater way to get the current user's ID than to manually parse or extract the ID from the HttpSession? Can that xquery be executed on some API-available object to get the same results?

Edit: Yeah, that'll do the trick, =D. Thanks you guys.

Displaying a (really) variable variable on an otherwise cached page

patricka

It just so happens that I was training this topic today!

The document "Personalization Toolkit" is your friend. Also, take a peek at the XMLdebug info to find out the XPATH expression to the userid.

In short: I'm guessing that making a "select" expression for "/root/system/user/userid", tagging it as "wm-cthulhu-loves-userid" and typing a tag <wm-cthulhu-loves-userid/> somewhere on the page would do the trick.

Greetings,

Patrick

Displaying a (really) variable variable on an otherwise cached page

Cthulhu

I'll go give those personalization expressions a look at, thanks. And yeah, I guessed as much about the caching and JSP snippets, .

Displaying a (really) variable variable on an otherwise cached page

martinvm

Hi Cthulhu

It is not recommended to use Java snippets in JSPs (as is stated in the Design API manual) because their behavior is unpredictable in environments with heavy caching. JSPs are only rendered again if the timestamp expires, which is not on every request.
If you need truly dynamic calls you have to use other methods such as personalization or filters or a combination of both.

Displaying a (really) variable variable on an otherwise cached page

williamb

While I was reading the upper half of your message I was thinking "Would the cache allow this? As the page itself doesn't change, the JSP wouldn't be rendered again...".
Reading the rest of the question confirmed my thoughts: that is caching!

Why not add a personalization expression here like <wm-userid> and use personalizations to render your data here?