How to set GLOBAL VARIABLE at Page level, which is used by all LS component

Hi ,
I have got a scenario in which I have around 300 pages and each having around 15 LiveSite components. Each component make a call to there respective External Java Class.
In each of this Component we have to set a Common Value in the Component Properties, which is being used by the External component.
So in this scenario for a page we have to perform the same activity for all the 15 components. This is very tough for the content Authors.

Is there any way we can Set some GLOBAL VARIABLE at page level , which can be used by all the LS Components on that page.

Any suggestion will be very much appreciated.

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annu1

Hi,

I am not very sure that we can set the global variable at page level may be some other member can suggest u better.

I have one work around to do this...

U needs to set the too many global variables? If yes then u can do the following steps.

1) Create a DCT for all the required global variables.
2) Create a DCR with all the information (It provide the flexibility to content creator to modify or update the DCR info at any point of time. With the DCR u can provide the language specific info if u’r site is language specific and also create the separate DCR for each site)
3) As you are calling the external java classes so get the Workarea path and append the templatedata data path to get the full DCR path.
4) Append the xml (DCR) to the result using document.
5) As information is available in as a result XML use that info in xslt

You can also cache the DCR xml so that you don’t need to parse it again(Increase performance tm)

Thanks
Anu

Anu

AlexC

PageScope was designed for this purpose. You would use a site controller (which is executed for all pages in a given site, or page controller which is executed for a specific page) and set the variable inside the map. This value is then available to all components by accessing the same map (via component controllers, prefix or external calls) or $PAGE_SCOPE[] page token directly on the page. See RequestContext interface and the developers guide for more information. This is available in TS672Sp2 and later.

eaparicio

Hi, I am having similar trouble. Using page pre-controller, I am calling the following method:

public ForwardAction setPageScopeVar(RequestContext context)
{
try{
String mboxValue = context.getParameterString("mbox");
if(mboxValue != null){
context.getPageScopeData().put("mbox", mboxValue);
}
}

catch(Exception e){
System.out.println(e);
e.printStackTrace();
}

return null;
}

and using this to write to servletd_out.log

System.out.printf("context.getPageScopeData() equals %s\n",context.getPageScopeData());
System.out.printf("context.getPageScopeData().keySet() equals %s\n", context.getPageScopeData().keySet());
System.out.printf("context.getPageScopeData().get(\"mbox\") equals %s", context.getPageScopeData().get("mbox"));
System.out.println("\n*****\n");

I have 7 components that read from same pagescope map set at page level with pre-controller but all but 1 display null value.

Any suggestions on how to get all 7 components to read from pagemap consistently?

Adam Stoller

Hi, I am having similar trouble. Using page pre-controller, I am calling the following method:

public ForwardAction setPageScopeVar(RequestContext context)
{
    try{
        String mboxValue = context.getParameterString("mbox");  
        if(mboxValue != null){
            context.getPageScopeData().put("mbox", mboxValue);
        }
    }
    catch(Exception e){
        System.out.println(e);
        e.printStackTrace();
    }
    return null;
}

I won't profess to know anything about page controllers, but the above code always returns

null

which cannot be what you want / need.

AlexC

There is an isolated PageScope map for each component and one for the wntire page available to page/site controllers. You cannot use PageScope to communicate data from controller to component (use session for that). When a page is rendered, all page scope maps are merged and you have to use $PAGE_SCOPE[name] to extract the value. This allows isolation of component execution and also accounts for no guarantee to order of execution constraint. The code puts name/value pairs into the page scope map and during rendering $PAGE_SCOPE token extracts it, you can't programatically extract values from it since the actual map is different for each component.

eaparicio

Ghoti: Thanks for your reply, in this case, my goal is to add to PageScope map using context.getPageScopeData().put("mbox", mboxValue);

Alex: I almost get it, just need clarification on the session. Are you saying I should do this?

1. Page controller creates session variables (key/value)
2. Each component reads from session variables to set local pagemap within each component instance
3. Use $PAGE_SCOPE[] page token to extract value

Two questions however, are:
1. In an earlier exercise, I discovered session variables are not read during page generation, wouldn't this create null values for step 2 above?
2. I want to extract value directly from pagescope map via external and test value in an xsl test. I discovered earlier that page tokens are evaluated after xslt transformation so this wouldn't help either.

Thank you very much for your help.

Adam Stoller

Ghoti: Thanks for your reply, in this case, my goal is to add to PageScope map using context.getPageScopeData().put("mbox", mboxValue);

Be that as it may - the code you posted always returns null regardless of whether the above code succeeds or not - and as the method is defined as returning an object of type ForwardAction, presumably somewhere you would need to create such an object and return it (on success).

Like I said, I don't know anything about LiveSite development work - I'm just saying that the code you posted appears to be definitively wrong with regard to distinguishing between success and failure.

eaparicio

Very strong argument Ghoti and I thought about it early on too. Here's an abstract from the doc, ls_310_spdev_v02.

The payload for a Controller (all types) is an optional ForwardAction based class
that can be used to redirect the user to a different page. If a controller returns null,
the rendering engine assumes that no redirection is needed and execution is to
continue.

AlexC

Since you are offline generating the actual page into HTML, then true the session does not exist and page scope will only let you place items into it so they can be read during rendering.

Here is how to get the token to work:

1. In your controller (site/page/component) or external do:
context.getPageScope().put("mbox", mBoxValue);

2. In your XSL/skin you access it using:
$PAGE_SCOPE[mbox]

eaparicio

Is $PAGE_SCOPE[mbox] available during xsl test?

[HTML]

yes

no

[/HTML]

In the past, testing with page token values always failed since value was null (page tokens evaluated after xsl). Nevertheless, I'll give it a try.

vpatel

Be that as it may - the code you posted always returns null regardless of whether the above code succeeds or not - and as the method is defined as returning an object of type ForwardAction, presumably somewhere you would need to create such an object and return it (on success).

Like I said, I don't know anything about LiveSite development work - I'm just saying that the code you posted appears to be definitively wrong with regard to distinguishing between success and failure.

Returning null is fine for this use case. He/she is not trying to redirect to some page that is why it should be null. All that is tried is setting some variable.

vpatel

Is $PAGE_SCOPE[mbox] available during xsl test?

In the past, testing with page token values always failed since value was null (page tokens evaluated after xsl). Nevertheless, I'll give it a try.

This will likely fail. $PAGE_SCOPE token in XSL is being resolved during the XSL transformation and so is the XSL choose / when statement. You can render the token value just fine in XSL -- but trying to put a conditional statement around it in XSL will likely fail.

You should put that logic somewhere else -- Page level controller or something.

Stokes

Regarding the original question, are we talking about a configuration value, something that's the same on all 15 components on all 300 pages, but has to be set by the page author when they use the component on a page?

Or is this something that's dynamically computed?

For the former, I'd use a properties file. The idol-enabled components have an example of this. All the components use the same idol.properties file for site-wide configuration.

This is done using the PropertyConfiguration class, which is in developer.spar (in /install but not pre-installed in SP by default). The javadoc for that class says:

/** * A lightweight utility class that returns configuration properties that * ultimately reside in a properties file. The properties file can be read at * design-time or run-time, and gets cached at runtime using an * application-scoped cache.
...

Seems like even if you needed to set a global variable dynamically at the page level, but you want the value to outlive page rendering, then you'll want to use a technique similar to what that class does. Its source is in the spar.

Stokes.

Migrateduser

Be that as it may - the code you posted always returns null regardless of whether the above code succeeds or not - and as the method is defined as returning an object of type ForwardAction, presumably somewhere you would need to create such an object and return it (on success).

Like I said, I don't know anything about LiveSite development work - I'm just saying that the code you posted appears to be definitively wrong with regard to distinguishing between success and failure.

I didn't initially catch this when this was posted, but I believe you're wrong in this instance, ghoti. I'm assuming that LS's request routing in controllers is basically a thin layer over Struts based on some of the naming. If that is true, returning a null ForwardAction is perfectly acceptable. It's a signal to the caller that the request has been completed. I believe that prevents it from routing you to a different page. Mind you, that answer is a combination of speculation and reading of the Struts reference. The LiveSite documentation on this particular point is poor - so it's possible that your interpretation is correct and mine is wrong.

Migrateduser

Since you are offline generating the actual page into HTML, then true the session does not exist and page scope will only let you place items into it so they can be read during rendering.

Here is how to get the token to work:

1. In your controller (site/page/component) or external do:
context.getPageScope().put("mbox", mBoxValue);

2. In your XSL/skin you access it using:
$PAGE_SCOPE[mbox]

I have a related issue. I have a component that is setting RuntimePage.PAGESCOPE_TITLE as described in the docs, e.g.:

[PHP]context.getPageScopeData().put(RuntimePage.PAGESCOPE_TITLE, title);[/PHP]

If I log right after setting, I can see that it has set it, that is this:

[PHP]LOGGER.warn("After set PSD has " + context.getPageScopeData().entrySet().size() + " entries");[/PHP]

logs out this:
16:17:46,983 WARN [SetPageTitleRob] After set PSD has 1 entries

The issue I am having is that I have another component that needs to access that entry, but it needs to do it earlier in the lifecycle than token rendering. Basically, its a header component that displays the page title. Ordinarily it uses the node name from the site map, but in certain instances it is overridden with a value stored in page scope. When I try to access that value via an external on the other component, it appears that the map is empty:

That is, this:
[PHP]Map PSD = context.getPageScopeData();
LOGGER.warn("Map has " + PSD.entrySet().size() + " entries");[/PHP]

logs out this:
16:17:47,077 WARN [RobDebugController] Map has 0 entries

If I drop the Debug component on the page, it too shows that PAGE_SCOPE is empty, however, it shows the proper values in the $CONTEXT{pageScopeData} token.

I have a theory that this paragraph in the documentation:

Components are all executed and each updates their own local map first. Then, the page is redered and all component maps are combined and used in the output. This token is accessed using external code RequestContext.getPageScopeData() as a Map type where you can add name or value pairs via prefix or external code and extract it to the page.

is implying that context.getPageScopeData() is returning just the local component's map. Is that correct, and if so, is there any way to get the aggregated map prior to the token rendering phase?

If not, is it possible for data that is manipulated by a Prefix on one component to be available to an ordinary Object External on another?

Thanks,
Rob

AlexC

Inter-component communication is not available due to "undefined" order of component execution. However the final output on a page can contain contributions from controllers and components.

The page has a page scope map.
Each component has a page scope map.

When a page is rendered, the page scope of the page is merged with page scope of each component (if there is a conflict the string value data is appended for all cases except the special keywords where the data is comma separated and title which is replaced by latest). Based on that title should only be set by 1 component (or controller) for predictability.

The title has always been a special case since you can set it from the RequestContext (old functionality that was left in for compatibility).

So the merge occurs when the entire page is being rendered and after all the components have executed, so there is no customization point to allow access to the merged map except to get values out using $PAGE_SCOPE.

For your issue I gather that you want 2 components to communicate which is not reliable due to unpredictable rendering order (it is related to order in which the component appears in the actual page HTML). You can use the session to communicate between site/page controllers and components which is guaranteed to occur in order (site controller first, the page controller, then components).

Does that help?

Migrateduser

Thanks, Alex.

Yes, that is helpful. In an ideal world, I think what I would want would be more granular control of the lifecycle, similar to the set of events that one has in ASP.NET. It seems like you guys could put some more thought into inter-component communication in a future release. I'm not super-familiar with how this sort of thing is handled in portal products, but from a quick read it seems like implementing something analogous to the JSR-286 IPC spec would provide all the necessary bits.

Then again, PAGE_SCOPE seems to function a bit like public render parameters, and I guess the intent of events is more for interaction as a result of a user action.