How to use/understand AEM Sling Resource Merger, override and Overlay concepts - aem

Am trying to understand the AEM Sling Resource Merger concept. As per the Adobe docs examples Override (Configuring your Page Properties), Overlay (Customizing the Consoles (touch-optimized UI)) am getting confused how to use this, can any one explain with simple component to understand it in more better way.

Here you go with an explanation
Overlay:
When you overlay a component in AEM means that copy component from /libs/ folder to /apps/.. folder. And you can impose your own definitions(like change title,group,business logic functionalities) on the newly copied components under /apps/..
As per the default OSGI preferences AEM uses a search path to find a resource, searching first the /apps/ branch and then the /libs branch so your newly copied components under /apps/ gets priority than the /libs/.
Note that we can modify search paths and its priority order by changing it from the Felix console Apache Sling Resource Resolver Factory configurations.
You can try overlaying these libs/foundation/components/ list, image, Text&Image, Carousel, etc,. simple components to play around and change the dialogs, jsp level functionalities and see the behaviour.
When you are overlaying a component remember that both components can show up in the authors sidekick, For your overlay /apps/.. component , if the title, componentGroups are the same as /libs/.. component, in design mode of the parsys to enable component can distinguish them with parenthesis around the component (foundation) vs (your project).
Override:
Also you can extend/override Component behaviour by using sling:resourceSuperType property.
Creating a custom component manually by creating all necessary nodes and setting value of sling:superResourceType property to that component will inherit all the feature from /libs/ component, even after upgrade you still inherit the features of image component.
Here we can use the sling:superResourceType for any component that you want to inherit functionality (example from projectA component to ProjectB etc., not only restricted to libs).
There is a usage difference for the overlay from AEM 6.0 versions onwards as the new Granite Touch UI has been introduced, have a look at Adobe Documentation
Sling Resource Merger:
Have look at the Sling Resource Merger for understanding the Resource Merger bundle concept. It’s a Sling framework bundle (org.apache.sling.resourcemerger) which gives you flexibility to have merged view on multiple other resources. The exact merging mechanism depends on the resource picker implementation (i.e. Overlay or Override).
By this Sling Resource Merger It is possible to
remove existing resource/properties from the underlying resources,
modify existing properties/child resources of the underlying resources and
add new properties/child resources
The resource merger provides the following properties to achieve the above
sling:hideProperties (String or String[]) -- Specifies the property, or list of properties, to hide.The wildcard * hides all.
sling:hideResource (Boolean) -- Indicates whether the resources should be completely hidden, including its children.
sling:hideChildren (String or String[]) -- Contains the child node, or list of child nodes, to hide. The properties of the node will be maintained.
The wildcard * hides all.
sling:orderBefore (String) -- Contains the name of the sibling node that the current node should be positioned in front of.
AEM default installation you will have this bundle available the same can be verified from your Felix console with bundle symbolic name org.apache.sling.resourcemerger
The goals for using the Sling Resource Merger in AEM are to:
ensure that customization changes are not made in /libs.
reduce the structure that is replicated from /libs.
Let’s go to an AEM example to implement or utilize it
Currently am going to overlay the Tools related node jcr:title value which is under /libs/ to /apps
Now update the jcr:title property alone on the overlay component node property which is under /apps/..
Like this you can overlay any component from libs and update the required functionality changes to that particular nodes
Let's see one more example usage of sling Resource Merger property
Here as shown above I have overlayed the sites node also along with the jcr:title property I have added the sling:hideProperties as shown below.
Now look at the output of the sites title in the touch UI page navigation.
Similar way you can play with other properties as well. Hope it helps.

Related

Is it possible to have a container prepopulated with a specific component through a prototype page in Hippo CMS / brXM?

In an attempt to set up a new page with a single vbox container I'm able to get the container to show in the Channel Manager but this requires the CMS editor to add all of the individual components by hand. Alternatively we can place components directly on the page and through the configuration in the prototype but that does not allow the CMS editor to edit the component configuration (Info) or associate a document. The question is then, in an attempted compromise, is it possible to repopulate the container with a specific component so that the the CMS editor is provided a default set of components in the containers when creating a new page from a prototype/template page?
I believe the key term you are looking for is hst:prototypepages
Their documentation can be found at https://documentation.bloomreach.com/14/library/concepts/hst-configuration-model/prototypepages-configuration.html but basically you can define the prototype having certain components already on the page - and possibly even default settings for those components.
A similar concept at the component level is the hst:catalog
You can define "component prototypes" with default settings for when they are placed onto a page.

Setting sling:resourceSuperType to a carousel and remove property not working in AEM 6.1

I have a test web page that contains one component, a carousel.
That component was copied from /libs/foundation/components/carousel and what i have modified from the copied component was the property:
sling:resourceSuperType from foundation/components/list to foundation/components/carousel.
My next step was to remove a property from the touch dialog (the property Controls Style).
My problem is that in my web page i keep seeing this property even when it was deleted.
Is this because the resourceSuperType is foundation/components/carousel and because this component stills have the property i'm seeing in the dialog?
This behavior was not like this in AEM 5.
My intention was to copy the component, keep the inheritance (resourceSuperType) and modify the copied component.
What i'm doing wrong?
EDIT: Making some tests i figure out that in AEM 6.0 if i delete a property of the carousel (my copied carousel), the property doesn't appear. BUT in AEM 6.1 the property appears. Where can i found this change between the two versions? or is something else?
When creating an overlay, you're going to find all properties from the original component even if they don't exist in the overlay.
You'll have to explicitly remove the property by adding the sling:hideProperties property of type String[] to your overlay. This will allow you to hide the values otherwise inherited from the node from /libs that you're trying to overlay.
I think you'll find the descriptions of various use cases for the sling:hideProperties property in the documentation quite useful.
As part of of it's resource resolution process, the Sling Resource Resolver has search paths that it looks in to locate a resource.
The two most common search paths are /apps and /libs. With the /apps path taking precedence. The most common usage of this in sling:resourceType where the value is defined as the path below one of these search paths. In your case having a sling:resourceType of foundation/components/carousel would originally return the OOTB components under /libs and when you copied it to the /apps directory it would return the component you put under /apps.
This concept of replacing the existing component with your own component is called an overlay another method is called extending an component where you define a sling:resourceSuperType which, if a resource is not found in the existing path, will pass the request to the superType to see if the resource can be found there.
Before 6.0 this concept of overlay applied only to resource. Which is a node that contains properties (simplistically speaking.) And in most common usage you have to reflect the majority of the component into the new search path to get what you are trying to do.
Starting in 6.0 there was a new concept of a merged resource. That would combine the values of a resource located in multiple search paths. This allowed you to modify or alter the functionality of a component without replicating everything else. You could just change a property at a particular level.
None of this happens automatically. To get this functionality the component needs to be aware of the ResourceMergerApi and use that API when attempting to resolve resources for it to use.
That's why the documentation mentions granite. Granite refers to the new components being written by Adobe that uses the TouchUI and is aware of this new API. With each new release more and more older components are being replaced by the new TouchUI based ones that supports resource merging. Including the carousel.

how properties are stored in /etc/designs for design dialog

I'm new to CQ5 and working on a project that deals with refactoring code that uses design dialogs.
Currently, I have a property declared as part of design dialog of my component. It creates a folder in /etc/designs/ for each template my component is used on. Is there a way we can make sure that those property values are stored at one particular configuration in /etc/design(as opposed to multiple)? I need to make sure only one set of configurations is used for all pages that use my component.
Thanks in advance!
Pallavi
The designs are linked to the template and not the whole site.
Hence whenever you configure the component in design mode, the values are stored within the corresponding template under the jcr:content of the configured design page or under /etc/designs/default/jcr:content in case no design is configured.
As far as I know, there is no way to tell AEM to store all the design configurations under one single path, unless you are using absolute paths in your dialog / page configurations.
If you are using multiple templates in your site, there must be one master template (which render global components eg. header/logo/navigation & footer), and all other templates should extend master template to get these global components and change pagelayout for content section.
Saying so, if templates are structured & inherited properly, you should be able to set design dialog property on home page (created using master template) and all internal pages will be able to access those design property OOB. Though child pages (created using other template) can override those design property (if needed for that template) to break inheritance.

Why exactly templates are needed in CQ?

Why exactly do we need templates when all a template does is to have a resourceType property attached to a content-page component.
At the time of creating new page, shouldn't authors directly select that component instead?
The template nodes define the metadata for the page that will be created, one aspect of which is the underlying resource type (i.e. the Page component that will be used to render out the content).
Some example of other things configured at a template level include:
The default content that is included when the page is created. This
is stored under the template node itself, i.e. in /apps/[your-site]/templates/homepage.
For example, you could add a carouselnode underneath the homepage node, to ensure that any page created with the homepage template will have a carousel node added by default.
The allowed parents & children of the template — e.g. configuring the homepage template so that it can't be placed beneath other templates.
The allowed components in each parsys — In /etc/designs/[your-design]/jcr:content, you can defined what components can be added to a particular parsys, which applies to any page using that template.
By having a separation between templates & page components it allows us to re-use the same renderers (e.g. JSP scripts), but have aspects like these configured differently for different templates.

Adobe CQ5 component properties for templates

It seems to be quite basic problem, but I still cannot find a nice solution.
I made a component that uses a dialog property.
How could I avoid setting this property for every single page if this component is used also in template?
What I already have tried:
I set name attribute in dialog.xml to absolute path - Component stops working as standalone (dropped into parsys).
Move it to design_dialog.xml - First of all it's conceptually content, so I do not like such move, and again it doeas not make much sense for standalone versions.
Change resource path to absolute, while including in template:
<cq:include path="/content/site/somepage" resourceType="/apps/portal/components/myComponent" />
For the first look it was almost it. Instances included via parsys has it's own path, and Content for template is fetched from single resource... But where to store it, to make template code independent from pages tree structure?
Is there any other nice way to do so? or at least way to improve 3.?
To the original poster, the functionality you are looking for is now supported by Shared Component Properties in ACS AEM Commons (http://adobe-consulting-services.github.io/acs-aem-commons/features/shared-component-properties.html)
Compared to your suggested solutions:
No need for absolute property path required for SCP
Agreed these are "content" properties, so they should be stored as "content" instead of "design". SCP stores these values under the homepage node of a site, making them as genuine of content as any other piece of content.
Agreed that it is bad to have a template hard-coded to a content path of a single site, especially since this makes a multi-site implementation impossible without creating a bunch of templates. SCP does not have this problem, because each site has its own homepage under which the properties are stored.
If I understand correctly, you have a component which may work in two modes:
it may be included statically in the main page renderer via <cq:include>
it may be also dropped into some parsys.
In the first mode component should have some common configuration for all pages and in the second mode it should be configured separately per-instance. The problem is how to create such common configuration.
I think your 3rd solution is perfectly fine assuming that the component configuration is shared by all sites in your CQ instance. At some point it may be too strong assumption, eg. you may have a 3 language branches under /content/site-en, /content/site-fr and /content/site-de and you'd like to make a separate configuration for each branch.
I'd suggest following improvement to the 3rd solution: you may create the shared component under some relative path which will be the same for all pages, like /content/.../configuration/shared-component (where ... may be site1, site2 or site3). Then take first two parts of the current page path, add the /configuration/shared-component suffix and use <cq:include> to include path created in such way.
You may also take a different approach and create a common configuration page referenced by all statically included components. These components may try to find their configuration automatically (via the relative path as above) or they may have a single pathfield that references configuration page.
If you don't like these options (as they assume some site structure or they need some minimal configuration for each component), consider using HierarchyNodeInheritanceValueMap. It allows you to get property from the current resource and if there is no such property, it'll look into the same resource on ancestor pages. Using this you could configure your component just once, in the site root page and inherit configuration across the whole site.