Sling Dynamic Include

The purpose of the sling dynamic includes (SDI) is to replace dynamically generated components (eg. current time or foreign exchange rates) with server-side include tag (eg. SSI or ESI). Therefore the dispatcher is able to cache the whole page but dynamic components are generated and included with every request. Components to include are chosen in filter configuration using the resourceType attribute.

When the filter intercepts request for a component with given resourceType, it'll return a server-side include tag (eg.  for Apache server). However, the path is extended by a new selector (nocache by default). This is required because the filter has to know when to return actual content.
Components don't have to be modified in order to use this module (or even aware of its existence). It's servlet filter, installed as an OSGi bundle and it can be enabled, disabled, or reconfigured without touching AEM installation.

Let's try ☺
Let's do this practically by loading a component with and without SDI.

Component without SDI:
Load the page without configuring SDI and check the view source.

Configure SDI:
Let's configure the SDI from ConfigMgr.

SDI Configuration

The filter is delivered as a standard OSGi bundle. SDI is configured via the configuration factory called SDI Configuration.

In the above screenshot, I have enabled SDI and entered the base path and the component to be included using SDI. I have selected include type as Javascript. So in view of the source we can observe that component is replaced with Javascript code.

Following properties are available:

Enabled - enable SDI
Base path - given SDI configuration will be enabled only for this path
Resource types - which components should be replaced with tags
Include type - a type of include tag (Apache SSI, ESI or Javascript)
Add comment - adds debug comment:  to every replaced component
Filter selector - selector used to get the actual content
Component TTL - time to live in seconds, set for rendered component (require Dispatcher 4.1.11+)
Required header - SDI will be enabled only if the configured header is present in the request. By default, it's Server-Agent=Communique-Dispatcher header, added by the AEM dispatcher. You may enter just the header name only or the name and the value split with =.
Ignore URL params - SDI normally skips all requests containing any GET parameters. This option allows setting a list of parameters that should be ignored in the test. See the Ignoring URL parameters section in the dispatcher documentation.
Include path rewriting - enable rewriting link (according to sling mappings) that is used for dynamic content including.

Component with SDI (Javascript):
Now configure the SDI include type as "Javascript". Reload the page and go to view source.

In view source, we can observe that SDI script is included.

<!-- SDI include (path: /content/sightly-test/_jcr_content/par/langcomp.nocache.html,

resourceType: sightlyProject/components/content/langComp) -->

<div id="dynamic_include_filter_div_1007"></div>

<script type="text/javascript">

jQuery.get("\/content\/sightly-test\/_jcr_content\/par\/langcomp.nocache.html",

function(data) {

jQuery("#dynamic_include_filter_div_1007").replaceWith(data);

});

</script>

Component loaded with SDI (Javascript)

Component with SDI (Apache SSI):
Now configure the SDI include type as "Apache SSI". Reload the page and go to view source.
In view source, we can observe that SDI script is included.

<!-- SDI include (path: /content/sightly-test/_jcr_content/par/langcomp.nocache.html,

resourceType: sightlyProject/components/content/langComp) -->