On Monday 21 December 2015 18:01:40 Stefan Seifert wrote:
> the current sightly script engine implementation provides some hooks for
> extensibility: - provide own script bindings via
> o.a.s.scripting.api.BindingsValuesProvider - provide own runtime extensions
> vis o.a.s.scripting.sightly.extension.RuntimeExtension
>
> but it does not seem to support defining custom block statements (custom
> data-sly-xxx functions). although the sightly implementation is nicely
> modularized here and uses OSGi to define it's own plugins for block
> statements, the Plugin interface [1] is in a private package.
>
> is this intentional, or can we change it to support customizations here?
AFAIK it is intentional [and I have no strong opinion if it should be opened
up for customizations or not (yet)].
> ---
>
> i understand that sightly was designed to overcome several problems in JSP,
> one of it was the "taglib hell" with overuse of custom tags leading to
> quite proprietary tag syntaxes difficult to understand and maintain. but
> still there are some use cases where it would be useful to define own block
> statements because using the use API needs too much boilerplate code.
>
> example - consider a usecase for building a link from a set of resource
> properties, and this involves more logic than just getting a path and
> adding ".html" to it, so business logic on the java is involved and a sling
> model to access it. example markup (link.attributes returns a map):
>
> <a data-sly-use.link="com.myapp.ResourceLink"
> data-sly-attribute="${link.attributes}" data-sly-test="${link.valid}">
> ${properties.linkTitle}
> </a>
>
> using a custom sightly extension this would remove a lot of boilerplate
> code:
>
> <a data-sly-resource-link>
> ${properties.linkTitle}
> </a>
>
> an alternative would be to use a slightly template, but this still requires
> more code for calling and the specific inclusion and management of a
> sightly template library file.
This can easily be done with a custom tag processor in Thymeleaf also, see
Sling Dialect and Sling Include for example:
https://github.com/apache/sling/blob/trunk/contrib/scripting/thymeleaf/src/main/java/org/apache/sling/scripting/thymeleaf/internal/dialect/SlingDialect.java
https://github.com/apache/sling/blob/trunk/contrib/scripting/thymeleaf/src/main/java/org/apache/sling/scripting/thymeleaf/internal/processor/SlingIncludeAttributeTagProcessor.java
Thymeleaf allows you to plug in your own template resolvers, message resolvers
(i18n), dialects and cache manager. This is realized in Sling Scripting
Thymeleaf with OSGi Services[2]. So you can provide your custom dialect and
tag processors (with a custom namespace, e.g. data-wcmio-*) at runtime to
extend Thymeleaf.
Regards,
O.
[2]
https://github.com/apache/sling/blob/trunk/contrib/scripting/thymeleaf/src/main/java/org/apache/sling/scripting/thymeleaf/internal/ThymeleafScriptEngineFactory.java
> stefan
>
> [1]
> https://svn.apache.org/repos/asf/sling/trunk/bundles/scripting/sightly/engi
> ne/src/main/java/org/apache/sling/scripting/sightly/impl/plugin/Plugin.java
