Sling Pipes

Ever encountered a situation where code changes were introduced after the client started authoring and some pages had to be re-authored? Ever spent time writing code just to modify a few hundred pages that were already authored, or with removing a component from hundreds of authored pages? Have you struggled to modify content already in the repository? Need a script to change existing production content? Sling Pipes to the rescue.

Sling Pipes is a tool for doing extract – transform – load operations through a resource tree configuration. This tiny toolset provides the ability to do such transformations with proven and reusable blocks, called pipes, streaming resources from one to the other.

A pipe is a JCR node with:

• sling:resourceType property – Must be a pipe type registered by the plumber
• name property – Used in bindings as an id
• path property – Defines pipe’s input
• expr property – Expression through which the pipe will execute
• additionalBinding node – Node you can add to set “global” bindings (property=value) in pipe execution
• additionalScripts – Multivalue property to declare scripts that can be reused in expressions
• conf child node – Contains addition configuration of the pipe

Registered Pipes:

Container Pipes

Pipe	Description	sling:resourceType
Container Pipe	assemble a sequence of pipes	slingPipes/container
ReferencePipe	execute the pipe referenced in path property	slingPipes/reference

Reader Pipes

Pipe	Description	sling:resourceType
Base Pipe	outputs what is in input	slingPipes/base
SlingQuery Pipe	executes $(getInput()).children(expression)	slingPipes/slingQuery
JsonPipe	feeds bindings with remote json	slingPipes/json
MultiPropertyPipe	iterates through values of input multi value property and write them to bindings	slingPipes/multiProperty
XPathPipe	retrieve resources resulting of an xpath query	slingPipes/xpath
AuthorizablePipe	retrieve authorizable resource corresponding to the id passed in expression	slingPipes/authorizable
ParentPipe	outputs the parent resource of input resource	slingPipes/parent
FilterPipe	outputs the input resource if its matches its configuration	slingPipes/filter

Writer Pipes

Pipe	Description	sling:resourceType
Write Pipe	writes given nodes & properties to current input	slingPipes/write
MovePipe	JCR move of current input to target path (can be a node or a property)	slingPipes/mv
RemovePipe	removes the input resource	slingPipes/rm
PathPipe	get or create path given in expression	slingPipes/path

Here is a demo video with more on how to use and execute sling pipes in AEM.

Vid

More details can be found in the official documentation at https://sling.apache.org/documentation/bundles/sling-pipes.html