Workflow Example 2

Create Workflow Definition

Let create a workflow that monitors specified folders and when a video file appears in some of them transcodes it with selected transcoding template.

LAPIS emits BPMN signals related to an object's lifecycle. The workflow will monitor two specific signals using Signal Start Events:

objectCreated – Triggered when a new object is added to the system.
objectUpdated – Triggered when an existing object is modified.

When an object is created, the workflow will verify whether it is linked to one of the monitored folders. Similarly, when an existing object is modified, the workflow will check if it is linked to any of the monitored folders.

Let assume we have some folders:

For this example we will monitor "Folder 1" and "Folder 2". We will need their IDs which we can get by displaying the ID column:

We will also use a Transcoding Template holding the transcoding parameters, so get its ID, too:

Now let's create a new workflow definition as shown:

Set general properties Name, ID and Executable:
Important is also to add the following "Extension Property", so that workflow history is not flooded with all workflow instances that are created for any object creation or modification:
Set the properties for Object Created signal start event:
Set the properties for Object Updated signal start event:
Set the following properties to object created Yes flow:

The script is:
```
def folders = [
  '679d0faa3063823d2ba9a45c@1', // ID of "Folder 1"
  '679d0fb73063823d2ba9a45e@1', // ID of "Folder 2"
]

def containers = (object.get('containers') ?: []).collect { it.id.toString() }

def addedToAnyFolder = folders.intersect(containers)

(object.unwrap().isInstanceOf('Video')) && !['draft', 'newObjectDraft'].contains(object.get('lifeCycleStatus')) && object.get('containers') != null && addedToAnyFolder
```
Replace/add IDs of the folders you want to be monitored in folders variable.

The object variable is defined for the workflow instances that start with objectCreated and/or objectUpdated signal events. With object.get() you can get any property value from the object (querying for non existing or undefined properties' values will return null), so similarly you may check for other object's properties and act as needed. In this example containers property holds IDs of folders (and/or other containers) to which this object is linked.

The final script statement must evaluate to a Boolean value, which determines the outcome of the condition check. In this example, the script checks the following:
1. Whether the newly created object is of type 'Video'.
2. Whether the object is not in the process of being created (e.g., autosaves during data entry will have this state).
3. Whether the object is linked to one of the monitored folders (as required in this example).

Set the following properties to object updated Yes flow:

The script is:

def folders = [
  '679d0faa3063823d2ba9a45c@1', // ID of "Folder 1"
  '679d0fb73063823d2ba9a45e@1', // ID of "Folder 2"
]

def originalContainers = (originalObject.get('containers') ?: []).collect { it.id.toString() }
def containers = (object.get('containers') ?: []).collect { it.id.toString() }

def intersectOriginal = folders.intersect(originalContainers) ?: []
def intersectNew = folders.intersect(containers) ?: []

def addedToAnyFolder = intersectOriginal.size() == 0 && intersectNew.size() > 0

execution.hasVariable('originalObject') && (object.unwrap().isInstanceOf('Video')) && !['draft', 'newObjectDraft'].contains(object.get('lifeCycleStatus')) && addedToAnyFolder

Match folders variable to the previous script. (Note that there is way to set this variable ones in the workflow and use it on other places, but for simplicity we have put it in both scripts).

Set the following properties to the scripting task:

The script is:

def operationId = Context.operationHelpers.getOperationByName('TranscodeOperation', godUser).id
def templateId = '679d218d3063823d2ba9a46d@1' // ID of the transcoding template
Context.operations.executeOperationById(operationId, [object.id].toImmutableList(), helpers.getSubject(subject), [  templateId: helpers.relationFromString(templateId),
].toImmutableMap(), null)

Change the templateId with your own.

You can download the BPMN of the above example from here.

Test the new workflow

Upload a video file to one of the monitored folders:
The transcoding should start after upload is finished:
You can also drag and drop an existing video into one of the monitored folders, and the workflow will automatically initiate the transcoding process for it.