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Introduced in version 23.1

Introduction

From version 23.1 you can create a batch offering rich metadata expressions where the new metadata of the item can be determined by

  • The (previous) metadata of the item

  • Combinations of fields

  • Conditions

  • Textual operations

Batch with metadata expressions

The new Using Metadata Expressions a new batch task is available and named BatchExpressionTemplatesTask. It takes as an argument a list of metadata sidecar-like arguments. An example of such metadata sidecar is

Code Block
{
    "Descriptive": {
       "Title": "#{R('Descriptive.Title').toUpperCase()}",
       "Description": "#{R('Descriptive.Title') + ': ' + R('Dynamic.CustomDescription')}",
       "Keywords": {"Keyword": "#{R('Dynamic.CustomTag')}"}
    },
    "Dynamic": {
        "Orientation": "#{(R('Technical.Width') > R('Technical.Height')) ? 'Horizontal' : 'Vertical'}",
        "AdditionalInformation": "My custom field"
    }
}

When putting a string in metadata sidecar that has the pattern #{...} it will be evaluated using the Spring Expression Language. Inside an expression, you can reference the metadata using R(<Dotted key>) or record(<Dotted key>) for example R('Descriptive.Title') or record('Descriptive.Title'). Only dotted keys having a field definition are allowed.

Info

The R takes an optional second argument, which is the default value when the metadata field is not present.

Variants

The expression can formulated in two manners

  • Multiple Spel expressions with textual information in between text A #{...} text B #{...}

  • A single Spel expression using #{...} where extra text needs to be concatenated using +

Code Block
Multiple
Spel = #{R('Descriptive.Title')} - #{R('Descriptive.Description')}
Single
Spel = #{R('Descriptive.Title') + ' - ' + R('Descriptive.Description')}

Merging

When the templated sidecar is evaluated against a record it will result for example in the following metadata sidecar

...

This metadata sidecar will then be merged against the record using the same rules as when MediaHaven Rest API - Updating a record.

...

The output of the metadata accessor R or record is the following depending on which field type the dotted key refers to:

...

Level

...

Case

...

Effect

...

Example Expression

...

Output

...

Top

...

SimpleField

...

String

...

R('Descriptive.Title')

...

My title

...

Top

...

ListField

...

List of Strings

...

R('Descriptive.Keywords')

...

["A", "B", "C"]

...

Top

...

MapField

...

Map of Strings

...

R('Structural.Versioning')

...

{"Status": "HEAD", "Version": "2"}

...

Top

...

MultiItemField

...

Map of List of Strings

...

R('Descriptive.Authors')

...

{"Authors": ["Cedric"], "Director": ["Alice", "Bob"]}

...

Top

Others

...

Not allowed

...

Sub

...

Child of ListField

...

List of Strings

...

R('Descriptive.Keywords.Keyword')

...

["A", "B", "C"]

...

Sub

...

Child of MultiItemField

...

List of Strings

...

R('Descriptive.Authors.Director')

...

["Alice", "Bob"]

...

Sub

...

Child of MapField

...

String

...

R('Structural.Versioning.Status')

...

HEAD

...

Sub

...

Other

...

Not allowed

Output after evaluating the expression

...

Notice how the string "#{R('Dynamic.CustomTag')}" is evaluated into an array ["My custom tag"]. The end result is a valid metadata sidecar for “Keywords” namely "Keywords": {"Keyword": ["My custom tag"]} whereas before evaluating the expression "Keywords": {"Keyword": "#{...}"} is not a strictly valid metadata sidecar because the value of "Keyword" must be an array and not a string.

Restrictions

The available features of SPel are for security reasons restricted to the following patterns

...

Literal expressions

...

Boolean and relational operators

...

Inline lists, maps, etc

...

Ternary operator

...