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Introduction

For the wishlist item

Requirements

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Introduction

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

• The (previous/current ) metadata of the item

• Combinations of fields

• Conditions

• Textual operations

Solution

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Batch with metadata expressions

The new batch task is available and named “BatchMetadataExpressionTask”. It takes as an argument a list of metadata sidecar e.g.-like arguments. An example of such metadata sidecar is

{
    "Descriptive": {
       "Title": "#{R('Descriptive.Title').toUpperCase()}",
       "Description": "#{R('Descriptive.Title') + ': ' + R('Dynamic.Description')}",
"Metadata Expression Analysis"       "Keywords": {"Keyword": "#{{R('Dynamic.CustomTag')}}"}
    },
    "Dynamic": {
        "Orientation": "#{R('Technical.Width') > R('Technical.Height') ? 'Horizontal' : 'Vertical'}",
        "CustomFieldAdditionalInformation": "SomeMy custom valuefield"
    }
}

This metadata sidecar can now use a strict Spring Expression Language (Spel) subset to perform more complex operations. You can put one or more expressions When putting a string in metadata sidecar that has the pattern #{...} in the JSON or XML 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').

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Merging

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The system ensures the result after evaluating the expression it is correctly escaped

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

{
    "Descriptive": {
       "Title": "R('Descriptive.Title').toUpperCase()MY TEST FILE",
       "Description": "R('Descriptive.Title') + ': ' + R('Dynamic.CustomField')My test file: this is a test file",
       "Keywords": {"Keyword": "{R('Dynamic.CustomField')}"["My custom tag"]}
    },
    "Dynamic": {
        "CustomFieldOrientation": "R('Dynamic.CustomField2') == 'X' ? 'Option A' : 'Option B'"Horizontal",
        "AdditionalInformation": "My custom field"
    }
}

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

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

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Security

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Output after evaluating the expression

After evaluating all expressions in the input metadata sidecar, the result is a new metadata sidecar in JSON. The conversion follows the following rules

Restrictions

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

• Literal expressions

• Boolean and relational operators

• Method invocation

• Inline lists, maps, etc

• Ternary operator

• The method name named “R” or “record”

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