rules_transformer.md

RulesTransformer

Uses a set of rules to apply some set of transformers on a value. Basically behaves like a if/elseif/else block.

By default a rule uses a variable named value containing anything you passed in input (array, string, ...). But this can be overridden using options use_value_as_variables as true and setting expression_variables to a static list of input variables.

Note that expression_variables can also be set to null for more flexibility, but this disable initial parsing and decrease performances.

See The ExpressionLanguage Component Reference for more information.

Task reference

• Service: CleverAge\ProcessBundle\Transformer\RulesTransformer
• Transformer code: rules

Accepted inputs

any or an array of variable code => value injectable into an expression

Possible outputs

any resulting from a transformation set.

Without any matching rules, the value itself is returned.

Options

Code	Type	Required	Default	Description
rules_set	array	X		Ordered list of rules, see bellow for details
use_value_as_variables	bool		false	Use given value as an array of variable to inject in expression
expression_variables	array or null		[value]	Name of variables injected in the expression at initialization time

Foreach rule there is the following options.

Code	Type	Required	Default	Description
condition	string or null		null	An expression used to match a value
default	bool		false	Mark this rule as a default rule. The given rule must be the last, cannot have a condition, and there cannot have 2 default in the same time
transformers	array		[]	List of sub-transformers, see TransformerTrait
constant	any		null	If not null, given value will be directly output (takes precedence on transformers)
set_null	bool		false	If true, null will be directly output (takes precedence on constant)

Examples

• Simple rules with default value
  • input value is an array containing an order object and a customer object
  • output will be either a value from customer, or a numeric constant, or null

# Transformer options level
rules:
    rules_set:
        -   condition: 'value["order"].origin === "marketplace"'
            transformers:
                property_accessor:
                    property_path: '[customer].id'
        -   condition: 'value["order"].origin === "e-commerce"'
            constant: 1234
        -   default: true
            set_null: true

• Use value as variables
  • same example as above
  • can be useful for more verbose expression
  • transformers still get the input as the initial array

# Transformer options level
rules:
    use_value_as_variables: true
    expression_variables: [order, customer]
    rules_set:
        -   condition: 'order.origin === "marketplace"'
            transformers:
                property_accessor:
                    property_path: '[customer].id'
        -   condition: 'order.origin === "e-commerce"'
            constant: 1234
        -   default: true
            set_null: true