generic_transformer.md

GenericTransformer

Class behind the transformers declared in the clever_age_process.generic_transformers configuration (see Generic transformers definition). It is not a service by itself: one instance is created per declared generic transformer, and it simply applies a preconfigured chain of transformers, optionally parametrized by contextual_options.

For each entry of generic_transformers, the bundle extension (CleverAgeProcessExtension) registers a private service CleverAge\ProcessBundle\Transformer\GenericTransformer\<code>, tagged cleverage.transformer, and calls initialize(<code>, <configuration>) on it. The instance is then added to the transformer registry like any other transformer, under the configured code (which must not collide with an existing transformer code).

When the generic transformer is used, its options are the declared contextual options. The {{ option_code }} placeholders in the preconfigured transformers (keys and values, recursively) are replaced by the option values, then the resulting transformer chain is resolved and applied, as with TransformerTrait. A placeholder that is the whole string is replaced by the raw value (keeping its type, e.g. int or null); otherwise the value is inserted in the string.

Transformer reference

• Service: CleverAge\ProcessBundle\Transformer\GenericTransformer\<code> (one service per generic transformer)
• Transformer code: <code>: the key used under clever_age_process.generic_transformers

Accepted inputs

any: depends on the preconfigured transformers.

Possible outputs

any: result of the preconfigured transformer chain.

Options

The definition (clever_age_process.generic_transformers.<code>) accepts:

Code	Type	Required	Default	Description
contextual_options	array		[]	List of option code => option definition (see below); each one becomes an option of the transformer
transformers	array		[]	Transformer chain, see TransformerTrait. May contain {{ option_code }} placeholders

Each contextual option definition (~ is allowed to use all defaults) accepts:

Code	Type	Required	Default	Description
required	bool		true	The option must be provided when using the transformer (unless it has a default)
default	any		null	If not null, default value of the option
default_is_null	bool		false	Use null as default value (not possible with default)

When using the generic transformer, only its contextual options are accepted; passing transformers throws an InvalidArgumentException.

Examples

• Definition without option, and usage

# Bundle configuration level (config/packages/*.yaml)
clever_age_process:
  generic_transformers:
    uppercase:
      transformers:
        callback:
          callback: strtoupper

# Transformer options level
uppercase: ~

• Definition with contextual options, and usage: substr($value, 2, null)

# Bundle configuration level (config/packages/*.yaml)
clever_age_process:
  generic_transformers:
    substr:
      contextual_options:
        offset:
          required: true
        length:
          default_is_null: true
      transformers:
        callback:
          callback: substr
          right_parameters: ['{{ offset }}', '{{ length }}']

# Transformer options level
substr:
  offset: 2

Notes

• Contextual options are transformer options, unrelated to the process context (-c key:value).
• An option declared with required: false and no default may be omitted: its placeholders are then replaced by null.