Given a value, return an portable version of it as either a string, int, float or array

If an array is returned, it should only contain: strings, ints, floats or more arrays of those types. This is intended for web service exports.

When applicable, this method should map things like internal IDs to named equivalents (name, path, etc.).

If not overridden, this takes on the same behavior as Fieldtype::sleepValue(). However, if overridden, it is intended to be more verbose than wakeupValue, where applicable.

Usage

// basic usage
$string = $fieldtype->exportValue(Page $page, Field $field, $value);

// usage with all arguments
$string = $fieldtype->exportValue(Page $page, Field $field, $value, array $options = []);

Arguments

NameType(s)Description
$pagePage
$fieldField
$valuestring or int or float or array or object or null
$options (optional)array

Optional settings to shape the exported value, if needed:

  • system (boolean): Indicates value is being used for a system export via $pages->export() call (default=false).
  • human (boolean): When true, Fieldtype may optionally emphasize human readability over importability (default=false).

Return value

string, float, int or array

Hooking Fieldtype::exportValue(…)

You can add your own hook events that are executed either before or after the Fieldtype::exportValue(…) method is executed. Examples of both are included below. A good place for hook code such as this is in your /site/ready.php file.

Hooking before

The 'before' hooks are called immediately before each Fieldtype::exportValue(…) method call is executed. This type of hook is especially useful for modifying arguments before they are sent to the method.

$this->addHookBefore('Fieldtype::exportValue', function(HookEvent $event) {
  // Get the object the event occurred on, if needed
  $Fieldtype = $event->object;

  // Get values of arguments sent to hook (and optionally modify them)
  $page = $event->arguments(0);
  $field = $event->arguments(1);
  $value = $event->arguments(2);
  $options = $event->arguments(3);

  /* Your code here, perhaps modifying arguments */

  // Populate back arguments (if you have modified them)
  $event->arguments(0, $page);
  $event->arguments(1, $field);
  $event->arguments(2, $value);
  $event->arguments(3, $options);
});

Hooking after

The 'after' hooks are called immediately after each Fieldtype::exportValue(…) method call is executed. This type of hook is especially useful for modifying the value that was returned by the method call.

$this->addHookAfter('Fieldtype::exportValue', function(HookEvent $event) {
  // Get the object the event occurred on, if needed
  $Fieldtype = $event->object;

  // An 'after' hook can retrieve and/or modify the return value
  $return = $event->return;

  // Get values of arguments sent to hook (if needed)
  $page = $event->arguments(0);
  $field = $event->arguments(1);
  $value = $event->arguments(2);
  $options = $event->arguments(3);

  /* Your code here, perhaps modifying the return value */

  // Populate back return value, if you have modified it
  $event->return = $return;
});

Fieldtype methods and properties

API reference based on ProcessWire core version 3.0.78