Why do we need metadata wrappers in Drupal?
All nodes have a title property and all user accounts have a name property. Given a standard Drupal entity it can be hard to know which property should be treated as the label. Metadata wrappers provide us with a consistent way of getting at this kind of information for any entity.
How are entity wrappers used in Drupal 7?
Wrappers make it easier to get and set the values of fields and properties as well as to programmatically retrieve additional information about these elements and iterate over lists of values in a consistent manner. For example consider the following method of accessing the value of a field attached to a node.
How to delete the entity metadata in Drupal?
To delete values, there is no ->delete() method on the fields. You have to use this way to correctly delete a value: It’s recommended to wrap code in try…catch section when you work with entity_metadata_wrapper() to catch EntityMetadataWrapperException.
How to use a field wrapper in Drupal?
The field wrapper can be appended to using square bracket syntax, the same as when working with a normal array: Finally, you can get the array out of the field, manipulate it, and set it back: To delete values, there is no ->delete() method on the fields.
How to iterate over entity field wrappers in Drupal?
A list value that contains wrappers, such as a multi-valued reference field, can be iterated over thus: Setting values or adding values to a list value, such as a multi-valued entity reference field, can be accomplished in several ways. The field wrapper can be appended to using square bracket syntax, the same as when working with a normal array:
What does contributed entity API do in Drupal?
The contributed Entity API module provides wrapper classes that make dealing with the values of an entity’s properties and fields easier.
How does the node presave hook work in Drupal?
Act on a node being inserted or updated. This hook is invoked from node_save () before the node is saved to the database. $node : The node that is being inserted or updated. Allow modules to interact with the Drupal core. Functions to define and modify content types.