Change the Value of a Field

The following DataWeave examples show how to use update and mask to change the values of some XML elements.

Before you begin, note that DataWeave version 2 (%dw 2.0) is for Mule 4 apps. For a Mule 3 app, refer to DataWeave version 1 (%dw 1.0) examples, within the Mule 3.9 documentation set. For other Mule versions, you can use the Mule Runtime version selector in the table of contents.

Example: Using Update to Change Values

This example uses:

update to update specified fields of the payload with new values
single-value (.) and multi-value (.*) selectors to navigate the payload and select the fields to update

The following script shows how the update operator works. The example creates a new users list by updating each user in the payload with a new user. The transformation converts first_name, middle_name and last_name to uppercase values:

DataWeave Script:

%dw 2.0
output application/xml
---
payload update {
  case user at .users.*user -> user update {
    case .personal_information.first_name -> upper(user.personal_information.first_name)
    case .personal_information.middle_name -> upper(user.personal_information.middle_name)
    case .personal_information.last_name -> upper(user.personal_information.last_name)
  }
}

Input XML Payload:

<users>
    <user>
        <personal_information>
            <first_name>Emiliano</first_name>
            <middle_name>Romoaldo</middle_name>
            <last_name>Lesende</last_name>
            <ssn>001-08-84382</ssn>
        </personal_information>
        <login_information>
            <username>3miliano</username>
            <password>mypassword1234</password>
        </login_information>
    </user>
    <user>
        <personal_information>
            <first_name>Mariano</first_name>
            <middle_name>Toribio</middle_name>
            <last_name>de Achaval</last_name>
            <ssn>002-05-34738</ssn>
        </personal_information>
        <login_information>
            <username>machaval</username>
            <password>mypassword4321</password>
        </login_information>
    </user>
</users>

Output XML:

<?xml version="1.0" encoding="UTF-8"?>
<users>
  <user>
    <personal_information>
      <first_name>EMILIANO</first_name>
      <middle_name>ROMOALDO</middle_name>
      <last_name>LESENDE</last_name>
      <ssn>001-08-84382</ssn>
    </personal_information>
    <login_information>
      <username>3miliano</username>
      <password>mypassword1234</password>
    </login_information>
  </user>
  <user>
    <personal_information>
      <first_name>MARIANO</first_name>
      <middle_name>TORIBIO</middle_name>
      <last_name>DE ACHAVAL</last_name>
      <ssn>002-05-34738</ssn>
    </personal_information>
    <login_information>
      <username>machaval</username>
      <password>mypassword4321</password>
    </login_information>
  </user>
</users>

Example: Using Mask to Change Values

DataWeave provides a simple way to mask values, without specifying the path to each field:

mask updates all simple elements that match the selected name throughout the input with the specified mask.

The following example masks the ssn and password values with a set of asterisks (****):