Contact Us 1-800-596-4880
  1. Homepage
  2. DataWeave (2.8)
  3. DataWeave Examples

  4. Reference Multiple Inputs

Reference Multiple Inputs

This DataWeave example takes three different input JSON files, one in the payload, another in a variable and the third in an attribute. All of them are parts of the same Mule Event. The payload contains an array of book objects, the variable has a set of currency exchange rates, and the attribute specifies a year to be used as a query. Before you begin, note that 2.x versions of DataWeave are used by Mule 4 apps. For DataWeave in Mule 3 apps, refer to DataWeave version 1.2 examples. For other DataWeave versions, you can use the version selector in the DataWeave table of contents.

The example uses the following:

  • filter to leave out the books that are older than the date specified in the incoming attribute.

  • map to go through each book in the incoming array. Another map function then goes through the currencies in the variable to calculates the book’s price in each one. A third map function lists out all authors of a book in case there are more than one.

  • @ to define an XML attribute in the output.

DataWeave Script:
%dw 2.0
output application/xml
---
books: {
  (payload filter ($.properties.year > attributes.publishedAfter) map  (item)   ->  {
    book @(year: item.properties.year): {
      (vars.exchangeRate.USD map {
        price @(currency: $.currency): $.ratio * item.price
      }),
      title: item.properties.title,
      authors: { (item.properties.author map {
        author: $
      }) }
    }
  } )
}
Input JSON Payload:
[
  {
      "type": "book",
      "price": 30,
      "properties": {
        "title": "Everyday Italian",
        "author": [
          "Giada De Laurentiis"
        ],
        "year": 2005
      }
  },
  {
      "type": "book",
      "price": 29.99,
      "properties": {
        "title": "Harry Potter",
        "author": [
          "J K. Rowling"
        ],
        "year": 2005
      }
  },
  {
      "type": "book",
      "price": 41.12,
      "properties": {
        "title": "Mule in Action",
        "author": [
          "David Dossot",
          "John D'Emic"
        ],
        "year": 2009
      }
  },
  {
      "type": "book",
      "price": 49.99,
      "properties": {
        "title": "XQuery Kick Start",
        "author": [
          "James McGovern",
          "Per Bothner",
          "Kurt Cagle",
          "James Linn",
          "Kurt Cagle",
          "Vaidyanathan Nagarajan"
        ],
        "year": 2003
      }
  },
  {
      "type": "book",
      "price": 39.95,
      "properties": {
        "title": "Learning XML",
        "author": [
          "Erik T. Ray"
        ],
        "year": 2003
      }
  }
]
Input Attributes:
{
  "publishedAfter": 2004
}
Input Variable exchangeRate:
{
  "USD": [
    {"currency": "EUR", "ratio":0.92},
    {"currency": "ARS", "ratio":8.76},
    {"currency": "GBP", "ratio":0.66}
  ]
}
Output XML:
<?xml version='1.0' encoding='US-ASCII'?>
<books>
  <book year="2005">
    <price currency="EUR">27.60</price>
    <price currency="ARS">262.80</price>
    <price currency="GBP">19.80</price>
    <title>Everyday Italian</title>
    <authors>
      <author>Giada De Laurentiis</author>
    </authors>
  </book>
  <book year="2005">
    <price currency="EUR">27.5908</price>
    <price currency="ARS">262.7124</price>
    <price currency="GBP">19.7934</price>
    <title>Harry Potter</title>
    <authors>
      <author>J K. Rowling</author>
    </authors>
  </book>
  <book year="2009">
    <price currency="EUR">37.8304</price>
    <price currency="ARS">360.2112</price>
    <price currency="GBP">27.1392</price>
    <title>Mule in Action</title>
    <authors>
      <author>David Dossot</author>
      <author>John D'Emic</author>
    </authors>
  </book>
</books>

See Also