Cookbook

Groovy can have some sweet sugar syntax.

Consider the XML Builder combined with a database query using the zero.data module:

def data = zero.data.groovy.Manager.create('mydb')
def xml = new groovy.xml.MarkupBuilder(request.writer[])
 
xml.records() {
    data.eachRow('SELECT * FROM person') { row ->
        item(id: row.id, name: row.name)
    }
}
 
request.headers.out.'Content-Type' = 'application/xml'

Drop this script in the public folder, “public/sql2xml.groovy” for instance. Assuming a database is configured in zero.config for “mydb” and there exists a “person” table with at least the “id” and “name” as columns and some data, then this short snippet of code, accessible at http://localhost:8080/sql2xml.groovy” will output the following XML:

<records>
  <item id='1' name='brandon' />
  <item id='2' name='justin' />
</records>

Let’s break down the example:

1. Get an instance of data API configured to connect to the database in zero.config

   def data = zero.data.groovy.Manager.create('mydb')

2. Create a new XML builder provided by Groovy and make it output to the HTTP response

   def xml = new groovy.xml.MarkupBuilder(request.writer[])

3. Start building the XML with as the root XML node

   xml.records() {

4. Execute the SQL statement using zero.data APIs and loop over each row in the ResultSet; the “row” parameter into the Groovy closure is actually a Map where the key is the column name and the value is the row value from the ResultSet; this ResultSet to Map conversion is provided by the zero.data API

       data.eachRow('SELECT * FROM person') { row ->

5. Use the Groovy builder syntax to add data from the “row” to the XML output; the syntax on this line says that if “item” method is not found, it becomes a node in the XML output <item id=”idValue” name=”nameValue />

           item(id: row.id, name: row.name)

6. End the closures

       }
   }