XML

To declare that a type should be read/written as XML, add the flow.formats.Xml annotation to a model:

import flow.formats.Xml

@Xml
model Person {
  firstName : FirstName inherits String
}

Declare attributes

By default, scalar items within a model are expected to be an XML element.

To declare something should be read/written as an attribute, use the @lang.taxi.xml.XmlAttribute annotation.

For example:

import flow.formats.Xml
import lang.taxi.xml.XmlAttribute

@Xml
model Actor inherits Person {
  @XmlAttribute
  id: ActorId

  fullName: FullName
}

Would read/write the following XML:

<?xml version='1.0' encoding='UTF-8'?>
<Actor id="3">
    <fullName>Jimmy Smith</fullName>
</Actor>

Collections

Collections are indicated by a repeating group with the attribute name.

For example:

@Xml
model Movie {
  actors: Actor[]
}

Would expect a repeated actors element:

<?xml version='1.0' encoding='UTF-8'?>
<Movie>
    <actors id="1">
        <firstName>Mel</firstName>
        <lastName>Gibson</lastName>
    </actors>
    <actors id="2">
        <firstName>Jack</firstName>
        <lastName>Spratt</lastName>
    </actors>
</Movie>

Expressions

Expressions can be declared on a model.

Serializing

Expression values are written out as normal elements.

Deserializing

If an element or attribute is present for the field where the expression is declared, the expression is ignored, and the value from the source is taken.

If there’s no value present, then the expression is evaluated.

import flow.formats.Xml
import lang.taxi.xml.XmlAttribute

@Xml
model Actor {
    firstName : FirstName inherits String
    lastName : LastName inherits String
    fullName : FullName inherits String = FirstName + ' ' + LastName
}

Given the following XML:

<?xml version='1.0' encoding='UTF-8'?>
<Actor id="3">
    <firstName>Jimmy</firstName>
    <lastName>Smith</lastName>
</Actor>

Then the value is read as:

{
  "firstName" : "Jimmy",
  "lastName" : "Smith",
  "fullName" : "Jimmy Smith"
}
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