XML

Go offers built-in support for XML and XML-like formats with the encoding.xml package.

package main

import (
    "encoding/xml"
    "fmt"
)

// Plant will be mapped to XML. Similarly to the JSON examples
// field tags contain directives for the encoder and decoder.
// Here we use some special features of the XML package:
// the XMLName field name dictates the name of the 
// XML element representing this struct;
// id,attr means that the Id field is an XML attribute rather than a nested element.
type Plant struct {
    XMLName xml.Name `xml:"plant"`
    Id      int      `xml:"id,attr"`
    Name    string   `xml:"name"`
    Origin  []string `xml:"origin"`
}

func (p Plant) String() string {
    return fmt.Sprintf("Plant id=%v, name=%v, origin=%v",
        p.Id, p.Name, p.Origin)
}

func main() {
    coffee := &Plant{Id: 27, Name: "Coffee"}
    coffee.Origin = []string{"Ethiopia", "Brazil"}

    // Emit XML representing our plant;
    // using MarshalIndent to produce a more human-readable output.
    out, _ := xml.MarshalIndent(coffee, " ", "  ")
    fmt.Println(string(out))

    // To add a generic XML header to the output, append it explicitly.
    fmt.Println(xml.Header + string(out))

    // Use Unmarshal to parse a stream of bytes with
    // XML into a data structure.
    // If the XML is malformed or cannot be mapped onto Plant
    // a descriptive error will be returned.
    var p Plant
    if err := xml.Unmarshal(out, &p); err != nil {
        panic(err)
    }
    fmt.Println(p)

    tomato := &Plant{Id: 81, Name: "Tomato"}
    tomato.Origin = []string{"Mexico", "California"}

    // The parent>child>plant field tag tells the encoder
    // to nest all plants under <parent><child>...
    type Nesting struct {
        XMLName xml.Name `xml:"nesting"`
        Plants  []*Plant `xml:"parent>child>plant"`
    }

    nesting := &Nesting{}
    nesting.Plants = []*Plant{coffee, tomato}

    out, _ = xml.MarshalIndent(nesting, " ", "  ")
    fmt.Println(string(out))
}

$ go run xml.go
 <plant id="27">
   <name>Coffee</name>
   <origin>Ethiopia</origin>
   <origin>Brazil</origin>
 </plant>
<?xml version="1.0" encoding="UTF-8"?>
 <plant id="27">
   <name>Coffee</name>
   <origin>Ethiopia</origin>
   <origin>Brazil</origin>
 </plant>
Plant id=27, name=Coffee, origin=[Ethiopia Brazil]
 <nesting>
   <parent>
     <child>
       <plant id="27">
         <name>Coffee</name>
         <origin>Ethiopia</origin>
         <origin>Brazil</origin>
       </plant>
       <plant id="81">
         <name>Tomato</name>
         <origin>Mexico</origin>
         <origin>California</origin>
       </plant>
     </child>
   </parent>
 </nesting>