Go by Example: 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">