将XML元素名称解组为其他属性

Question

I am currently writing a library for the NameSilo API. I am stuck on the getPriceList api, which returns XML like this:

<namesilo>
    <request>
        <operation>getPrices</operation>
        <ip>55.555.55.55</ip>
    </request>
    <reply>
        <code>300</code>
        <detail>success</detail>
        <com>
            <registration>8.99</registration>
            <transfer>8.39</transfer>
            <renew>8.99</renew>
        </com>
        <net>
            <registration>9.29</registration>
            <transfer>8.99</transfer>
            <renew>9.29</renew>
        </net>
    </reply>
</namesilo>

As you can see, there is an element for each TLD. I would like to unmarshal the element name (example: com, net) into a property which is not called XMLName (I want it to be called TLD).

After reading lines 34-39 of https://golang.org/src/encoding/xml/marshal.go, it seems like this is not possible.

I have tried the following code, but it does not work.

type APIResponse struct {
    Request struct {
        Operation string `xml:"operation"`
        IP        string `xml:"ip"`
    } `xml:"request"`
}

type GetPricesResponse struct {
    APIResponse
    Reply []struct {
        Domains []struct {
            TLD xml.name
            Registration string `xml:"registration"`
            Transfer     string `xml:"transfer"`
            Renew        string `xml:"renew"`
        } `xml:",any"`
    } `xml:"reply"`
}

Is there any way I can do this, or is it not possible to have a property name other than XMLName for the xml element name.

UPDATE: I looked a bit more into the code, and I found this, which makes me think I cannot do this easily.

Answer 1

There's no simpler alternative to XMLName xml.Name.

It's possible to do what you want with a type satisfying the unmarshaller interface. The added complexity is probably not worthwhile. Playground example:

package main

import (
    "encoding/xml"
    "fmt"
    "log"
)

func main() {
    var data Data
    if err := xml.Unmarshal(payload, &data); err != nil {
        log.Fatal(err)
    }

    for k, v := range data.Reply.Domains {
        fmt.Printf("%d: %#v
", k, v)
    }

}

type Domain struct {
    TLD          string
    Registration string `xml:"registration"`
    Transfer     string `xml:"transfer"`
    Renew        string `xml:"renew"`
}

func (domain *Domain) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
    v := struct {
        XMLName      xml.Name
        Registration string `xml:"registration"`
        Transfer     string `xml:"transfer"`
        Renew        string `xml:"renew"`
    }{}
    d.DecodeElement(&v, &start)

    domain.TLD = v.XMLName.Local
    domain.Registration = v.Registration
    domain.Transfer = v.Transfer
    domain.Renew = v.Renew

    return nil
}

type Data struct {
    Request struct {
        Operation string `xml:"operation"`
        Ip        string `xml:"ip"`
    } `xml:"request"`
    Reply struct {
        Code    string   `xml:"code"`
        Detail  string   `xml:"detail"`
        Domains []Domain `xml:",any"`
    } `xml:"reply"`
}

var payload = []byte(`<namesilo>
    <request>
        <operation>getPrices</operation>
        <ip>55.555.55.55</ip>
    </request>
    <reply>
        <code>300</code>
        <detail>success</detail>
        <com>
            <registration>8.99</registration>
            <transfer>8.39</transfer>
            <renew>8.99</renew>
        </com>
        <net>
            <registration>9.29</registration>
            <transfer>8.99</transfer>
            <renew>9.29</renew>
        </net>
    </reply>
</namesilo>`)