inanzzz | Parsing XML with Golang

In this example we are going to read an XML file and map it to its struct type. At the end, the result will be printed for the sake of confirmation. One special note, if the XML content is "beautified", the output will contain some special characters such as #xA; (line feed), #x9; (tab) and spaces. If it is "minified", the output should be clean.

XML file (beautified)

<!-- User Bank Account and History -->
<?xml version="1.0" encoding="UTF-8"?>
<user>
    <id>1</id>
	<first_name>John</first_name>
	<middle_name></middle_name>
	<last_name>Doe</last_name>
    <address>Line 1
Line 2

    Line 3
    
Line 4</address>
    <random>
        <nickname>Dummy User</nickname>
        <favourite_colour>Blue</favourite_colour>
    </random>
    <accounts>
        <account number="11" sort_code="111">
            <history>
                <transaction time="2020-09-25T20:41:30+01:00">
                    <operation>Debit</operation>
                    <amount>1021</amount>
                </transaction>
                <transaction time="2019-12-31T00:33:10+01:00">
                    <operation>Credit</operation>
                    <amount>50</amount>
                </transaction>
            </history>
        </account>
        <account number="22" sort_code="222">
            <history>
                <transaction time="2021-03-11T10:11:10+01:00">
                    <operation>Credit</operation>
                    <amount>5000</amount>
                </transaction>
            </history>
        </account>
    </accounts>
</user>

Code

package main

import (
	"encoding/xml"
	"fmt"
	"io/ioutil"
	"log"
	"os"
)

func main() {
	// Open file
	xmlFile, err := os.Open("input.xml")
	if err != nil {
		log.Fatalln(err)
	}
	defer xmlFile.Close()

	// Read file
	val, err := ioutil.ReadAll(xmlFile)
	if err != nil {
		log.Fatalln(err)
	}

	// Map data
	var user User
	if err := xml.Unmarshal(val, &user); err != nil {
		log.Fatalln(err)
	}

	// Print result (as-is)
	dat, err := xml.MarshalIndent(user, "", "   ")
	if err != nil {
		log.Fatalln(err)
	}
	fmt.Println(string(dat))
}

type User struct {
	XMLName    xml.Name `xml:"user"`
	Text       string   `xml:",chardata"`
	ID         string   `xml:"id"`
	FirstName  string   `xml:"first_name"`
	MiddleName string   `xml:"middle_name"`
	LastName   string   `xml:"last_name"`
	Address    string   `xml:"address"`
	Random     Random   `xml:"random"`
	Accounts   Accounts `xml:"accounts"`
}

type Random struct {
	Text            string `xml:",chardata"`
	Nickname        string `xml:"nickname"`
	FavouriteColour string `xml:"favourite_colour"`
}

type Accounts struct {
	Accounts []Account `xml:"account"`
}

type Account struct {
	Text     string  `xml:",chardata"`
	Number   string  `xml:"number,attr"`
	SortCode string  `xml:"sort_code,attr"`
	History  History `xml:"history"`
}

type History struct {
	Text        string        `xml:",chardata"`
	Transaction []Transaction `xml:"transaction"`
}

type Transaction struct {
	Text      string `xml:",chardata"`
	Time      string `xml:"time,attr"`
	Operation string `xml:"operation"`
	Amount    string `xml:"amount"`
}