Process MARC XML with golang

marc.go

package main

import (
	"encoding/xml"
	"fmt"
	"strings"
	"time"
 	"io/ioutil"
	"os"
)

type Collection struct {
	Records   []Record   `xml:"record"`
}

type Record struct {
	Controlfields  []Controlfield `xml:"controlfield"`
	Datafields     []Datafield `xml:"datafield"`
}

type Controlfield struct {
	Tag   string `xml:"tag,attr"`
	Value string `xml:",chardata"`
}

type Datafield struct {
	Tag  string `xml:"tag,attr"`
	Subfields  []Subfield `xml:"subfield"`
}

type Subfield struct {
	Code   string `xml:"code,attr"`
	Value string `xml:",chardata"`
}

func controlfield_value(record Record, tag string) (value string) {
	for i := 0; i < len(record.Controlfields); i++ {
		if record.Controlfields[i].Tag == tag {
			value = record.Controlfields[i].Value	
		}
	}
	return value
}

func datafield_value(record Record, tag string, codes []string) (value string) {
	for i := 0; i < len(record.Datafields); i++ {
		if record.Datafields[i].Tag == tag {
			value = concat_subfields(record.Datafields[i].Subfields, codes)
		}
	}
	return value
}

func concat_subfields(subfields []Subfield, codes []string) (string) {
	var values []string

	for i :=0; i < len(subfields); i++ {
		var subfield Subfield
		subfield = subfields[i]
		if stringInSlice(subfield.Code, codes) {
			values = append(values, subfield.Value)
		}
	}
	
	return strings.Join(values[:], " ")
}

func stringInSlice(a string, list []string) bool {
    for _, b := range list {
        if b == a {
            return true
        }
    }
    return false
}

func main() {
	start := time.Now()

	xmlFile, err := os.Open("1520931620")

	if err != nil {
		fmt.Println(err)
	}
	defer xmlFile.Close()

	byteValue, _ := ioutil.ReadAll(xmlFile)

	var marc Collection
	xml.Unmarshal(byteValue	, &marc)

	for i := 0; i < len(marc.Records); i++ {
		var record Record

		record = marc.Records[i]
		// fmt.Println(controlfield_value(record, "001"))
		// fmt.Println(datafield_value(record, "245", []string {"a","b","c","f","g","h","k","n","p","s"}))
		controlfield_value(record, "001")
		datafield_value(record, "245", []string {"a","b","c","f","g","h","k","n","p","s"})
	}

	fmt.Println(time.Since(start))
}