Generate an xml file, write to file and load it from file.

pom.go

package models

import (
	"encoding/xml"
	"errors"
	"io/ioutil"
	"os"
	"gopkg.in/resty.v1"
	"crypto/tls"
	"encoding/json"
	"encoding/base64"
	"fmt"
)

var defaultXMLNS = "http://maven.apache.org/POM/4.0.0"
var defaultXSI = "http://www.w3.org/2001/XMLSchema-instance"
var defaultSchemaLocation = "http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"

type Pom struct {
	XMLName        xml.Name `xml:"project"`
	XMLNS          string   `xml:"xmlns,attr"`
	XSI            string   `xml:"xmlns:xsi,attr"`
	SchemaLocation string   `xml:"xsi:schemaLocation,attr"`
	ModelVersion   string   `xml:"modelVersion"`
	GroupId        string   `xml:"groupId,omitempty"`
	ArtifactId     string   `xml:"artifactId"`
	Version        string   `xml:"version"`
	Description    string   `xml:"description,omitempty"`
	Packaging      string   `xml:"packaging,omitempty"`
	Parent         *Unit     `xml:"parent,omitempty"`
	Modules        *[]string `xml:"modules>module"`
	Dependencies   *[]Unit   `xml:"dependencies>dependency"`
}

type Unit struct {
	GroupId      string `xml:"groupId,omitempty"`
	ArtifactId   string `xml:"artifactId,omitempty"`
	Version      string `xml:"version,omitempty"`
	Scope        string `xml:"scope,omitempty"`
	Type         string `xml:"type,omitempty"`
	RelativePath string `xml:"relativePath,omitempty"`
}

func LoadPomFromFile(pomFilePath string) (*Pom, error) {
	pomFileBytes, err := ioutil.ReadFile(pomFilePath)
	if err != nil {
		return nil, errors.New("error reading pom file: " + pomFilePath + " error: " + err.Error())
	}
	pom, err := parsePom(pomFileBytes)
	if err != nil {
		return nil, errors.New("error parsing pom file: " + pomFilePath + " error: " + err.Error())
	}
	return pom, nil
}


func NewPom(groupId string, artifactId string, version string) (*Pom, error) {
	return &Pom{
		XMLNS:          defaultXMLNS,
		XSI:            defaultXSI,
		SchemaLocation: defaultSchemaLocation,
		ModelVersion:   "4.0.0",
		GroupId:        groupId,
		ArtifactId:     artifactId,
		Version:        version,
	}, nil
}

func (p *Pom) ToByteArray() ([]byte, error) {
	b, err := xml.MarshalIndent(p, " ", "    ")
	if err == nil {
		b = []byte(xml.Header + string(b))
		return b, nil
	}
	return nil, err
}

func (p *Pom) WriteToFile(filePath string) error {
	if filePath == "" {
		filePath = "pom.xml"
	}

	bytes, err := p.ToByteArray()
	if err != nil {
		return err
	}
	return ioutil.WriteFile(filePath, bytes, os.ModePerm)
}

func parsePom(pomContentBytes []byte) (*Pom, error) {
	pomContent := Pom{}
	pomParseErr := xml.Unmarshal(pomContentBytes, &pomContent)
	return &pomContent, pomParseErr
}