added icon support

main.go

@@ -3,13 +3,16 @@ package main
 import (
 	"flag"
 	"fmt"
+	"image"
 	"io"
 	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
+	"strings"
 	"text/template"
 
+	"github.com/JackMordaunt/icns"
 	"github.com/pkg/errors"
 )
 
@@ -26,6 +29,7 @@ func run() error {
 		author     = flag.String("author", "Appify by Machine Box", "author")
 		version    = flag.String("version", "1.0", "app version")
 		identifier = flag.String("id", "", "bundle identifier")
+		icon       = flag.String("icon", "", "icon image file (.icns|.png|.jpg|.jpeg)")
 	)
 	flag.Parse()
 	args := flag.Args()
@@ -34,13 +38,14 @@ func run() error {
 	}
 	bin := args[0]
 	appname := *name + ".app"
-	contentspath := filepath.Join(appname, "Contents")
-	apppath := filepath.Join(contentspath, "MacOS")
-	binpath := filepath.Join(apppath, appname)
-	if err := os.MkdirAll(apppath, 0777); err != nil {
-		return errors.Wrap(err, "os.MkdirAll")
+	contentsPath := filepath.Join(appname, "Contents")
+	appPath := filepath.Join(contentsPath, "MacOS")
+	resouresPath := filepath.Join(contentsPath, "Resources")
+	binPath := filepath.Join(appPath, appname)
+	if err := os.MkdirAll(appPath, 0777); err != nil {
+		return errors.Wrap(err, "os.MkdirAll appPath")
 	}
-	fdst, err := os.Create(binpath)
+	fdst, err := os.Create(binPath)
 	if err != nil {
 		return errors.Wrap(err, "create bin")
 	}
@@ -56,11 +61,11 @@ func run() error {
 	if _, err := io.Copy(fdst, fsrc); err != nil {
 		return errors.Wrap(err, "copy bin")
 	}
-	if err := exec.Command("chmod", "+x", apppath).Run(); err != nil {
-		return errors.Wrap(err, "chmod: "+apppath)
+	if err := exec.Command("chmod", "+x", appPath).Run(); err != nil {
+		return errors.Wrap(err, "chmod: "+appPath)
 	}
-	if err := exec.Command("chmod", "+x", binpath).Run(); err != nil {
-		return errors.Wrap(err, "chmod: "+binpath)
+	if err := exec.Command("chmod", "+x", binPath).Run(); err != nil {
+		return errors.Wrap(err, "chmod: "+binPath)
 	}
 	id := *identifier
 	if id == "" {
@@ -74,11 +79,18 @@ func run() error {
 		InfoString:         *name + " by " + *author,
 		ShortVersionString: *version,
 	}
+	if *icon != "" {
+		iconPath, err := prepareIcons(*icon, resouresPath)
+		if err != nil {
+			return errors.Wrap(err, "icon")
+		}
+		info.IconFile = filepath.Base(iconPath)
+	}
 	tpl, err := template.New("template").Parse(infoPlistTemplate)
 	if err != nil {
 		return errors.Wrap(err, "infoPlistTemplate")
 	}
-	fplist, err := os.Create(filepath.Join(contentspath, "Info.plist"))
+	fplist, err := os.Create(filepath.Join(contentsPath, "Info.plist"))
 	if err != nil {
 		return errors.Wrap(err, "create Info.plist")
 	}
@@ -86,12 +98,51 @@ func run() error {
 	if err := tpl.Execute(fplist, info); err != nil {
 		return errors.Wrap(err, "execute Info.plist template")
 	}
-	if err := ioutil.WriteFile(filepath.Join(contentspath, "README"), []byte(readme), 0666); err != nil {
+	if err := ioutil.WriteFile(filepath.Join(contentsPath, "README"), []byte(readme), 0666); err != nil {
 		return errors.Wrap(err, "ioutil.WriteFile")
 	}
 	return nil
 }
 
+func prepareIcons(iconPath, resourcesPath string) (string, error) {
+	ext := filepath.Ext(strings.ToLower(iconPath))
+	fsrc, err := os.Open(iconPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return "", errors.New("icon file not found")
+		}
+		return "", errors.Wrap(err, "open icon file")
+	}
+	defer fsrc.Close()
+	if err := os.MkdirAll(resourcesPath, 0777); err != nil {
+		return "", errors.Wrap(err, "os.MkdirAll resourcesPath")
+	}
+	destFile := filepath.Join(resourcesPath, "icon.icns")
+	fdst, err := os.Create(destFile)
+	if err != nil {
+		return "", errors.Wrap(err, "create icon.icns file")
+	}
+	defer fdst.Close()
+	switch ext {
+	case ".icns": // just copy the .icns file
+		_, err := io.Copy(fdst, fsrc)
+		if err != nil {
+			return destFile, errors.Wrap(err, "copying "+iconPath)
+		}
+	case ".png", ".jpg", ".jpeg", ".gif": // process any images
+		srcImg, _, err := image.Decode(fsrc)
+		if err != nil {
+			return destFile, errors.Wrap(err, "decode image")
+		}
+		if err := icns.Encode(fdst, srcImg); err != nil {
+			return destFile, errors.Wrap(err, "generate icns file")
+		}
+	default:
+		return destFile, errors.New(ext + " icons not supported")
+	}
+	return destFile, nil
+}
+
 type infoListData struct {
 	Name               string
 	Executable         string
@@ -99,6 +150,7 @@ type infoListData struct {
 	Version            string
 	InfoString         string
 	ShortVersionString string
+	IconFile           string
 }
 
 const infoPlistTemplate = `<?xml version="1.0" encoding="UTF-8"?>
@@ -121,6 +173,10 @@ const infoPlistTemplate = `<?xml version="1.0" encoding="UTF-8"?>
 		<string>{{ .InfoString }}</string>
 		<key>CFBundleShortVersionString</key>
 		<string>{{ .ShortVersionString }}</string>
+		{{ if .IconFile -}}
+		<key>CFBundleIconFile</key>
+		<string>{{ .IconFile }}</string>
+		{{- end }}
 	</dict>
 </plist>
 `