refactor: replace magic values with constants

app/internal/qrcode/service/url/validation.go

@@ -2,24 +2,30 @@ package url
 
 import (
 	neturl "net/url"
+
+	"git.heldm.com/held/qrcode/internal/qrcode/vo"
 )
 
 func IsValidURL(newURL string) bool {
 	if newURL == "" || len(newURL) > 2048 {
 		return false
 	}
+
 	u, err := neturl.Parse(newURL)
 	if err != nil {
 		return false
 	}
+
 	if u.Scheme == "" || u.Host == "" {
 		return false
 	}
+
 	switch u.Scheme {
-	case "http", "https", "ftp", "ftps", "mailto":
+	case vo.SchemeHTTP, vo.SchemeHTTPS, vo.SchemeFTP, vo.SchemeFTPS, vo.SchemeMAILTO:
 		break
 	default:
 		return false
 	}
+
 	return true
 }

app/internal/qrcode/vo/qrimg.go

@@ -7,6 +7,23 @@ import (
 	"git.heldm.com/held/qrcode/internal/qrcode"
 )
 
+const (
+	SchemeHTTP   = "http"
+	SchemeHTTPS  = "https"
+	SchemeFTP    = "ftp"
+	SchemeFTPS   = "ftps"
+	SchemeMAILTO = "mailto"
+
+	ImgFormatPNG = "png"
+	ImgFormatSVG = "svg"
+
+	ImgDefaultFormat = ImgFormatPNG
+
+	ImgMinSize     = 256
+	ImgMaxSize     = 2048
+	ImgDefaultSize = 256
+)
+
 type QRImg struct {
 	link      string
 	img       []byte
@@ -27,23 +44,28 @@ func NewQR(link, imgFormat string, imgSize int) (*QRImg, error) {
 		return nil, qrcode.ErrInvalidURL
 	}
 
-	if u.Scheme != "http" && u.Scheme != "https" {
+	if u.Scheme != SchemeHTTP &&
+		u.Scheme != SchemeHTTPS &&
+		u.Scheme != SchemeFTP &&
+		u.Scheme != SchemeFTPS &&
+		u.Scheme != SchemeMAILTO {
 		return nil, qrcode.ErrInvalidURL
 	}
 
 	// imgFormat should be either "png" or "svg", default to "png" if invalid
 	switch imgFormat {
-	case "png", "svg":
+	case ImgFormatPNG, ImgFormatSVG:
 	default:
-		imgFormat = "png"
+		imgFormat = ImgDefaultFormat
 	}
 
 	// imgSize should be between 256 and 2048, default to 256 if invalid
 	if imgSize <= 0 {
-		imgSize = 256
+		imgSize = ImgDefaultSize
 	}
-	if imgSize > 2048 {
+
-		imgSize = 2048
+	if imgSize > ImgMaxSize {
+		imgSize = ImgMaxSize
 	}
 
 	return &QRImg{