Added authorization

internal/utils/mime_image.go

@@ -0,0 +1,29 @@
+package utils
+
+import (
+	"errors"
+	"net/http"
+)
+
+var allowedTypes = map[string]bool{
+	"image/jpeg": true,
+	"image/jpg":  true,
+	"image/png":  true,
+	"image/gif":  true,
+	"image/webp": true,
+	"image/bmp":  true,
+}
+
+func IsImageMime(data string) bool {
+	return allowedTypes[data]
+}
+
+func GetImageMimeType(data []byte) (string, error) {
+	content_type := http.DetectContentType(data)
+
+	if !IsImageMime(content_type) {
+		return "", errors.New("Unexpected image format.")
+	}
+
+	return content_type, nil
+}