Merge pull request #2 from 9iksans/feat/svg

add validator for .svg file

signature.go

@@ -1,5 +1,7 @@
 package filesig
 
+import "regexp"
+
 var (
 	AVIF       = []byte{0x00, 0x00, 0x00}
 	BMP        = []byte{0x42, 0x4D}
@@ -32,4 +34,7 @@ var (
 	ZIP_1      = []byte{0x50, 0x4B, 0x05, 0x06}
 	ZIP_2      = []byte{0x50, 0x4B, 0x07, 0x08}
 	WEBP       = []byte{0x52, 0x49, 0x46, 0x46}
+
+	HtmlCommentRegex = regexp.MustCompile(`(?i)<!--([\s\S]*?)-->`)
+	SvgRegex         = regexp.MustCompile(`(?i)^\s*(?:<\?xml[^>]*>\s*)?(?:<!doctype svg[^>]*>\s*)?<svg[^>]*>[^*]*<\/svg>\s*$`)
 )

validator.go

@@ -211,3 +211,14 @@ func IsMp4(r io.ReadSeeker) bool {
 
 	return validMpFour1 == 0 && validMpFour2 == 0
 }
+
+// IsSvg function will return true if File is a valid SVG
+func IsSvg(r io.ReadSeeker) bool {
+	buff, err := io.ReadAll(r)
+	if err != nil {
+		return false
+	}
+	r.Seek(0, io.SeekStart)
+
+	return SvgRegex.Match(HtmlCommentRegex.ReplaceAll(buff, []byte{}))
+}

validator_test.go

@@ -395,3 +395,20 @@ func TestGenericMultipleCompareBuffer(t *testing.T) {
 		t.Error("error: one of buffer type is invalid")
 	}
 }
+
+func TestIsSvg(t *testing.T) {
+	buff, err := os.Open("./tmp/sample-0.svg")
+
+	if err != nil {
+		t.Error("error: SVG file not found")
+	}
+
+	defer func() {
+		buff.Close()
+	}()
+
+	valid := IsSvg(buff)
+	if !valid {
+		t.Error("error: buffer not valid SVG file")
+	}
+}