strip <style> in html emails

utils/html.go

@@ -0,0 +1,44 @@
+package utils
+
+import (
+	"bytes"
+	"strings"
+
+	"golang.org/x/net/html"
+)
+
+// StripHTMLTag from text
+//
+// Source: https://siongui.github.io/2018/01/16/go-remove-html-inline-style/
+func StripHTMLTag(text, tag string) (string, error) {
+	doc, err := html.Parse(strings.NewReader(text))
+	if err != nil {
+		return "", err
+	}
+	stripHTMLTag(doc, tag)
+
+	var out bytes.Buffer
+	err = html.Render(&out, doc)
+	if err != nil {
+		return "", err
+	}
+
+	return out.String(), nil
+}
+
+func stripHTMLTag(node *html.Node, tag string) {
+	i := -1
+	for index, attr := range node.Attr {
+		if attr.Key == tag {
+			i = index
+			break
+		}
+	}
+	if i != -1 {
+		node.Attr = append(node.Attr[:i], node.Attr[i+1:]...)
+	}
+
+	for child := node.FirstChild; child != nil; child = child.NextSibling {
+		stripHTMLTag(child, tag)
+	}
+}