Force undefined content of category and link to be empty or valid xml

link.go

@@ -19,6 +19,10 @@ type Link struct {
 
 // NewLink creates a new Link. It returns a *Link and an error.
 func NewLink(href, content string) (*Link, error) {
+	if !isValidXML(content) {
+		return nil, fmt.Errorf("%v not valid XML", content)
+	}
+
 	return &Link{Href: IRI(href), Content: content}, nil
 }
 
@@ -51,8 +55,10 @@ func (l *Link) Check() error {
 		}
 	}
 
-	if l.Content == "" {
-		return errors.New("content element of link empty")
+	if l.Content != "" {
+		if !isValidXML(l.Content) {
+			return fmt.Errorf("content element %v of link not valid XML", l.Content)
+		}
 	}
 
 	return nil