From f8c36a7045f7ee1d63d818fb57af473fc667721b Mon Sep 17 00:00:00 2001
From: Jason Streifling <jason@streifling.com>
Date: Wed, 16 Oct 2024 18:31:13 +0200
Subject: [PATCH] Change title to string type and add checks

---
 link.go | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/link.go b/link.go
index 8ff5381..c937aef 100644
--- a/link.go
+++ b/link.go
@@ -3,11 +3,12 @@ package atomfeed
 import (
 	"errors"
 	"fmt"
+	"strings"
 )
 
 type Link struct {
 	*CommonAttributes
-	Title    Text        `xml:"title,attr,omitempty"`
+	Title    string      `xml:"title,attr,omitempty"`
 	Content  Content     `xml:"content"` // undefinedContent in RFC4287
 	Href     IRI         `xml:"href,attr"`
 	Rel      string      `xml:"rel,attr,omitempty"`
@@ -28,12 +29,22 @@ func NewLink(href string) (*Link, error) {
 func (l *Link) Check() error {
 	if l.Href == "" {
 		return errors.New("href attribute of link empty")
+	} else {
+		if !isValidIRI(l.Href) {
+			return fmt.Errorf("href attribute %v of link not correctly formatted", l.Href)
+		}
 	}
 
-	if l.Title != nil {
-		if err := l.Title.Check(); err != nil {
-			return fmt.Errorf("title attribute of link %v: %v", l.Href, err)
-		}
+	if strings.Contains(l.Rel, ":") || !isValidIRI(IRI(l.Rel)) {
+		return fmt.Errorf("rel attribute %v of link %v not correctly formatted", l.Rel, l.Href)
+	}
+
+	if !isValidMediaType(string(l.Type)) {
+		return fmt.Errorf("type attribute %v of link %v invalid media type", l.Type, l.Href)
+	}
+
+	if !isValidLanguageTag(l.HrefLang) {
+		return fmt.Errorf("hreflang attribute %v of link %v invalid language tag", l.Type, l.HrefLang)
 	}
 
 	if l.Content == nil {