entry.go

@@ -43,16 +43,6 @@ func (e *Entry) checkAuthors() error {
 	return nil
 }
 
-func alternateRelExists(l []*Link) bool {
-	for _, link := range l {
-		if link.Rel == "alternate" {
-			return true
-		}
-	}
-
-	return false
-}
-
 func (e *Entry) AddExtension(name string, value any) {
 	e.Extensions = append(e.Extensions, &ExtensionElement{XMLName: xml.Name{Local: name}, Value: value})
 }
@@ -70,9 +60,11 @@ func (e *Entry) Check() error {
 		return fmt.Errorf("entry %v: %v", e.ID.URI, err)
 	}
 
-	for i, c := range e.Categories {
-		if err := c.Check(); err != nil {
-			return fmt.Errorf("category element %v of entry %v: %v", i, e.ID.URI, err)
+	if e.Categories != nil {
+		for i, c := range e.Categories {
+			if err := c.Check(); err != nil {
+				return fmt.Errorf("category element %v of entry %v: %v", i, e.ID.URI, err)
+			}
 		}
 	}
 
@@ -80,21 +72,21 @@ func (e *Entry) Check() error {
 		if err := (*e.Content).Check(); err != nil {
 			return fmt.Errorf("content element of entry %v: %v", e.ID.URI, err)
 		}
-	} else {
-		if !alternateRelExists(e.Links) {
-			return errors.New("no content element of entry %v and no link element with rel \"alternate\"")
+	}
+
+	if e.Contributors != nil {
+		for i, c := range e.Contributors {
+			if err := c.Check(); err != nil {
+				return fmt.Errorf("contributor element %v of entry %v: %v", i, e.ID.URI, err)
+			}
 		}
 	}
 
-	for i, c := range e.Contributors {
-		if err := c.Check(); err != nil {
-			return fmt.Errorf("contributor element %v of entry %v: %v", i, e.ID.URI, err)
-		}
-	}
-
-	for i, l := range e.Links {
-		if err := l.Check(); err != nil {
-			return fmt.Errorf("link element %v of entry %v: %v", i, e.ID.URI, err)
+	if e.Links != nil {
+		for i, l := range e.Links {
+			if err := l.Check(); err != nil {
+				return fmt.Errorf("link element %v of entry %v: %v", i, e.ID.URI, err)
+			}
 		}
 	}
 
@@ -138,9 +130,11 @@ func (e *Entry) Check() error {
 		}
 	}
 
-	for i, x := range e.Extensions {
-		if err := x.Check(); err != nil {
-			return fmt.Errorf("extension element %v of entry %v: %v", i, e.ID.URI, err)
+	if e.Extensions != nil {
+		for i, x := range e.Extensions {
+			if err := x.Check(); err != nil {
+				return fmt.Errorf("extension element %v of entry %v: %v", i, e.ID.URI, err)
+			}
 		}
 	}
 

feed.go

@@ -156,15 +156,19 @@ func (f *Feed) Check() error {
 		}
 	}
 
-	for i, c := range f.Categories {
-		if err := c.Check(); err != nil {
-			return fmt.Errorf("category element %v of feed %v: %v", i, f.ID.URI, err)
+	if f.Categories != nil {
+		for i, c := range f.Categories {
+			if err := c.Check(); err != nil {
+				return fmt.Errorf("category element %v of feed %v: %v", i, f.ID.URI, err)
+			}
 		}
 	}
 
-	for i, c := range f.Contributors {
-		if err := c.Check(); err != nil {
-			return fmt.Errorf("contributor element %v of feed %v: %v", i, f.ID.URI, err)
+	if f.Contributors != nil {
+		for i, c := range f.Contributors {
+			if err := c.Check(); err != nil {
+				return fmt.Errorf("contributor element %v of feed %v: %v", i, f.ID.URI, err)
+			}
 		}
 	}
 
@@ -180,9 +184,11 @@ func (f *Feed) Check() error {
 		}
 	}
 
-	for i, l := range f.Links {
-		if err := l.Check(); err != nil {
-			return fmt.Errorf("link element %v of feed %v: %v", i, f.ID.URI, err)
+	if f.Links != nil {
+		for i, l := range f.Links {
+			if err := l.Check(); err != nil {
+				return fmt.Errorf("link element %v of feed %v: %v", i, f.ID.URI, err)
+			}
 		}
 	}
 	if hasAlternateDuplicateLinks(f.Links) {
@@ -223,15 +229,19 @@ func (f *Feed) Check() error {
 		}
 	}
 
-	for i, x := range f.Extensions {
-		if err := x.Check(); err != nil {
-			return fmt.Errorf("extension element %v of feed %v: %v", i, f.ID.URI, err)
+	if f.Extensions != nil {
+		for i, x := range f.Extensions {
+			if err := x.Check(); err != nil {
+				return fmt.Errorf("extension element %v of feed %v: %v", i, f.ID.URI, err)
+			}
 		}
 	}
 
-	for i, n := range f.Entries {
-		if err := n.Check(); err != nil {
-			return fmt.Errorf("entry element %v of feed %v: %v", i, f.ID.URI, err)
+	if f.Entries != nil {
+		for i, n := range f.Entries {
+			if err := n.Check(); err != nil {
+				return fmt.Errorf("entry element %v of feed %v: %v", i, f.ID.URI, err)
+			}
 		}
 	}