add general Update* in fetch.go

TODO: implement backend protocol functions

fetch/fetch.go

@@ -42,13 +42,43 @@ func NewPage(remoteURL *url.URL, title string) (*core.Page, error) {
 }
 
 // UpdateFeed will check an existing core.Feed for updates
-func UpdateFeed(feed *core.Feed) error {
+func UpdateFeed(f *core.Feed) error {
+	switch f.FeedLink.Scheme {
+	case "gemini":
+		// return updateGeminiFeed(f)
 		// TODO
+		fallthrough
+	case "http", "https":
+		// return updateHTTPFeed(f)
+		// TODO
+		fallthrough
+	case "gopher", "gophers":
+		// return updateGopherFeed(f)
+		// TODO
+		fallthrough
+	default:
+		return fmt.Errorf("Unsupported protocol '%s'", f.FeedLink.Scheme)
+	}
 	return nil
 }
 
 // UpdatePage will check an existing core.Page for updages
-func UpdatePage(page *core.Page) error {
+func UpdatePage(p *core.Page) error {
+	switch p.Link.Scheme {
+	case "gemini":
+		// return updateGeminiPage(p)
 		// TODO
+		fallthrough
+	case "http", "https":
+		// return updateHTTPPage(p)
+		// TODO
+		fallthrough
+	case "gopher", "gophers":
+		// return updateGopherPage(p)
+		// TODO
+		fallthrough
+	default:
+		return fmt.Errorf("Unsupported protocol '%s'", p.Link.Scheme)
+	}
 	return nil
 }