feat: support YouTube video thumbnail in link preview (#4427)

plugin/httpgetter/html_meta.go

 package httpgetter
 
 import (
+	"fmt"
 	"io"
 	"net"
 	"net/http"
@@ -53,6 +54,7 @@ func GetHTMLMeta(urlStr string) (*HTMLMeta, error) {
 	// TODO: limit the size of the response body
 
 	htmlMeta := extractHTMLMeta(response.Body)
+	enrichSiteMeta(response.Request.URL, htmlMeta)
 	return htmlMeta, nil
 }
 
@@ -151,3 +153,14 @@ func validateURL(urlStr string) error {
 
 	return nil
 }
+
+func enrichSiteMeta(url *url.URL, meta *HTMLMeta) {
+	if url.Hostname() == "www.youtube.com" {
+		if url.Path == "/watch" {
+			vid := url.Query().Get("v")
+			if vid != "" {
+				meta.Image = fmt.Sprintf("https://img.youtube.com/vi/%s/mqdefault.jpg", vid)
+			}
+		}
+	}
+}

web/src/components/MemoContent/Link.tsx

@@ -54,6 +54,9 @@ const Link: React.FC<Props> = ({ text, url }: Props) => {
             {linkMetadata.description && (
               <p className="mt-1 w-full text-sm leading-snug opacity-80 line-clamp-3">{linkMetadata.description}</p>
             )}
+            {linkMetadata.image && (
+              <img className="mt-1 w-full h-32 object-cover rounded" src={linkMetadata.image} alt={linkMetadata.title} />
+            )}
           </div>
         )
       }