bskyweb: extract gallery media for SEO

Posts using app.bsky.embed.gallery (Photos v2) were rendering with no
og:image and an empty JSON-LD image[] because extractPostMedia only
covered the legacy images and video embed shapes. This adds gallery
support in both the top-level embed slot and the record-with-media
media slot, preserving the byte-equality contract between og:image
and JSON-LD image[].

bskyweb/cmd/bskyweb/jsonld.go

@@ -136,9 +136,9 @@ func bskyProfileURL(handle string) string {
 	return fmt.Sprintf("https://bsky.app/profile/%s", handle)
 }
 
-// extractPostMedia returns thumbnail URLs for the post's image or video
+// extractPostMedia returns thumbnail URLs for the post's image, gallery,
-// embed, byte-identical to what we put in og:image. Callers derive
+// or video embed, byte-identical to what we put in og:image. Callers
-// thumbnailUrl from urls[0].
+// derive thumbnailUrl from urls[0].
 func extractPostMedia(pv *appbsky.FeedDefs_PostView, embedHidden bool) []string {
 	if pv == nil || pv.Embed == nil || embedHidden {
 		return nil
@@ -147,6 +147,9 @@ func extractPostMedia(pv *appbsky.FeedDefs_PostView, embedHidden bool) []string
 	if pv.Embed.EmbedImages_View != nil {
 		return imageThumbs(pv.Embed.EmbedImages_View.Images)
 	}
+	if pv.Embed.EmbedGallery_View != nil {
+		return galleryThumbs(pv.Embed.EmbedGallery_View.Items)
+	}
 	if pv.Embed.EmbedVideo_View != nil && pv.Embed.EmbedVideo_View.Thumbnail != nil {
 		return []string{*pv.Embed.EmbedVideo_View.Thumbnail}
 	}
@@ -155,6 +158,9 @@ func extractPostMedia(pv *appbsky.FeedDefs_PostView, embedHidden bool) []string
 		if media.EmbedImages_View != nil {
 			return imageThumbs(media.EmbedImages_View.Images)
 		}
+		if media.EmbedGallery_View != nil {
+			return galleryThumbs(media.EmbedGallery_View.Items)
+		}
 		if media.EmbedVideo_View != nil && media.EmbedVideo_View.Thumbnail != nil {
 			return []string{*media.EmbedVideo_View.Thumbnail}
 		}
@@ -174,6 +180,27 @@ func imageThumbs(images []*appbsky.EmbedImages_ViewImage) []string {
 	return urls
 }
 
+// galleryThumbs returns the thumbnail URLs of image items in a gallery
+// embed, or nil if empty. Items_Elem is a union; non-image variants and
+// nil entries are skipped so future gallery item types don't break SEO
+// extraction.
+func galleryThumbs(items []*appbsky.EmbedGallery_View_Items_Elem) []string {
+	if len(items) == 0 {
+		return nil
+	}
+	urls := make([]string, 0, len(items))
+	for _, item := range items {
+		if item == nil || item.EmbedGallery_ViewImage == nil {
+			continue
+		}
+		urls = append(urls, item.EmbedGallery_ViewImage.Thumbnail)
+	}
+	if len(urls) == 0 {
+		return nil
+	}
+	return urls
+}
+
 // extractQuotedPostURL returns the canonical URL of a quoted post, or ""
 // if the embed is blocked / not-found / detached / a non-post record.
 func extractQuotedPostURL(pv *appbsky.FeedDefs_PostView) string {

bskyweb/cmd/bskyweb/jsonld_test.go

@@ -72,6 +72,60 @@ func withImages(thumbs ...string) func(*appbsky.FeedDefs_PostView) {
 	}
 }
 
+// withGallery adds an app.bsky.embed.gallery view with image items.
+func withGallery(thumbs ...string) func(*appbsky.FeedDefs_PostView) {
+	return func(pv *appbsky.FeedDefs_PostView) {
+		var items []*appbsky.EmbedGallery_View_Items_Elem
+		for _, t := range thumbs {
+			items = append(items, &appbsky.EmbedGallery_View_Items_Elem{
+				EmbedGallery_ViewImage: &appbsky.EmbedGallery_ViewImage{
+					Thumbnail: t,
+					Fullsize:  t + "_full",
+				},
+			})
+		}
+		pv.Embed = &appbsky.FeedDefs_PostView_Embed{
+			EmbedGallery_View: &appbsky.EmbedGallery_View{Items: items},
+		}
+	}
+}
+
+// withRecordWithMediaGallery adds a record-with-media embed whose media slot
+// is an app.bsky.embed.gallery view.
+func withRecordWithMediaGallery(qHandle, qDid, qRkey string, thumbs ...string) func(*appbsky.FeedDefs_PostView) {
+	return func(pv *appbsky.FeedDefs_PostView) {
+		var items []*appbsky.EmbedGallery_View_Items_Elem
+		for _, t := range thumbs {
+			items = append(items, &appbsky.EmbedGallery_View_Items_Elem{
+				EmbedGallery_ViewImage: &appbsky.EmbedGallery_ViewImage{
+					Thumbnail: t,
+					Fullsize:  t + "_full",
+				},
+			})
+		}
+		pv.Embed = &appbsky.FeedDefs_PostView_Embed{
+			EmbedRecordWithMedia_View: &appbsky.EmbedRecordWithMedia_View{
+				Record: &appbsky.EmbedRecord_View{
+					Record: &appbsky.EmbedRecord_View_Record{
+						EmbedRecord_ViewRecord: &appbsky.EmbedRecord_ViewRecord{
+							Uri: "at://" + qDid + "/app.bsky.feed.post/" + qRkey,
+							Cid: "bafy-quoted",
+							Author: &appbsky.ActorDefs_ProfileViewBasic{
+								Did:    qDid,
+								Handle: qHandle,
+							},
+							IndexedAt: "2024-01-01T00:00:00Z",
+						},
+					},
+				},
+				Media: &appbsky.EmbedRecordWithMedia_View_Media{
+					EmbedGallery_View: &appbsky.EmbedGallery_View{Items: items},
+				},
+			},
+		}
+	}
+}
+
 // withVideo adds a video embed with a thumbnail.
 func withVideo(thumb string) func(*appbsky.FeedDefs_PostView) {
 	return func(pv *appbsky.FeedDefs_PostView) {
@@ -299,6 +353,86 @@ func TestBuildPostJSONLD_WithImages(t *testing.T) {
 	}
 }
 
+func TestBuildPostJSONLD_WithGallery(t *testing.T) {
+	thumb1 := "https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:alice/g1@jpeg"
+	thumb2 := "https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:alice/g2@jpeg"
+	thumb3 := "https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:alice/g3@jpeg"
+	pv := makePostView("alice.bsky.social", "did:plc:alice", "abc123", "gallery", withGallery(thumb1, thumb2, thumb3))
+	out, err := buildPostJSONLD(pv, nil, "https://bsky.app/profile/alice.bsky.social/post/abc123", hideEmbedLabels, hideReplyLabels)
+	if err != nil {
+		t.Fatal(err)
+	}
+	main := unmarshalLD(t, out)["mainEntity"].(map[string]any)
+	imgs, ok := main["image"].([]any)
+	if !ok {
+		t.Fatalf("image should be array, got %T", main["image"])
+	}
+	if len(imgs) != 3 {
+		t.Errorf("expected 3 gallery images, got %d", len(imgs))
+	}
+	if imgs[0] != thumb1 || imgs[1] != thumb2 || imgs[2] != thumb3 {
+		t.Errorf("gallery image[] order wrong: %v", imgs)
+	}
+	if main["thumbnailUrl"] != thumb1 {
+		t.Errorf("thumbnailUrl should equal image[0] (Google byte-equality requirement), got %v", main["thumbnailUrl"])
+	}
+}
+
+// Gallery in the media slot of a record-with-media embed should still
+// produce og:image / JSON-LD image[]. Quote-post URL still emits
+// alongside via isBasedOn.
+func TestBuildPostJSONLD_GalleryInRecordWithMedia(t *testing.T) {
+	thumb := "https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:alice/g@jpeg"
+	pv := makePostView("alice.bsky.social", "did:plc:alice", "abc123", "quote+gallery",
+		withRecordWithMediaGallery("bob.example.com", "did:plc:bob", "xyz", thumb))
+	out, err := buildPostJSONLD(pv, nil, "u", hideEmbedLabels, hideReplyLabels)
+	if err != nil {
+		t.Fatal(err)
+	}
+	main := unmarshalLD(t, out)["mainEntity"].(map[string]any)
+	imgs, ok := main["image"].([]any)
+	if !ok || len(imgs) != 1 || imgs[0] != thumb {
+		t.Errorf("expected single gallery thumb in image[], got %v", main["image"])
+	}
+	if main["thumbnailUrl"] != thumb {
+		t.Errorf("thumbnailUrl wrong: %v", main["thumbnailUrl"])
+	}
+	if main["isBasedOn"] != "https://bsky.app/profile/bob.example.com/post/xyz" {
+		t.Errorf("isBasedOn should still emit for record-with-media gallery, got %v", main["isBasedOn"])
+	}
+}
+
+// Forward-compat: nil items and unknown-variant union elements must be
+// skipped, not panic. Unknown variants are dropped silently so older
+// deploys keep working when new gallery item types ship.
+func TestExtractPostMedia_GallerySkipsUnknownItems(t *testing.T) {
+	thumb := "https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:alice/g@jpeg"
+	pv := makePostView("alice.bsky.social", "did:plc:alice", "abc123", "gallery")
+	pv.Embed = &appbsky.FeedDefs_PostView_Embed{
+		EmbedGallery_View: &appbsky.EmbedGallery_View{
+			Items: []*appbsky.EmbedGallery_View_Items_Elem{
+				nil,
+				{}, // empty union, no variant set
+				{EmbedGallery_ViewImage: &appbsky.EmbedGallery_ViewImage{Thumbnail: thumb}},
+			},
+		},
+	}
+	got := extractPostMedia(pv, false)
+	if len(got) != 1 || got[0] != thumb {
+		t.Errorf("expected single thumb, got %v", got)
+	}
+
+	// All-nil / all-unknown gallery should produce no thumbs (not [""]).
+	pv.Embed = &appbsky.FeedDefs_PostView_Embed{
+		EmbedGallery_View: &appbsky.EmbedGallery_View{
+			Items: []*appbsky.EmbedGallery_View_Items_Elem{nil, {}},
+		},
+	}
+	if got := extractPostMedia(pv, false); got != nil {
+		t.Errorf("expected nil for empty/unknown-only gallery, got %v", got)
+	}
+}
+
 func TestBuildPostJSONLD_WithVideo(t *testing.T) {
 	thumb := "https://cdn.bsky.app/img/video_thumbnail/plain/did:plc:alice/v@jpeg"
 	pv := makePostView("alice.bsky.social", "did:plc:alice", "abc123", "watch", withVideo(thumb))

bskyweb/cmd/bskyweb/render_test.go

@@ -98,6 +98,40 @@ func TestRenderPost_OGImageMatchesJSONLD(t *testing.T) {
 	}
 }
 
+// Gallery posts must hit the same og:image / JSON-LD image[] byte-equality
+// contract that legacy images posts do. Regression guard for the
+// app.bsky.embed.gallery extraction path.
+func TestRenderPost_OGImageMatchesJSONLD_Gallery(t *testing.T) {
+	thumb1 := "https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:alice/g1@jpeg"
+	thumb2 := "https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:alice/g2@jpeg"
+	pv := makePostView("alice.bsky.social", "did:plc:alice", "abc123", "gallery", withGallery(thumb1, thumb2))
+	thumbs := extractPostMedia(pv, false)
+	ld, _ := buildPostJSONLD(pv, nil, "https://bsky.app/profile/alice.bsky.social/post/abc123", hideEmbedLabels, hideReplyLabels)
+	html := renderTemplate(t, "post.html", pongo2.Context{
+		"postView":     pv,
+		"requestURI":   "https://bsky.app/profile/alice.bsky.social/post/abc123",
+		"canonicalURL": "https://bsky.app/profile/alice.bsky.social/post/abc123",
+		"postJSONLD":   ld,
+		"imgThumbUrls": thumbs,
+	})
+
+	if !strings.Contains(html, `<meta property="og:image" content="`+thumb1+`">`) {
+		t.Errorf("og:image[0] not found in rendered HTML for gallery post")
+	}
+	if !strings.Contains(html, `<meta property="og:image" content="`+thumb2+`">`) {
+		t.Errorf("og:image[1] not found in rendered HTML for gallery post")
+	}
+	body := extractJSONLD(t, html)
+	var parsed map[string]any
+	_ = json.Unmarshal([]byte(body), &parsed)
+	main := parsed["mainEntity"].(map[string]any)
+	imgs := main["image"].([]any)
+	if len(imgs) != 2 || imgs[0] != thumb1 || main["thumbnailUrl"] != thumb1 {
+		t.Errorf("JSON-LD image strings drifted from og:image for gallery; image=%v thumbnailUrl=%v",
+			imgs, main["thumbnailUrl"])
+	}
+}
+
 func TestRenderPost_FallsBackToCanonicalizeFilter(t *testing.T) {
 	// Without canonicalURL, the template falls back to requestURI|canonicalize_url.
 	pv := makePostView("alice.bsky.social", "did:plc:alice", "abc123", "hi")

bskyweb/go.mod

@@ -3,7 +3,7 @@ module github.com/bluesky-social/social-app/bskyweb
 go 1.26
 
 require (
-	github.com/bluesky-social/indigo v0.0.0-20260529183052-5368f55344e0
+	github.com/bluesky-social/indigo v0.0.0-20260605210604-af2fec94f34c
 	github.com/flosch/pongo2/v6 v6.0.0
 	github.com/ipfs/go-log v1.0.5
 	github.com/joho/godotenv v1.5.1

bskyweb/go.sum

@@ -2,8 +2,8 @@ github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03
 github.com/benbjohnson/clock v1.1.0/go.mod h1:J11/hYXuz8f4ySSvYwY0FKfm+ezbsZBKZxNJlLklBHA=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
-github.com/bluesky-social/indigo v0.0.0-20260529183052-5368f55344e0 h1:eijBaF59A5c+kPqufH7YO1GOqDMkyUhtM9P9aAWtfJY=
+github.com/bluesky-social/indigo v0.0.0-20260605210604-af2fec94f34c h1:Jr82+1HUmwwZzDpt/eeU4sieya27iXjuPMdXZkOXoBc=
-github.com/bluesky-social/indigo v0.0.0-20260529183052-5368f55344e0/go.mod h1:JqQkz8lrOI6YZivP38GHmtVOTtzsNToITKj1gMpU5Jo=
+github.com/bluesky-social/indigo v0.0.0-20260605210604-af2fec94f34c/go.mod h1:JqQkz8lrOI6YZivP38GHmtVOTtzsNToITKj1gMpU5Jo=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=