[bugfix] Add support for public:remote stream type (#4899)

Adds support for the `public:remote` stream type, ie., the federated timeline with *only* remote posts in it (as used by masto-fe in the "live feeds -> other servers" tab).

Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4899

docs/api/swagger.yaml

@@ -15965,6 +15965,7 @@ paths:
                     `user:notification`: receive notifications for the account.
                     `public`: receive updates for the public timeline.
                     `public:local`: receive updates for the local timeline.
+                    `public:remote`: receive updates for the public remote-only timeline
                     `hashtag`: receive updates for a given hashtag.
                     `hashtag:local`: receive local updates for a given hashtag.
                     `list`: receive updates for a certain list of accounts.
@@ -15974,6 +15975,7 @@ paths:
                     - user:notification
                     - public
                     - public:local
+                    - public:remote
                     - hashtag
                     - hashtag:local
                     - list
@@ -16035,6 +16037,7 @@ paths:
                                         - user:notification
                                         - public
                                         - public:local
+                                        - public:remote
                                         - hashtag
                                         - hashtag:local
                                         - list

internal/api/client/streaming/stream.go

@@ -76,6 +76,7 @@ var pingMsg = []byte("ping!")
 //			- user:notification
 //			- public
 //			- public:local
+//			- public:remote
 //			- hashtag
 //			- hashtag:local
 //			- list
@@ -89,6 +90,7 @@ var pingMsg = []byte("ping!")
 //			`user:notification`: receive notifications for the account.
 //			`public`: receive updates for the public timeline.
 //			`public:local`: receive updates for the local timeline.
+//			`public:remote`: receive updates for the public remote-only timeline
 //			`hashtag`: receive updates for a given hashtag.
 //			`hashtag:local`: receive local updates for a given hashtag.
 //			`list`: receive updates for a certain list of accounts.
@@ -128,6 +130,7 @@ var pingMsg = []byte("ping!")
 //							- user:notification
 //							- public
 //							- public:local
+//							- public:remote
 //							- hashtag
 //							- hashtag:local
 //							- list
@@ -218,6 +221,12 @@ func (m *Module) StreamGETHandler(c *gin.Context) {
 	// Get the initial requested stream type, if there is one.
 	streamType := c.Query(StreamQueryKey)
 
+	// Rewrite "allow_local_only" type as we always
+	// allow local-only posts in the public timeline.
+	if streamType == "public:allow_local_only" {
+		streamType = "public"
+	}
+
 	// By appending other query params to the streamType, we
 	// can allow streaming for specific list IDs or hashtags.
 	// The streamType in this case will end up looking like
@@ -292,7 +301,7 @@ func (m *Module) handleWSConn(l *log.Entry, wsConn *websocket.Conn, stream *stre
 		defer cncl()
 
 		// Read messages from websocket to server.
-		m.readFromWSConn(ctx, wsConn, stream, l)
+		m.readFromWSConn(wsConn, stream, l)
 	}()
 
 	go func() {
@@ -325,7 +334,6 @@ func (m *Module) handleWSConn(l *log.Entry, wsConn *websocket.Conn, stream *stre
 // This is a blocking function; will return only on read error or
 // if the given context is canceled.
 func (m *Module) readFromWSConn(
-	ctx context.Context,
 	wsConn *websocket.Conn,
 	stream *streampkg.Stream,
 	l *log.Entry,
@@ -359,6 +367,12 @@ func (m *Module) readFromWSConn(
 		// and usually interesting, so log this at info.
 		l.Infof("received websocket message: %+v", msg)
 
+		// Rewrite "allow_local_only" type as we always
+		// allow local-only posts in the public timeline.
+		if msg.Stream == "public:allow_local_only" {
+			msg.Stream = "public"
+		}
+
 		// Ignore if the updateStreamType is unknown (or missing),
 		// so a bad client can't cause extra memory allocations
 		if !slices.Contains(streampkg.AllStatusTimelines, msg.Stream) {

internal/stream/stream.go

@@ -59,10 +59,16 @@ const (
 	TimelineLocal = "public:local"
 
 	// TimelinePublic:
-	// All public posts known to the server.
+	// All public posts known to the server,
+	// including local ones too.
 	// Analogous to the federated timeline.
 	TimelinePublic = "public"
 
+	// TimelinePublicRemote:
+	// All *remote* public posts known to
+	// the server, excluding local posts.
+	TimelinePublicRemote = "public:remote"
+
 	// TimelineHome:
 	// Events related to the current user, such
 	// as home feed updates and notifications.
@@ -87,6 +93,7 @@ const (
 var AllStatusTimelines = []string{
 	TimelineLocal,
 	TimelinePublic,
+	TimelinePublicRemote,
 	TimelineHome,
 	TimelineDirect,
 	TimelineList,

internal/surfacing/surfacetimeline.go

@@ -77,6 +77,12 @@ func (s *Surfacer) TimelineAndNotifyStatus(ctx context.Context, status *gtsmodel
 
 			// Stream the status model as public timeline update event.
 			s.stream.Update(ctx, account, apiStatus, stream.TimelinePublic)
+
+			// If this is a remote status, stream it to
+			// the public remote-only timeline as well.
+			if status.Account.IsRemote() {
+				s.stream.Update(ctx, account, apiStatus, stream.TimelinePublicRemote)
+			}
 		},
 	)