feat: Monitor tab dynamically updates when messages are deleted (#337)

* WIP: msghub handles deletes, UI does not yet display them

Signed-off-by: James Hillyerd <james@hillyerd.com>

* socket and UI support message deletes

Signed-off-by: James Hillyerd <james@hillyerd.com>

* use Delete naming for consistency

Signed-off-by: James Hillyerd <james@hillyerd.com>

---------

Signed-off-by: James Hillyerd <james@hillyerd.com>

pkg/msghub/hub.go

@@ -15,6 +15,7 @@ const opChanLen = 100
 // Listener receives the contents of the history buffer, followed by new messages
 type Listener interface {
 	Receive(msg event.MessageMetadata) error
+	Delete(mailbox string, id string) error
 }
 
 // Hub relays messages on to its listeners
@@ -42,6 +43,12 @@ func New(historyLen int, extHost *extension.Host) *Hub {
 			return nil
 		})
 
+	extHost.Events.AfterMessageDeleted.AddListener("msghub",
+		func(msg event.MessageMetadata) *extension.Void {
+			hub.Delete(msg.Mailbox, msg.ID)
+			return nil
+		})
+
 	return hub
 }
 
@@ -68,7 +75,7 @@ func (hub *Hub) Dispatch(msg event.MessageMetadata) {
 			h.history.Value = msg
 			h.history = h.history.Next()
 
-			// Deliver message to all listeners, removing listeners if they return an error
+			// Relay event to all listeners, removing listeners if they return an error.
 			for l := range h.listeners {
 				if err := l.Receive(msg); err != nil {
 					delete(h.listeners, l)
@@ -78,6 +85,37 @@ func (hub *Hub) Dispatch(msg event.MessageMetadata) {
 	}
 }
 
+// Delete removes the message from the history buffer and instructs listeners to do the same.
+func (hub *Hub) Delete(mailbox string, id string) {
+	hub.opChan <- func(h *Hub) {
+		if h.history == nil {
+			return
+		}
+
+		// Locate and remove history entry.
+		p := h.history
+		end := p
+		for {
+			if next, ok := p.Next().Value.(event.MessageMetadata); ok {
+				if mailbox == next.Mailbox && id == next.ID {
+					p.Unlink(1) // Remove next node.
+					break
+				}
+			}
+			if p = p.Next(); p == end {
+				break
+			}
+		}
+
+		// Relay event to all listeners, removing listeners if they return an error.
+		for l := range h.listeners {
+			if err := l.Delete(mailbox, id); err != nil {
+				delete(h.listeners, l)
+			}
+		}
+	}
+}
+
 // AddListener registers a listener to receive broadcasted messages.
 func (hub *Hub) AddListener(l Listener) {
 	hub.opChan <- func(h *Hub) {

pkg/msghub/hub_test.go

@@ -3,6 +3,7 @@ package msghub
 import (
 	"context"
 	"fmt"
+	"strconv"
 	"testing"
 	"time"
 
@@ -13,8 +14,10 @@ import (
 // testListener implements the Listener interface, mock for unit tests
 type testListener struct {
 	messages   []*event.MessageMetadata // received messages
-	wantMessages int                      // how many messages this listener wants to receive
+	deletes    []string                 // received deletes
-	errorAfter   int                      // when != 0, messages until Receive() begins returning error
+	wantEvents int                      // how many events this listener wants to receive
+	errorAfter int                      // when != 0, event count until Receive() begins returning error
+	gotEvents  int
 
 	done     chan struct{} // closed once we have received wantMessages
 	overflow chan struct{} // closed if we receive wantMessages+1
@@ -23,7 +26,8 @@ type testListener struct {
 func newTestListener(want int) *testListener {
 	l := &testListener{
 		messages:   make([]*event.MessageMetadata, 0, want*2),
-		wantMessages: want,
+		deletes:    make([]string, 0, want*2),
+		wantEvents: want,
 		done:       make(chan struct{}),
 		overflow:   make(chan struct{}),
 	}
@@ -36,22 +40,29 @@ func newTestListener(want int) *testListener {
 // Receive a Message, store it in the messages slice, close applicable channels, and return an error
 // if instructed
 func (l *testListener) Receive(msg event.MessageMetadata) error {
+	l.gotEvents++
 	l.messages = append(l.messages, &msg)
-	if len(l.messages) == l.wantMessages {
+	if l.gotEvents == l.wantEvents {
 		close(l.done)
 	}
-	if len(l.messages) == l.wantMessages+1 {
+	if l.gotEvents == l.wantEvents+1 {
 		close(l.overflow)
 	}
-	if l.errorAfter > 0 && len(l.messages) > l.errorAfter {
+	if l.errorAfter > 0 && l.gotEvents > l.errorAfter {
 		return fmt.Errorf("Too many messages")
 	}
 	return nil
 }
 
+func (l *testListener) Delete(mailbox string, id string) error {
+	l.gotEvents++
+	l.deletes = append(l.deletes, mailbox+"/"+id)
+	return nil
+}
+
 // String formats the got vs wanted message counts
 func (l *testListener) String() string {
-	return fmt.Sprintf("got %v messages, wanted %v", len(l.messages), l.wantMessages)
+	return fmt.Sprintf("got %v messages, wanted %v", len(l.messages), l.wantEvents)
 }
 
 func TestHubNew(t *testing.T) {
@@ -198,6 +209,55 @@ func TestHubHistoryReplay(t *testing.T) {
 	}
 }
 
+func TestHubHistoryDelete(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	hub := New(100, extension.NewHost())
+	go hub.Start(ctx)
+	l1 := newTestListener(3)
+	hub.AddListener(l1)
+
+	// Broadcast 3 messages with no listeners
+	msgs := make([]event.MessageMetadata, 3)
+	for i := 0; i < len(msgs); i++ {
+		msgs[i] = event.MessageMetadata{
+			Mailbox: "hub",
+			ID:      strconv.Itoa(i),
+			Subject: fmt.Sprintf("subj %v", i),
+		}
+		hub.Dispatch(msgs[i])
+	}
+
+	// Wait for messages (live)
+	select {
+	case <-l1.done:
+	case <-time.After(time.Second):
+		t.Fatal("Timeout:", l1)
+	}
+
+	hub.Delete("hub", "1") // Delete a message
+	hub.Delete("zzz", "0") // Attempt to delete non-existent mailbox message
+
+	// Add a new listener, waits for 2 messages
+	l2 := newTestListener(2)
+	hub.AddListener(l2)
+
+	// Wait for messages (history)
+	select {
+	case <-l2.done:
+	case <-time.After(time.Second):
+		t.Fatal("Timeout:", l2)
+	}
+
+	want := []string{"subj 0", "subj 2"}
+	for i := 0; i < len(want); i++ {
+		got := l2.messages[i].Subject
+		if got != want[i] {
+			t.Errorf("msg[%v].Subject == %q, want %q", i, got, want[i])
+		}
+	}
+}
+
 func TestHubHistoryReplayWrap(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()

pkg/rest/model/apiv1_model.go

@@ -4,7 +4,7 @@ import (
 	"time"
 )
 
-// JSONMessageHeaderV1 contains the basic header data for a message
+// JSONMessageHeaderV1 contains the basic header data for a message.
 type JSONMessageHeaderV1 struct {
 	Mailbox     string    `json:"mailbox"`
 	ID          string    `json:"id"`
@@ -17,7 +17,7 @@ type JSONMessageHeaderV1 struct {
 	Seen        bool      `json:"seen"`
 }
 
-// JSONMessageV1 contains the same data as the header plus a JSONMessageBody
+// JSONMessageV1 contains the same data as the header plus a JSONMessageBody.
 type JSONMessageV1 struct {
 	Mailbox     string                     `json:"mailbox"`
 	ID          string                     `json:"id"`
@@ -33,7 +33,7 @@ type JSONMessageV1 struct {
 	Attachments []*JSONMessageAttachmentV1 `json:"attachments"`
 }
 
-// JSONMessageAttachmentV1 contains information about a MIME attachment
+// JSONMessageAttachmentV1 contains information about a MIME attachment.
 type JSONMessageAttachmentV1 struct {
 	FileName     string `json:"filename"`
 	ContentType  string `json:"content-type"`
@@ -42,8 +42,15 @@ type JSONMessageAttachmentV1 struct {
 	MD5          string `json:"md5"`
 }
 
-// JSONMessageBodyV1 contains the Text and HTML versions of the message body
+// JSONMessageBodyV1 contains the Text and HTML versions of the message body.
 type JSONMessageBodyV1 struct {
 	Text string `json:"text"`
 	HTML string `json:"html"`
 }
+
+// JSONMonitorEventV1 contains events for the Inbucket mailbox and monitor tabs.
+type JSONMonitorEventV1 struct {
+	// Event variant: `message-deleted`, `message-stored`.
+	Variant string               `json:"variant"`
+	Header  *JSONMessageHeaderV1 `json:"header"`
+}

pkg/rest/socketv1_controller.go

@@ -35,9 +35,9 @@ var upgrader = websocket.Upgrader{
 
 // msgListener handles messages from the msghub
 type msgListener struct {
-	hub     *msghub.Hub                // Global message hub
+	hub     *msghub.Hub                    // Global message hub.
-	c       chan event.MessageMetadata // Queue of messages from Receive()
+	c       chan *model.JSONMonitorEventV1 // Queue of incoming events.
-	mailbox string                     // Name of mailbox to monitor, "" == all mailboxes
+	mailbox string                         // Name of mailbox to monitor, "" == all mailboxes.
 }
 
 // newMsgListener creates a listener and registers it.  Optional mailbox parameter will restrict
@@ -45,20 +45,45 @@ type msgListener struct {
 func newMsgListener(hub *msghub.Hub, mailbox string) *msgListener {
 	ml := &msgListener{
 		hub:     hub,
-		c:       make(chan event.MessageMetadata, 100),
+		c:       make(chan *model.JSONMonitorEventV1, 100),
 		mailbox: mailbox,
 	}
 	hub.AddListener(ml)
 	return ml
 }
 
-// Receive handles an incoming message
+// Receive handles an incoming message.
 func (ml *msgListener) Receive(msg event.MessageMetadata) error {
 	if ml.mailbox != "" && ml.mailbox != msg.Mailbox {
-		// Did not match mailbox name
+		// Did not match the watched mailbox name.
 		return nil
 	}
-	ml.c <- msg
+
+	// Enqueue for websocket.
+	ml.c <- &model.JSONMonitorEventV1{
+		Variant: "message-stored",
+		Header:  metadataToHeader(&msg),
+	}
+
+	return nil
+}
+
+// Delete handles a deleted message.
+func (ml *msgListener) Delete(mailbox string, id string) error {
+	if ml.mailbox != "" && ml.mailbox != mailbox {
+		// Did not match watched mailbox name.
+		return nil
+	}
+
+	// Enqueue for websocket.
+	ml.c <- &model.JSONMonitorEventV1{
+		Variant: "message-deleted",
+		Header: &model.JSONMessageHeaderV1{
+			Mailbox: mailbox,
+			ID:      id,
+		},
+	}
+
 	return nil
 }
 
@@ -104,24 +129,14 @@ func (ml *msgListener) WSWriter(conn *websocket.Conn) {
 	// Handle messages from hub until msgListener is closed
 	for {
 		select {
-		case msg, ok := <-ml.c:
+		case event, ok := <-ml.c:
 			conn.SetWriteDeadline(time.Now().Add(writeWait))
 			if !ok {
 				// msgListener closed, exit
 				conn.WriteMessage(websocket.CloseMessage, []byte{})
 				return
 			}
-			header := &model.JSONMessageHeaderV1{
+			if conn.WriteJSON(event) != nil {
-				Mailbox:     msg.Mailbox,
-				ID:          msg.ID,
-				From:        stringutil.StringAddress(msg.From),
-				To:          stringutil.StringAddressList(msg.To),
-				Subject:     msg.Subject,
-				Date:        msg.Date,
-				PosixMillis: msg.Date.UnixNano() / 1000000,
-				Size:        msg.Size,
-			}
-			if conn.WriteJSON(header) != nil {
 				// Write failed
 				return
 			}
@@ -198,3 +213,16 @@ func MonitorMailboxMessagesV1(
 	ml.WSReader(conn)
 	return nil
 }
+
+func metadataToHeader(msg *event.MessageMetadata) *model.JSONMessageHeaderV1 {
+	return &model.JSONMessageHeaderV1{
+		Mailbox:     msg.Mailbox,
+		ID:          msg.ID,
+		From:        stringutil.StringAddress(msg.From),
+		To:          stringutil.StringAddressList(msg.To),
+		Subject:     msg.Subject,
+		Date:        msg.Date,
+		PosixMillis: msg.Date.UnixNano() / 1000000,
+		Size:        msg.Size,
+	}
+}

ui/src/Data/MonitorEvent.elm

@@ -0,0 +1,44 @@
+module Data.MonitorEvent exposing (MessageID, MonitorEvent(..), decoder)
+
+import Data.MessageHeader as MessageHeader exposing (MessageHeader)
+import Json.Decode exposing (Decoder, andThen, fail, field, string, succeed)
+import Json.Decode.Pipeline exposing (required)
+
+
+type alias MessageID =
+    { mailbox : String
+    , id : String
+    }
+
+
+type MonitorEvent
+    = MessageStored MessageHeader
+    | MessageDeleted MessageID
+
+
+decoder : Decoder MonitorEvent
+decoder =
+    field "variant" string
+        |> andThen variantDecoder
+
+
+variantDecoder : String -> Decoder MonitorEvent
+variantDecoder variant =
+    case variant of
+        "message-deleted" ->
+            succeed MessageDeleted
+                |> required "header" messageIdDecoder
+
+        "message-stored" ->
+            succeed MessageStored
+                |> required "header" MessageHeader.decoder
+
+        unknown ->
+            fail <| "Unknown variant: " ++ unknown
+
+
+messageIdDecoder : Decoder MessageID
+messageIdDecoder =
+    succeed MessageID
+        |> required "mailbox" string
+        |> required "id" string

ui/src/Page/Monitor.elm

@@ -1,7 +1,8 @@
 module Page.Monitor exposing (Model, Msg, init, update, view)
 
 import Api
-import Data.MessageHeader as MessageHeader exposing (MessageHeader)
+import Data.MessageHeader exposing (MessageHeader)
+import Data.MonitorEvent as MonitorEvent
 import Data.Session exposing (Session)
 import DateFormat as DF
 import Effect exposing (Effect)
@@ -68,8 +69,20 @@ update msg model =
             ( { model | connected = False }, Effect.none )
 
         MessageReceived value ->
-            case D.decodeValue (MessageHeader.decoder |> D.at [ "detail" ]) value of
+            case D.decodeValue (MonitorEvent.decoder |> D.at [ "detail" ]) value of
-                Ok header ->
+                Ok event ->
+                    case event of
+                        MonitorEvent.MessageDeleted deleted ->
+                            ( { model
+                                | messages =
+                                    List.filter
+                                        (\x -> x.mailbox /= deleted.mailbox || x.id /= deleted.id)
+                                        model.messages
+                              }
+                            , Effect.none
+                            )
+
+                        MonitorEvent.MessageStored header ->
                             ( { model | messages = header :: List.take 500 model.messages }
                             , Effect.none
                             )