Recipients see a message only once it is sent

README.md

@@ -571,6 +571,10 @@ ws.onmessage = (e) => {
 
 Returns messages where the authenticated identity is a recipient (listed in `msg_to` or `msg_add_to`), ordered by message ID descending.
 
+Only sent messages are listed. A draft is its sender's alone: until it is sent,
+its recipients get `404` for it on every route (get, data, attachments, thread,
+read, react and add-to), as if it did not exist.
+
 Visibility is always scoped to exactly the one identity the caller
 authenticated as — the owner, or (via a sub-account's own API-key token or
 the owner's `X-FMSG-Act-As` header) a single sub-account. A request never

internal/handlers/attachments.go

@@ -187,7 +187,8 @@ func (h *AttachmentHandler) Download(c *gin.Context) {
 
 	// Check ownership or recipient access.
 	var fromAddr string
-	err := h.q().QueryRow(ctx, "SELECT from_addr FROM msg WHERE id = $1", msgID).Scan(&fromAddr)
+	var timeSent *float64
+	err := h.q().QueryRow(ctx, "SELECT from_addr, time_sent FROM msg WHERE id = $1", msgID).Scan(&fromAddr, &timeSent)
 	if err != nil {
 		if errors.Is(err, pgx.ErrNoRows) {
 			c.JSON(http.StatusNotFound, gin.H{"error": "message not found"})
@@ -197,6 +198,10 @@ func (h *AttachmentHandler) Download(c *gin.Context) {
 		}
 		return
 	}
+	if draftHidden([]string{identity}, fromAddr, timeSent) {
+		c.JSON(http.StatusNotFound, gin.H{"error": "message not found"})
+		return
+	}
 
 	// Check recipients (to or add_to) if not owner.
 	if fromAddr != identity {

internal/handlers/drafts_integration_test.go

@@ -0,0 +1,78 @@
+package handlers
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+// A draft is its sender's alone: its recipients can neither list nor reach it
+// by any route until it is sent.
+func TestRecipientsCannotSeeDrafts(t *testing.T) {
+	a := newFinalizationAPI(t)
+	const alice, bob = "@alice@example.com", "@bob@example.com"
+	id := a.draft(t, alice, "not ready yet", nil)
+	a.upload(t, id)
+
+	listed := func() bool {
+		t.Helper()
+		w := a.request(bob, "GET", "/fmsg", nil)
+		if w.Code != 200 {
+			t.Fatalf("list %d: %s", w.Code, w.Body)
+		}
+		var items []struct {
+			ID json.Number `json:"id"`
+		}
+		if err := json.Unmarshal(w.Body.Bytes(), &items); err != nil {
+			t.Fatal(err)
+		}
+		for _, it := range items {
+			if it.ID.String() == id {
+				return true
+			}
+		}
+		return false
+	}
+	if listed() {
+		t.Fatal("bob's inbox lists alice's draft")
+	}
+
+	for _, r := range []struct{ method, path string }{
+		{"GET", "/fmsg/" + id},
+		{"GET", "/fmsg/" + id + "/data"},
+		{"GET", "/fmsg/" + id + "/attach/note.txt"},
+		{"GET", "/fmsg/" + id + "/thread"},
+		{"GET", "/fmsg/" + id + "/thread/messages"},
+		{"POST", "/fmsg/" + id + "/read"},
+	} {
+		if w := a.request(bob, r.method, r.path, map[string]any{}); w.Code != 404 {
+			t.Errorf("bob %s %s: HTTP %d, want 404: %s", r.method, r.path, w.Code, w.Body)
+		}
+	}
+	if w := a.request(bob, "POST", "/fmsg/"+id+"/react", map[string]any{"emoji": "👍"}); w.Code != 404 {
+		t.Errorf("bob react: HTTP %d, want 404: %s", w.Code, w.Body)
+	}
+	if w := a.request(bob, "POST", "/fmsg/"+id+"/add-to", map[string]any{"add_to": []string{"@carol@example.com"}}); w.Code != 404 {
+		t.Errorf("bob add-to: HTTP %d, want 404: %s", w.Code, w.Body)
+	}
+
+	// The sender still has it.
+	for _, path := range []string{"/fmsg/" + id, "/fmsg/" + id + "/data", "/fmsg/" + id + "/attach/note.txt", "/fmsg/" + id + "/thread/messages"} {
+		if w := a.request(alice, "GET", path, nil); w.Code != 200 {
+			t.Errorf("alice GET %s: HTTP %d: %s", path, w.Code, w.Body)
+		}
+	}
+
+	// Once sent, bob has it.
+	jsonResponse(t, a.request(alice, "POST", "/fmsg/"+id+"/send", map[string]any{}), 200)
+	if !listed() {
+		t.Fatal("bob's inbox does not list the sent message")
+	}
+	for _, path := range []string{"/fmsg/" + id, "/fmsg/" + id + "/data", "/fmsg/" + id + "/attach/note.txt", "/fmsg/" + id + "/thread/messages"} {
+		if w := a.request(bob, "GET", path, nil); w.Code != 200 {
+			t.Errorf("bob GET %s after send: HTTP %d: %s", path, w.Code, w.Body)
+		}
+	}
+	if w := a.request(bob, "POST", "/fmsg/"+id+"/read", map[string]any{}); w.Code != 200 {
+		t.Errorf("bob read after send: HTTP %d: %s", w.Code, w.Body)
+	}
+}

internal/handlers/messages.go

@@ -322,8 +322,9 @@ func (h *MessageHandler) List(c *gin.Context) {
 		            (SELECT mat.time_read FROM msg_add_to mat WHERE mat.msg_id = m.id AND lower(mat.addr) = ANY($1))
 		        ) AS time_read
 		 FROM msg m
-		 WHERE EXISTS (SELECT 1 FROM msg_to mt WHERE mt.msg_id = m.id AND lower(mt.addr) = ANY($1))
-		    OR EXISTS (SELECT 1 FROM msg_add_to mat WHERE mat.msg_id = m.id AND lower(mat.addr) = ANY($1))
+		 WHERE m.time_sent IS NOT NULL
+		   AND (EXISTS (SELECT 1 FROM msg_to mt WHERE mt.msg_id = m.id AND lower(mt.addr) = ANY($1))
+		     OR EXISTS (SELECT 1 FROM msg_add_to mat WHERE mat.msg_id = m.id AND lower(mat.addr) = ANY($1)))
 		 ORDER BY m.id DESC
 		 LIMIT $2 OFFSET $3`,
 		addrs, limit, offset,
@@ -620,6 +621,11 @@ func (h *MessageHandler) Get(c *gin.Context) {
 		return
 	}
 
+	if draftHidden(addrs, msg.From, msg.Time) {
+		c.JSON(http.StatusNotFound, gin.H{"error": "message not found"})
+		return
+	}
+
 	// Authorization: owner or recipient (to or add_to), across all visible addrs.
 	isSender := isRecipient(addrs, msg.From)
 	if !isSender && !anyRecipient(addrs, msg.To) && !anyAddToContains(addrs, msg.AddTo) {
@@ -673,9 +679,10 @@ func (h *MessageHandler) DownloadData(c *gin.Context) {
 	// Fetch message metadata for auth check and file path.
 	var fromAddr string
 	var dataPath string
+	var timeSent *float64
 	err = h.q().QueryRow(ctx,
-		"SELECT from_addr, filepath FROM msg WHERE id = $1", msgID,
-	).Scan(&fromAddr, &dataPath)
+		"SELECT from_addr, filepath, time_sent FROM msg WHERE id = $1", msgID,
+	).Scan(&fromAddr, &dataPath, &timeSent)
 	if err != nil {
 		if errors.Is(err, pgx.ErrNoRows) {
 			c.JSON(http.StatusNotFound, gin.H{"error": "message not found"})
@@ -685,6 +692,10 @@ func (h *MessageHandler) DownloadData(c *gin.Context) {
 		}
 		return
 	}
+	if draftHidden(addrs, fromAddr, timeSent) {
+		c.JSON(http.StatusNotFound, gin.H{"error": "message not found"})
+		return
+	}
 
 	// Authorize: must be owner or recipient (across all visible addrs).
 	if !isRecipient(addrs, fromAddr) {
@@ -1042,8 +1053,9 @@ func (h *MessageHandler) MarkRead(c *gin.Context) {
 		        (SELECT mt.time_read FROM msg_to mt WHERE mt.msg_id = $1 AND lower(mt.addr) = lower($2)),
 		        (SELECT mat.time_read FROM msg_add_to mat WHERE mat.msg_id = $1 AND lower(mat.addr) = lower($2))
 		    ),
-		    EXISTS (SELECT 1 FROM msg_to mt WHERE mt.msg_id = $1 AND lower(mt.addr) = lower($2))
-		    OR EXISTS (SELECT 1 FROM msg_add_to mat WHERE mat.msg_id = $1 AND lower(mat.addr) = lower($2))`,
+		    (EXISTS (SELECT 1 FROM msg_to mt WHERE mt.msg_id = $1 AND lower(mt.addr) = lower($2))
+		     OR EXISTS (SELECT 1 FROM msg_add_to mat WHERE mat.msg_id = $1 AND lower(mat.addr) = lower($2)))
+		    AND EXISTS (SELECT 1 FROM msg m WHERE m.id = $1 AND m.time_sent IS NOT NULL)`,
 		msgID, identity,
 	).Scan(&existing, &recipient)
 	if err != nil {
@@ -1138,6 +1150,10 @@ func (h *MessageHandler) AddRecipients(c *gin.Context) {
 		}
 		return
 	}
+	if draftHidden([]string{identity}, fromAddr, timeSent) {
+		c.JSON(http.StatusNotFound, gin.H{"error": "message not found"})
+		return
+	}
 	// A terminal message is a leaf: recipients cannot be added to it (fmsg
 	// Specification v0.6.0 §12).
 	if terminal {
@@ -1603,6 +1619,13 @@ func sameAddr(a, b string) bool {
 	return strings.EqualFold(a, b)
 }
 
+// draftHidden reports whether a message is a draft that none of addrs sent. A
+// draft is its sender's alone: until it is sent, its recipients get 404 for it
+// on every route, as if it did not exist.
+func draftHidden(addrs []string, from string, timeSent *float64) bool {
+	return timeSent == nil && !isRecipient(addrs, from)
+}
+
 func isRecipient(to []string, addr string) bool {
 	for _, a := range to {
 		if strings.EqualFold(a, addr) {

internal/handlers/reactions.go

@@ -326,6 +326,10 @@ func (h *MessageHandler) React(c *gin.Context) {
 		return
 	}
 
+	if draftHidden([]string{identity}, subject.From, subject.Time) {
+		c.JSON(http.StatusNotFound, gin.H{"error": "message not found"})
+		return
+	}
 	// Only a participant of the subject may react to it (the host enforces
 	// the same rule on the wire).
 	if !strings.EqualFold(subject.From, identity) && !isRecipient(subject.To, identity) && !addToContains(subject.AddTo, identity) {

internal/handlers/thread.go

@@ -289,8 +289,9 @@ func (h *MessageHandler) ThreadText(c *gin.Context) {
 		)
 		SELECT c.id, c.from_addr, c.time_sent, c.type, c.size, c.filepath,
 		       (lower(c.from_addr) = ANY($2)
-		        OR EXISTS (SELECT 1 FROM msg_to t WHERE t.msg_id = c.id AND lower(t.addr) = ANY($2))
-		        OR EXISTS (SELECT 1 FROM msg_add_to a WHERE a.msg_id = c.id AND lower(a.addr) = ANY($2))) AS readable
+		        OR (c.time_sent IS NOT NULL
+		            AND (EXISTS (SELECT 1 FROM msg_to t WHERE t.msg_id = c.id AND lower(t.addr) = ANY($2))
+		                 OR EXISTS (SELECT 1 FROM msg_add_to a WHERE a.msg_id = c.id AND lower(a.addr) = ANY($2))))) AS readable
 		FROM chain c ORDER BY c.depth DESC`,
 		msgID, addrs, threadMaxHops,
 	)
@@ -326,8 +327,12 @@ func (h *MessageHandler) ThreadText(c *gin.Context) {
 
 	// Authorization gate is the requested message itself, same as GET
 	// /fmsg/:id — a non-participant learns nothing, not even chain shape.
-	if !entries[len(entries)-1].Readable {
-		c.JSON(http.StatusForbidden, gin.H{"error": "access denied"})
+	if last := entries[len(entries)-1]; !last.Readable {
+		if last.TimeSent == nil { // someone else's draft
+			c.JSON(http.StatusNotFound, gin.H{"error": "message not found"})
+		} else {
+			c.JSON(http.StatusForbidden, gin.H{"error": "access denied"})
+		}
 		return
 	}
 
@@ -395,8 +400,9 @@ func (h *MessageHandler) ThreadMessages(c *gin.Context) {
 		       c.is_terminal, c.time_sent, c.from_addr, c.topic, c.type, c.size, c.filepath,
 		       encode(c.sha256, 'hex'), encode(c.psha256, 'hex'),
 		       (lower(c.from_addr) = ANY($2)
-		        OR EXISTS (SELECT 1 FROM msg_to t WHERE t.msg_id = c.id AND lower(t.addr) = ANY($2))
-		        OR EXISTS (SELECT 1 FROM msg_add_to a WHERE a.msg_id = c.id AND lower(a.addr) = ANY($2)))
+		        OR (c.time_sent IS NOT NULL
+		            AND (EXISTS (SELECT 1 FROM msg_to t WHERE t.msg_id = c.id AND lower(t.addr) = ANY($2))
+		                 OR EXISTS (SELECT 1 FROM msg_add_to a WHERE a.msg_id = c.id AND lower(a.addr) = ANY($2)))))
 		FROM chain c ORDER BY c.depth DESC`, msgID, addrs, threadMaxHops)
 	if err != nil {
 		log.Printf("thread messages: walk %d: %v", msgID, err)
@@ -429,8 +435,12 @@ func (h *MessageHandler) ThreadMessages(c *gin.Context) {
 		c.JSON(http.StatusNotFound, gin.H{"error": "message not found"})
 		return
 	}
-	if !messages[len(messages)-1].Visible {
-		c.JSON(http.StatusForbidden, gin.H{"error": "access denied"})
+	if last := messages[len(messages)-1]; !last.Visible {
+		if last.Time == nil { // someone else's draft
+			c.JSON(http.StatusNotFound, gin.H{"error": "message not found"})
+		} else {
+			c.JSON(http.StatusForbidden, gin.H{"error": "access denied"})
+		}
 		return
 	}
 	if len(messages) == threadMaxHops && messages[0].PID != nil {