Client UUID nodes from server sync count

main.go

@@ -124,6 +124,7 @@ func main() { // {{{
 
 	http.HandleFunc("/user/authenticate", AuthManager.AuthenticationHandler)
 
+	http.HandleFunc("/sync/from_server/count", authenticated(actionSyncFromServerCount))
 	http.HandleFunc("/sync/from_server/{sequence}/{offset}", authenticated(actionSyncFromServer))
 	http.HandleFunc("/sync/to_server", authenticated(actionSyncToServer))
 
@@ -252,12 +253,12 @@ func actionSyncFromServer(w http.ResponseWriter, r *http.Request) { // {{{
 
 	nodes, maxSeq, moreRowsExist, err := Nodes(user.UserID, offset, uint64(changedFrom), user.ClientUUID)
 	if err != nil {
-		Log.Error("/node/tree", "error", err)
+		Log.Error("/sync/from_server", "error", err)
 		httpError(w, err)
 		return
 	}
 
-	Log.Debug("/node/tree", "num_nodes", len(nodes), "maxSeq", maxSeq)
+	Log.Debug("/sync/from_server", "num_nodes", len(nodes), "maxSeq", maxSeq)
 	foo, _ := json.Marshal(nodes)
 	os.WriteFile(fmt.Sprintf("/tmp/nodes-%d.json", offset), foo, 0644)
 
@@ -269,6 +270,29 @@ func actionSyncFromServer(w http.ResponseWriter, r *http.Request) { // {{{
 	}{true, nodes, maxSeq, moreRowsExist})
 	w.Write(j)
 } // }}}
+func actionSyncFromServerCount(w http.ResponseWriter, r *http.Request) { // {{{
+	// The purpose of the Client UUID is to avoid
+	// sending nodes back once again to a client that
+	// just created or modified it.
+	user := getUser(r)
+	changedFrom, _ := strconv.Atoi(r.PathValue("sequence"))
+
+	count, err := NodesCount(user.UserID, uint64(changedFrom), user.ClientUUID)
+	if err != nil {
+		Log.Error("/sync/from_server/count", "error", err)
+		httpError(w, err)
+		return
+	}
+
+	j, _ := json.Marshal(struct {
+		OK    bool
+		Count int
+	}{
+		true,
+		count,
+	})
+	w.Write(j)
+} // }}}
 func actionNodeRetrieve(w http.ResponseWriter, r *http.Request) { // {{{
 	user := getUser(r)
 	var err error

node.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	// External
+	werr "git.gibonuddevalla.se/go/wrappederror"
 	"github.com/jmoiron/sqlx"
 
 	// Standard
@@ -183,6 +184,39 @@ func Nodes(userID, offset int, synced uint64, clientUUID string) (nodes []Node,
 
 	return
 } // }}}
+func NodesCount(userID int, synced uint64, clientUUID string) (count int, err error) { // {{{
+	row := db.QueryRow(`
+		SELECT
+			COUNT(*)
+		FROM
+			public.node
+		WHERE
+			user_id = $1 AND
+			client != $5 AND
+			NOT history AND (
+				created_seq > $4 OR
+				updated_seq > $4 OR
+				deleted_seq > $4
+			)
+		`,
+		userID,
+		synced,
+		clientUUID,
+	)
+	row.Scan(&row)
+	if err != nil {
+		err = werr.Wrap(err).WithData(
+			struct {
+				UserID     uint64
+				Synced     uint64
+				ClientUUID string
+			}{
+				userID, synced, clientUUID,
+			},
+		)
+	}
+	return
+} // }}}
 func RetrieveNode(userID int, nodeUUID string) (node Node, err error) { // {{{
 	var rows *sqlx.Row
 	rows = db.QueryRowx(`