Working sync engine!

engine.go

@@ -4,7 +4,9 @@ import (
 	"encoding/json"
 	"log/slog"
 	"net/http"
+	"sync"
 
+	"github.com/cespare/xxhash"
 	"github.com/wisplite/tether/reactivity"
 	"gorm.io/gorm"
 )
@@ -12,9 +14,11 @@ import (
 type Engine struct {
 	db           *gorm.DB
 	dbType       string // sqlite or postgres
-	mutations    map[string]func(ctx *MutationCtx) error
+	mutations    map[string]func(ctx *MutationCtx) interface{}
-	queries      map[string]func(ctx *QueryCtx) error
+	queries      map[string]func(ctx *QueryCtx) interface{}
 	dependencies map[string][]string
+	hashMu       sync.RWMutex
+	queryHashes  map[string]uint64
 	tracker      *reactivity.Tracker
 }
 
@@ -24,7 +28,7 @@ func NewEngine(db *gorm.DB, dbType string) *Engine {
 	if dbType != "sqlite" && dbType != "postgres" {
 		panic("Invalid database type")
 	}
-	e := &Engine{db: db, dbType: dbType, mutations: make(map[string]func(ctx *MutationCtx) error), queries: make(map[string]func(ctx *QueryCtx) error), dependencies: make(map[string][]string), tracker: tracker}
+	e := &Engine{db: db, dbType: dbType, mutations: make(map[string]func(ctx *MutationCtx) interface{}), queries: make(map[string]func(ctx *QueryCtx) interface{}), dependencies: make(map[string][]string), queryHashes: make(map[string]uint64), tracker: tracker}
 	db.Callback().Create().After("gorm:create").Register("tether:after_create", func(tx *gorm.DB) {
 		if dbType == "postgres" {
 			return
@@ -34,12 +38,12 @@ func NewEngine(db *gorm.DB, dbType string) *Engine {
 	return e
 }
 
-func (e *Engine) RegisterMutation(name string, mutation func(ctx *MutationCtx) error) {
+func (e *Engine) RegisterMutation(name string, mutation func(ctx *MutationCtx) interface{}) {
 	e.mutations[name] = mutation // stores the mutation in the list of valid mutations
 	slog.Debug("Registered mutation", "name", name)
 }
 
-func (e *Engine) RegisterQuery(name string, query func(ctx *QueryCtx) error, dependencies []string) {
+func (e *Engine) RegisterQuery(name string, query func(ctx *QueryCtx) interface{}, dependencies []string) {
 	e.queries[name] = query // stores the query in the list of valid queries
 	for _, dependency := range dependencies {
 		e.dependencies[dependency] = append(e.dependencies[dependency], name)
@@ -78,11 +82,16 @@ func (e *Engine) InvalidateTable(tableName string) {
 	for _, query := range dependentQueries {
 		slog.Debug("Invalidating query", "query", query)
 		subscriptions := e.tracker.GetQuerySubscriptions(query)
+		slog.Debug("Subscriptions", "subscriptions", subscriptions)
 		for _, subscription := range subscriptions {
 			slog.Debug("Invalidating subscription", "subscription", subscription["clientID"])
 			params := map[string]interface{}{}
-			json.Unmarshal([]byte(subscription["params"]), &params)
+			err := json.Unmarshal([]byte(subscription["params"]), &params)
-			_, err := e.ExecuteQuery(query, params, subscription["clientID"])
+			if err != nil {
+				slog.Error("Failed to unmarshal params", "error", err)
+				continue
+			}
+			_, err = e.ExecuteQuery(query, params, subscription["clientID"])
 			if err != nil {
 				slog.Error("Failed to execute query", "error", err)
 				continue
@@ -101,9 +110,31 @@ func (e *Engine) ExecuteQuery(query string, params map[string]interface{}, clien
 		4. Calculate hash for every query
 		5. Send the updated queries if hash changed
 	*/
+	paramsJSON, err := json.Marshal(params)
+	if err != nil {
+		return nil, err
+	}
+	cacheKey := query + "?" + string(paramsJSON)
+	e.hashMu.Lock()
+	lastHash := e.queryHashes[cacheKey]
+	e.hashMu.Unlock()
 	slog.Debug("Executing query", "query", query, "params", params)
-	e.queries[query](&QueryCtx{DB: e.db, AuthCtx: &AuthCtx{UserID: "", IsLoggedIn: true}, Params: params})
+	result := e.queries[query](&QueryCtx{DB: e.db, AuthCtx: &AuthCtx{UserID: "", IsLoggedIn: true}, Params: params})
-	return nil, nil
+	responseJSON, err := json.Marshal(map[string]interface{}{"type": "query", "location": query, "data": result})
+	if err != nil {
+		return nil, err
+	}
+	queryHash := xxhash.Sum64(responseJSON)
+	if lastHash == queryHash {
+		return result, nil
+	}
+
+	e.hashMu.Lock()
+	e.queryHashes[cacheKey] = queryHash
+	e.hashMu.Unlock()
+
+	e.tracker.SendMessage(clientID, responseJSON)
+	return result, nil
 }
 
 func (e *Engine) ExecuteMutation(mutation string, params map[string]interface{}, clientID string) (interface{}, error) {
@@ -114,8 +145,12 @@ func (e *Engine) ExecuteMutation(mutation string, params map[string]interface{},
 func (e *Engine) OnReceiveMessage(clientID string, msg map[string]interface{}) error {
 	slog.Debug("Received message", "from", clientID, "message", msg)
 	switch msg["type"] {
-	case "query":
+	case "subscribe":
-		e.tracker.SubscribeToQuery(clientID, msg["location"].(string), msg["params"].(map[string]string))
+		paramsJSON, err := json.Marshal(msg["params"])
+		if err != nil {
+			return err
+		}
+		e.tracker.SubscribeToQuery(clientID, msg["location"].(string), string(paramsJSON))
 	case "mutation":
 		e.ExecuteMutation(msg["location"].(string), msg["params"].(map[string]interface{}), clientID)
 	}

example/client/index.ts

@@ -4,8 +4,8 @@ import { createInterface } from "node:readline/promises";
 const client = new TetherClient();
 client.connect("ws://localhost:8080/tether");
 
-client.subscribe("messages", { room: "1" }, (message) => {
+client.subscribe("getMessages", { room: "1" }, (messages) => {
-	console.log("Received message", message);
+	console.log("Received messages", messages);
 });
 
 const rl = createInterface({

example/main.go

@@ -35,15 +35,13 @@ func main() {
 	engine.CreateTable("users", &User{})
 	engine.CreateTable("messages", &Messages{})
 
-	engine.RegisterMutation("createUser", func(ctx *tether.MutationCtx) error {
+	engine.RegisterQuery("getMessages", func(ctx *tether.QueryCtx) interface{} {
-		return nil
+		var messages []Messages
-	})
+		ctx.DB.Where("room_id = ?", ctx.Params["room"].(string)).Find(&messages)
+		return messages
+	}, []string{"messages"})
 
-	engine.RegisterQuery("getUser", func(ctx *tether.QueryCtx) error {
+	engine.RegisterMutation("createMessage", func(ctx *tether.MutationCtx) interface{} {
-		return nil
-	}, []string{"users"})
-
-	engine.RegisterMutation("createMessage", func(ctx *tether.MutationCtx) error {
 		ctx.DB.Create(&Messages{ID: uuid.NewString(), Message: ctx.Params["message"].(string), SenderID: ctx.AuthCtx.UserID, RoomID: ctx.Params["room"].(string)})
 		return nil
 	})

go.mod

@@ -3,6 +3,7 @@ module github.com/wisplite/tether
 go 1.25.6
 
 require (
+	github.com/cespare/xxhash v1.1.0 // indirect
 	github.com/dustin/go-humanize v1.0.1 // indirect
 	github.com/glebarez/go-sqlite v1.21.2 // indirect
 	github.com/glebarez/sqlite v1.11.0 // indirect

go.sum

@@ -1,3 +1,6 @@
+github.com/OneOfOne/xxhash v1.2.2/go.mod h1:HSdplMjZKSmBqAxg5vPj2TmRDmfkzw+cTzAElWljhcU=
+github.com/cespare/xxhash v1.1.0 h1:a6HrQnmkObjyL+Gs60czilIUGqrzKutQD6XZog3p+ko=
+github.com/cespare/xxhash v1.1.0/go.mod h1:XrSqR1VqqWfGrhpAt58auRo0WTKS1nRRg3ghfAqPWnc=
 github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
 github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
 github.com/glebarez/go-sqlite v1.21.2 h1:3a6LFC4sKahUunAmynQKLZceZCOzUthkRkEAl9gAXWo=
@@ -17,6 +20,7 @@ github.com/mattn/go-isatty v0.0.17/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/
 github.com/remyoudompheng/bigfft v0.0.0-20200410134404-eec4a21b6bb0/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
 github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94icq4NjY3clb7Lk8O1qJ8BdBEF8z0ibU0rE=
 github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
+github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72/go.mod h1:JwIasOWyU6f++ZhiEuf87xNszmSA2myDM2Kzu9HwQUA=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.7.0 h1:3jlCCIQZPdOYu1h8BkNvLz8Kgwtae2cagcG/VamtZRU=
 golang.org/x/sys v0.7.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

reactivity/tracker.go

@@ -1,7 +1,6 @@
 package reactivity
 
 import (
-	"encoding/json"
 	"log/slog"
 	"sync"
 )
@@ -33,19 +32,15 @@ func (t *Tracker) Untrack(c *Client) {
 	delete(t.clients, c.ID)
 }
 
-func (t *Tracker) SubscribeToQuery(clientID string, query string, params map[string]string) {
+func (t *Tracker) SubscribeToQuery(clientID string, query string, params string) {
 	t.mu.Lock()
 	defer t.mu.Unlock()
 	if t.subscriptions[query] == nil {
 		t.subscriptions[query] = make([]map[string]string, 0)
 	}
 	// set t.subscriptions[query] to a map of client IDs and their params
-	paramsJSON, err := json.Marshal(params)
+	t.subscriptions[query] = append(t.subscriptions[query], map[string]string{"clientID": clientID, "params": params})
-	if err != nil {
+	slog.Debug("Tracker: Subscribed to query", "query", query, "clientID", clientID, "params", params)
-		slog.Error("Tracker: Failed to marshal params", "error", err)
-		return
-	}
-	t.subscriptions[query] = append(t.subscriptions[query], map[string]string{"clientID": clientID, "params": string(paramsJSON)})
 }
 
 func (t *Tracker) UnsubscribeFromQuery(clientID string, query string) {