feat: add keyboard grid example

8x8 grid game demonstrating OnKeyDownMap with WASD and arrow key
bindings. Arrow keys use WithPreventDefault to avoid page scrolling.

actiontrigger.go

@@ -21,6 +21,8 @@ type triggerOpts struct {
 	hasSignal      bool
 	signalID       string
 	value          string
+	window         bool
+	preventDefault bool
 }
 
 type withSignalOpt struct {
@@ -34,6 +36,28 @@ func (o withSignalOpt) apply(opts *triggerOpts) {
 	opts.value = o.value
 }
 
+type withWindowOpt struct{}
+
+func (o withWindowOpt) apply(opts *triggerOpts) {
+	opts.window = true
+}
+
+// WithWindow makes the event listener attach to the window instead of the element.
+func WithWindow() ActionTriggerOption {
+	return withWindowOpt{}
+}
+
+type withPreventDefaultOpt struct{}
+
+func (o withPreventDefaultOpt) apply(opts *triggerOpts) {
+	opts.preventDefault = true
+}
+
+// WithPreventDefault calls evt.preventDefault() for matched keys.
+func WithPreventDefault() ActionTriggerOption {
+	return withPreventDefaultOpt{}
+}
+
 // WithSignal sets a signal value before triggering the action.
 func WithSignal(sig *signal, value string) ActionTriggerOption {
 	return withSignalOpt{
@@ -54,7 +78,7 @@ func buildOnExpr(base string, opts *triggerOpts) string {
 	if !opts.hasSignal {
 		return base
 	}
-	return fmt.Sprintf("$%s=%s;%s", opts.signalID, opts.value, base)
+	return fmt.Sprintf("$%s=%s,%s", opts.signalID, opts.value, base)
 }
 
 func applyOptions(options ...ActionTriggerOption) triggerOpts {
@@ -92,5 +116,49 @@ func (a *actionTrigger) OnKeyDown(key string, options ...ActionTriggerOption) h.
 	if key != "" {
 		condition = fmt.Sprintf("evt.key==='%s' &&", key)
 	}
-	return h.Data("on:keydown", fmt.Sprintf("%s%s", condition, buildOnExpr(actionURL(a.id), &opts)))
+	attrName := "on:keydown"
+	if opts.window {
+		attrName = "on:keydown__window"
+	}
+	return h.Data(attrName, fmt.Sprintf("%s%s", condition, buildOnExpr(actionURL(a.id), &opts)))
+}
+
+// KeyBinding pairs a key with an action and per-binding options.
+type KeyBinding struct {
+	Key     string
+	Action  *actionTrigger
+	Options []ActionTriggerOption
+}
+
+// KeyBind creates a KeyBinding for use with OnKeyDownMap.
+func KeyBind(key string, action *actionTrigger, options ...ActionTriggerOption) KeyBinding {
+	return KeyBinding{Key: key, Action: action, Options: options}
+}
+
+// OnKeyDownMap produces a single window-scoped keydown attribute that dispatches
+// to different actions based on the pressed key. Each binding can reference a
+// different action and carry its own signal/preventDefault options.
+func OnKeyDownMap(bindings ...KeyBinding) h.H {
+	if len(bindings) == 0 {
+		return nil
+	}
+
+	expr := ""
+	for i, b := range bindings {
+		opts := applyOptions(b.Options...)
+
+		branch := ""
+		if opts.preventDefault {
+			branch = "evt.preventDefault(),"
+		}
+		branch += buildOnExpr(actionURL(b.Action.id), &opts)
+
+		if i > 0 {
+			expr += " : "
+		}
+		expr += fmt.Sprintf("evt.key==='%s' ? (%s)", b.Key, branch)
+	}
+	expr += " : void 0"
+
+	return h.Data("on:keydown__window", expr)
 }

context.go

@@ -32,6 +32,7 @@ type Context struct {
 	reqCtx            context.Context
 	subscriptions     []Subscription
 	subsMu            sync.Mutex
+	disposeOnce       sync.Once
 }
 
 // View defines the UI rendered by this context.
@@ -350,11 +351,23 @@ func (c *Context) ReplaceURLf(format string, a ...any) {
 	c.ReplaceURL(fmt.Sprintf(format, a...))
 }
 
-// stopAllRoutines stops all go routines tied to this Context preventing goroutine leaks.
+// dispose idempotently tears down this context: unsubscribes all pubsub
+// subscriptions and closes ctxDisposedChan to stop routines and exit the SSE loop.
+func (c *Context) dispose() {
+	c.disposeOnce.Do(func() {
+		c.unsubscribeAll()
+		c.stopAllRoutines()
+	})
+}
+
+// stopAllRoutines closes ctxDisposedChan, broadcasting to all listening
+// goroutines (OnIntervalRoutine, SSE loop) that this context is done.
 func (c *Context) stopAllRoutines() {
 	select {
-	case c.ctxDisposedChan <- struct{}{}:
+	case <-c.ctxDisposedChan:
+		// already closed
 	default:
+		close(c.ctxDisposedChan)
 	}
 }
 

internal/examples/keyboard/main.go

@@ -0,0 +1,74 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/ryanhamamura/via"
+	"github.com/ryanhamamura/via/h"
+)
+
+const gridSize = 8
+
+func main() {
+	v := via.New()
+	v.Config(via.Options{DocumentTitle: "Keyboard", ServerAddress: ":7331"})
+
+	v.Page("/", func(c *via.Context) {
+		x, y := 0, 0
+		dir := c.Signal("")
+
+		move := c.Action(func() {
+			switch dir.String() {
+			case "up":
+				y = max(0, y-1)
+			case "down":
+				y = min(gridSize-1, y+1)
+			case "left":
+				x = max(0, x-1)
+			case "right":
+				x = min(gridSize-1, x+1)
+			}
+			c.Sync()
+		})
+
+		c.View(func() h.H {
+			var rows []h.H
+			for row := range gridSize {
+				var cells []h.H
+				for col := range gridSize {
+					bg := "#e0e0e0"
+					if col == x && row == y {
+						bg = "#4a90d9"
+					}
+					cells = append(cells, h.Div(
+						h.Attr("style", fmt.Sprintf(
+							"width:48px;height:48px;background:%s;border:1px solid #ccc;",
+							bg,
+						)),
+					))
+				}
+				rows = append(rows, h.Div(
+					append([]h.H{h.Attr("style", "display:flex;")}, cells...)...,
+				))
+			}
+
+			return h.Div(
+				h.H1(h.Text("Keyboard Grid")),
+				h.P(h.Text("Move with WASD or arrow keys")),
+				h.Div(rows...),
+				via.OnKeyDownMap(
+					via.KeyBind("w", move, via.WithSignal(dir, "up")),
+					via.KeyBind("a", move, via.WithSignal(dir, "left")),
+					via.KeyBind("s", move, via.WithSignal(dir, "down")),
+					via.KeyBind("d", move, via.WithSignal(dir, "right")),
+					via.KeyBind("ArrowUp", move, via.WithSignal(dir, "up"), via.WithPreventDefault()),
+					via.KeyBind("ArrowLeft", move, via.WithSignal(dir, "left"), via.WithPreventDefault()),
+					via.KeyBind("ArrowDown", move, via.WithSignal(dir, "down"), via.WithPreventDefault()),
+					via.KeyBind("ArrowRight", move, via.WithSignal(dir, "right"), via.WithPreventDefault()),
+				),
+			)
+		})
+	})
+
+	v.Start()
+}

via.go

@@ -7,6 +7,7 @@
 package via
 
 import (
+	"context"
 	"crypto/rand"
 	_ "embed"
 	"encoding/hex"
@@ -16,9 +17,12 @@ import (
 	"net/http"
 	"net/url"
 	"os"
+	ossignal "os/signal"
 	"path/filepath"
 	"strings"
 	"sync"
+	"syscall"
+	"time"
 
 	"github.com/alexedwards/scs/v2"
 	"github.com/rs/zerolog"
@@ -34,6 +38,7 @@ var datastarJS []byte
 type V struct {
 	cfg                       Options
 	mux                       *http.ServeMux
+	server                    *http.Server
 	logger                    zerolog.Logger
 	contextRegistry           map[string]*Context
 	contextRegistryMutex      sync.RWMutex
@@ -254,14 +259,82 @@ func (v *V) getCtx(id string) (*Context, error) {
 	return nil, fmt.Errorf("ctx '%s' not found", id)
 }
 
-// Start starts the Via HTTP server on the given address.
+// Start starts the Via HTTP server and blocks until a SIGINT or SIGTERM
+// signal is received, then performs a graceful shutdown.
 func (v *V) Start() {
-	v.logInfo(nil, "via started at [%s]", v.cfg.ServerAddress)
 	handler := http.Handler(v.mux)
 	if v.sessionManager != nil {
 		handler = v.sessionManager.LoadAndSave(v.mux)
 	}
-	v.logger.Fatal().Err(http.ListenAndServe(v.cfg.ServerAddress, handler)).Msg("http server failed")
+	v.server = &http.Server{
+		Addr:    v.cfg.ServerAddress,
+		Handler: handler,
+	}
+
+	errCh := make(chan error, 1)
+	go func() {
+		errCh <- v.server.ListenAndServe()
+	}()
+
+	v.logInfo(nil, "via started at [%s]", v.cfg.ServerAddress)
+
+	sigCh := make(chan os.Signal, 1)
+	ossignal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
+
+	select {
+	case sig := <-sigCh:
+		v.logInfo(nil, "received signal %v, shutting down", sig)
+	case err := <-errCh:
+		if err != nil && err != http.ErrServerClosed {
+			v.logger.Fatal().Err(err).Msg("http server failed")
+		}
+		return
+	}
+
+	v.shutdown()
+}
+
+// Shutdown gracefully shuts down the server and all contexts.
+// Safe for programmatic or test use.
+func (v *V) Shutdown() {
+	v.shutdown()
+}
+
+func (v *V) shutdown() {
+	v.logInfo(nil, "draining all contexts")
+	v.drainAllContexts()
+
+	if v.server != nil {
+		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+		if err := v.server.Shutdown(ctx); err != nil {
+			v.logErr(nil, "http server shutdown error: %v", err)
+		}
+	}
+
+	if v.pubsub != nil {
+		if err := v.pubsub.Close(); err != nil {
+			v.logErr(nil, "pubsub close error: %v", err)
+		}
+	}
+
+	v.logInfo(nil, "shutdown complete")
+}
+
+func (v *V) drainAllContexts() {
+	v.contextRegistryMutex.Lock()
+	contexts := make([]*Context, 0, len(v.contextRegistry))
+	for _, c := range v.contextRegistry {
+		contexts = append(contexts, c)
+	}
+	v.contextRegistry = make(map[string]*Context)
+	v.contextRegistryMutex.Unlock()
+
+	for _, c := range contexts {
+		v.logDebug(c, "disposing context")
+		c.dispose()
+	}
+	v.logInfo(nil, "drained %d context(s)", len(contexts))
 }
 
 // HTTPServeMux returns the underlying HTTP request multiplexer to enable user extentions, middleware and
@@ -445,10 +518,10 @@ func New() *V {
 			case <-sse.Context().Done():
 				v.logDebug(c, "SSE connection ended")
 				return
-			case patch, ok := <-c.patchChan:
-				if !ok {
-					continue
-				}
+			case <-c.ctxDisposedChan:
+				v.logDebug(c, "context disposed, closing SSE")
+				return
+			case patch := <-c.patchChan:
 				switch patch.typ {
 				case patchTypeElements:
 					if err := sse.PatchElements(patch.content); err != nil {
@@ -530,8 +603,7 @@ func New() *V {
 			v.logErr(c, "failed to handle session close: %v", err)
 			return
 		}
-		c.unsubscribeAll()
-		c.stopAllRoutines()
+		c.dispose()
 		v.logDebug(c, "session close event triggered")
 		if v.cfg.DevMode {
 			v.devModeRemovePersisted(c)

via_test.go

@@ -128,6 +128,101 @@ func TestAction(t *testing.T) {
 	assert.Contains(t, body, "/_action/")
 }
 
+func TestOnKeyDownWithWindow(t *testing.T) {
+	var trigger *actionTrigger
+	v := New()
+	v.Page("/", func(c *Context) {
+		trigger = c.Action(func() {})
+		c.View(func() h.H {
+			return h.Div(trigger.OnKeyDown("Enter", WithWindow()))
+		})
+	})
+
+	req := httptest.NewRequest("GET", "/", nil)
+	w := httptest.NewRecorder()
+	v.mux.ServeHTTP(w, req)
+	body := w.Body.String()
+	assert.Contains(t, body, "data-on:keydown__window")
+	assert.Contains(t, body, "evt.key==='Enter'")
+}
+
+func TestOnKeyDownMap(t *testing.T) {
+	t.Run("multiple bindings with different actions", func(t *testing.T) {
+		var move, shoot *actionTrigger
+		var dir *signal
+		v := New()
+		v.Page("/", func(c *Context) {
+			dir = c.Signal("none")
+			move = c.Action(func() {})
+			shoot = c.Action(func() {})
+			c.View(func() h.H {
+				return h.Div(
+					OnKeyDownMap(
+						KeyBind("w", move, WithSignal(dir, "up")),
+						KeyBind("ArrowUp", move, WithSignal(dir, "up"), WithPreventDefault()),
+						KeyBind(" ", shoot, WithPreventDefault()),
+					),
+				)
+			})
+		})
+
+		req := httptest.NewRequest("GET", "/", nil)
+		w := httptest.NewRecorder()
+		v.mux.ServeHTTP(w, req)
+		body := w.Body.String()
+
+		// Single attribute, window-scoped
+		assert.Contains(t, body, "data-on:keydown__window")
+
+		// Key dispatching
+		assert.Contains(t, body, "evt.key==='w'")
+		assert.Contains(t, body, "evt.key==='ArrowUp'")
+		assert.Contains(t, body, "evt.key===' '")
+
+		// Different actions referenced
+		assert.Contains(t, body, "/_action/"+move.id)
+		assert.Contains(t, body, "/_action/"+shoot.id)
+
+		// preventDefault only on ArrowUp and space branches
+		assert.Contains(t, body, "evt.key==='ArrowUp' ? (evt.preventDefault()")
+		assert.Contains(t, body, "evt.key===' ' ? (evt.preventDefault()")
+
+		// 'w' branch should NOT have preventDefault
+		assert.NotContains(t, body, "evt.key==='w' ? (evt.preventDefault()")
+	})
+
+	t.Run("WithSignal per binding", func(t *testing.T) {
+		var move *actionTrigger
+		var dir *signal
+		v := New()
+		v.Page("/", func(c *Context) {
+			dir = c.Signal("none")
+			move = c.Action(func() {})
+			c.View(func() h.H {
+				return h.Div(
+					OnKeyDownMap(
+						KeyBind("w", move, WithSignal(dir, "up")),
+						KeyBind("s", move, WithSignal(dir, "down")),
+					),
+				)
+			})
+		})
+
+		req := httptest.NewRequest("GET", "/", nil)
+		w := httptest.NewRecorder()
+		v.mux.ServeHTTP(w, req)
+		body := w.Body.String()
+
+		assert.Contains(t, body, "$"+dir.ID()+"='up'")
+		assert.Contains(t, body, "$"+dir.ID()+"='down'")
+	})
+
+	t.Run("empty bindings returns nil", func(t *testing.T) {
+		result := OnKeyDownMap()
+		assert.Nil(t, result)
+	})
+}
+
 func TestConfig(t *testing.T) {
 	v := New()
 	v.Config(Options{DocumentTitle: "Test"})