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)
 }

configuration.go

@@ -1,15 +1,17 @@
 package via
 
-import "github.com/alexedwards/scs/v2"
+import (
+	"github.com/alexedwards/scs/v2"
+	"github.com/rs/zerolog"
+)
 
-type LogLevel int
+func ptr(l zerolog.Level) *zerolog.Level { return &l }
 
-const (
+var (
-	undefined LogLevel = iota
+	LogLevelDebug = ptr(zerolog.DebugLevel)
-	LogLevelError
+	LogLevelInfo  = ptr(zerolog.InfoLevel)
-	LogLevelWarn
+	LogLevelWarn  = ptr(zerolog.WarnLevel)
-	LogLevelInfo
+	LogLevelError = ptr(zerolog.ErrorLevel)
-	LogLevelDebug
 )
 
 // Plugin is a func that can mutate the given *via.V app runtime. It is useful to integrate popular JS/CSS UI libraries or tools.
@@ -23,9 +25,12 @@ type Options struct {
 	// The http server address. e.g. ':3000'
 	ServerAddress string
 
-	// Level of the logs to write to stdout.
+	// LogLevel sets the minimum log level. nil keeps the default (Info).
-	// Options: Error, Warn, Info, Debug.
+	LogLevel *zerolog.Level
-	LogLvl LogLevel
+
+	// Logger overrides the default logger entirely. When set, LogLevel and
+	// DevMode have no effect on logging.
+	Logger *zerolog.Logger
 
 	// The title of the HTML document.
 	DocumentTitle string

context.go

@@ -5,7 +5,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"log"
 	"maps"
 	"reflect"
 	"sync"
@@ -33,6 +32,7 @@ type Context struct {
 	reqCtx            context.Context
 	subscriptions     []Subscription
 	subsMu            sync.Mutex
+	disposeOnce       sync.Once
 }
 
 // View defines the UI rendered by this context.
@@ -351,11 +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)
 	}
 }
 
@@ -456,7 +468,7 @@ func (c *Context) unsubscribeAll() {
 
 func newContext(id string, route string, v *V) *Context {
 	if v == nil {
-		log.Fatal("create context failed: app pointer is nil")
+		panic("create context failed: app pointer is nil")
 	}
 
 	return &Context{

go.mod

@@ -11,6 +11,7 @@ require (
 	github.com/delaneyj/toolbelt v0.9.1
 	github.com/mattn/go-sqlite3 v1.14.32
 	github.com/nats-io/nats.go v1.48.0
+	github.com/rs/zerolog v1.34.0
 	github.com/starfederation/datastar-go v1.0.3
 	github.com/stretchr/testify v1.11.1
 )
@@ -24,6 +25,8 @@ require (
 	github.com/google/go-tpm v0.9.7 // indirect
 	github.com/klauspost/compress v1.18.2 // indirect
 	github.com/kr/text v0.2.0 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/minio/highwayhash v1.0.4-0.20251030100505-070ab1a87a76 // indirect
 	github.com/nats-io/jwt/v2 v2.8.0 // indirect
 	github.com/nats-io/nats-server/v2 v2.12.2 // indirect

go.sum

@@ -13,6 +13,7 @@ github.com/antithesishq/antithesis-sdk-go v0.5.0 h1:cudCFF83pDDANcXFzkQPUHHedfnn
 github.com/antithesishq/antithesis-sdk-go v0.5.0/go.mod h1:IUpT2DPAKh6i/YhSbt6Gl3v2yvUZjmKncl7U91fup7E=
 github.com/cenkalti/backoff v2.2.1+incompatible h1:tNowT99t7UNflLxfYYSlKYsBpXdEet03Pg2g16Swow4=
 github.com/cenkalti/backoff v2.2.1+incompatible/go.mod h1:90ReRw6GdpyfrHakVjL/QHaoyV4aDUVVkXQJJJ3NXXM=
+github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -20,6 +21,7 @@ github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/delaneyj/toolbelt v0.9.1 h1:QJComn2qoaQ4azl5uRkGpdHSO9e+JtoxDTXCiQHvH8o=
 github.com/delaneyj/toolbelt v0.9.1/go.mod h1:eNXpPuThjTD4tpRNCBl4JEz9jdg9LpyzNuyG+stnIbs=
+github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/google/brotli/go/cbrotli v0.0.0-20230829110029-ed738e842d2f h1:jopqB+UTSdJGEJT8tEqYyE29zN91fi2827oLET8tl7k=
 github.com/google/brotli/go/cbrotli v0.0.0-20230829110029-ed738e842d2f/go.mod h1:nOPhAkwVliJdNTkj3gXpljmWhjc4wCaVqbMJcPKWP4s=
 github.com/google/go-tpm v0.9.7 h1:u89J4tUUeDTlH8xxC3CTW7OHZjbjKoHdQ9W7gCUhtxA=
@@ -33,6 +35,12 @@ github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
 github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
+github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
+github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
+github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
+github.com/mattn/go-isatty v0.0.19/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/mattn/go-sqlite3 v1.14.6/go.mod h1:NyWgC/yNuGj7Q9rpYnZvas74GogHl5/Z4A/KQRfk6bU=
 github.com/mattn/go-sqlite3 v1.14.32 h1:JD12Ag3oLy1zQA+BNn74xRgaBbdhbNIDYvQUEuuErjs=
 github.com/mattn/go-sqlite3 v1.14.32/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxUwlHK0RXw+Y=
@@ -50,11 +58,15 @@ github.com/nats-io/nuid v1.0.1 h1:5iA8DT8V7q8WK2EScv2padNa/rTESc1KdnPw4TC2paw=
 github.com/nats-io/nuid v1.0.1/go.mod h1:19wcPz3Ph3q0Jbyiqsd0kePYG7A95tJPxeL+1OSON2c=
 github.com/pierrec/lz4/v4 v4.1.18 h1:xaKrnTkyoqfh1YItXl56+6KJNVYWlEEPuAQW9xsplYQ=
 github.com/pierrec/lz4/v4 v4.1.18/go.mod h1:gZWDp/Ze/IJXGXf23ltt2EXimqmTUXEy0GFuRQyBid4=
+github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/rogpeppe/go-internal v1.14.1 h1:UQB4HGPB6osV0SQTLymcB4TgvyWu6ZyliaW0tI/otEQ=
 github.com/rogpeppe/go-internal v1.14.1/go.mod h1:MaRKkUm5W0goXpeCfT7UZI6fk/L7L7so1lCWt35ZSgc=
+github.com/rs/xid v1.6.0/go.mod h1:7XoLgs4eV+QndskICGsho+ADou8ySMSjJKDIan90Nz0=
+github.com/rs/zerolog v1.34.0 h1:k43nTLIwcTVQAncfCw4KZ2VY6ukYoZaBPNOE8txlOeY=
+github.com/rs/zerolog v1.34.0/go.mod h1:bJsvje4Z08ROH4Nhs5iH600c3IkWhwp44iRc54W6wYQ=
 github.com/starfederation/datastar-go v1.0.3 h1:DnzgsJ6tDHDM6y5Nxsk0AGW/m8SyKch2vQg3P1xGTcU=
 github.com/starfederation/datastar-go v1.0.3/go.mod h1:stm83LQkhZkwa5GzzdPEN6dLuu8FVwxIv0w1DYkbD3w=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
@@ -74,6 +86,9 @@ github.com/xyproto/randomstring v1.0.5 h1:YtlWPoRdgMu3NZtP45drfy1GKoojuR7hmRcnhZ
 github.com/xyproto/randomstring v1.0.5/go.mod h1:rgmS5DeNXLivK7YprL0pY+lTuhNQW3iGxZ18UQApw/E=
 golang.org/x/crypto v0.45.0 h1:jMBrvKuj23MTlT0bQEOBcAE0mjg8mK9RXFhRH6nyF3Q=
 golang.org/x/crypto v0.45.0/go.mod h1:XTGrrkGJve7CYK7J8PEww4aY7gM3qMCElcJQ8n8JdX4=
+golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.21.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/sys v0.38.0 h1:3yZWxaJjBmCWXqhN1qh02AkOnCQ1poK6oF+a7xWL6Gc=
 golang.org/x/sys v0.38.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=

internal/examples/chatroom/main.go

@@ -22,7 +22,7 @@ func main() {
 	v.Config(via.Options{
 		DevMode:       true,
 		DocumentTitle: "ViaChat",
-		LogLvl:        via.LogLevelInfo,
+		LogLevel:      via.LogLevelInfo,
 	})
 
 	v.AppendToHead(

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()
+}

internal/examples/livereload/main.go

@@ -14,7 +14,7 @@ func main() {
 	v.Config(via.Options{
 		DocumentTitle: "Live Reload Demo",
 		DevMode:       true,
-		LogLvl:        via.LogLevelDebug,
+		LogLevel:      via.LogLevelDebug,
 		Plugins:       []via.Plugin{
 			// picocss.Default
 		},

internal/examples/nats-chatroom/main.go

@@ -60,7 +60,7 @@ func main() {
 	v.Config(via.Options{
 		DevMode:       true,
 		DocumentTitle: "NATS Chat",
-		LogLvl:        via.LogLevelInfo,
+		LogLevel:      via.LogLevelInfo,
 		ServerAddress: ":7331",
 		PubSub:        ps,
 	})

internal/examples/realtimechart/main.go

@@ -14,7 +14,7 @@ func main() {
 	v := via.New()
 
 	v.Config(via.Options{
-		LogLvl:  via.LogLevelDebug,
+		LogLevel: via.LogLevelDebug,
 		DevMode: true,
 		Plugins: []via.Plugin{
 			// picocss.Default,

internal/examples/shakespeare/main.go

@@ -54,7 +54,7 @@ func main() {
 	v.Config(via.Options{
 		DevMode:       true,
 		DocumentTitle: "Search",
-		LogLvl:        via.LogLevelWarn,
+		LogLevel:      via.LogLevelWarn,
 	})
 
 	v.AppendToHead(

via.go

@@ -7,21 +7,25 @@
 package via
 
 import (
+	"context"
 	"crypto/rand"
 	_ "embed"
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
 	"io"
-	"log"
 	"net/http"
 	"net/url"
 	"os"
+	ossignal "os/signal"
 	"path/filepath"
 	"strings"
 	"sync"
+	"syscall"
+	"time"
 
 	"github.com/alexedwards/scs/v2"
+	"github.com/rs/zerolog"
 	"github.com/ryanhamamura/via/h"
 	"github.com/starfederation/datastar-go/datastar"
 )
@@ -34,6 +38,8 @@ var datastarJS []byte
 type V struct {
 	cfg                       Options
 	mux                       *http.ServeMux
+	server                    *http.Server
+	logger                    zerolog.Logger
 	contextRegistry           map[string]*Context
 	contextRegistryMutex      sync.RWMutex
 	documentHeadIncludes      []h.H
@@ -46,52 +52,52 @@ type V struct {
 	datastarOnce    sync.Once
 }
 
+func (v *V) logEvent(evt *zerolog.Event, c *Context) *zerolog.Event {
+	if c != nil && c.id != "" {
+		evt = evt.Str("via-ctx", c.id)
+	}
+	return evt
+}
+
 func (v *V) logFatal(format string, a ...any) {
-	log.Printf("[fatal] msg=%q", fmt.Sprintf(format, a...))
+	v.logEvent(v.logger.WithLevel(zerolog.FatalLevel), nil).Msgf(format, a...)
 }
 
 func (v *V) logErr(c *Context, format string, a ...any) {
-	cRef := ""
+	v.logEvent(v.logger.Error(), c).Msgf(format, a...)
-	if c != nil && c.id != "" {
-		cRef = fmt.Sprintf("via-ctx=%q ", c.id)
-	}
-	log.Printf("[error] %smsg=%q", cRef, fmt.Sprintf(format, a...))
 }
 
 func (v *V) logWarn(c *Context, format string, a ...any) {
-	cRef := ""
+	v.logEvent(v.logger.Warn(), c).Msgf(format, a...)
-	if c != nil && c.id != "" {
-		cRef = fmt.Sprintf("via-ctx=%q ", c.id)
-	}
-	if v.cfg.LogLvl >= LogLevelWarn {
-		log.Printf("[warn] %smsg=%q", cRef, fmt.Sprintf(format, a...))
-	}
 }
 
 func (v *V) logInfo(c *Context, format string, a ...any) {
-	cRef := ""
+	v.logEvent(v.logger.Info(), c).Msgf(format, a...)
-	if c != nil && c.id != "" {
-		cRef = fmt.Sprintf("via-ctx=%q ", c.id)
-	}
-	if v.cfg.LogLvl >= LogLevelInfo {
-		log.Printf("[info] %smsg=%q", cRef, fmt.Sprintf(format, a...))
-	}
 }
 
 func (v *V) logDebug(c *Context, format string, a ...any) {
-	cRef := ""
+	v.logEvent(v.logger.Debug(), c).Msgf(format, a...)
-	if c != nil && c.id != "" {
+}
-		cRef = fmt.Sprintf("via-ctx=%q ", c.id)
+
-	}
+func newConsoleLogger(level zerolog.Level) zerolog.Logger {
-	if v.cfg.LogLvl == LogLevelDebug {
+	return zerolog.New(zerolog.ConsoleWriter{Out: os.Stderr, TimeFormat: "15:04:05"}).
-		log.Printf("[debug] %smsg=%q", cRef, fmt.Sprintf(format, a...))
+		With().Timestamp().Logger().Level(level)
-	}
 }
 
 // Config overrides the default configuration with the given options.
 func (v *V) Config(cfg Options) {
-	if cfg.LogLvl != undefined {
+	if cfg.Logger != nil {
-		v.cfg.LogLvl = cfg.LogLvl
+		v.logger = *cfg.Logger
+	} else if cfg.LogLevel != nil || cfg.DevMode != v.cfg.DevMode {
+		level := zerolog.InfoLevel
+		if cfg.LogLevel != nil {
+			level = *cfg.LogLevel
+		}
+		if cfg.DevMode {
+			v.logger = newConsoleLogger(level)
+		} else {
+			v.logger = zerolog.New(os.Stderr).With().Timestamp().Logger().Level(level)
+		}
 	}
 	if cfg.DocumentTitle != "" {
 		v.cfg.DocumentTitle = cfg.DocumentTitle
@@ -253,14 +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)
 	}
-	log.Fatalf("[fatal] %v", http.ListenAndServe(v.cfg.ServerAddress, handler))
+	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
@@ -284,7 +358,7 @@ func (v *V) ensureDatastarHandler() {
 func (v *V) devModePersist(c *Context) {
 	p := filepath.Join(".via", "devmode", "ctx.json")
 	if err := os.MkdirAll(filepath.Dir(p), 0755); err != nil {
-		log.Fatalf("failed to create directory for devmode files: %v", err)
+		v.logFatal("failed to create directory for devmode files: %v", err)
 	}
 
 	// load persisted list from file, or empty list if file not found
@@ -398,6 +472,7 @@ func New() *V {
 
 	v := &V{
 		mux:                  mux,
+		logger:               newConsoleLogger(zerolog.InfoLevel),
 		contextRegistry:      make(map[string]*Context),
 		devModePageInitFnMap: make(map[string]func(*Context)),
 		sessionManager:       scs.New(),
@@ -406,7 +481,6 @@ func New() *V {
 		cfg: Options{
 			DevMode:       false,
 			ServerAddress: ":3000",
-			LogLvl:        LogLevelInfo,
 			DocumentTitle: "⚡ Via",
 		},
 	}
@@ -444,10 +518,10 @@ func New() *V {
 			case <-sse.Context().Done():
 				v.logDebug(c, "SSE connection ended")
 				return
-			case patch, ok := <-c.patchChan:
+			case <-c.ctxDisposedChan:
-				if !ok {
+				v.logDebug(c, "context disposed, closing SSE")
-					continue
+				return
-				}
+			case patch := <-c.patchChan:
 				switch patch.typ {
 				case patchTypeElements:
 					if err := sse.PatchElements(patch.content); err != nil {
@@ -518,7 +592,7 @@ func New() *V {
 	v.mux.HandleFunc("POST /_session/close", func(w http.ResponseWriter, r *http.Request) {
 		body, err := io.ReadAll(r.Body)
 		if err != nil {
-			log.Printf("Error reading body: %v", err)
+			v.logErr(nil, "error reading body: %v", err)
 			w.WriteHeader(http.StatusBadRequest)
 			return
 		}
@@ -529,8 +603,7 @@ func New() *V {
 			v.logErr(c, "failed to handle session close: %v", err)
 			return
 		}
-		c.unsubscribeAll()
+		c.dispose()
-		c.stopAllRoutines()
 		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"})