fix: try solution for race conditions; use brotli included in datastar sdk; small improvements

context.go

@@ -2,13 +2,13 @@ package via
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
 	"log"
 	"reflect"
 	"sync"
 
 	"github.com/go-via/via/h"
-	"github.com/starfederation/datastar-go/datastar"
 )
 
 // Context is the living bridge between Go and the browser.
@@ -21,10 +21,10 @@ type Context struct {
 	view              func() h.H
 	componentRegistry map[string]*Context
 	parentPageCtx     *Context
-	sse               *datastar.ServerSentEventGenerator
+	patchChan         chan patch
 	actionRegistry    map[string]func()
-	signals           map[string]*signal
+	signals           *sync.Map
-	signalsMux        sync.Mutex
+	mutex             sync.RWMutex
 }
 
 // View defines the UI rendered by this context.
@@ -155,9 +155,9 @@ func (c *Context) Signal(v any) *signal {
 
 	// components register signals on parent page
 	if c.isComponent() {
-		c.parentPageCtx.signals[sigID] = sig
+		c.parentPageCtx.signals.Store(sigID, sig)
 	} else {
-		c.signals[sigID] = sig
+		c.signals.Store(sigID, sig)
 	}
 	return sig
 
@@ -168,56 +168,72 @@ func (c *Context) injectSignals(sigs map[string]any) {
 		c.app.logErr(c, "signal injection failed: nil signals in ctx")
 		return
 	}
-	for k, v := range sigs {
+
-		if _, ok := c.signals[k]; !ok {
+	c.mutex.Lock()
-			c.signals[k] = &signal{
+	defer c.mutex.Unlock()
-				id: k,
+
-				t:  reflect.TypeOf(v),
+	for sigID, val := range sigs {
-				v:  reflect.ValueOf(v),
+		if _, ok := c.signals.Load(sigID); !ok {
-			}
+			c.signals.Store(sigID, &signal{
+				id: sigID,
+				t:  reflect.TypeOf(val),
+				v:  reflect.ValueOf(val),
+			})
 			continue
 		}
-		c.signals[k].v = reflect.ValueOf(v)
+		item, _ := c.signals.Load(sigID)
-		c.signals[k].changed = false
+		if sig, ok := item.(*signal); ok {
+			sig.v = reflect.ValueOf(val)
+			sig.changed = false
+		}
 	}
 }
 
-func (c *Context) getSSE() *datastar.ServerSentEventGenerator {
+func (c *Context) getSSE() chan patch {
 	// components use parent page sse stream
-	var sse *datastar.ServerSentEventGenerator
+	var patchChan chan patch
 	if c.isComponent() {
-		sse = c.parentPageCtx.sse
+		patchChan = c.parentPageCtx.parentPageCtx.patchChan
 	} else {
-		sse = c.sse
+		patchChan = c.patchChan
 	}
-	return sse
+	return patchChan
+}
+
+func (c *Context) prepareSignalsForPatch() map[string]any {
+	updatedSigs := make(map[string]any)
+	c.signals.Range(func(sigID, value any) bool {
+		if sig, ok := value.(*signal); ok {
+			if sig.err != nil {
+				c.app.logWarn(c, "signal '%s' is out of sync: %v", sig.id, sig.err)
+				return true
+			}
+			if sig.changed {
+				updatedSigs[sigID.(string)] = fmt.Sprintf("%v", sig.v)
+			}
+		}
+		return true
+	})
+	return updatedSigs
 }
 
 // Sync pushes the current view state and signal changes to the browser immediately
 // over the live SSE event stream.
 func (c *Context) Sync() {
-	sse := c.getSSE()
-	if sse == nil {
-		c.app.logWarn(c, "view out of sync: no sse stream")
-		return
-	}
 	elemsPatch := bytes.NewBuffer(make([]byte, 0))
 	if err := c.view().Render(elemsPatch); err != nil {
 		c.app.logErr(c, "sync view failed: %v", err)
 		return
 	}
-	_ = sse.PatchElements(elemsPatch.String())
+	c.patchChan <- patch{patchTypeElements, elemsPatch.String()}
-	updatedSigs := make(map[string]any)
+
-	for id, sig := range c.signals {
+	c.mutex.RLock()
-		if sig.err != nil {
+	defer c.mutex.RUnlock()
-			c.app.logWarn(c, "failed to sync signal '%s': %v", sig.id, sig.err)
+	updatedSigs := c.prepareSignalsForPatch()
-		}
+
-		if sig.changed && sig.err == nil {
-			updatedSigs[id] = fmt.Sprintf("%v", sig.v)
-		}
-	}
 	if len(updatedSigs) != 0 {
-		_ = sse.MarshalAndPatchSignals(updatedSigs)
+		outgoingSigs, _ := json.Marshal(updatedSigs)
+		c.patchChan <- patch{patchTypeSignals, string(outgoingSigs)}
 	}
 }
 
@@ -254,28 +270,19 @@ func (c *Context) SyncElements(elem h.H) {
 	}
 	b := bytes.NewBuffer(make([]byte, 0))
 	_ = elem.Render(b)
-	_ = sse.PatchElements(b.String())
+	c.patchChan <- patch{patchTypeElements, b.String()}
 }
 
 // SyncSignals pushes the current signal changes to the browser immediately
 // over the live SSE event stream.
 func (c *Context) SyncSignals() {
-	sse := c.getSSE()
+	c.mutex.RLock()
-	if sse == nil {
+	updatedSigs := c.prepareSignalsForPatch()
-		c.app.logWarn(c, "signals out of sync: no sse stream")
+	defer c.mutex.RUnlock()
-		return
+
-	}
-	updatedSigs := make(map[string]any)
-	for id, sig := range c.signals {
-		if sig.err != nil {
-			c.app.logWarn(c, "signal out of sync'%s': %v", sig.id, sig.err)
-		}
-		if sig.changed && sig.err == nil {
-			updatedSigs[id] = fmt.Sprintf("%v", sig.v)
-		}
-	}
 	if len(updatedSigs) != 0 {
-		_ = sse.MarshalAndPatchSignals(updatedSigs)
+		outgoingSignals, _ := json.Marshal(updatedSigs)
+		c.patchChan <- patch{patchTypeSignals, string(outgoingSignals)}
 	}
 }
 
@@ -285,7 +292,7 @@ func (c *Context) ExecScript(s string) {
 		c.app.logWarn(c, "script out of sync: no sse stream")
 		return
 	}
-	_ = sse.ExecuteScript(s)
+	c.patchChan <- patch{patchTypeScript, s}
 }
 
 func newContext(id string, route string, app *V) *Context {
@@ -299,6 +306,7 @@ func newContext(id string, route string, app *V) *Context {
 		app:               app,
 		componentRegistry: make(map[string]*Context),
 		actionRegistry:    make(map[string]func()),
-		signals:           make(map[string]*signal),
+		signals:           new(sync.Map),
+		patchChan:         make(chan patch, 100),
 	}
 }

go.mod

@@ -5,20 +5,21 @@ go 1.25.4
 require maragu.dev/gomponents v1.2.0
 
 require (
-	github.com/CAFxX/httpcompression v0.0.9
 	github.com/andybalholm/brotli v1.2.0
 	github.com/fsnotify/fsnotify v1.9.0
-	github.com/go-via/via-plugin-picocss v0.0.0-20251112183909-4485ba2e31d8
+	github.com/go-via/via-plugin-picocss v0.1.0
 	github.com/starfederation/datastar-go v1.0.3
 	github.com/stretchr/testify v1.10.0
 )
 
 require (
+	github.com/CAFxX/httpcompression v0.0.9 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/klauspost/compress v1.18.0 // indirect
 	github.com/kr/pretty v0.1.0 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/valyala/bytebufferpool v1.0.0 // indirect
+	golang.org/x/sys v0.13.0 // indirect
 	gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -8,8 +8,8 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/fsnotify/fsnotify v1.9.0 h1:2Ml+OJNzbYCTzsxtv8vKSFD9PbJjmhYF14k/jKC7S9k=
 github.com/fsnotify/fsnotify v1.9.0/go.mod h1:8jBTzvmWwFyi3Pb8djgCCO5IBqzKJ/Jwo8TRcHyHii0=
-github.com/go-via/via-plugin-picocss v0.0.0-20251112183909-4485ba2e31d8 h1:FRjqaCz+MbG53a8EJOJglSK/dcUx7LwR8+UuJBs5bGU=
+github.com/go-via/via-plugin-picocss v0.1.0 h1:ytVtBlfYBhidos5ub4a8liYqadz1AkeHhh7e7Paz620=
-github.com/go-via/via-plugin-picocss v0.0.0-20251112183909-4485ba2e31d8/go.mod h1:5LEnLE7q8YfYY7jtH/TLPvfquB7Qt9WZ7TbKrskUW+0=
+github.com/go-via/via-plugin-picocss v0.1.0/go.mod h1:5LEnLE7q8YfYY7jtH/TLPvfquB7Qt9WZ7TbKrskUW+0=
 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/klauspost/compress v1.16.7/go.mod h1:ntbaceVETuRiXiv4DpjP66DpAtAGkEQskQzEyD//IeE=
@@ -42,6 +42,8 @@ github.com/valyala/gozstd v1.20.1 h1:xPnnnvjmaDDitMFfDxmQ4vpx0+3CdTg2o3lALvXTU/g
 github.com/valyala/gozstd v1.20.1/go.mod h1:y5Ew47GLlP37EkTB+B4s7r6A5rdaeB7ftbl9zoYiIPQ=
 github.com/xyproto/randomstring v1.0.5 h1:YtlWPoRdgMu3NZtP45drfy1GKoojuR7hmRcnhZqKjWU=
 github.com/xyproto/randomstring v1.0.5/go.mod h1:rgmS5DeNXLivK7YprL0pY+lTuhNQW3iGxZ18UQApw/E=
+golang.org/x/sys v0.13.0 h1:Af8nKPmuFypiUBjVoU9V20FiaFXOcuZI21p0ycVYYGE=
+golang.org/x/sys v0.13.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 h1:YR8cESwS4TdDjEe65xsg0ogRM/Nc3DYOhEAlW+xobZo=
 gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

internal/examples/picocss/main.go

@@ -2,29 +2,48 @@ package main
 
 import (
 	"github.com/go-via/via"
+	"github.com/go-via/via-plugin-picocss/picocss"
 	"github.com/go-via/via/h"
 )
 
+type Counter struct{ Count int }
+
 func main() {
 	v := via.New()
 
-	v.AppendToHead(h.Link(h.Rel("stylesheet"), h.Href("https://cdn.jsdelivr.net/npm/@picocss/pico@2/css/pico.min.css")))
+	v.Config(via.Options{
+		DocumentTitle: "Via Counter",
+		// Plugin is placed here. Use picocss.WithOptions(pococss.Options) to add the plugin
+		// with a different color theme or to enable a classes for a wide range of colors.
+		Plugins: []via.Plugin{
+			picocss.Default,
+		},
+	})
 
 	v.Page("/", func(c *via.Context) {
+		data := Counter{Count: 0}
+		step := c.Signal(1)
+
+		increment := c.Action(func() {
+			data.Count += step.Int()
+			c.Sync()
+		})
+
 		c.View(func() h.H {
-			return h.Div(
+			return h.Main(h.Class("container"), h.Br(),
-				h.H1(h.Text("Hello PicoCSS!")),
+				h.H1(h.Text("⚡ Via Counter")), h.Hr(),
-				h.H2(h.Text("Hello PicoCSS!")),
+				h.Div(
-				h.H3(h.Text("Hello PicoCSS!")),
+					h.H2(h.Textf("Count - %d", data.Count)),
-				h.H4(h.Text("Hello PicoCSS!")),
+					h.H5(h.Text("Step - "), step.Text()),
-				h.H5(h.Text("Hello PicoCSS!")),
+					h.Div(h.Role("group"),
-				h.H6(h.Text("Hello PicoCSS!")),
+						h.Input(h.Type("number"), step.Bind()),
-				h.Div(h.Class("grid"),
+						h.Button(h.Text("Increment"), increment.OnClick()),
-					h.Button(h.Text("Primary")),
+					),
-					h.Button(h.Class("secondary"), h.Text("Secondary")),
 				),
 			)
 		})
 	})
+
 	v.Start()
 }
+

signal.go

@@ -51,7 +51,7 @@ func (s *signal) Bind() h.H {
 //
 //	h.Div(mysignal.Text())
 func (s *signal) Text() h.H {
-	return h.Data("text", "$"+s.id)
+	return h.Span(h.Data("text", "$"+s.id))
 }
 
 // SetValue updates the signal’s value and marks it for synchronization with the browser.

via.go

@@ -18,7 +18,6 @@ import (
 	"strings"
 	"sync"
 
-	"github.com/CAFxX/httpcompression"
 	"github.com/go-via/via/h"
 	"github.com/starfederation/datastar-go/datastar"
 )
@@ -31,9 +30,8 @@ var datastarJS []byte
 type V struct {
 	cfg                  Options
 	mux                  *http.ServeMux
-	handler              http.Handler
 	contextRegistry      map[string]*Context
-	contextRegistryMutex sync.Mutex
+	contextRegistryMutex sync.RWMutex
 	documentHeadIncludes []h.H
 	documentFootIncludes []h.H
 	devModePageInitFnMap map[string]func(*Context)
@@ -149,10 +147,13 @@ func (v *V) Page(route string, initContextFn func(c *Context)) {
 		headElements := v.documentHeadIncludes
 		headElements = append(headElements, h.Meta(h.Data("signals", fmt.Sprintf("{'via-ctx':'%s'}", id))))
 		headElements = append(headElements, h.Meta(h.Data("init", `window.addEventListener('beforeunload', (evt) => {
-			evt.preventDefault(); evt.returnValue = ''; @post('/_session/close'); return ''; })`)))
+			evt.preventDefault(); evt.returnValue = ''; @get('/_session/close'); return ''; })`)))
 		headElements = append(headElements, h.Meta(h.Data("init", "@get('/_sse')")))
 		bottomBodyElements := []h.H{c.view()}
 		bottomBodyElements = append(bottomBodyElements, v.documentFootIncludes...)
+		if v.cfg.DevMode {
+			bottomBodyElements = append(bottomBodyElements, h.Script(h.Type("module"), h.Src("https://cdn.jsdelivr.net/gh/dataSPA/dataSPA-inspector@latest/dataspa-inspector.bundled.js")))
+		}
 		view := h.HTML5(h.HTML5Props{
 			Title:     v.cfg.DocumentTitle,
 			Head:      headElements,
@@ -185,8 +186,8 @@ func (v *V) unregisterCtx(id string) {
 }
 
 func (v *V) getCtx(id string) (*Context, error) {
-	v.contextRegistryMutex.Lock()
+	v.contextRegistryMutex.RLock()
-	defer v.contextRegistryMutex.Unlock()
+	defer v.contextRegistryMutex.RUnlock()
 	if c, ok := v.contextRegistry[id]; ok {
 		return c, nil
 	}
@@ -205,7 +206,7 @@ func (v *V) Start() {
 		v.devModeRestore()
 	}
 	v.logInfo(nil, "via started at [%s]", v.cfg.ServerAddress)
-	log.Fatalf("[fatal] %v", http.ListenAndServe(v.cfg.ServerAddress, v.handler))
+	log.Fatalf("[fatal] %v", http.ListenAndServe(v.cfg.ServerAddress, v.mux))
 }
 
 func (v *V) devModePersist(c *Context) {
@@ -273,22 +274,25 @@ func (v *V) devModeRestore() {
 	os.Remove(p)
 }
 
+type patchType int
+
+const (
+	patchTypeElements = iota
+	patchTypeSignals
+	patchTypeScript
+)
+
+type patch struct {
+	typ     patchType
+	content string
+}
+
 // New creates a new *V application with default configuration.
 func New() *V {
 	mux := http.NewServeMux()
 
-	compressionAdapter, err := httpcompression.DefaultAdapter(
-		httpcompression.MinSize(1024),
-		httpcompression.BrotliCompressionLevel(5),
-		httpcompression.ZstandardCompressor(nil),
-	)
-	if err != nil {
-		log.Fatalf("failed to create compression adapter: %v", err)
-	}
-
 	v := &V{
 		mux:                  mux,
-		handler:              compressionAdapter(mux),
 		contextRegistry:      make(map[string]*Context),
 		devModePageInitFnMap: make(map[string]func(*Context)),
 		cfg: Options{
@@ -310,20 +314,53 @@ func New() *V {
 		cID, _ := sigs["via-ctx"].(string)
 		c, err := v.getCtx(cID)
 		if err != nil {
-			v.logErr(nil, "failed to render page: %v", err)
+			v.logErr(nil, "sse stream failed to start: %v", err)
 			return
 		}
-		c.sse = datastar.NewSSE(w, r)
+
+		sse := datastar.NewSSE(w, r, datastar.WithCompression(datastar.WithBrotli(datastar.WithBrotliLevel(5))))
+
 		v.logDebug(c, "SSE connection established")
-		if v.cfg.DevMode {
+
-			c.Sync()
+		go func() {
-		} else {
+			if v.cfg.DevMode {
-			c.SyncSignals()
+				c.Sync()
+			} else {
+				c.SyncSignals()
+			}
+		}()
+
+		for {
+			select {
+			case <-sse.Context().Done():
+				v.logDebug(c, "SSE context done, exiting handler loop")
+				return
+			case patch, ok := <-c.patchChan:
+				if !ok {
+					v.logDebug(c, "patchChan closed, exiting handler loop")
+					return
+				}
+				switch patch.typ {
+				case patchTypeElements:
+					if err := sse.PatchElements(patch.content); err != nil {
+						v.logErr(c, "PatchElements failed: %v", err)
+						return
+					}
+				case patchTypeSignals:
+					if err := sse.PatchSignals([]byte(patch.content)); err != nil {
+						v.logErr(c, "PatchSignals failed: %v", err)
+						return
+					}
+				case patchTypeScript:
+					if err := sse.ExecuteScript(patch.content, datastar.WithExecuteScriptAutoRemove(true)); err != nil {
+						v.logErr(c, "ExecuteScript failed: %v", err)
+						return
+					}
+				}
+			}
 		}
-		<-c.sse.Context().Done()
-		c.sse = nil
-		v.logDebug(c, "SSE connection closed")
 	})
+
 	v.mux.HandleFunc("GET /_action/{id}", func(w http.ResponseWriter, r *http.Request) {
 		actionID := r.PathValue("id")
 		var sigs map[string]any
@@ -345,12 +382,12 @@ func New() *V {
 				v.logErr(c, "action '%s' failed: %v", actionID, r)
 			}
 		}()
-		c.signalsMux.Lock()
+
-		defer c.signalsMux.Unlock()
 		c.injectSignals(sigs)
 		actionFn()
 	})
-	v.mux.HandleFunc("POST /_session/close", func(w http.ResponseWriter, r *http.Request) {
+
+	v.mux.HandleFunc("GET /_session/close", func(w http.ResponseWriter, r *http.Request) {
 		var sigs map[string]any
 		_ = datastar.ReadSignals(r, &sigs)
 		cID, _ := sigs["via-ctx"].(string)