feat: introduce ctx close mechanism using beforeunload event; small fixes and improvements; improve live reload example

configuration.go

@@ -3,7 +3,8 @@ package via
 type LogLevel int
 
 const (
-	LogLevelError LogLevel = iota
+	undefined LogLevel = iota
+	LogLevelError
 	LogLevelWarn
 	LogLevelInfo
 	LogLevelDebug
@@ -12,7 +13,7 @@ const (
 // 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.
 type Plugin func(v *V)
 
-// Config defines configuration options for the via application
+// Config defines configuration options for the via application.
 type Options struct {
 	// The development mode flag. If true, enables server and browser auto-reload on `.go` file changes.
 	DevMode bool

go.mod

@@ -1,11 +1,12 @@
 module github.com/go-via/via
 
-go 1.25.3
+go 1.25.4
 
 require maragu.dev/gomponents v1.2.0
 
 require (
 	github.com/fsnotify/fsnotify v1.9.0
+	github.com/go-via/via-plugin-picocss v0.0.0-20251112183909-4485ba2e31d8
 	github.com/starfederation/datastar-go v1.0.3
 	github.com/stretchr/testify v1.10.0
 )

go.sum

@@ -8,6 +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 v0.0.0-20251112183909-4485ba2e31d8/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=

internal/examples/livereload/.air.toml

@@ -5,7 +5,7 @@ tmp_dir = "tmp"
 [build]
   args_bin = []
   bin = "./tmp/main"
-  cmd = "go build -o ./tmp/main ."
+  cmd = "go build -race -o ./tmp/main ."
   delay = 1000
   exclude_dir = ["assets", "tmp", "vendor", "testdata"]
   exclude_file = []

internal/examples/livereload/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"github.com/go-via/via"
+	"github.com/go-via/via-plugin-picocss/picocss"
 	"github.com/go-via/via/h"
 )
 
@@ -11,9 +12,10 @@ func main() {
 	v := via.New()
 
 	v.Config(via.Options{
-		DocumentTitle: "Live Reload",
+		DocumentTitle: "Live Reload Demo",
 		DevMode:       true,
 		LogLvl:        via.LogLevelDebug,
+		Plugins:       []via.Plugin{picocss.Default},
 	})
 
 	v.Page("/", func(c *via.Context) {
@@ -26,15 +28,17 @@ func main() {
 		})
 
 		c.View(func() h.H {
-			return h.Div(
+			return h.Main(h.Class("container"), h.Br(),
-				h.H1(h.Text("⚡Via Live Reload!")),
+				h.H1(h.Text("⚡Via Live Reload Demo")),
-				h.P(h.Textf("Count: %d", data.Count)),
+				h.Hr(),
-				h.P(h.Span(h.Text("Step: ")), h.Span(step.Text())),
+				h.Div(
-				h.Label(
+					h.H2(h.Strong(h.Text("Count - ")), h.Textf("%d", data.Count)),
-					h.Text("Update Step: "),
+					h.H5(h.Strong(h.Text("Step - ")), h.Span(step.Text())),
+					h.Div(h.Role("group"),
 						h.Input(h.Type("number"), step.Bind()),
-				),
 						h.Button(h.Text("Increment"), increment.OnClick()),
+					),
+				),
 			)
 		})
 	})

via.go

@@ -14,7 +14,6 @@ import (
 	"log"
 	"net/http"
 	"os"
-	"path"
 	"path/filepath"
 	"strings"
 	"sync"
@@ -32,7 +31,7 @@ type V struct {
 	cfg                  Options
 	mux                  *http.ServeMux
 	contextRegistry      map[string]*Context
-	contextRegistryMutex sync.RWMutex
+	contextRegistryMutex sync.Mutex
 	documentHeadIncludes []h.H
 	documentFootIncludes []h.H
 	devModePageInitFnMap map[string]func(*Context)
@@ -78,7 +77,7 @@ func (v *V) logDebug(c *Context, format string, a ...any) {
 
 // Config overrides the default configuration with the given options.
 func (v *V) Config(cfg Options) {
-	if cfg.LogLvl != v.cfg.LogLvl {
+	if cfg.LogLvl != undefined {
 		v.cfg.LogLvl = cfg.LogLvl
 	}
 	if cfg.DocumentTitle != "" {
@@ -141,12 +140,14 @@ func (v *V) Page(route string, initContextFn func(c *Context)) {
 		id := fmt.Sprintf("%s_/%s", route, genRandID())
 		c := newContext(id, route, v)
 		initContextFn(c)
-		v.registerCtx(c.id, c)
+		v.registerCtx(c)
 		if v.cfg.DevMode {
-			v.Persist()
+			v.devModePersist(c)
 		}
 		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 ''; })`)))
 		headElements = append(headElements, h.Meta(h.Data("init", "@get('/_sse')")))
 		bottomBodyElements := []h.H{c.view()}
 		bottomBodyElements = append(bottomBodyElements, v.documentFootIncludes...)
@@ -154,33 +155,36 @@ func (v *V) Page(route string, initContextFn func(c *Context)) {
 			Title:     v.cfg.DocumentTitle,
 			Head:      headElements,
 			Body:      bottomBodyElements,
+			HTMLAttrs: []h.H{},
 		})
 		_ = view.Render(w)
 	}))
 }
 
-func (v *V) registerCtx(id string, c *Context) {
+func (v *V) registerCtx(c *Context) {
 	v.contextRegistryMutex.Lock()
 	defer v.contextRegistryMutex.Unlock()
 	if c == nil {
 		v.logErr(c, "failed to add nil context to registry")
 		return
 	}
-	v.contextRegistry[id] = c
+	v.contextRegistry[c.id] = c
 	v.logDebug(c, "new context added to registry")
 }
 
-// func (a *App) unregisterCtx(id string) {
+func (v *V) unregisterCtx(id string) {
-// 	if _, ok := a.contextRegistry[id]; ok {
+	v.contextRegistryMutex.Lock()
-// 		a.contextRegistryMutex.Lock()
+	defer v.contextRegistryMutex.Unlock()
-// 		defer a.contextRegistryMutex.Unlock()
+	if id == "" {
-// 		delete(a.contextRegistry, id)
+		return
-// 	}
+	}
-// }
+	v.logDebug(nil, "ctx '%s' removed from registry", id)
+	delete(v.contextRegistry, id)
+}
 
 func (v *V) getCtx(id string) (*Context, error) {
-	v.contextRegistryMutex.RLock()
+	v.contextRegistryMutex.Lock()
-	defer v.contextRegistryMutex.RUnlock()
+	defer v.contextRegistryMutex.Unlock()
 	if c, ok := v.contextRegistry[id]; ok {
 		return c, nil
 	}
@@ -195,59 +199,75 @@ func (v *V) HandleFunc(pattern string, f http.HandlerFunc) {
 
 // Start starts the Via HTTP server on the given address.
 func (v *V) Start() {
+	if v.cfg.DevMode {
+		v.devModeRestore()
+	}
 	v.logInfo(nil, "via started at [%s]", v.cfg.ServerAddress)
 	log.Fatalf("[fatal] %v", http.ListenAndServe(v.cfg.ServerAddress, v.mux))
 }
 
-func (v *V) Persist() {
+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)
 	}
-	file, err := os.Create(p)
+
+	// load persisted list from file, or empty list if file not found
+	file, err := os.Open(p)
+	ctxRegMap := make(map[string]string)
+	if err == nil {
+		json.NewDecoder(file).Decode(&ctxRegMap)
+	}
+	file.Close()
+
+	// add ctx to persisted list
+	if _, ok := ctxRegMap[c.id]; !ok {
+		ctxRegMap[c.id] = c.route
+	}
+
+	// write persisted list to file
+	file, err = os.Create(p)
 	if err != nil {
-		log.Printf("devmode: failed to persist ctx: %v", err)
+		v.logErr(c, "devmode failed to percist ctx: %v", err)
+
 	}
 	defer file.Close()
-	m := make(map[string]string)
+
-	for ctxID, ctx := range v.contextRegistry {
-		m[ctxID] = ctx.route
-	}
 	encoder := json.NewEncoder(file)
-	if err := encoder.Encode(m); err != nil {
+	if err := encoder.Encode(ctxRegMap); err != nil {
-		log.Printf("devmode: failed to persist ctx: %s", err)
+		v.logErr(c, "devmode failed to persist ctx")
 	}
-	log.Printf("devmode persisted ctx registryv")
+	v.logDebug(c, "devmode persisted ctx to file")
 }
 
-func (v *V) Restore() {
+func (v *V) devModeRestore() {
-	p := path.Join(".via", "devmode", "ctx.json")
+	p := filepath.Join(".via", "devmode", "ctx.json")
 	file, err := os.Open(p)
 	if err != nil {
-		v.logErr(nil, "devmode failed to restore ctx: %v", err)
+		v.logWarn(nil, "devmode could not restore ctx from file: %v", err)
 		return
 	}
 	defer file.Close()
 	var ctxRegMap map[string]string
 	if err := json.NewDecoder(file).Decode(&ctxRegMap); err != nil {
-		v.logErr(nil, "devmode failed to restore ctx: %v", err)
+		v.logWarn(nil, "devmode could not restore ctx from file: %v", err)
 		return
 	}
 	for ctxID, pageRoute := range ctxRegMap {
 		pageInitFn, ok := v.devModePageInitFnMap[pageRoute]
 		if !ok {
-			fmt.Println("devmode failed to restore ctx: page init func of ctx not found")
+			v.logWarn(nil, "devmode could not restore ctx from file: page init fn for route '%s' not found", pageRoute)
-			return
+			continue
 		}
 
 		c := newContext(ctxID, pageRoute, v)
 		pageInitFn(c)
-		v.registerCtx(ctxID, c)
+		v.registerCtx(c)
-		v.logDebug(nil, "devmode restored ctx reg=%v", v.contextRegistry)
 	}
+	v.logDebug(nil, "devmode restored ctx registry")
 }
 
-// New creates a new Via application with default configuration.
+// New creates a new *V application with default configuration.
 func New() *V {
 	mux := http.NewServeMux()
 	v := &V{
@@ -271,9 +291,6 @@ func New() *V {
 		var sigs map[string]any
 		_ = datastar.ReadSignals(r, &sigs)
 		cID, _ := sigs["via-ctx"].(string)
-		if v.cfg.DevMode && len(v.contextRegistry) == 0 {
-			v.Restore()
-		}
 		c, err := v.getCtx(cID)
 		if err != nil {
 			v.logErr(nil, "failed to render page: %v", err)
@@ -313,10 +330,22 @@ func New() *V {
 		}()
 		c.signalsMux.Lock()
 		defer c.signalsMux.Unlock()
-		v.logDebug(c, "signals=%v", sigs)
 		c.injectSignals(sigs)
 		actionFn()
 	})
+	v.mux.HandleFunc("POST /_session/close", func(w http.ResponseWriter, r *http.Request) {
+		var sigs map[string]any
+		_ = datastar.ReadSignals(r, &sigs)
+		cID, _ := sigs["via-ctx"].(string)
+		c, err := v.getCtx(cID)
+		if err != nil {
+			v.logErr(c, "failed to handle session close: %v", err)
+			return
+		}
+		v.logDebug(c, "session close event triggered")
+		v.unregisterCtx(c.id)
+
+	})
 	return v
 }