feat: introduce support for plugins

configuration.go

@@ -11,8 +11,10 @@ const (
 	LogLevelDebug
 )
 
+type Plugin func(v *V)
+
 // Config defines configuration options for the via application
-type Configuration struct {
+type Options struct {
 	// Level of the logs to write to stdout.
 	// Options: Error, Warn, Info, Debug.
 	LogLvl LogLevel
@@ -27,4 +29,8 @@ type Configuration struct {
 	// Elements to include in the bottom of the body of the base
 	// HTML document.Useful for including JS scripts or a footer.
 	DocumentBodyIncludes []h.H
+
+	// Plugins to extend the capabilities of the `Via` application.
+	// Check `https://github.com/go-via/plugins` for a list of available plugins.
+	Plugins []Plugin
 }

context.go

@@ -17,7 +17,7 @@ import (
 // It binds user state and actions, manages reactive signals, and defines UI through View.
 type Context struct {
 	id                string
-	app               *via
+	app               *V
 	view              func() h.H
 	componentRegistry map[string]*Context
 	parentPageCtx     *Context
@@ -302,7 +302,7 @@ func (c *Context) ExecScript(s string) {
 	_ = sse.ExecuteScript(s)
 }
 
-func newContext(id string, a *via) *Context {
+func newContext(id string, a *V) *Context {
 	if a == nil {
 		log.Fatalf("create context failed: app pointer is nil")
 	}

internal/examples/picocss/main.go

@@ -8,7 +8,7 @@ import (
 func main() {
 	v := via.New()
 
-	v.Config(via.Configuration{
+	v.Config(via.Options{
 		DocumentTitle: "Via",
 		DocumentHeadIncludes: []h.H{
 			h.Link(h.Rel("stylesheet"), h.Href("https://cdn.jsdelivr.net/npm/@picocss/pico@2/css/pico.min.css")),

internal/examples/plugins/main.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	_ "embed"
+	"net/http"
+
+	"github.com/go-via/via"
+	"github.com/go-via/via/h"
+)
+
+// In this example we create a Via application with a plugin that adds PicoCSS. The plugin
+// is handed to Via in the app Configuration.
+
+//go:embed pico.yellow.min.css
+var picoCSSFile []byte
+
+func main() {
+	v := via.New()
+	v.Config(via.Options{
+		DocumentTitle: "Via With PicoCSS Plugin",
+		Plugins:       []via.Plugin{PicoCSSPlugin},
+	})
+
+	v.Page("/", func(c *via.Context) {
+		c.View(func() h.H {
+			return h.Section(h.Class("container"),
+
+				h.H1(h.Text("Hello from ⚡Via")),
+				h.Div(h.Class("grid"),
+					h.Button(h.Text("Primary")),
+					h.Button(h.Class("secondary"), h.Text("Secondary")),
+				),
+			)
+		})
+	})
+	v.Start(":3000")
+}
+
+func PicoCSSPlugin(v *via.V) {
+	v.HandleFunc("GET /_plugins/picocss/assets/style.css", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "text/css")
+		_, _ = w.Write(picoCSSFile)
+	})
+	v.Config(via.Options{
+		DocumentHeadIncludes: []h.H{
+			h.Link(h.Rel("stylesheet"), h.Href("/_plugins/picocss/assets/style.css")),
+		},
+	})
+}

internal/examples/realtimechart/main.go

@@ -13,7 +13,7 @@ import (
 func main() {
 	v := via.New()
 
-	v.Config(via.Configuration{
+	v.Config(via.Options{
 		DocumentTitle: "Via",
 		DocumentHeadIncludes: []h.H{
 			h.Link(h.Rel("stylesheet"), h.Href("https://cdn.jsdelivr.net/npm/@picocss/pico@2/css/pico.min.css")),

via.go

@@ -22,17 +22,17 @@ import (
 //go:embed datastar.js
 var datastarJS []byte
 
-// via is the root application.
+// V is the root application.
 // It manages page routing, user sessions, and SSE connections for live updates.
-type via struct {
-	cfg                  Configuration
+type V struct {
+	cfg                  Options
 	mux                  *http.ServeMux
 	contextRegistry      map[string]*Context
 	contextRegistryMutex sync.RWMutex
 	baseLayout           func(h.HTML5Props) h.H
 }
 
-func (v *via) logErr(c *Context, format string, a ...any) {
+func (v *V) logErr(c *Context, format string, a ...any) {
 	cRef := ""
 	if c != nil && c.id != "" {
 		cRef = fmt.Sprintf("via-ctx=%q ", c.id)
@@ -40,7 +40,7 @@ func (v *via) logErr(c *Context, format string, a ...any) {
 	log.Printf("[error] %smsg=%q", cRef, fmt.Sprintf(format, a...))
 }
 
-func (v *via) logWarn(c *Context, format string, a ...any) {
+func (v *V) logWarn(c *Context, format string, a ...any) {
 	cRef := ""
 	if c != nil && c.id != "" {
 		cRef = fmt.Sprintf("via-ctx=%q ", c.id)
@@ -50,7 +50,7 @@ func (v *via) logWarn(c *Context, format string, a ...any) {
 	}
 }
 
-func (v *via) logInfo(c *Context, format string, a ...any) {
+func (v *V) logInfo(c *Context, format string, a ...any) {
 	cRef := ""
 	if c != nil && c.id != "" {
 		cRef = fmt.Sprintf("via-ctx=%q ", c.id)
@@ -60,7 +60,7 @@ func (v *via) logInfo(c *Context, format string, a ...any) {
 	}
 }
 
-func (v *via) logDebug(c *Context, format string, a ...any) {
+func (v *V) logDebug(c *Context, format string, a ...any) {
 	cRef := ""
 	if c != nil && c.id != "" {
 		cRef = fmt.Sprintf("via-ctx=%q ", c.id)
@@ -71,7 +71,7 @@ func (v *via) logDebug(c *Context, format string, a ...any) {
 }
 
 // Config overrides the default configuration with the given configuration options.
-func (v *via) Config(cfg Configuration) {
+func (v *V) Config(cfg Options) {
 	if cfg.LogLvl != v.cfg.LogLvl {
 		v.cfg.LogLvl = cfg.LogLvl
 	}
@@ -81,6 +81,13 @@ func (v *via) Config(cfg Configuration) {
 	if cfg.DocumentBodyIncludes != nil {
 		v.cfg.DocumentBodyIncludes = cfg.DocumentBodyIncludes
 	}
+	if cfg.Plugins != nil {
+		for _, plugin := range cfg.Plugins {
+			if plugin != nil {
+				plugin(v)
+			}
+		}
+	}
 }
 
 // Page registers a route and its associated page handler.
@@ -93,7 +100,7 @@ func (v *via) Config(cfg Configuration) {
 //			return h.H1(h.Text("Hello, Via!"))
 //		})
 //	})
-func (v *via) Page(route string, composeContext func(c *Context)) {
+func (v *V) Page(route string, composeContext func(c *Context)) {
 	v.mux.HandleFunc("GET "+route, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if strings.Contains(r.URL.Path, "favicon") {
 			return
@@ -119,7 +126,7 @@ func (v *via) Page(route string, composeContext func(c *Context)) {
 	}))
 }
 
-func (v *via) registerCtx(id string, c *Context) {
+func (v *V) registerCtx(id string, c *Context) {
 	v.contextRegistryMutex.Lock()
 	defer v.contextRegistryMutex.Unlock()
 	v.contextRegistry[id] = c
@@ -134,7 +141,7 @@ func (v *via) registerCtx(id string, c *Context) {
 // 	}
 // }
 
-func (v *via) getCtx(id string) (*Context, error) {
+func (v *V) getCtx(id string) (*Context, error) {
 	if c, ok := v.contextRegistry[id]; ok {
 		return c, nil
 	}
@@ -143,23 +150,23 @@ func (v *via) getCtx(id string) (*Context, error) {
 
 // HandleFunc registers the HTTP handler function for a given pattern. The handler function panics if
 // in conflict with another registered handler with the same pattern.
-func (v *via) HandleFunc(pattern string, f http.HandlerFunc) {
+func (v *V) HandleFunc(pattern string, f http.HandlerFunc) {
 	v.mux.HandleFunc(pattern, f)
 }
 
 // Start starts the Via HTTP server on the given address.
-func (v *via) Start(addr string) {
+func (v *V) Start(addr string) {
 	v.logInfo(nil, "via started")
 	log.Fatalf("via failed: %v", http.ListenAndServe(addr, v.mux))
 }
 
 // New creates a new Via application with default configuration.
-func New() *via {
+func New() *V {
 	mux := http.NewServeMux()
-	app := &via{
+	app := &V{
 		mux:             mux,
 		contextRegistry: make(map[string]*Context),
-		cfg: Configuration{
+		cfg: Options{
 			LogLvl:               LogLevelDebug,
 			DocumentTitle:        "Via Application",
 			DocumentHeadIncludes: make([]h.H, 0),