Add a local web dashboard and "share web"

Daemon now also runs a plain HTTP server bound to 127.0.0.1 only (never
the network), serving an embedded vanilla HTML/CSS/JS page plus a small
JSON API (status/join/stop/leave/restart) that calls the same internal
methods the Unix-socket protocol already uses. No frontend framework or
build step — the page is embedded straight into the binary via
go:embed, keeping distribution a single file.

"share web" ensures the daemon is running, asks it (a new "web" control
action) for the dashboard's address, and opens it in the default browser
(open/xdg-open), falling back to printing the URL if that fails.

RoomStatus/FileStatus gained JSON tags for clean camelCase output, and
RoomStatus now carries RelayAddress so the dashboard can show it.

src/cli/cli.go

@@ -4,6 +4,7 @@ import (
 	"flag"
 	"fmt"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"runtime"
 	"strconv"
@@ -56,10 +57,14 @@ USAGE EXAMPLES:
    Restart (or resume a paused) room on its own:
       share restart secret-code
 
+   Open the local web dashboard in your browser:
+      share web
+
 COMMANDS:
    send     seed file(s) into a room (see options with: share send -h)
    relay    start your own relay (optional; see options with: share relay -h)
    status   show the rooms the background daemon knows about
+   web      open the local web dashboard in your browser
    stop     stop the daemon, or pause just one room if given a room code
    leave    forget one specific room for good
    restart  restart the daemon, or just one room if given a room code
@@ -105,6 +110,8 @@ func Run() error {
 			return runRestart(splice(args, i))
 		case "status":
 			return runStatus(splice(args, i))
+		case "web":
+			return runWeb(splice(args, i))
 		case "daemon":
 			return runDaemon(splice(args, i))
 		}
@@ -384,6 +391,48 @@ func runStatus(args []string) error {
 	return nil
 }
 
+func runWeb(args []string) error {
+	fs := flag.NewFlagSet("web", flag.ExitOnError)
+	fs.Usage = func() {
+		fmt.Fprintln(os.Stderr, "share web [options]")
+		fs.PrintDefaults()
+	}
+	debug := fs.Bool("debug", false, "toggle debug mode")
+	if err := fs.Parse(args); err != nil {
+		return err
+	}
+
+	if err := daemon.EnsureRunning(*debug); err != nil {
+		return err
+	}
+	addr, err := daemon.WebAddr()
+	if err != nil {
+		return err
+	}
+	url := "http://" + addr + "/"
+
+	if err := openBrowser(url); err != nil {
+		log.Debugf("could not open a browser automatically: %v", err)
+		fmt.Println(url)
+		return nil
+	}
+	fmt.Printf("Opened %s\n", url)
+	return nil
+}
+
+// openBrowser launches the OS's default browser at url. There's no
+// portable stdlib way to do this — each OS has its own launcher command.
+func openBrowser(url string) error {
+	switch runtime.GOOS {
+	case "darwin":
+		return exec.Command("open", url).Start()
+	case "linux":
+		return exec.Command("xdg-open", url).Start()
+	default:
+		return fmt.Errorf("don't know how to open a browser on %s", runtime.GOOS)
+	}
+}
+
 func runDaemon(args []string) error {
 	fs := flag.NewFlagSet("daemon", flag.ExitOnError)
 	fs.Usage = func() {

src/daemon/client.go

@@ -157,6 +157,19 @@ func Status() ([]swarm.RoomStatus, error) {
 	return resp.Rooms, nil
 }
 
+// WebAddr returns the address (host:port) of the running daemon's local
+// web dashboard.
+func WebAddr() (string, error) {
+	if !IsRunning() {
+		return "", fmt.Errorf("daemon is not running")
+	}
+	resp, err := call(request{Action: "web"})
+	if err != nil {
+		return "", err
+	}
+	return resp.WebAddr, nil
+}
+
 func call(req request) (response, error) {
 	path, err := socketPath()
 	if err != nil {

src/daemon/protocol.go

@@ -5,7 +5,7 @@ import "github.com/tzgyn/share/src/swarm"
 // request/response are the only vocabulary spoken over the control
 // socket between a CLI invocation and the background daemon.
 type request struct {
-	Action string       `json:"action"` // "join", "stop-room", "leave", "restart-room", "stop", or "status"
+	Action string       `json:"action"` // "join", "stop-room", "leave", "restart-room", "stop", "status", or "web"
 	Join   *joinRequest `json:"join,omitempty"`
 	Code   string       `json:"code,omitempty"` // "stop-room"/"leave"/"restart-room" only
 }
@@ -26,4 +26,5 @@ type response struct {
 	OK      bool               `json:"ok"`
 	Error   string             `json:"error,omitempty"`
 	Rooms   []swarm.RoomStatus `json:"rooms,omitempty"`   // "status" only
+	WebAddr string             `json:"webAddr,omitempty"` // "web" only
 }

src/daemon/server.go

@@ -28,6 +28,10 @@ type server struct {
 	// completion goroutine (started in join) knows what to do next.
 	leaving    map[string]bool
 	restarting map[string]bool
+
+	// webAddr is set once, before the Accept loop starts, and never
+	// written again — safe to read from any goroutine without a lock.
+	webAddr string
 }
 
 // Serve runs the daemon: it listens on the control socket and services
@@ -61,6 +65,14 @@ func Serve() error {
 	}
 	log.Infof("daemon listening on %s", path)
 
+	webAddr, err := s.startWebServer()
+	if err != nil {
+		log.Warnf("could not start web dashboard: %v", err)
+	} else {
+		s.webAddr = webAddr
+		log.Infof("web dashboard on http://%s/", webAddr)
+	}
+
 	// Resuming persisted rooms happens in the background, not before the
 	// Accept loop below: joining a room can block for a while (e.g. its
 	// relay is slow or unreachable), and this socket already looks
@@ -164,6 +176,13 @@ func (s *server) handleConn(conn net.Conn) (shutdown bool) {
 	case "status":
 		respond(conn, response{OK: true, Rooms: s.status()})
 		return false
+	case "web":
+		if s.webAddr == "" {
+			respond(conn, response{OK: false, Error: "web dashboard is not running"})
+			return false
+		}
+		respond(conn, response{OK: true, WebAddr: s.webAddr})
+		return false
 	default:
 		respond(conn, response{OK: false, Error: fmt.Sprintf("unknown action %q", req.Action)})
 		return false

src/daemon/web.go

@@ -0,0 +1,118 @@
+package daemon
+
+import (
+	"embed"
+	"encoding/json"
+	"fmt"
+	"io/fs"
+	"net"
+	"net/http"
+	"path/filepath"
+
+	log "github.com/tzgyn/share/src/logger"
+	"github.com/tzgyn/share/src/utils"
+)
+
+//go:embed webui/index.html webui/app.js
+var webUI embed.FS
+
+// startWebServer starts the local dashboard: a plain HTTP server bound to
+// 127.0.0.1 only (never the network — this controls file transfers, so it
+// must never be reachable by anything but the same machine) on an
+// OS-assigned free port. It talks to this same server's state directly,
+// not through the Unix socket — it's just another transport for the same
+// join/stop/leave/restart/status operations.
+func (s *server) startWebServer() (string, error) {
+	assets, err := fs.Sub(webUI, "webui")
+	if err != nil {
+		return "", err
+	}
+
+	l, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		return "", fmt.Errorf("could not start web dashboard: %w", err)
+	}
+	addr := l.Addr().String()
+
+	mux := http.NewServeMux()
+	mux.Handle("/", http.FileServer(http.FS(assets)))
+	mux.HandleFunc("/api/status", s.handleAPIStatus)
+	mux.HandleFunc("/api/join", s.handleAPIJoin)
+	mux.HandleFunc("/api/stop", s.handleAPIRoomAction(s.stopRoom))
+	mux.HandleFunc("/api/leave", s.handleAPIRoomAction(s.leave))
+	mux.HandleFunc("/api/restart", s.handleAPIRoomAction(s.restartRoom))
+
+	go func() {
+		if err := http.Serve(l, mux); err != nil {
+			log.Debugf("web dashboard stopped: %v", err)
+		}
+	}()
+
+	return addr, nil
+}
+
+func (s *server) handleAPIStatus(w http.ResponseWriter, r *http.Request) {
+	writeJSON(w, http.StatusOK, s.status())
+}
+
+func (s *server) handleAPIJoin(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		http.Error(w, "POST required", http.StatusMethodNotAllowed)
+		return
+	}
+	var req joinRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	for _, f := range req.Files {
+		if !filepath.IsAbs(f) {
+			http.Error(w, fmt.Sprintf("file path must be absolute: %s", f), http.StatusBadRequest)
+			return
+		}
+	}
+	if req.OutDir != "" && !filepath.IsAbs(req.OutDir) {
+		http.Error(w, fmt.Sprintf("output folder must be absolute: %s", req.OutDir), http.StatusBadRequest)
+		return
+	}
+	if req.Code == "" {
+		req.Code = utils.GetRandomName()
+	}
+
+	if err := s.join(req); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	writeJSON(w, http.StatusOK, map[string]string{"code": req.Code})
+}
+
+// handleAPIRoomAction adapts a single-room server method (which all share
+// the same "code in, error out" shape) into an HTTP handler.
+func (s *server) handleAPIRoomAction(action func(code string) error) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodPost {
+			http.Error(w, "POST required", http.StatusMethodNotAllowed)
+			return
+		}
+		var body struct {
+			Code string `json:"code"`
+		}
+		if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+		if err := action(body.Code); err != nil {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+		writeJSON(w, http.StatusOK, map[string]bool{"ok": true})
+	}
+}
+
+func writeJSON(w http.ResponseWriter, status int, v any) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	if err := json.NewEncoder(w).Encode(v); err != nil {
+		log.Debugf("could not write JSON response: %v", err)
+	}
+}

src/daemon/webui/app.js

@@ -0,0 +1,100 @@
+async function refresh() {
+	const res = await fetch('/api/status');
+	const rooms = await res.json();
+	const container = document.getElementById('rooms');
+	if (!rooms || rooms.length === 0) {
+		container.innerHTML = '<p>No rooms.</p>';
+		return;
+	}
+	container.innerHTML = rooms.map(roomHTML).join('');
+}
+
+function roomHTML(r) {
+	const badge = r.stopped
+		? '<span class="badge stopped">stopped</span>'
+		: `<span class="badge running">running &middot; ${r.peers} peer${r.peers === 1 ? '' : 's'}</span>`;
+	const files = (r.files || []).map(f => `
+		<div class="file">
+			<span>${escapeHTML(f.name)} (${formatBytes(f.size)})</span>
+			<span>${f.haveChunks}/${f.totalChunks} chunks${f.complete ? ' &middot; complete' : ''}</span>
+		</div>
+	`).join('');
+	return `
+		<div class="room">
+			<div class="room-header">
+				<span class="code">${escapeHTML(r.code)}</span>
+				${badge}
+			</div>
+			<div class="relay">relay: ${escapeHTML(r.relayAddress)}</div>
+			${files}
+			<div class="actions">
+				${r.stopped
+					? `<button onclick="act('restart','${escapeAttr(r.code)}')">Restart</button>`
+					: `<button onclick="act('stop','${escapeAttr(r.code)}')">Stop</button>`}
+				<button onclick="act('leave','${escapeAttr(r.code)}')">Leave</button>
+			</div>
+		</div>
+	`;
+}
+
+async function act(action, code) {
+	const res = await fetch('/api/' + action, {
+		method: 'POST',
+		headers: { 'Content-Type': 'application/json' },
+		body: JSON.stringify({ code }),
+	});
+	if (!res.ok) {
+		alert('Could not ' + action + ': ' + await res.text());
+	}
+	refresh();
+}
+
+document.getElementById('joinForm').addEventListener('submit', async (e) => {
+	e.preventDefault();
+	const files = document.getElementById('files').value
+		.split('\n').map(s => s.trim()).filter(Boolean);
+	const body = {
+		code: document.getElementById('code').value.trim(),
+		relay: document.getElementById('relay').value.trim(),
+		files,
+		out: document.getElementById('out').value.trim(),
+		oneTime: document.getElementById('oneTime').checked,
+	};
+	const res = await fetch('/api/join', {
+		method: 'POST',
+		headers: { 'Content-Type': 'application/json' },
+		body: JSON.stringify(body),
+	});
+	if (!res.ok) {
+		alert('Could not join: ' + await res.text());
+		return;
+	}
+	const result = await res.json();
+	if (result.code) {
+		alert('Joined room: ' + result.code);
+	}
+	document.getElementById('joinForm').reset();
+	refresh();
+});
+
+function escapeHTML(s) {
+	return (s || '').replace(/[&<>"']/g, c => ({ '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;' }[c]));
+}
+
+function escapeAttr(s) {
+	return (s || '').replace(/'/g, "\\'");
+}
+
+function formatBytes(n) {
+	if (n < 1024) return n + ' B';
+	const units = ['KB', 'MB', 'GB', 'TB'];
+	let i = -1;
+	do {
+		n /= 1024;
+		i++;
+	} while (n >= 1024 && i < units.length - 1);
+	return n.toFixed(1) + ' ' + units[i];
+}
+
+refresh();
+setInterval(refresh, 2000);

src/daemon/webui/index.html

@@ -0,0 +1,59 @@
+<!doctype html>
+<html>
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width, initial-scale=1">
+<title>share</title>
+<style>
+  body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; max-width: 720px; margin: 2rem auto; padding: 0 1rem; color: #1a1a1a; }
+  h1 { font-size: 1.25rem; }
+  h3 { font-size: 1rem; margin-top: 0; }
+  .room { border: 1px solid #ddd; border-radius: 8px; padding: 0.75rem 1rem; margin-bottom: 0.75rem; }
+  .room-header { display: flex; justify-content: space-between; align-items: center; }
+  .code { font-weight: 600; font-family: ui-monospace, monospace; }
+  .badge { font-size: 0.75rem; padding: 0.15rem 0.5rem; border-radius: 999px; white-space: nowrap; }
+  .badge.running { background: #dcf5e0; color: #14631f; }
+  .badge.stopped { background: #f2f2f2; color: #666; }
+  .relay { font-size: 0.85rem; color: #777; margin-top: 0.3rem; }
+  .file { display: flex; justify-content: space-between; font-size: 0.9rem; color: #444; margin-top: 0.4rem; gap: 1rem; }
+  .file span:first-child { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
+  .actions { margin-top: 0.6rem; }
+  .actions button { margin-right: 0.4rem; }
+  form.join { border: 1px dashed #ccc; border-radius: 8px; padding: 1rem; margin-top: 1.5rem; }
+  input, textarea { width: 100%; box-sizing: border-box; padding: 0.4rem; margin: 0.2rem 0 0.6rem; font: inherit; }
+  label { font-size: 0.85rem; color: #555; }
+  .checkbox-row { display: flex; align-items: center; gap: 0.4rem; margin-bottom: 0.8rem; }
+  .checkbox-row input { width: auto; margin: 0; }
+  .checkbox-row label { margin: 0; }
+  button { cursor: pointer; }
+</style>
+</head>
+<body>
+  <h1>share</h1>
+  <div id="rooms"></div>
+
+  <form class="join" id="joinForm">
+    <h3>Join or seed a room</h3>
+    <label>Room code (leave empty to generate one when seeding)</label>
+    <input id="code" placeholder="e.g. 1234-apple-tree-monkey">
+
+    <label>Relay address</label>
+    <input id="relay" placeholder="127.0.0.1:9009">
+
+    <label>Files to seed — one absolute path per line (leave empty to just receive)</label>
+    <textarea id="files" rows="3" placeholder="/Users/me/file.txt"></textarea>
+
+    <label>Output folder (for receiving)</label>
+    <input id="out" placeholder=".">
+
+    <div class="checkbox-row">
+      <input type="checkbox" id="oneTime">
+      <label for="oneTime">One-time: exit once complete instead of reseeding</label>
+    </div>
+
+    <button type="submit">Join</button>
+  </form>
+
+  <script src="/app.js"></script>
+</body>
+</html>

src/swarm/client.go

@@ -143,11 +143,11 @@ func (cl *Client) Wait() error {
 
 // FileStatus summarizes one file's transfer progress within a room.
 type FileStatus struct {
-	Name        string
-	Size        int64
-	HaveChunks  int64
-	TotalChunks int64
-	Complete    bool
+	Name        string `json:"name"`
+	Size        int64  `json:"size"`
+	HaveChunks  int64  `json:"haveChunks"`
+	TotalChunks int64  `json:"totalChunks"`
+	Complete    bool   `json:"complete"`
 }
 
 // RoomStatus summarizes one room this client is participating in. A
@@ -155,11 +155,11 @@ type FileStatus struct {
 // but RelayAddress/Files are still filled in from what's on record so
 // the display looks the same whether the room is running or paused.
 type RoomStatus struct {
-	Code         string
-	RelayAddress string
-	Stopped      bool
-	Peers        int
-	Files        []FileStatus
+	Code         string       `json:"code"`
+	RelayAddress string       `json:"relayAddress"`
+	Stopped      bool         `json:"stopped"`
+	Peers        int          `json:"peers"`
+	Files        []FileStatus `json:"files"`
 }
 
 // Status reports this room's current code, peer count, and per-file