feat: add session-based authentication to the web interface and API routes

internal/api/auth.go

@@ -0,0 +1,131 @@
+package api
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+	"encoding/json"
+	"net/http"
+	"os"
+	"sync"
+	"time"
+)
+
+var (
+	currentSession string
+	sessionMu      sync.Mutex
+)
+
+func generateSession() string {
+	b := make([]byte, 32)
+	rand.Read(b)
+	return hex.EncodeToString(b)
+}
+
+func AuthMiddleware(next http.HandlerFunc) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		user := os.Getenv("WEB_USER")
+		pass := os.Getenv("WEB_PASS")
+		if user == "" || pass == "" {
+			next(w, r)
+			return
+		}
+
+		cookie, err := r.Cookie("nucleus_session")
+		if err != nil {
+			http.Error(w, "Unauthorized", http.StatusUnauthorized)
+			return
+		}
+
+		sessionMu.Lock()
+		valid := currentSession != "" && currentSession == cookie.Value
+		sessionMu.Unlock()
+
+		if !valid {
+			http.Error(w, "Unauthorized", http.StatusUnauthorized)
+			return
+		}
+
+		next(w, r)
+	}
+}
+
+func LoginHandler(w http.ResponseWriter, r *http.Request) {
+	user := os.Getenv("WEB_USER")
+	pass := os.Getenv("WEB_PASS")
+	if user == "" || pass == "" {
+		w.WriteHeader(http.StatusOK)
+		return
+	}
+
+	var creds struct {
+		Username string `json:"username"`
+		Password string `json:"password"`
+	}
+	if err := json.NewDecoder(r.Body).Decode(&creds); err != nil {
+		http.Error(w, "Bad Request", http.StatusBadRequest)
+		return
+	}
+
+	if creds.Username != user || creds.Password != pass {
+		http.Error(w, "Unauthorized", http.StatusUnauthorized)
+		return
+	}
+
+	sessionMu.Lock()
+	currentSession = generateSession()
+	token := currentSession
+	sessionMu.Unlock()
+
+	http.SetCookie(w, &http.Cookie{
+		Name:     "nucleus_session",
+		Value:    token,
+		Path:     "/",
+		Expires:  time.Now().Add(24 * time.Hour),
+		HttpOnly: true,
+	})
+	
+	w.WriteHeader(http.StatusOK)
+}
+
+func LogoutHandler(w http.ResponseWriter, r *http.Request) {
+	sessionMu.Lock()
+	currentSession = ""
+	sessionMu.Unlock()
+
+	http.SetCookie(w, &http.Cookie{
+		Name:     "nucleus_session",
+		Value:    "",
+		Path:     "/",
+		Expires:  time.Now().Add(-1 * time.Hour),
+		HttpOnly: true,
+	})
+	
+	w.WriteHeader(http.StatusOK)
+}
+
+func StatusHandler(w http.ResponseWriter, r *http.Request) {
+	user := os.Getenv("WEB_USER")
+	pass := os.Getenv("WEB_PASS")
+	if user == "" || pass == "" {
+		w.Header().Set("Content-Type", "application/json")
+		w.Write([]byte(`{"auth_required": false, "authenticated": true}`))
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	cookie, err := r.Cookie("nucleus_session")
+	if err != nil {
+		w.Write([]byte(`{"auth_required": true, "authenticated": false}`))
+		return
+	}
+
+	sessionMu.Lock()
+	valid := currentSession != "" && currentSession == cookie.Value
+	sessionMu.Unlock()
+
+	if valid {
+		w.Write([]byte(`{"auth_required": true, "authenticated": true}`))
+	} else {
+		w.Write([]byte(`{"auth_required": true, "authenticated": false}`))
+	}
+}