initial commit

handler/middleware.go

@@ -0,0 +1,118 @@
+package handler
+
+import (
+	"context"
+	"log/slog"
+	"net/http"
+	"strings"
+	"uptimemonitor"
+)
+
+type contextKey string
+
+const (
+	sessionContextKey contextKey = "session"
+	userContextKey    contextKey = "user"
+)
+
+func (m *Handler) Installed(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		count, err := m.Store.CountUsers(r.Context())
+		if err != nil {
+			http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+			return
+		}
+
+		if count == 0 && r.Method == http.MethodGet {
+			http.Redirect(w, r, "/setup", http.StatusSeeOther)
+			return
+		}
+
+		if count == 0 {
+			http.Error(w, http.StatusText(http.StatusForbidden), http.StatusForbidden)
+			return
+		}
+
+		next.ServeHTTP(w, r)
+	})
+}
+
+func (m *Handler) UserFromCookie(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		c, err := r.Cookie("session")
+		if err != nil || c.Value == "" {
+			next.ServeHTTP(w, r)
+			return
+		}
+
+		session, err := m.Store.GetSessionByUuid(r.Context(), c.Value)
+		if err != nil {
+			next.ServeHTTP(w, r)
+			return
+		}
+
+		ctx := context.WithValue(r.Context(), sessionContextKey, session)
+		ctx = context.WithValue(ctx, userContextKey, session.User)
+
+		next.ServeHTTP(w, r.WithContext(ctx))
+	})
+}
+
+func (m *Handler) Authenticated(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		value := r.Context().Value(sessionContextKey)
+		if value == nil {
+			http.Redirect(w, r, "/login", http.StatusSeeOther)
+			return
+		}
+
+		_, ok := value.(uptimemonitor.Session)
+		if !ok {
+			http.Redirect(w, r, "/login", http.StatusSeeOther)
+			return
+		}
+
+		next.ServeHTTP(w, r)
+	})
+}
+
+func (m *Handler) Guest(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		value := r.Context().Value(sessionContextKey)
+		if value != nil {
+			http.Redirect(w, r, "/", http.StatusSeeOther)
+			return
+		}
+
+		next.ServeHTTP(w, r)
+	})
+}
+
+func (m *Handler) Recoverer(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		defer func() {
+			if err := recover(); err != nil {
+				slog.Error("panic", "error", err)
+				w.WriteHeader(http.StatusInternalServerError)
+			}
+		}()
+
+		next.ServeHTTP(w, r)
+	})
+}
+
+func (m *Handler) NoCache(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method == http.MethodGet && strings.HasPrefix(r.URL.Path, "/static") {
+			w.Header().Set("Cache-Control", "public, max-age=31536000")
+			next.ServeHTTP(w, r)
+			return
+		}
+
+		w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
+		w.Header().Set("Pragma", "no-cache")
+		w.Header().Set("Expires", "0")
+
+		next.ServeHTTP(w, r)
+	})
+}