Initial

listify-client/src/app/auth/auth.interceptor.ts

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+import {
+  HttpErrorResponse,
+  HttpEvent,
+  HttpHandlerFn,
+  HttpInterceptorFn,
+  HttpRequest,
+} from '@angular/common/http';
+import { inject } from '@angular/core';
+import { Router } from '@angular/router';
+import { Observable, catchError, switchMap, throwError } from 'rxjs';
+import { AuthService } from './auth.service';
+
+export const authInterceptor: HttpInterceptorFn = (
+  request: HttpRequest<unknown>,
+  next: HttpHandlerFn,
+): Observable<HttpEvent<unknown>> => {
+  const auth = inject(AuthService);
+  const router = inject(Router);
+  const authenticatedRequest = withAccessToken(request, auth.accessToken());
+
+  return next(authenticatedRequest).pipe(
+    catchError((error: unknown) => {
+      if (!shouldRefresh(request, error)) {
+        return throwError(() => error);
+      }
+
+      return auth.refreshSession().pipe(
+        switchMap((response) =>
+          next(withAccessToken(request, response.accessToken)),
+        ),
+        catchError((refreshError: unknown) => {
+          auth.logout();
+          void router.navigateByUrl('/login');
+          return throwError(() => refreshError);
+        }),
+      );
+    }),
+  );
+};
+
+function withAccessToken(
+  request: HttpRequest<unknown>,
+  accessToken: string | null,
+): HttpRequest<unknown> {
+  if (!accessToken || !isApiRequest(request) || isAuthRequest(request)) {
+    return request;
+  }
+
+  return request.clone({
+    setHeaders: {
+      Authorization: `Bearer ${accessToken}`,
+    },
+  });
+}
+
+function shouldRefresh(request: HttpRequest<unknown>, error: unknown): boolean {
+  return (
+    isApiRequest(request) &&
+    !isAuthRequest(request) &&
+    error instanceof HttpErrorResponse &&
+    error.status === 401
+  );
+}
+
+function isApiRequest(request: HttpRequest<unknown>): boolean {
+  return request.url.startsWith('/api/');
+}
+
+function isAuthRequest(request: HttpRequest<unknown>): boolean {
+  return request.url.startsWith('/api/auth/');
+}