# TokenRefreshInterceptor

**Kind:** Class

**Source:** `Frontend/src/app/InterceptorTokenRefresh.ts` (line 13)

**Part of:** [Frontend](subsystem-frontend-src-app)

`TokenRefreshInterceptor` handles token refresh behavior within the Angular HTTP request pipeline. Its `intercept()` method receives HTTP events, coordinates refresh handling when authentication state requires it, and returns an `Observable<HttpEvent<any>>` to continue the request flow.

**Implements:** `HttpInterceptor`

## Methods

| Method | Signature | Returns |
|---|---|---|
| `intercept` | `intercept(request: HttpRequest<any>, next: HttpHandler)` | `Observable<HttpEvent<any>>` |

## Properties

| Property | Type |
|---|---|
| `countRequest` | `number` |

## Where it refuses work

- `TokenRefreshInterceptor` stops the work with an early return when `event.body instanceof Blob || event.body instanceof ArrayBuffer`, in 3 places.
- `TokenRefreshInterceptor` stops the work with an early return when `!this.networkService.isOnline()`.
- `TokenRefreshInterceptor` stops the work with an early return when `error.status === 401 && !this.isRefreshTokenRequest(request)`.
- `TokenRefreshInterceptor` stops the work with an early return when `body === null || body === undefined`.
- `TokenRefreshInterceptor` stops the work with an early return when `Array.isArray(body)`.
- `TokenRefreshInterceptor` stops the work with an early return when `typeof body === 'string' && this.isoDateRegex.test(body)`.

## Diagram

```mermaid
graph LR
  A[Application Request] --> B[HttpClient]
  B --> C[TokenRefreshInterceptor]
  C --> D{Token requires refresh?}
  D -->|No| E[Send Request]
  D -->|Yes| F[Refresh Token]
  F --> E
  E --> G[HTTP Response]
  G --> C
  C --> H[Application]
```

## Usage

```ts
import { HTTP_INTERCEPTORS } from '@angular/common/http';
import { TokenRefreshInterceptor } from './InterceptorTokenRefresh';

@NgModule({
  providers: [
    {
      provide: HTTP_INTERCEPTORS,
      useClass: TokenRefreshInterceptor,
      multi: true,
    },
  ],
})
export class AppModule {}
```

## AI Coding Instructions

- Keep `intercept()` compatible with the Angular `HttpInterceptor` contract and return an `Observable<HttpEvent<any>>`.
- Do not subscribe inside the interceptor; compose refresh and request handling with RxJS operators.
- Register this class through the `HTTP_INTERCEPTORS` provider with `multi: true`.
- Prevent token refresh requests from being intercepted again, or they may trigger a refresh loop.
- Preserve HTTP errors when refresh handling fails so calling code can handle authentication failures.

## Relationships

- IMPORTS → `AuthService`
- IMPORTS → `SppinerService`
- IMPORTS → `AppSettings`
- IMPORTS → `NetworkService`

## Used by

1 reference from 1 file. Each is a place in this repository where the symbol is actually used — go read one rather than trusting an example.

### Imported by (1)

- `TranslateHandler` — `Frontend/src/app/app.module.ts`:1