在 RxJS mergeMap 之间导航时如何避免多个 HttpInterceptor 调用？

Question

我正在使用两个 JWT 令牌 - 刷新令牌（7 天后过期）和访问令牌（15 分钟后过期）。它们存储在 httpOnly cookie 中，可以通过服务器访问。 Refresh 方法对新令牌进行签名并将其存储在 cookie 中。我需要在每次这样的请求后检查这些令牌是否过期：

@Injectable()
export class AuthInterceptor implements HttpInterceptor {

    constructor(private authService: AuthService, private cookieService: CookieService) { }

    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
            const expirationToken = this.cookieService.get('tokenexp'); // access token expiration
            const expirationTokenRefresh = this.cookieService.get('tokenrefexp'); // refresh expiration
            
            // refresh token -> access token -> original request
            return of(Number(expirationTokenRefresh) < Date.now()).pipe(
              mergeMap(expire => expire
                ? this.authService.refreshTokenRefresh()
                : of(Number(expirationToken) < Date.now())
              ),
              mergeMap(expire => expire
                ? this.authService.refreshToken()
                : of(true)
              ),
              mergeMap(ok => next.handle(req.clone({ withCredentials: true })))
            );
    }

}

// auth service
refreshToken() {
  return this.http.get(`${BACKEND_URL}/refreshtoken`);
}
refreshTokenRefresh() {
  return this.http.get(`${BACKEND_URL}/refreshtokenref`);
}

我可能会发送一个刷新令牌的请求，然后发送另一个刷新第二个令牌的请求，最后是带有更新 cookie 的原始请求。总之，我可能需要在原始请求之前发送请求。

问题是：每次发出请求时，都会有一个请求循环到AuthInterceptor。请求一和二（令牌）不应调用AuthInterceptor。

Answer 1

如果请求 url 是用于令牌，则进行条件检查以跳过拦截器。

@Injectable()
export class AuthInterceptor implements HttpInterceptor {

    constructor(private authService: AuthService, private cookieService: CookieService) { }

    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    
            if(req.url===`${BACKEND_URL}/refreshtoken` || req.url ===`${BACKEND_URL}/refreshtokenref`)
              return next.handle(req.clone({ withCredentials: true }))
            
            const expirationToken = this.cookieService.get('tokenexp'); // access token expiration
            const expirationTokenRefresh = this.cookieService.get('tokenrefexp'); // refresh expiration
            
            // refresh token -> access token -> original request
            return of(Number(expirationTokenRefresh) < Date.now()).pipe(
              mergeMap(expire => expire
                ? this.authService.refreshTokenRefresh()
                : of(Number(expirationToken) < Date.now())
              ),
              mergeMap(expire => expire
                ? this.authService.refreshToken()
                : of(true)
              ),
              mergeMap(ok => next.handle(req.clone({ withCredentials: true })))
            );
    }

}

// auth service
refreshToken() {
  return this.http.get(`${BACKEND_URL}/refreshtoken`);
}
refreshTokenRefresh() {
  return this.http.get(`${BACKEND_URL}/refreshtokenref`);
}

请同意@Xinan 的观点，即拦截器有时会成为更大的问题。创建自己的http服务可能会更好

class HttpService{
   constructoer(private _http:HttpClient)

   preIntercept(url,options){
     this._http.get(tokenUrl).pipe(
       map(res=>{
           //do your stuff
            return {url,options}
        }))

}

get(url,options={}){
    return this.preIntercept(url,options).pipe(
    mergeMap(({url,options})=>this._http.get(url,options))
}

}