Angular HttpInterceptor:如何在多种条件下使用RxJS

Question

这是AuthInterceptor:

@Injectable()
export class AuthInterceptor implements HttpInterceptor {

    constructor(private authService: AuthService) { }

    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {

        const Token = this.authService.getToken();

        if (!Token) {
            return next.handle(req);
        }
 
        // Refresh Token first
        if (Token.expiresRefreshToken && Number(Token.expiresRefreshToken) < Date.now()) {
            this.authService.refreshTokenRefresh(Token.tokenref)
            .subscribe((response) => {
                localStorage.setItem('tokenref', response.tokenref);
                localStorage.setItem('tokenrefexp', response.tokenrefexp);
            });
        }
        // Then next Access Token
        if (Token.expiresToken && Number(Token.expiresToken) < Date.now()) {
            this.authService.refreshToken(Token.tokenref)
            .subscribe((response) => {
                localStorage.setItem('token', response.token);
                localStorage.setItem('tokenexp', response.tokenexp);
            });
        }
        // Original request with updated custom headers
        return next.handle(req.clone({
            headers: req.headers
            .set('Authorization', 'Bearer ' + localStorage.getItem('token'))
            .set('X-Auth-Provider', localStorage.getItem('provider'))
        }));
    }

}

我需要在发送请求之前评估这些条件,因为一些自定义标头可能会在方法refreshToken和之后发生变化refreshTokenRefresh.有没有办法评估RxJS运算符内的所有内容？第一个条件(refreshTokenRefresh),然后第二个(refreshToken),最后是req.

更新:我收到此错误:RangeError: Maximum call stack size exceeded.如何解决此问题？

Answer 1

我们希望等到某些请求完成（评估顺序并不重要？）而不是执行另一个请求。

const queue = this.handleRefreshToke(this.handleRefreshTokenRefresh([]));- 在我们打电话之前，将所有应完成的请求放在那里next.handle。使用forkJoin等待所有请求（放入队列中）完成，然后映射到另一个 Obervable ( mergeMap)。

PS 我们还可以将handleRefreshTokenRefresh和handleRefreshToke移至单独的 HttpInterceptor。

编辑为了防止拦截器的递归调用，我们应该跳过刷新令牌调用的拦截器。

export const InterceptorSkipHeader = 'X-Skip-Interceptor';

@Injectable()
export class AuthInterceptor implements HttpInterceptor {

    constructor(private authService: AuthService) { }

    handleRefreshTokenRefresh(queue: Observable<void>[]) {
        const Token = this.authService.getToken();
        if (Token.expiresRefreshToken && 
            const req = this.authService.refreshTokenRefresh(Token.tokenref)
              .pipe(tap((response) => {
                localStorage.setItem('tokenref', response.tokenref);
                localStorage.setItem('tokenrefexp', response.tokenrefexp);
            }));
            return [...queue, req];
        }
        return queue;
    }

    handleRefreshToke(queue: Observable<void>[]) {
        const Token = this.authService.getToken();
        if (Token.expiresToken && Number(Token.expiresToken) < Date.now()) {
            const req = this.authService.refreshToken(Token.tokenref)
              .subscribe((response) => {
                localStorage.setItem('token', response.token);
                localStorage.setItem('tokenexp', response.tokenexp);
            });
            return [...queue, req];
        }
        return queue;
    }

    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
       if (req.headers.has(InterceptorSkipHeader)) {
            const headers = req.headers.delete(InterceptorSkipHeader);
            return next.handle(req.clone({ headers }));
        }

        const Token = this.authService.getToken();

        if (!Token) {
            return next.handle(req);
        }

        const queue = this.handleRefreshToke(this.handleRefreshTokenRefresh([]));

        return forkJoin(queue).pipe(
            mergeMap(()=>{
                return next.handle(req.clone({
                    headers: req.headers
                        .set('Authorization', 'Bearer ' + localStorage.getItem('token'))
                        .set('X-Auth-Provider', localStorage.getItem('provider')),
                }));
            })
        );
    }

}

添加InterceptorSkipHeader到refreshTokens以跳过拦截器。

// AuthService

refreshTokenRefresh(token){
   const headers = new HttpHeaders().set(InterceptorSkipHeader, '');
   return this.httpClient
    .get(someUrl, { headers })
}

refreshToken(token){
   const headers = new HttpHeaders().set(InterceptorSkipHeader, '');
   return this.httpClient
    .get(someUrl, { headers })
}