问题与HttpInterceptor observables混合的承诺?
问题描述:
我正在使用HttpInterceptor重新发送带有令牌的请求,以防它们返回401. 在我刚刚使用缓存的令牌之前,这很有效。由于Firebase标记似乎没有自动刷新(尽管使用forceRefresh),我现在试图在拦截器类中实时获取新标记。问题是现在请求没有被重新发送。问题与HttpInterceptor observables混合的承诺?
这里是我的全部拦截:
export class CustomHttpInterceptor implements HttpInterceptor {
constructor(private injector: Injector) {
}
intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
const formRequest = req.clone({ headers: req.headers.set('Content-Type', 'application/x-www-form-urlencoded') });
return next.handle(formRequest).map((event: HttpEvent<any>) => {
if (event instanceof HttpResponse) {
console.log("GOT RESPONSE WITHOUT ERROR. JUST PASSING THROUGH.");
return event;
}
}).catch(err => {
console.log("==INTERCEPTOR== CATCH ERROR RESPONSE");
if (err instanceof HttpErrorResponse) {
console.log("==INTERCEPTOR== IS HTTP ERROR RESPONSE");
if (err.status === 401) {
console.log("==INTERCEPTOR== IS 401");
let postParams = new HttpParams({ fromString: req.body });
if (postParams.has('t')) {
//401 while we already provided a token, so a real login is required
console.log("==INTERCEPTOR== PROVIDED TOKEN, STILL PROBLEM");
throw new Error("NOT_AUTH");
} else {
// most likely session expired, resend token
console.log("==INTERCEPTOR== REQUEST WAS WITHOUT TOKEN, RESEND WITH TOKEN");
// get AuthProvider here
const auth = this.injector.get(AuthProvider);
// token will come in a promise
return auth.getToken().then(idToken => {
console.log("GOT NEW TOKEN, resending request with token " + idToken);
//add token to post params
let newPostParams = postParams.append('t', idToken); ====> SUCCESFULLY GOT NEW TOKEN
//clone request and add new body
const changedReq = formRequest.clone({
method: 'POST',
body: newPostParams.toString()
});
return next.handle(changedReq); ====> THIS IS NOT PERFORMED
},
error => {
throw(error);
});
}
}
} else {
throw(err);
}
})
}
}
没有这个承诺函数来获取一个新的令牌,该请求被重发使用最后的“next.handle(changedReq);”。我在这里找不到我做错了什么。这是因为我将promise和observables混合在一起吗?
答
由承诺转化为可观察到的由拉胡尔·辛格的建议,并使用flatMap为了嵌套观察到的回报解决:
let promise = auth.getToken();
let observable = Observable.fromPromise(promise);
return observable.first().flatMap(idToken => {
console.log("GOT NEW TOKEN, resending request with token " + idToken);
//add token to post params
let newPostParams = postParams.append('t', idToken);
//clone request and add new body
const changedReq = formRequest.clone({
method: 'POST',
body: newPostParams.toString()
});
return next.handle(changedReq);
});
是什么'formRequest'我想这是'undefined' –
喜@ RahulSingh,谢谢你的回复。在这里复制时,我意外地删除了一行,它定义了formRequest。这是请求的克隆(因为我在那里添加了一个头文件)。我更新了上面的代码块。 –
为什么你使用'return auth.getToken()。then(idToken => {'尝试并删除返回 –