[英]CORS preflight issue in Angular 7 application - response headers ignored
[英]Angular 4: unable to read headers from response - not a CORS issue
在服務器自動更新令牌的上下文中,我正在努力解決基本問題:從響應中獲取頭數據。
它似乎與CORS無關,因為我的Node / express allwos授權/ x-access-token並相應地響應(請參閱下面的網絡選項卡screeencap)。
我希望看到工作的第一步是簡單地從響應中讀取標題。 請參閱我的代碼,它是文檔中的樣板文件。 獲取“Content-Length”的事件返回null。
AUTH-service.ts
login(username:string, password:string):Observable<boolean>{
this.loggedIn = false;
return new Observable( (observer:Observer<boolean>) => {
const body = {user: username, pwd: password};
const url = this.config.API_ENDPOINT_PUBLIC_AUTH;
this.httpClient.post(url, body, {
responseType: 'text',
observe: "response"
}).first().subscribe(
(response:HttpResponse<string>) => {
// DEBUG
console.log(response.headers.get('Authorization'));
console.log(response.headers.get('X-Test-Header'));
console.log(response.headers.get('Content-length'));
this.token = response.headers.get('Authorization');
this.storeToken(this.token);
this.currentUser = username;
this.loggedIn = true;
this.authChanged$.next('auth');
observer.next(true);
},
(err) => observer.next(false),
() => {},
);
});
}
控制台輸出:
空值
空值
空值
將此與此請求的網絡選項卡的內容進行比較:
不用說我的HttpInterceptor也不起作用 - 在響應中提供“Authorization”標頭時,它將該值用作新標記。 這樣可以實現令牌的自動續訂:
token.interceptor.ts
intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
const authService = this.injector.get(AuthService);
const token = authService.getToken();
if(token){
request = request.clone({
setHeaders: { 'x-access-token' : token }
});
}
return next.handle(request).do(
(event: HttpEvent<any>) => {
if (event instanceof HttpResponse) {
const response:HttpResponse<any> = (<HttpResponse<any>> event);
const authorizationHeader = response.headers.get('Authorization');
console.log('Authorization header value: ' + authorizationHeader);
if(authorizationHeader){
authService.setToken(authorizationHeader);
}
}
},
(err: any) => {
if (err instanceof HttpErrorResponse){
if (err.status === 401) {
this.router.navigate(['/']);
}
}
});
}
好的,這就是答案:我使用Node.js / Express作為后端,即使標題在Chrome的網絡標簽中可見,也不會使它們可供Angular處理。
“他們怎么可見但卻無法使用?” 我還不清楚。
配置您的Node / Express應用程序(查找評論“SOLUTION HERE”):
function configureExpress(expressApp){
expressApp.use(bodyparser.urlencoded({ extended: true }));
expressApp.use(bodyparser.json());
// Middleware: Use CORS, add headers and allow methods
expressApp.use(expressMiddleware);
}
function expressMiddleware(req, res, next) {
// Request origin: Allow ALL
res.header("Access-Control-Allow-Origin", "*");
// Allowed headers
res.header("Access-Control-Allow-Headers",
"Origin"
+",X-Requested-With" // Dont allow AJAX CORS without server consent - see http://stackoverflow.com/questions/17478731/whats-the-point-of-the-x-requested-with-header
+",x-access-token"
+",Content-Type"
+",Authorization"
+",Accept"
);
// SOLUTION HERE
// Allow headers access
res.header("access-control-expose-headers",
",Authorization"
+",Content-Length"
);
// Allowed methods
res.header('Access-Control-Allow-Methods',
'GET,'
+',POST'
+',OPTIONS'
+',PUT,'
+',DELETE'
);
// Handle CORS requests: cross-domain/origin requests will begin with an OPTION request to the same endpoint.
if('OPTIONS' === req.method){
res.sendStatus(200);
}
else{
// Request validations complete
next();
}
}
添加一些更相關的信息
我正在使用Angular 7 ,只是在API中的Access-Control-Expose-Headers中添加自定義標頭對我來說不起作用。
這里的問題是自定義標頭必須是小寫,因為Access-Control-Expose-Headers中的逗號分隔值
示例(快遞)
const cors = require('cors');
const corsOptions = {
allowedHeaders: 'x-custom-one,x-custom-two',
exposedHeaders: 'x-custom-one,x-custom-two'
}
app.use(cors(corsOptions));
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