IONIC 3-IOS：[错误] Access-Control-Allow-Headers不允许请求标头字段Content-Type

Question

我正在尝试在Mac中调试离子应用程序：

$ ionic cordova emulate ios -- --buildFlag="-UseModernBuildSystem=0" --debug

在API SERVER（.NET）的请求之一中，出现错误：

  

Access-Control-Allow-Headers不允许请求标头字段Content-Type

login(login: LoginModel | null): Observable<LoginInfo | null> {
  let url_ = this.baseUrl + "/API/Login/Login";
  url_ = url_.replace(/[?&]$/, "");

  const content_ = JSON.stringify(login);

  let options_ : any = {
    body: content_,
    observe: "response",
    responseType: "blob",
    headers: new HttpHeaders({
      "Content-Type": "application/json", 
      "Accept": "application/json"
    })
  };

  return this.http.request("post", url_, options_).flatMap((response_ : any) => {
    return this.processLogin(response_);
  }).catch((response_: any) => {
    if (response_ instanceof HttpResponseBase) {
      try {
        return this.processLogin(<any>response_);
      } catch (e) {
        return <Observable<LoginInfo | null>><any>Observable.throw(e);
      }
    } else
      return <Observable<LoginInfo | null>><any>Observable.throw(response_);
   });
 }

Answer 1

因此正确地在服务器中设置Access-Control-Allow-...。

• Safari不允许类似的*：

HttpContext.Current.Response.AddHeader("Access-Control-Allow-Methods", "*");

正确的设置是：

HttpContext.Current.Response.AddHeader("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS");

Answer 2

您可以在express.js服务器中设置一些配置。

app.use(function(req, res, next) {
  var allowedOrigins = [
    'http://localhost',
    'http://localhost:8000',
    'http://127.0.0.1',
    'http://127.0.0.1:8000',
    'http://yourdomain.com',
  ];
  var origin = req.headers.origin;
  if (allowedOrigins.indexOf(origin) > -1) {
    res.setHeader('Access-Control-Allow-Origin', origin);
  }
  res.header('Access-Control-Allow-Methods', 'GET, PUT, POST, DELETE, OPTIONS');
  res.header('Access-Control-Allow-Headers', 'Content-Type, Authorization');
  res.header('Access-Control-Allow-Credentials', true);
  next();
});