小编shi*_*hiv的帖子

响应具有图像数据,但我无法从响应中提取它.

客户代码 -

download() {
    this._http.get('http://localhost:9000/download/' + this._fileid)
    .subscribe(
    data => {
        this.image = data;
    },
    err => console.log('Error is..:' + err)
    );
}

服务器代码 -

app.get('/download/:fileid', function(req, res) {
    var id = req.params.fileid;
    res.set('Content-Type', 'image/jpeg');
    gfs.createReadStream({_id: id}).pipe(res);
});

[编辑] - 我已经调整了我的代码以使用CustomXhr但是我得到一个没有数据的空blob.

CUSTOM XHR代码 -

@Injectable()
export class CustomBrowserXhr extends BrowserXhr {
  build(): any {
    let xhr = super.build();
    xhr.responseType = "blob";
    return <any>(xhr);
  }
}

BOOTSTRAP CODE-导出函数main(initialHmrState？:any):Promise {

export function main(initialHmrState?: any): Promise<any> {

  return bootstrap(App, [
    ...ENV_PROVIDERS,
    ...PROVIDERS, …

下面的指令使用MessageBus类注册一个监听器.在调用调度函数时执行已注册的回调.我需要从回调中访问"dragZoneElems"并对其执行操作.请告知如何做到这一点.目前它说dropZoneElems = undefined,因为这个数据在回调范围之外.但是数据存在且未定义.

export class DragZoneDirective implements OnInit{
   private _messageBus : IMessageBus

   @Input() dragZoneElems: Object[];
   constructor() {
      this._messageBus = MessageBus;
   }

   ngOnInit(){
    this._messageBus.listen("dragStart", function(val) {
        console.log("DragStart", this.dragZoneElems);
        let index = this.dragZoneElems.indexOf(val);
        if(index > -1)
            this.dragZoneElems.slice(index, 1);
    });
    this._messageBus.listen("dragStop", function(val) { console.log("DragStop"); });
   }
 }

消息总线 -

static dispatch(event: string, info?: any): void {
     this.listeners
        .forEach((l) => {
           if (l["event"] === event) {
               l["cb"](info);
           }
        });
}