无法从后端响应获取“Content Disposition”

我想从 Content-Disposition

这是我的代码:

public getQuoteImage(sharedQuote):Observable<any> {
    return this.http.post(environment.downloadSummarUrl, JSON.stringify(sharedQuote), { 
      headers: this.params.headers.validate,
      observe: "response",
      responseType : 'blob'
    });
  }

我想得到 filename 内容处理

downloadSummaryContent() {
    this.server.getQuoteImage(this.sharedQuote).subscribe((data) => {
      console.log( 'headers are', '\n', data, '\n',  data.headers.get('Content-Disposition') ); //but not getting the file name
      var url = window.URL.createObjectURL(data);
      var a = document.createElement('a');
      document.body.appendChild(a);
      a.setAttribute('style', 'display: none');
      a.href = url;
      a.download = 'quote.pdf';
      a.click();
      window.URL.revokeObjectURL(url);
      a.remove(); // remove the element
    });
  }

但根本没有得到价值。

{
  "headers": {
    "normalizedNames": {

    },
    "lazyUpdate": null,
    "lazyInit": null,
    "headers": {

    }
  },
  "status": 200,
  "statusText": "OK",
  "url": "https:XXXXXXservice/p/shipment/download/",
  "ok": true,
  "type": 4,
  "body": {

  }
}