Set File Name while downloading via blob in Angular 5

Question

Below is my Typescript code to download file From API

DownloadLM() {
var ID= sessionStorage.getItem("UserID");
    return this.http.get(this.baseurl + 'api/DownloadFiles/DownloadLM/' + ID,
      {
        headers: {
          'Content-Type': 'application/json'
        },
        responseType: 'arraybuffer'
      }
    )
      .subscribe(respData => {
        this.downLoad(respData, this.type);
      }, error => {
      });
  }

  downLoad(data: any, type: string) {
    var blob = new Blob([data], { type: type.toString() });
    var url = window.URL.createObjectURL(blob);
    var pwa = window.open(url);
    if (!pwa || pwa.closed || typeof pwa.closed == 'undefined') {
      alert('Please disable your Pop-up blocker and try again.');
    }
  }

This is Fine to download Excel File , but it gives a random name to file which I don't want , I want to set file name of my choice when downloading it ,

Where can I set file name here ? any property of Blob ?

Answer 1

If you want the exact filename of the uploaded file, set a custom header of the filename from backed API stream.

You can use it like this: my Excel API response headers:

content-disposition: inline;filename="salesReport.xls" 
content-type: application/octet-stream 
date: Wed, 22 Aug 2018 06:47:28 GMT 
expires: 0 
file-name: salesReport.xls 
pragma: no-cache 
transfer-encoding: chunked 
x-application-context: application:8080 
x-content-type-options: nosniff 
x-xss-protection: 1; mode=block

Service.ts

excel(data: any) {
  return this.httpClient.post(this.config.domain + 
  `/api/registration/excel/download`,data, {observe: 'response', responseType: 'blob'})
  .map((res) => {
      let data = {
                     image: new Blob([res.body], {type: res.headers.get('Content-Type')}),
                     filename: res.headers.get('File-Name')
                  }
    return data ;
  }).catch((err) => {
    return Observable.throw(err);
  });
}

Component.ts

excelDownload (data) {
   this.registration.excel(data).subscribe(
    (res) => {
     const element = document.createElement('a');
      element.href = URL.createObjectURL(res.image);
      element.download = res.filename;
      document.body.appendChild(element);
      element.click();
     this.toastr.success("Excel generated  successfully");
    },
  (error) =>{
     this.toastr.error('Data Not Found');
  });
}