node.js - Download file sent in response angular2

Question

I know it is a dumb question but can someone tell me how can I prompt the user to download a file that is sent by the backend in the response?

Answer 1

You have two possibilities:

1. If the backend sends the file directly to the browser by clicking a link then the backend should use the content type application/octet-stream in the headers. That causes the browser to ask the user how to save/open the file.

2. If you load the file from the backend through Angular code (Http Module) then you could use filesaver.js or a similar library. Then you have the full control and can prompt the user yourself.

   npm install file-saver --save
   

   ... and the typings:

   npm install @types/file-saver --save-dev
   

   The code in the service:

   public getFile(path: string):Observable<Blob>{
     let options = new RequestOptions({responseType: ResponseContentType.Blob});
   
     return this.http.get(path, options)
         .map((response: Response) => <Blob>response.blob())              
         .catch(this.handleError);
   }
   

   For using FileSaver.js put the following import to your component:

   import * as FileSaver from 'file-saver';
   

   To trigger the download use that:

   this.api.getFile("file.pdf")
   .subscribe(fileData => FileSaver.saveAs(fileData, "file.pdf"));