How to serve a file not saved in folder, stored in postgresql database, and to be rendered to HTML b-CodePudding

We first sent the file to be posted as following:

router.post('/savefile', multer().single('filesource'), (q,s) => {  
     db.query("insert into filesource  (filerefid, source) values ($1, $2) returning filerefid",   [ q.body.filerefid,  q.file ])
      .then (r=> s.send(r.rows[0]))
  })

And then tried to show that as following to the HTML:

<object type="application/pdf" data="http://localhost:3000/getsource/1"></object>

Which is requested by:

router.get('/getsource/:i', (q,s) => {
      db.query('select source from  filesource  where  filerefid = $1;',
               [q.params.i])
        .then (r=> s.send(Buffer.from(r.rows[0].source.buffer)))
    
})

However the files cant be showed or downloaded correctly like that, What is the best way of doing that, without saving file in any directory?

CodePudding user response：

I suppose you are missing content type header in the response.

res.set('Content-Type', 'application/pdf');

Also consider setting Content-Disposition header to present a correct file name. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Disposition

Content-Type: application/pdf
Content-Disposition: attachment; filename="file.pdf"

Update

file property which is provided by multer is a js object, which contains buffer property with binary data of the file. In http get method this binary data should be returned decorated by the required http headers mentioned above.

CodePudding user response：

As mentioned by Oleg Flores answer for correct header, and the notice in his comment, that we should use the buffer from the object, that in the case of not saving any file by Multer, values of the insert query should be

[ q.body.filerefid,  q.file.buffer]