How to handle the return of files (PDF) in an AJAX call?

Question

I made a code that selects the documents that are in a bank FTP and by clicking download it runs a AJAX call to the DJANGO where I call the FTP again, download the file and send back to the AJAX. But I can’t find how to handle the file .PDF.

I haven’t figured out why AJAX are treating as error and not as sucess. I should be defining the dataType differently? Or by treating rest in Django?

What I want to do is, select the file the user wants to download, pull it on ftp and download on the user’s machine.

Follows the codes:

AJAX:

    $.ajax({
        url:"{% url 'action_documents' %}",
        async: false,
        dataType: 'json',
        type: 'GET',
        data: {
            'documentos[]': documentos,
            'action': action,
    },
        success: function (data) {
            console.log('Sucess', data);
            result = 'S U C E S S O';
            // Tentando inserir o pdf em algum lugar para confimar que ele está -
            // chegando no Front End
            let html = ajax.decode(data.responseText).html;
            $('#main1').append(html);
            //ajax.get('pageContent').update(html);
        },
        error: function (response) {
            # o Ajax está saindo aqui
            console.log('Erro nos Documentos --> ', response);
            result = 'E R R O';
        }
    });

DJANGO:

if request.is_ajax:
    documentos = request.GET.get('documentos[]')
    # name é meramente ilustrativo
    name = documentos[1]
    ftp = logar_ftp()
    try:
        buffer = io.BytesIO()
        ftp.retrbinary('RETR ' + name, buffer.write)
        buffer.seek(0)
        # sending response
        response = HttpResponse(buffer, content_type='application/pdf')
        response['Content-Disposition'] = 'attachment; filename="' + name + '"'
    except IOError:
        # handle file not exist case here
        response = HttpResponseNotFound('<h1>File not exist</h1>')
else:
    response = HttpResponseNotFound('<h1>Request Ajax Error</h1>')
return response

• How should I effect request download on user’s machine?!

Answer 1

Ajax is a way to get data from a server without the need to reload the page, but it expects to receive a JSON with data from the server. You can save the file to your server and send as a response to Ajax a JSON object with the link to download, and in Success Voce USA window.location = data.url.

However your server may get very crowded with files, you can schedule a task on your server to clear the particular folder and delete the files from the previous day.