👷🏽‍♂️ use send_from_directory's download_name

fixes #3.

prolefeeder.py

@@ -21,7 +21,7 @@ app.config.from_object(Config)
 app.config['WTF_I18N_ENABLED'] = False  # enables WTForms built-in translations
 bootstrap = Bootstrap(app)
 
-attachment_filenames = {}
+download_filenames = {}
 
 
 class DownloadForm(FlaskForm):
@@ -48,8 +48,8 @@ def download():
         form.length.data = 60
     elif form.validate_on_submit():
         try:
-            output_filename, attachment_filename = prepare_download(form)
-            attachment_filenames[output_filename] = attachment_filename
+            output_filename, download_filename = prepare_download(form)
+            download_filenames[output_filename] = download_filename
             flash('Der Download sollte sofort starten.', 'success')
             return render_template('download.html', form=form, filename=output_filename)
         except ValueError as e:
@@ -73,14 +73,14 @@ def clean_out_dir():
 def download_file(filename):
     """Download an output file"""
 
-    if filename not in attachment_filenames:
+    if filename not in download_filenames:
         abort(404)
-    attachment_filename = attachment_filenames.pop(filename)
+    download_filename = download_filenames.pop(filename)
 
     clean_out_dir()
 
     return send_from_directory(app.config['OUT_DIR'], filename,
-                     as_attachment=True, attachment_filename=attachment_filename)
+            download_name=download_filename, as_attachment=True)
 
 
 def prepare_download(form):
@@ -123,7 +123,7 @@ def prepare_download(form):
     # Let ffmpeg do the rest of the job
     _, output_filename = mkstemp(prefix='prolefeeder', suffix='.mp3', dir=app.config['OUT_DIR'])
     output_filename = os.path.basename(output_filename)
-    attachment_filename = '{}_{}.mp3'.format(form.start_time.data, form.length.data)
+    download_filename = '{}_{}.mp3'.format(form.start_time.data, form.length.data)
 
     c = [
         'ffmpeg', '-y',
@@ -137,7 +137,7 @@ def prepare_download(form):
     app.logger.debug(' '.join(c))
     subprocess.call(c)
 
-    return output_filename, attachment_filename
+    return output_filename, download_filename
 
 
 if __name__ == '__main__':