wr_index.py

from flask import Flask, request, redirect, url_for, render_template, send_from_directory
from werkzeug.utils import secure_filename

@app.route('/', methods=['GET', 'POST'])
def index():
   if request.method == 'POST':
       if 'file' not in request.files:
           print('No file attached in request')
           return redirect(request.url)
       file = request.files['file']
       if file.filename == '':
           print('No file selected')
           return redirect(request.url)
       if file and allowed_file(file.filename):
           filename = secure_filename(file.filename)
           file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))
           process_file(os.path.join(app.config['UPLOAD_FOLDER'], filename), filename)
           return redirect(url_for('uploaded_file', filename=filename))
   return render_template('index.html')