Upload file with Flask microframework.

flask_upload.py

import os
from flask import Flask, flash, request, redirect, url_for
from werkzeug.utils import secure_filename

if not os.path.exists("uploads/"):
	os.mkdir("uploads")

UPLOAD_FOLDER = 'uploads/'
ALLOWED_EXTENSIONS = {'txt', 'pdf', 'png', 'jpg', 'jpeg', 'gif'}

app = Flask(__name__)
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER

def allowed_file(filename):
	return '.' in filename and \
		   filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS

@app.route('/', methods=['GET', 'POST'])
def upload_file():
	if request.method == 'POST':
		# check if the post request has the file part
		if 'file' not in request.files:
			flash('No file part')
			return redirect(request.url)
		file = request.files['file']
		# if user does not select file, browser also
		# submit an empty part without filename
		if file.filename == '':
			flash('No selected file')
			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))
			return redirect(request.url)
	
	return '''
	<!doctype htm
	<title>Upload new File</title>
	<h1>Upload new File</h1>
	<form method=post enctype=multipart/form-data>
	  <input type=file name=file>
	  <input type=submit value=Upload>
	</form>
	'''

if __name__ == '__main__':
   app.run(debug = True)