Flash de mensagens

from flask import Flask, flash, redirect, render_template, request, url_for
app = Flask(__name__)
app.secret_key = 'random string'


@app.route('/')
def index():
    return render_template('flash_index.html')


@app.route('/login', methods=['GET', 'POST'])
def login():
    error = None

    if request.method == 'POST':
        if request.form['username'] != 'admin' or \
                request.form['password'] != 'admin':
                    error = 'Invalid username or password. Please try again!'
        else:
            flash('You were successfully logged in')
            return redirect(url_for('index'))
    return render_template('flash_login.html', error=error)


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

Upload de arquivos

from flask import Flask, render_template, request
from werkzeug import secure_filename
app = Flask(__name__)


@app.route('/upload')
def upload_file():
    return render_template('upload.html')


@app.route('/uploader', methods=['GET', 'POST'])
def uploader():
    if request.method == 'POST':
        f = request.files['file']
        f.save(secure_filename(f.filename))
        return 'file uploaded successfully'


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