Web2py也有意思的

def index():
"""
example action using the internationalization operator T and flash
rendered by views/default/index.html or views/generic.html

if you need a simple wiki simply replace the two lines below with:
return auth.wiki()
"""
if not session.counter:
session.counter = 1
else:
session.counter += 1
#response.flash = T("Welcome to web2py!")
return dict(message="Hello, Sky from MyApp!", counter=session.counter)

def first():
form = SQLFORM.factory(Field('visitor_name', requires=IS_NOT_EMPTY()))
if form.process().accepted:
session.visitor_name = form.vars.visitor_name
redirect(URL('second'))
return dict(form=form)

def second():
if not request.function=='first' and not session.visitor_name:
redirect(URL('first'))
return dict()