I assume you use the webapp framework.
import cgi
from google.appengine.api import users
from google.appengine.ext import webapp
from google.appengine.ext.webapp.util import run_wsgi_app
class MainPage(webapp.RequestHandler):
def get(self):
self.response.out.write("""
<html>
<body>
<form action="/makepdf" method="post">
<div><textarea name="content" rows="3" cols="60"></textarea></div>
<div><input type="submit" value="Make a PDF for me"></div>
</form>
</body>
</html>""")
class MakePDF(webapp.RequestHandler):
def post(self):
# now here you can make your PDF like you did for the "Hello world" one
# and you can access the entered data like this: self.request.get('content')
application = webapp.WSGIApplication(
[('/', MainPage),
('/makepdf', MakePDF)],
debug=True)
def main():
run_wsgi_app(application)
if __name__ == "__main__":
main()