Rot13 Example: How do I run this piece code in Google App Engine?

Question

I'm having trouble running the code below.

The code should work (it's a Udacity source code solution for a problem set). It should run on Google App Engine.

In my terminal, I navigate to the hw2 folder which contains the following files at ~/python-docs-samples/appengine/standard

Then I run

dev_appserver.py .

However, I get a 404 error when I load the page at localhost:8080

It works fine for a 'Hello World' example in ~/python-docs-samples/appengine/standard

What am I doing wrong here? Thanks

import os
import re
from string import letters

import webapp2
import jinja2

from google.appengine.ext import db

template_dir = os.path.join(os.path.dirname(__file__), 'templates')
jinja_env = jinja2.Environment(loader = jinja2.FileSystemLoader(template_dir),
                               autoescape = True)

def render_str(template, **params):
    t = jinja_env.get_template(template)
    return t.render(params)

class BaseHandler(webapp2.RequestHandler):
    def render(self, template, **kw):
        self.response.out.write(render_str(template, **kw))

    def write(self, *a, **kw):
        self.response.out.write(*a, **kw)

class Rot13(BaseHandler):
    def get(self):
        self.render('rot13-form.html')

    def post(self):
        rot13 = ''
        text = self.request.get('text')
        if text:
            rot13 = text.encode('rot13')

        self.render('rot13-form.html', text = rot13)


USER_RE = re.compile(r"^[a-zA-Z0-9_-]{3,20}$")
def valid_username(username):
    return username and USER_RE.match(username)

PASS_RE = re.compile(r"^.{3,20}$")
def valid_password(password):
    return password and PASS_RE.match(password)

EMAIL_RE  = re.compile(r'^[\S]+@[\S]+\.[\S]+$')
def valid_email(email):
    return not email or EMAIL_RE.match(email)

class Signup(BaseHandler):

    def get(self):
        self.render("signup-form.html")

    def post(self):
        have_error = False
        username = self.request.get('username')
        password = self.request.get('password')
        verify = self.request.get('verify')
        email = self.request.get('email')

        params = dict(username = username,
                      email = email)

        if not valid_username(username):
            params['error_username'] = "That's not a valid username."
            have_error = True

        if not valid_password(password):
            params['error_password'] = "That wasn't a valid password."
            have_error = True
        elif password != verify:
            params['error_verify'] = "Your passwords didn't match."
            have_error = True

        if not valid_email(email):
            params['error_email'] = "That's not a valid email."
            have_error = True

        if have_error:
            self.render('signup-form.html', **params)
        else:
            self.redirect('/unit2/welcome?username=' + username)

class Welcome(BaseHandler):
    def get(self):
        username = self.request.get('username')
        if valid_username(username):
            self.render('welcome.html', username = username)
        else:
            self.redirect('/unit2/signup')

app = webapp2.WSGIApplication([('/unit2/rot13', Rot13),
                               ('/unit2/signup', Signup),
                               ('/unit2/welcome', Welcome)],
                              debug=True)

Answer 1

The following code defines the request handlers for the corresponding URL patterns:

app = webapp2.WSGIApplication([('/unit2/rot13', Rot13),
                               ('/unit2/signup', Signup),
                               ('/unit2/welcome', Welcome)],
                               debug=True)

Notice that you do not have a handler for / or a catch all. This is why you're getting an HTTP 404 error.