Google AppEngine Tutorial, difference between code snippets - google-app-engine

Question

can anyone tell me please the difference between these two code snippets:
1.
import webapp2
from google.appengine.api import users
class MainPage(webapp2.RequestHandler):
def get(self):
user = users.get_current_user()
if user:
self.response.headers['Content-Type'] = 'text/plain'
self.response.out.write('Hello, ' + user.nickname())
else:
self.redirect(users.create_login_url(self.request.uri))
app = webapp2.WSGIApplication([('/', MainPage)],
debug=True)
2.
import webapp2
from google.appengine.api import users
class MainPage(webapp2.RequestHandler):
def get(self):
user = users.get_current_user()
if user:
self.response.headers['Content-Type'] = 'text/plain'
self.response.out.write('Hello, ' + user.nickname())
else:
self.redirect(users.create_login_url(self.request.uri))
app = webapp2.WSGIApplication([('/', MainPage)],
debug=True)
The thing is that i'm trying to go over Google AppEngine introduction material and whenever i try to type the code myself, something's different and it doesn't work. And whenever i just copy it from their website, it works, although it looks identical.
Checked the coding in the View panel, it's same, ANSI (i'm using Notepad++).
Tried to play with indentation as well and it didn't made any difference.
Any comments would be appreciated.
Thank you.

Answer 1

You should always start your Pyhton code with these 3 lines:
#!/usr/bin/python
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
And your editor should encode in utf-8. Do not use ANSI.
The last line is optional, but I recommend it, to stay away from encoding problems. There are a few exceptions. So if you use unicode literals, you have to change the line with the headers:
import webapp2
from google.appengine.api import users
class MainPage(webapp2.RequestHandler):
def get(self):
user = users.get_current_user()
if user:
self.response.headers['Content-Type'.encode()] = 'text/plain'.encode()
self.response.out.write('Hello, ' + user.nickname())
else:
self.redirect(users.create_login_url(self.request.uri))
app = webapp2.WSGIApplication([('/', MainPage)],
debug=True)
And your app.yaml should look like:
application: helloworld
version: 1
runtime: python27
api_version: 1
threadsafe: false
handlers:
- url: /.*
script: helloworld.app
libraries:
- name: webapp2
version: latest
But Notepad++ is not a good development environment for app engine. You need a good Python IDE. I recommend Eclipse with PyDev. To setup, use this totorial see this question: Debug google app engine project line by line
And if you are a total newbie? go to this great web development course using google app engine : http://www.udacity.com/overview/Course/cs253/CourseRev/apr2012

Answer 2

Found a problem, it was indentation thing.
You can read about this here and here
There's difference whether you are using "space" or "tab" to indent and it can cause problems,
also problems can occur from settings in your program (in my case in Sublime Text's setting of "Tab" indent,it can be set to 4 or 8 etc.)