Migrating from appengine-toolkit 1 to Version2

Some suggestions on moving from Appengine Toolkit Version 1 (gaetk) to GAETK2. Obviously you need to add gaetk2 to your source tree:

git submodule add https://github.com/mdornseif/appengine-toolkit2.git lib/appengine-toolkit2

First get all the Error Handling Guide goodness from GAETK2.

Just ensure that you import the right WSGI Application:

from gaetk2.application import WSGIApplication
....
application = WSGIApplication([ ...

Often you might have to replace make_app by WSGIApplication.

With that you did the most important change. GAETK1 and GAETK2 get along quite well so you might leave it at that for a moment.

Change configuration-files

In app.yaml make sure lib/appengine-toolkit2/include.yaml is included and jinja2 is not included via Google (we need jinja 2.10, Google provides 2.6):

includes:
- lib/appengine-toolkit2/include.yaml
...
libraries:
- name: ssl
  version: latest
- name: pycrypto
  version: "latest"
- name: numpy
  version: "1.6.1"
- name: PIL
  version: latest

Your requirements.txt should end with -r lib/appengine-toolkit2/requirements-lib.txt.

At the top of your appengine_configuration.py include this:

# load gaetk2 bootstrap code without using `sys.path`
import imp
(fp, filename, data) = imp.find_module('boot', ['./lib/appengine-toolkit2/gaetk2/'])
imp.load_module('gaetk_boot', fp, filename, data)

This will set up paths as needed. To get error- and session-handling and add the following lines at the end of appengine_config.py.

from gaetk2.wsgi import webapp_add_wsgi_middleware # pylint: disable=W0611

Various configuration needs to be done in gaetk2_config.py. Try grep GAETK2_ >> gaetk2_config.py. Minimal contents would be:

GAETK2_SECRET='13f221234567890fae123-c0decafe'
GAETK2_TEMPLATE_DIRS=['./templates', './lib/CentralServices/templates']

Replace Imports

Replace this:

from google.appengine.ext.deferred import defer
from gaetk.infrastructure import taskqueue_add_multi
from gaetk2.tools import hujson2
from gaetk.tools import slugify
from huTools.unicode import deUmlaut
from huTools import cache

With this:

from gaetk2.taskqueue import defer
from gaetk2.taskqueue import taskqueue_add_multi
from gaetk2.tools import hujson2
from gaetk2.tools.unicode import slugify
from gaetk2.tools.unicode import de_umlaut
from gaetk2.tools.caching import lru_cache, lru_cache_memcache

s/import gaetk.handler/from gaetk2 import exc/ /raise gaetk.handler.HTTP/raise exc.HTTP/

Use a local logger

At the top of each module create a local logger instance:

logger = logging.getLogger(__name__)

Then replace calls to logging.info() et. al. with calls to logger.info() et. al.

Change your views / handlers

Todo

• Replace default_template_vars() with build_context() - no super() calls necessary anymore.
• Authentication has changed significanty. authchecker() now handled by pre_authentication_hook(), authentication_hook and authorisation_hook().
• if you used the get_impl() pattern to wrap your handler functions, you don’t need that anymore. The often used read_basedata() can be moved into method_preperation_hook().
• Replace self.is_admin() with self.is_staff() (or self.is_sysadmin()).

• attrencode to xmlattr:

  <meta property="og:price:amount" content="{{ preis|euroword|attrencode }}" /> to <meta property="og:price:amount" {{ {'content': preis|euroword}|xmlattr }} />

• authchecker to authorisation_hook

This:

def authchecker(self, method, *args, **kwargs):
    """Sicherstellen, das Sources diese Seiten nicht anschauen dürfen."""
    super(MasterdataHomepage, self).authchecker(method, *args, **kwargs)
    if self.credential.get_typ() == 'source':
        raise exc.HTTP403_Forbidden('Dies ist ein reiner Kundenbereich')

Becomes that:

def (self, method_name, *args, **kwargs):
    u"""Sicherstellen, dass nur kunden diese seite sehen düfen."""
    if self.credential.get_typ() == 'source':
        raise exc.HTTP403_Forbidden('Dies ist ein reiner Kundenbereich')

Templates

Todo

• Autoescaping

Migrate to Bootstrap 4

See Migrating to v4 for general guidelines. See Frontend Guidelines for the desired results.

Usually you want to use {% extends "gaetk_base_bs4.html" %}.

Breadcrubs are now implemented by gaetk. See breadcrumbs.