How to localize an app on Google App Engine?
- by Petri Pennanen
What options are there for localizing an app on Google App Engine? How do you do it using Webapp, Django, web2py or [insert framework here].
1. Readable URLs and entity key names
Readable URLs are good for usability and search engine optimization (Stack Overflow is a good example on how to do it). On Google App Engine, key based queries are recommended for performance reasons. It follows that it is good practice to use the entity key name in the URL, so that the entity can be fetched from the datastore as quickly as possible.
Currently I use the function below to create key names:
import re
import unicodedata
def urlify(unicode_string):
"""Translates latin1 unicode strings to url friendly ASCII.
Converts accented latin1 characters to their non-accented ASCII
counterparts, converts to lowercase, converts spaces to hyphens
and removes all characters that are not alphanumeric ASCII.
Arguments
unicode_string: Unicode encoded string.
Returns
String consisting of alphanumeric (ASCII) characters and hyphens.
"""
str = unicodedata.normalize('NFKD', unicode_string).encode('ASCII',
'ignore')
str = re.sub('[^\w\s-]', '', str).strip().lower()
return re.sub('[-\s]+', '-', str)
This works fine for English and Swedish, however it will fail for non-western scripts and remove letters from some western ones (like Norwegian and Danish with their œ and ø).
Can anyone suggest a method that works with more languages?
2. Translating templates
Does Django internationalization and localization work on Google App Engine? Are there any extra steps that must be performed? Is it possible to use Django i18n and l10n for Django templates while using Webapp?
The Jinja2 template language provides integration with Babel. How well does this work, in your experience?
What options are avilable for your chosen template language?
3. Translated datastore content
When serving content from (or storing it to) the datastore: Is there a better way than getting the *accept_language* parameter from the HTTP request and matching this with a language property that you have set with each entity?
