Template project for using Django on Google Appengine. Guido's codereview source code

This post is about how to use Django on Google Appengine with Guido van Rossum's code review source code. Now, Appengine needs to be patched to use Django. You can either use patches (Appengine helper, App-engine-patch) or patch it by yourself. Another better way is using Guido's code as a template project.

Pros include:

1. codereview is hosted on Appengine and uses Django framework.

2. one feature of Django is pluggable. Your applications can be added by modifying url configuration file urls.py.

3. this open source project is actively maintained. Both of Appengine and Django are updated frequenctly. This will provide more useful features, but new versions normally also need new patches. Since codereview is an actual appengine application, it will show you how to use new features and make them work. This poject has some contributors, which means better customer support.

4. Guido is owner. And, he has substantial knowledge about Python.
For example, main.py shows how to set a breakpoint for debugging in appengine. Rietveld.py provides some useful helper functions.

Links:
http://codereview.appspot.com/
http://code.google.com/p/rietveld/

Sample code.Python and Perl.RESTful interface.Language Ajax api. Post method. 5000. api limit.

The post title is a set of key words I used for googling to find answer. Basically, due to not familiar with protocols and few explicit explanation out there, the whole finding really took a while.

Perl sample code:
http://search.cpan.org/dist/WebService-Google-Language-0.09/lib/WebService/Google/Language.pm

this is Perl translation module utilizing google language Ajax api.

When encoded url with translation text is less than 2000 something or Maximum URL length set by google server, this module uses GET method.

When translation test is between 2000 and 5000, this module will put encoded translation text, api version, and langpair etc in body and send by POST.

You can download Perl from (http://www.perl.org/get.html) and install this module.

Python sample code:
POST method
First please download http://code.google.com/p/python-rest-client/
############################
#POST method
############################
from restful_lib import Connection
import urllib

conn = Connection('http://ajax.googleapis.com/ajax/services/language');

query = {'v':'1.0', 'langpair':'en|de','q':'hello world'};

print conn.request_post("/translate",body=urllib.urlencode(query), headers={'referer':'http://example.com', "content-type":"application/x-www-form-urlencoded" ,"charset":"UTF-8"})

#############################

notes:
1. query needs to be encoded as a string 'q=hello+world&langpair=en%7Cde&v=1.0' with urlencode()

2. "content-type":"application/x-www-form-urlencoded" ,"charset":"UTF-8" shold be added to headers to tell server how 'body' is encoded.
Without them, you will get 'invalid version' error in response.

3. based on perl module description (http://search.cpan.org/dist/WebService-Google-Language-0.09/lib/WebService/Google/Language.pm#CONSTRUCTOR)
header 'referer':'http://example.com' is mandatory, because Google demands a "valid and accurate http referer header" in requests to their service.

4. If you want to use it one google app engine, please use 'from gae_restful_lib import GAE_Connection as Connection' instead ( http://code.google.com/p/python-rest-client/wiki/REST_for_Google_App_Engine )

5. Please try a long translation text, after you get sample code work.

BTW, here is GET method sample code

############################
#POST method
############################
from restful_lib import Connection

print conn.request_get("/translate", args={'v':'1.0','langpair':'en|de','q':'Hello'}, headers={'referer':'http://example.com','Accept':'text/json'})

#############################

useful tool for restful testing:
http://code.google.com/p/rest-client/

Chef
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