File “C:\Python25\lib\urllib2.py”, line 360, in _call_chain
result = func(*args)
File “C:\Python25\lib\urllib2.py”, line 506, in http_error_default
raise HTTPError(req.get_full_url(), code, msg, hdrs, fp)
HTTPError: HTTP Error 403: Forbidden
Error 403: — begin server output —
You do not have permission to modify this app (app_id=u’myapp’).
— end server output —

Ok… If you faced this problem, it´s easy to solve. Just change your command line argument to skip cookies, and then, pass your right e-mail address. Example:

prompt> appcfg.py –email=myemail@server.com.br –no_cookies update .

This line will make appcfg.py ask you the password for the user myemail@server.com.br.

But it was annoying me, everytime doing this thing. As always I do, I want to figure out where the cookie file was saved, to see how it works, of course, and then kill the file. After browsing appengine_rpc.py, I realized that Google is using cookie_jar lib and on line 365 they´re setting the filename variable:

if self.save_cookies:
      self.cookie_jar.filename = os.path.expanduser(
          HttpRpcServer.DEFAULT_COOKIE_FILE_PATH)

I just pointed a print and found where it is! It´s located under your home profile/.appcfg_cookies file. On my windows box, located on c:\documents and settings\robson\.appcfg_cookies and on my linux bok located on /home/robson/.appcfg_cookies.

Hope someone from Google implement a better mechanism to improve it.

-Robson Dantas
Now with Java Appengine account!

I´m calling on wrapper to generate a log file, and calling this wrapper twice, makes the logger generate duplicated lines.

Just to make the things a bit clear, take a look at this routine:

import logging
import logging.handlers
def makelog(filepath):

	logger = logging.getLogger('applog')

	# remove diretorio
	dir = os.path.split(filepath)
	dir = diretorio[0]

	# cria dir tree
	if not os.path.exists(dir):
		os.makedirs( dir )

	# rotate 2mb de log, in 5 files
	hdl = logging.handlers.RotatingFileHandler(
              filepath, maxBytes=2097152, backupCount=5)

	formatter = logging.Formatter('%(asctime)s %(module)s, line %(lineno)d %(levelname)s %(message)s')
	hdl.setFormatter(formatter)

	logger.addHandler(hdl)
	logger.setLevel(logging.DEBUG)

	return logger

Now, make two different classes and call this function. Even though destroying the class and calling the other one, the records will be duplicated during your second call.

To make it work, it´s a bit complicated to find, and here is the solution:

Inside your __del__(self) function, include:

x = logging._handlers.copy()
for i in x:
	log.removeHandler(i)
	i.flush()
	i.close()

PS: I´m supposing that “log” is your return for the function, your in other words, the result of logging.getLogger(..) .

I hope it saves some hours of your work

-Robson

Since browsers do not allow to make ajax call from other domains (you´ll get some errors related to security issues), you can make a workaround to enable cross domain ajax queries.

I wrote a small piece of code using python and google appengine to show how to do that. It´s quite simple, take a look…

-*- coding: utf-8 -*-


import cgi
import urllib
import httplib
from google.appengine.ext import webapp
from google.appengine.api import urlfetch
from google.appengine.ext.webapp.util import run_wsgi_app

class ProxyController(webapp.RequestHandler):

	def doProxy(self, p, urlmethod)

		location=''
		page = self.response.out

		if p.get('a','') == '':
			page.write("page not found on query string")
		else:

			""" just a simple concatenation, just to make sure the file is a .php """
			location = p['a'] + '.php'
			p['a']=''

			""" encode params received from url """
			params=urllib.urlencode(p)

			""" concatenate params with the destination """
			location+='?'+params

			"""fetch data using urlfech. I´ve hard coded the other domain, just to prevent url injection
			you can change something here"""
			result = urlfetch.fetch(url = "http://www.otherdomain.com/" + location, method = urlmethod) 

			""" print out the response. I usually dump json, so i can parse it easily """
			self.response.out.write(result.content)

	""" handles get requisitions """
	def get(self):
		self.doProxy(self.request.str_GET,urlfetch.GET)

	""" handles post requisitions"""
	def post(self):
		self.doProxy(self.request.str_POST,urlfetch.POST)

"""
Some explanation:
To make it work, just point to the address http://www.mydomain.com/jsonProxy?a=somepage&param=1&param2=something

 ProxyController will call http://www.otherdomain.com/somepage.php and pass the other parameters on the query string using urlfetch.
After fetching, it will print the string and then you can use on your javascript.
application = webapp.WSGIApplication([('/jsonProxy', ProxyController)],debug=True)
"""
def main():
	run_wsgi_app(application)

if __name__ == "__main__":
	main()

Now you just have to edit a bit the code and make it work for you. It´s simple, as I said above, but it states how to solve the crossdomain problem, using a proxy which will make the work for you. Just remember that you need to put this wrapper on the same domain which you are using your javascripts, or whatever.

-Robson

I’ve played a while with AppEngine, helping another projects, setting up my stuff there and got lots of tricks to help another users. Today (March 31, 2009) I faced a small problem, related to index.

I was executing a query on my website, and got an error:  no matching index found. This query needs this index - kind: Comments properties: – name: page – name: data_issued direction: desc.

What went wrong ? Appengine tries to make everything for you, but depending on the way you execute the Gql, you need to edit index.yaml adding some information to make it work. The query which I was executing is something like: db.GqlQuery(“SELECT * from Comments where page=:1 order by date_issued”). Since I don’t have any index which matches with the filter page=something, order by date, it gives me an error.

To fix, just edit index.yaml, adding:

- kind: Comments
properties:
- name: page
- name: data_issued
direction: desc

After that, resync the index, using: appcfg.py update_indexes .

Now you’ll be able to run your query

Have any questions ? ask here.

-Robson

The steps to setup this plugin is really easy, but make it work under my windows box was really hard. After adjusting things and asking Yoichiro to help, I finally could make it work.

My environment:

• Windows Xp Pro – SP 3;
• Java SDK version 1.6.0_12;
• Eclipse 3.4.2

Setup steps:

• After installing the required software, open Eclipse and point to Help->Software Updates;
  
• Select “Available Software” tab and click on “Add site” on your right;
• Type http://opensocial-development-environment.googlecode.com/svn/update-site/site.xml on location field and click Ok;
• Mark OSDE checkbox and click “Install” on your right. Just wait it finish and Eclipse will restart. It took about 5 minutes on a 3Mbps connection;

Here goes the tricks:

• Make sure you have installed at least the version 0.2.5 of OSDE. Yoichiro fixed one problem when I asked for help;
• Create a new OSDE project, and switch your workspace to a directory which doesn’t contain any spaces on its name. On windows box, it assumes c:\documents and settings\user\local settings\temp and makes OSDE fail. I changed my workspace to c:\temp;
• Point to windows->preferences and choose OSDE on your left. Change “Jetty context directory” and “Shindig Database directory” to anywhere on c:\temp or other dir without spaces;
• Right click on gadgets.xml, choose “Run as->Run configuration”. Click on “Apache Shindig” and after the “Arguments” tab. Change the last few words to point to the temp directory. Repeat the same step for “Shindig Database”, just below “Apache Shindig”;
• Start the apache shindig server, clicking on the green button on the toolbar;
• Add some sample data;

If everything has worked fine, you will not see any exceptions on console screen.

Hope it helps.

Have any comment or doubt ? Just fill out the comments form.

-Robson Dantas
Opensocial Guru

To make all information available just in english, I decided to setup this new blog. Hope you enjoy!

I’m playing a bit with Zend GData Library to integrate some pictures from my own website with Picasa. Before trying to test my app on Firefox, I was coding and calling php-cgi from the prompt.

I have my wamp stack installed, since I’m using windows for coding. I dont why I started to get some weird errors:

Fatal error: Uncaught exception ‘Zend_Gdata_App_HttpException’ with message ‘Unable to Connect to ssl://www.google.com:443. Error #26464712: Unable to find the socket transport “ssl” – did you forget to enable it when you configured PHP?’ in C:\wamp\www\picasa\zend\library\Zend\Gdata\ClientLogin.php:140

This is a common error when you don’t have php_openssl.dll installed, but checking on wamp, the line was uncommented: extension=php_openssl.dll.

So what went wrong ? Easy.. wamp was pointing the config file to another place. So i went to php.ini file and uncommented that line again.

Now it’s working. Easy and quick.

Next post i’ll start to write something about php and picasa integration.

If you have any doubt, leave a message!

-Robson