Re: Pickle in a POST/GET request give EOFError

[Romaric DEFAUX]

Le 17/11/2010 18:52, geremy condra a écrit :

On Wed, Nov 17, 2010 at 6:44 AM, Romaric DEFAUX<r...@audaxis.com>  wrote:

Le 16/11/2010 17:47, Romaric DEFAUX a écrit :

Hi everybody !

First time I write to this mailing list :)
I started writing in python last week, that's probably why I can't
understand the following problem...


I create a list called web_site_list.
This list contain dictionaries called web_site.
And some values in this dictionaries are list too.

I do that in a function and I return this :
return pickle.dumps(web_site_list)

This is working fine :)

If I do :
print "%s" % pickle.loads(system.get_web_site_list())

I've got the right stuffs. For example it returns :
[{'documentroot_size': '120', 'servername': '---default---', 'client':
'undefined', 'documentroot': '/var/www/', 'client_contact': 'undefined',
'serveralias': []}]

I send this to a web service. I send it like that :
#I put it in params
def system_updateweb_site(server, login, password):
        params = {}
        params['login'] = login
        params['password'] = password
        params['action'] = 'updateweb_site'
        params['servername'] = get_servername()
        params['hosted_web_site'] = get_web_site_list()
        return call_system_ws(server, params)

#Here's how I send it (I tried in GET and POST)
def call_system_ws(host, params):
        query_string = urllib.urlencode(params)
#GET
#       f = urllib.urlopen("http://%s/ws?%s"; % (host, query_string))
#POST
        f = urllib.urlopen("http://%s/ws"; % (host), query_string)
        result = f.readline().strip()
        if result == 'ERROR':
                msg = f.readline().strip()
                return (False, msg)
        return (True, result)


On the server side :
                        if action == 'updateweb_site':
                                if not (fields.has_key('servername') and
fields.has_key('hosted_web_site')):
                                        raise WSError('missing parameter :
servername or hosted_web_site')
                                        log ('ERROR : missing parameter :
servername or hosted_web_site')
                                else:

  servername=g.db.escape_string(fields['servername'])

  hosted_web_site=g.db.escape_string(fields['hosted_web_site'])
                                        output =
systemserver.updateweb_site(cursor, servername, hosted_web_site)

In systemserver.py :
def updateweb_site(cursor, host, hosted_web_site):
        web_site_list = pickle.loads(hosted_web_site)
        return "%s" % (web_site_list)

I catch this error :*

<type 'exceptions.EOFError'>*:

args = ()
message = ''

Why ?

If I just print hosted_web_site, I get this on my web page :


(lp0\n(dp1\nS\'documentroot_size\'\np2\nS\'120\'\np3\nsS\'servername\'\np4\nS\'default\'\np5\nsS\'client\'\np6\nS\'undefined\'\np7\nsS\'documentroot\'\np8\nS\'/var/www/\'\np9\nsS\'client_contact\'\np10\ng7\nsS\'serveralias\'\np11\n(lp12\nsa.

It's the "pickled view" of
[{'documentroot_size': '120', 'servername': '---default---', 'client':
'undefined', 'documentroot': '/var/www/', 'client_contact': 'undefined',
'serveralias': []}]

Can someone help me please ? I spend my afternoon to google to try to find
a solution...


Thanks in advance !!!

Romaric Defaux

After entirely rewrite my code to not use Web service but socket (a real
client/server program) I finally found the problem... And it's not linked to
the POST or GET method...
It's because of that :
g.db.escape_string(fields['hosted_web_site'])
(escape_string is the function in MySQLdb library)
It escapes the simple quote of the pickled object, and break it...

It's good to know, NEVER escape a pickled object :)

Romaric Defaux

I'm not sure I understand what you're doing here, but I trust you've
read about and understand the security problems with pickle?

Geremy Condra

I read quickly the security problems with pickle. But I don't feel concern about that because I run my program in a private network, not over internet. And now I use socket to communicate on a non-standard port, not anymore web service on the 80 port. If I plan to run it through wan, I will encrypt datas for sure with SSL or something like that :)

Romaric Defaux

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