Pickle in a POST/GET request give EOFError

Michael Ricordeau michael.ricordeau at gmail.com
Thu Nov 18 11:26:00 CET 2010


When loading from json datas with simplejson, strings are unicode . 


Le Thu, 18 Nov 2010 11:22:30 +0100,
Romaric DEFAUX <rde at audaxis.com> a écrit :

> Hi again,
> 
> I try simplejson, but I have a problem. (I just replace pickle 
> everywhere by simplejson)
> 
> Here's a test I did :
> # python
> Python 2.5.2 (r252:60911, Jan 20 2010, 21:48:48)
> [GCC 4.2.4 (Ubuntu 4.2.4-1ubuntu3)] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
>  >>> import simplejson
>  >>> disk_list = []
>  >>> disk = {}
>  >>> disk['name'] = "disk1"
>  >>> disk['size'] = "52428800"
>  >>> disk_list.append(disk)
>  >>> print disk_list
> [{'name': 'disk1', 'size': '52428800'}]
>  >>> disk = {}
>  >>> disk['name'] = "disk2"
>  >>> disk['size'] = "647648"
>  >>> disk_list.append(disk)
>  >>> print disk_list
> [{'name': 'disk1', 'size': '52428800'}, {'name': 'disk2', 'size': '647648'}]
>  >>> disk_list_json = simplejson.dumps(disk_list)
>  >>> print disk_list_json
> [{"name": "disk1", "size": "52428800"}, {"name": "disk2", "size": "647648"}]
>  >>> disk_list2 = simplejson.loads(disk_list_json)
>  >>> print disk_list2
> [{u'name': u'disk1', u'size': u'52428800'}, {u'name': u'disk2', u'size': 
> u'647648'}]
>  >>> print repr(disk_list_json)
> '[{"name": "disk1", "size": "52428800"}, {"name": "disk2", "size": 
> "647648"}]'
> 
> Explanation :
> I "dumps" with json a list of dictionnaries into disk_list_json.
> When I "loads" it, I don't get my list of dictionnaries like before (see 
> disk_list2). It adds "u" letter everywhere.
> Why ?
> Thanks for help !
> 
> Romaric Defaux
> 
> Le 18/11/2010 09:43, Michael Ricordeau a écrit :
> > Hi,
> >
> > you can use json for passing list and dict .
> > Pickle is dangerous .
> >
> > Instead of pickle.loads/pickle.dumps use json.loads and json.dumps
> > (using stdlib json in python>= 2.6 or simplejson in python<  2.6)
> >
> > Regards
> >
> >
> >
> > Le Thu, 18 Nov 2010 09:29:00 +0100,
> > Romaric DEFAUX<rde at audaxis.com>  a écrit :
> >
> >    
> >> Le 17/11/2010 18:52, geremy condra a écrit :
> >>      
> >>> On Wed, Nov 17, 2010 at 6:44 AM, Romaric DEFAUX<rde at 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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