TypeError: cannot sort files and objects

Question

TypeError: cannot sort files and objects

I am trying to make this following code possible. But I keep getting "TypeError: can not pickle file objects" error. I am new to python and webpy. Can someone tell me how I can achieve this code.

import web 
import subprocess

web.config.debug = False
urls = ( 
   "/start", "start",
   "/end", "end"
)
app = web.application(urls, locals())
s = web.session.Session(app, web.session.DiskStore('sessions'), initializer={"p": None})

class start:
    def GET(self):
        s.p = subprocess.Popen(['ls', '-a'], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        return ""

class end:
    def GET(self):
        out, err = s.p.communicate();
        return out 

if __name__ == "__main__":
    app.run()

the error I see python27 / lib / python2.7 / copy_reg.py ", line 70, in _reduce_ex raise TypeError," cannot detect the number of% s objects "% base. name TypeError: cannot sort file objects

+3

python web.py session pickle

Aditya May 31 '15 at 8:30 am

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1 answer

boaz_shuster · Accepted Answer · 2015-05-31T09:19:44+0000

I am, myself, new to webpy. However, after some "research", it seems that the object webpy

cannot [1]. So let's try the next approach - that is, create it in a response and print its output.pickle

subprocess.Popen

end

In other words:

import web 
import subprocess

web.config.debug = False
urls = ( 
   "/start", "start",
   "/end", "end"
)
app = web.application(urls, locals())
s = web.session.Session(
        app, web.session.DiskStore('sessions'), initializer={"p": None})

class start:
    def GET(self):
        s.p = ['ls', '-a']
        return ""

class end:
    def GET(self):
        out, err = subprocess.Popen(
                       s.p , stdout=subprocess.PIPE,
                       stderr=subprocess.PIPE).communicate()
        s.kill() # kill the session.
        return out 

if __name__ == "__main__":
    app.run()

[1] As you can see:

import pickle
import subprocess

with open('bla', 'wb') as f:
    pickle.dump(subprocess.Popen(['ls'],
                stdout=subprocess.PIPE,
                stderr=subprocess.PIPE), f)

subprocess.Popen

returns a file descriptor and from the trace I conclude that pickle

I cannot serialize file descriptors.

Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
  File "/usr/lib64/python2.7/pickle.py", line 1370, in dump
    Pickler(file, protocol).dump(obj)
  File "/usr/lib64/python2.7/pickle.py", line 224, in dump
    self.save(obj)
  File "/usr/lib64/python2.7/pickle.py", line 331, in save
    self.save_reduce(obj=obj, *rv)
  File "/usr/lib64/python2.7/pickle.py", line 419, in save_reduce
    save(state)
  File "/usr/lib64/python2.7/pickle.py", line 286, in save
    f(self, obj) # Call unbound method with explicit self
  File "/usr/lib64/python2.7/pickle.py", line 649, in save_dict
    self._batch_setitems(obj.iteritems())
  File "/usr/lib64/python2.7/pickle.py", line 663, in _batch_setitems
    save(v)
  File "/usr/lib64/python2.7/pickle.py", line 306, in save
    rv = reduce(self.proto)
  File "/usr/lib64/python2.7/copy_reg.py", line 70, in _reduce_ex
    raise TypeError, "can't pickle %s objects" % base.__name__
TypeError: can't pickle file objects

Also, the documentation mentions that it only supports booleans, integers, floating point numbers, complex numbers, strings, byte objects, byte arrays, and None. So it seems hopeless. pickle

EDIT

If you insist on creating a process file descriptor when you receive a request start

from a client, you can use a dictionary to map the session to a file descriptor.

It should be like this:

s = web.session.Session(
        app, web.session.DiskStore('sessions'), initializer={"p": None})
session_map = {}

class start:
    def GET(self):
        session_map[s] = subprocess.Popen(['ls', '-a'],
                                          stdout=subprocess.PIPE,
                                          stderr=subprocess.PIPE)
        return ""

class end:
    def GET(self):
        out, err = session_process[s].communicate()
        session_process.pop(s, None)
        s.kill
        return out

TypeError: cannot sort files and objects

EDIT

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