I need create a real-time client-server application (like Dropbox).
Client application should listen one channel of data.
I can do it with python?
What solutions, technologies, modules exists in python for this task?
Yes, you can do it with Python.  You could do it with PHP, Bash, JavaScript, Ruby, C, C++, C#, Java, Haskell, Go, Assembler, Perl, Pascal, Oberon, Prolog, Lisp, or Caml if you like too.
Most interfaces to sockets fall into one of two categories:

Blocking interfaces
Event interfaces

There is no way to know which is right for your application without knowing what your application does.
python real-time client-server application