When to use '__main__' ?

When your script is run it as a command to the Python interpreter: python your_script.py all of the code that is at indentation level 0 gets executed and functions and classes that are defined but none of their code gets ran. If will then read :

if __name__ == '__main__'

so it will execute the block standalone. In other words, when you use the __main__ this means the module is being run standalone

if __name__ == '__main__':
 print '... is being run by itself'
else:
 print '... is being run directly'

The wx module - tutorial 02 - class and button function

In this tutorial I will show how to use wx using one class example.

This tutorial is based on some code from a previous tutorial.

Let's see the source code:

import wx

class my_gui_form(wx.Frame):
 def __init__(self):
  wx.Frame.__init__(self, None, -1, 'Example windows wx with Python',size=(300,150))
  wx.StaticText(self, -1, 'User', (10, 20))
  user = wx.TextCtrl(self, -1, '',  (110, 20), (160, -1))
  wx.StaticText(self, -1, 'Password', (10, 50))
  passwd = wx.TextCtrl(self, -1, "", (110,50),(160, -1), style=wx.TE_PASSWORD)
  conn = wx.Button(self, -1,'Connect',(10,80),(260, -1))
  conn.Bind(wx.EVT_BUTTON, self.onButton)
  
 def onButton(self, event):
  button = event.GetEventObject()
  print "The button's label is: " + button.GetLabel()
  print "The button's name is: " + button.GetName()

if __name__ == "__main__":
 app1 = wx.App(False)
 frame = my_gui_form()
 frame.Show()
 app1.MainLoop()

First , I make a class named my_gui_form.

Also I add the self on each function from this class.

I make the onButton function to working with the button Connect.

I read the event of the button with event.GetEventObject.

The link with this function is make by:

conn.Bind(wx.EVT_BUTTON, self.onButton)

Source Code Optimization:

The -1 from is can replace with wx.ID_ANY.

The wx module - tutorial 01

Install wx python module using root account.

# yum install wxPython.i686 

The most simple example is show bellow.

$python 
Python 2.7.2 (default, Oct 27 2011, 01:36:46) 
[GCC 4.6.1 20111003 (Red Hat 4.6.1-10)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import wx
>>> app1=wx.App()
>>> frame=wx.Frame(None,-1,'Example windows wx with Python')
>>> frame.Show()
True
>>> app1.MainLoop()
>>> 

Let's see the result of this python script:

Let's take a look at the source code.

import wx

This line of code allows us to use wx python module.

app1=wx.App()

This line defines our application named app1.

A frame is a window whose size and position can be changed by the user.

Let's see:

frame=wx.Frame(None,-1,'Example windows wx with Python')
frame.Show()

Finally, processing and display function in main function.

app1.MainLoop()

Bellow, we can see a more complex example, where we find : labels , two editbox and one button.

The event-processing function button has not been implemented.

import wx
app1=wx.App()
frame=wx.Frame(None,-1,'Example windows wx with Python',size=(300,150))
wx.StaticText(frame, -1, 'User', (10, 20))
user = wx.TextCtrl(frame, -1, '',  (110, 20), (160, -1))
wx.StaticText(frame, -1, 'Password', (10, 50))
passwd = wx.TextCtrl(frame, -1, "", (110,50),(160, -1), style=wx.TE_PASSWORD)
conn = wx.Button(frame, -1,'Connect',(10,80),(260, -1))
frame.Show()
app1.MainLoop()

Let's see the result of this python script:

I will illustrate how this working in a future tutorial.

Simple socket client with python

I made version of client server socket program.
This example was presented in a previous post named Simple socket server with python.
The program is simple, the algorithm uses connection and some data processing input from the console.
I used the same test method as for the program created in C + +.
The program breaks the connection when the client enter: end connection
Here's the source code:

import socket
import sys

HOST = 'your-IP'
PORT = 5001             
s = None
for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC, socket.SOCK_STREAM):
    af, socktype, proto, canonname, sa = res
    try:
 s = socket.socket(af, socktype, proto)
    except socket.error, msg:
 s = None
 continue
    try:
 s.connect(sa)
    except socket.error, msg:
 s.close()
 s = None
 continue
    break
if s is None:
    print 'could not open socket'
    sys.exit(1)
data=''
while data<>'end connection':
 data=raw_input()
 s.send(data)
 data = s.recv(1024)

s.close()
print 'Received', repr(data)

Simple socket server with python

It is a small example I created a server to see how it works with a client program made ​​in C + +.
I can not say that it really is a server that does not accept multiple connections.
The script worked stable sending manually entered text.
I not checked the stability for the large data streams.
It is also normal because as you see below is just one example.

import socket 
HOST = 'your-IP'
PORT = 5001
s= socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST,PORT))
s.listen(1)
conn,addr=s.accept()
print 'Conectat la =',addr
while 1:
 data = conn.recv(1024)
 if not data : 
  break
 conn.send(data)
 print data
conn.close()

The distance between me and the server was considerable.

The python module : spynner

On official site we see the description of the spynner module :

Spynner is a stateful programmatic web browser module for Python with Javascript/AJAX support based upon the QtWebKit framework.

The module is esay to use. With few lines of codes you can use this module to parse ,view and use web pages.

from __future__ import division
from __future__ import unicode_literals
from __future__ import print_function
import re
import spynner
from BeautifulSoup import BeautifulSoup
import time
br = spynner.Browser()
br.create_webview()
br.show()
br.set_html_parser(BeautifulSoup)
br.load("http://www.linuxtoday.com/")
br.fill("input[name=username]", "name")
br.fill("input[name=passwd]", "pass")
#br.simulate_click("input[name=submit]",True)
#br.select("IBESNA~US")
#br.select('option[value="IBESNA~US"]')
#br.wait_page_load()
br.browse()

The result is show in the image bellow:

The source code is not complete. I make this simple example just to show us how to fill some editbox.
If you wantthen you can develop this script and make more useful.
I wait your answers with source code additions and new ways of using this python module.