Author: masnun

Python

Building Command Line Interface using Python

Post author By masnun
Post date October 1, 2009
1 Comment on Building Command Line Interface using Python

Creating a command line interface with Python is pretty easy 🙂 Python has a built in module — “cmd” to assist you in building a command line interface of your application.

In this example, I have created a dummy shell that uses the os.system() call to execute a command in terminal. Here is the code explanations:

First, we import the modules required for the demo. Then, we create a subclass of the cmd.Cmd class. Then we define the commands by defining and naming methods in “do_” in scheme. When the user types something like “ “, the do_ is called and the parameters are passed as a single string. If a method returns True, the shell exits. We can define help docs by naming methods in “help_” scheme. do_EOF handles the “end of file” character. That’s this function is called when we press Ctrl+D on Linux shell. By default, pressing the enter key without any command executes the last command. We override this behaviour by re-defining the emptyline() method.

For a complete reference, please consult the python manual.

Here’s the source code of the program I wrote:
Type “shell date” or any other commands to try it out.
Type “help” to get help 🙂

import cmd
import os
class shell_cmd(cmd.Cmd):
	def do_shell(self, s):
		os.system(s)
	def emptyline(self):
		pass

	def help_shell(self):
		print "Type -> <shell> <command>"
		print "to execute the <command> in terminal"

	def help_help(self):
		print "Type -> <help>  to see available commands"
		print "Type -> <help> <command> to get detailed doc"

	def help_exit(self):
		print "Type -> <exit> or press <ctrl+D> to terminate the shell"

	def help_EOF(self):
		print "Press <ctrl+D> to terminate the shell"


	def do_exit(self,s):
		return True
	def do_EOF(self,s):
		print ""
		return True

shell = shell_cmd()
shell.cmdloop("\n \n maSnun's python shell \n ---------- \n Type: <help> to get help \n ---------- \n Created by: maSnun :) \n https://masnun.com \n masnun@gmail.com\n ---------- \n")

import cmd

import os

class shell_cmd(cmd.Cmd):

def do_shell(self, s):

os.system(s)

def emptyline(self):

pass

def help_shell(self):

print "Type -> <shell> <command>"

print "to execute the <command> in terminal"

def help_help(self):

print "Type -> <help> to see available commands"

print "Type -> <help> <command> to get detailed doc"

def help_exit(self):

print "Type -> <exit> or press <ctrl+D> to terminate the shell"

def help_EOF(self):

print "Press <ctrl+D> to terminate the shell"

def do_exit(self,s):

return True

def do_EOF(self,s):

print ""

return True

shell = shell_cmd()

shell.cmdloop("\n \n maSnun's python shell \n ---------- \n Type: <help> to get help \n ---------- \n Created by: maSnun :) \n https://masnun.com \n masnun@gmail.com\n ---------- \n")

PHP

PHP Text Flipper Library

Have you seen some cool webapps where you can write English texts upside down?

I have found out the techniques. They just use some Unicode characters to do the trick. Unicode has a vast collection of characters and you have to find the right one that looks like an upside down english character.

I have written a PHP library to do the job .
Visit the demo at:
https://masnun.com/flipper/ 😀
Download the Library at:
http://masnun.googlecode.com/files/flipper.php 🙂

Here’s the source code of the demo:

<?php
header("Content-type: text/html; charset='utf-8'");
echo "<html><head>
<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\">
<title>maSnun's string flipper</title><body>
<form action=\"index.php\" method=\"POST\">
<b>Enter a string:</b><br />
<input type=\"text\" name=\"string\" value=\"{$_POST['string']}\">
<input type=\"submit\" value=\"flipNow()\">
</form><br /><br />";

if(isset($_POST['string'])) {
include('flipper.php');
$stringFlipper = new StringFlipper;
$str = $stringFlipper->flipString($_POST['string']);
echo "<b>Flipped String:</b><input type=\"text\" value=\"$str\"> <br /><br />";

}

echo "</body><html>";

?>

<?php

header("Content-type: text/html; charset='utf-8'");

echo "<html><head>

<title>maSnun's string flipper</title><body>

<b>Enter a string:</b><br />

</form><br /><br />";

if(isset($_POST['string'])) {

include('flipper.php');

$stringFlipper = new StringFlipper;

$str = $stringFlipper->flipString($_POST['string']);

echo "<b>Flipped String:</b><input type=\"text\" value=\"$str\"> <br /><br />";

}

echo "</body><html>";

PS: PHP and web browsers have some issues regarding Unicode data. So please ensure the “Content-type” is set to “text/html” and the charset is “utf-8” 🙂

Happy flipping 😀

PHP

PHP DOM and XPATH

After checking out beautifulsoup in Python, I became very curious to know what we have in PHP for accessing the DOM nodes of a html document. After exploring a while, I found out the PHP DOM and XPATH.

Here’s a little example:

masnun.html – The HTML file

<html>
<head>
<title>
DOM Test
</title>
<body>
<font size="3">maSnun <a href="https://masnun.com">masnun.com</a></font>
</body>
</html>

<html>

<head>

<title>

DOM Test

</title>

<body>

<font size="3">maSnun <a href="https://masnun.com">masnun.com</a></font>

</body>

</html>

Now we use PHP to access the document:

#!/usr/bin/php

<?php
$dom = new DOMDocument; // construct a DOMDocument element
$dom->loadHTML(file_get_contents("masnun.html")); // load the contents of the html file
$xpath = new DOMXPath($dom); // build a new DOMXPath element with the loaded DOMDocument

// define the search pattern now
// here we search for every <a> tag
// inside <font> tags which have a
// attribute, size = 3
// the <font> tags would be under
// the <body> tag

// the pattern is quite easy to understand
// and I find it quite identical to the linux
// filesystem structure

$pattern = "/html/body/font[@size=3]/a";


$res = $xpath->evaluate($pattern); // use the evaluate method to get a DOMElement object

//Now, lets play with the objects
// Please see the DOMElement part of PHP Manual
// to get the details on the methods I have used here

for($i=0;$i < $res->length; $i++) { echo $res->item($i)->getAttribute("href"); }

?>

#!/usr/bin/php

<?php

$dom = new DOMDocument; // construct a DOMDocument element

$dom->loadHTML(file_get_contents("masnun.html")); // load the contents of the html file

$xpath = new DOMXPath($dom); // build a new DOMXPath element with the loaded DOMDocument

// define the search pattern now

// here we search for every <a> tag

// inside <font> tags which have a

// attribute, size = 3

// the <font> tags would be under

// the <body> tag

// the pattern is quite easy to understand

// and I find it quite identical to the linux

// filesystem structure

$pattern = "/html/body/font[@size=3]/a";

$res = $xpath->evaluate($pattern); // use the evaluate method to get a DOMElement object

//Now, lets play with the objects

// Please see the DOMElement part of PHP Manual

// to get the details on the methods I have used here

for($i=0;$i < $res->length; $i++) { echo $res->item($i)->getAttribute("href"); }

That’s it, pretty simple and easy ! 😀

Recent Posts

Recent Comments

Archives

Categories