JAGDEEP SINGH MALHI

Common Linux log files name and usage

2011-10-16T16:05:00.000+05:30

/var/log/message: General message and system related stuff
/var/log/auth.log: Authenication logs
/var/log/kern.log: Kernel logs
/var/log/cron.log: Crond logs (cron job)
/var/log/maillog: Mail server logs
/var/log/qmail/ : Qmail log directory (more files inside this directory)
/var/log/httpd/: Apache access and error logs directory
/var/log/lighttpd: Lighttpd access and error logs directory
/var/log/boot.log : System boot log
/var/log/mysqld.log: MySQL database server log file
/var/log/secure: Authentication log
/var/log/utmp or /var/log/wtmp : Login records files

Postfix Flush the Mail Queue commands

2011-10-14T08:35:00.000+05:30

# postfix flush

To see mail queue, enter:
# mailq

To remove all mail from the queue, enter:
# postsuper -d ALL

To remove all mails in the deferred queue, enter:
# postsuper -d ALL deferred

Install and Configure Mail Server on Linux System

2011-08-31T10:22:00.004+05:30

Mail Transfer Agent
A Mail Transfer Agent (MTA) is the program which receives and sends out the email from your server, and is therefore the key part. The default MTA in Ubuntu is Postfix, but exim4 is also fully supported and in the main repository.
Postfix - this guide explains how to set up Postfix.

In order to install Postfix with SMTP-AUTH and TLS, first install the postfix package from the Main repository using your favorite package manager. For example:
sudo aptitude install postfix

Configuration
From a terminal prompt:
sudo dpkg-reconfigure postfix
Insert the following details when asked (replacing server1.example.com with your domain name if you have one):
General type of mail configuration: Internet Site
NONE doesn't appear to be requested in current config
System mail name: server1.example.com
Root and postmaster mail recipient: <admin_user_name>
Other destinations for mail: server1.example.com, example.com, localhost.example.com, localhost
Force synchronous updates on mail queue?: No
Local networks: 127.0.0.0/8
Yes doesn't appear to be requested in current config
Mailbox size limit (bytes): 0
Local address extension character: +
Internet protocols to use: all

To configure the mailbox format for Maildir:
sudo postconf -e 'home_mailbox = Maildir/'
You may need to issue this as well:
sudo postconf -e 'mailbox_command ='
Note: This will place new mail in /home/username/Maildir so you will need to configure your Mail Delivery Agent to use the same path.

Configure Postfix to do SMTP AUTH using SASL (saslauthd):
sudo postconf -e 'smtpd_sasl_local_domain ='
sudo postconf -e 'smtpd_sasl_auth_enable = yes'
sudo postconf -e 'smtpd_sasl_security_options = noanonymous'
sudo postconf -e 'broken_sasl_auth_clients = yes'
sudo postconf -e 'smtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination'
sudo postconf -e 'inet_interfaces = all'
Next edit /etc/postfix/sasl/smtpd.conf and add the following lines:
pwcheck_method: saslauthd
mech_list: plain login

Generate certificates to be used for TLS encryption and/or certificate Authentication:
touch smtpd.key
chmod 600 smtpd.key
openssl genrsa 1024 > smtpd.key
openssl req -new -key smtpd.key -x509 -days 3650 -out smtpd.crt # has prompts
openssl req -new -x509 -extensions v3_ca -keyout cakey.pem -out cacert.pem -days 3650 # has prompts
sudo mv smtpd.key /etc/ssl/private/
sudo mv smtpd.crt /etc/ssl/certs/
sudo mv cakey.pem /etc/ssl/private/
sudo mv cacert.pem /etc/ssl/certs/

Configure Postfix to do TLS encryption for both incoming and outgoing mail:
sudo postconf -e 'smtp_tls_security_level = may'
sudo postconf -e 'smtpd_tls_security_level = may'
sudo postconf -e 'smtpd_tls_auth_only = no'
sudo postconf -e 'smtp_tls_note_starttls_offer = yes'
sudo postconf -e 'smtpd_tls_key_file = /etc/ssl/private/smtpd.key'
sudo postconf -e 'smtpd_tls_cert_file = /etc/ssl/certs/smtpd.crt'
sudo postconf -e 'smtpd_tls_CAfile = /etc/ssl/certs/cacert.pem'
sudo postconf -e 'smtpd_tls_loglevel = 1'
sudo postconf -e 'smtpd_tls_received_header = yes'
sudo postconf -e 'smtpd_tls_session_cache_timeout = 3600s'
sudo postconf -e 'tls_random_source = dev:/dev/urandom'
sudo postconf -e 'myhostname = server1.example.com' # remember to change this to yours

Authentication
The next steps are to configure Postfix to use SASL for SMTP AUTH.
First you will need to install the libsasl2-2, sasl2-bin and libsasl2-modules from the Main repository [i.e. sudo apt-get install them all].

We have to change a few things to make it work properly. Because Postfix runs chrooted in /var/spool/postfix we have change a couple paths to live in the false root. (ie. /var/run/saslauthd becomes /var/spool/postfix/var/run/saslauthd):

Note: by changing the saslauthd path other applications that use saslauthd may be affected.
First we edit /etc/default/saslauthd in order to activate saslauthd. Remove # in front of START=yes, add the PWDIR, PARAMS, and PIDFILE lines and edit the OPTIONS line at the end:
# This needs to be uncommented before saslauthd will be run automatically
START=yes
PWDIR="/var/spool/postfix/var/run/saslauthd"
PARAMS="-m ${PWDIR}"
PIDFILE="${PWDIR}/saslauthd.pid"

# You must specify the authentication mechanisms you wish to use.
# This defaults to "pam" for PAM support, but may also include
# "shadow" or "sasldb", like this:
# MECHANISMS="pam shadow"
MECHANISMS="pam"
# Other options (default: -c)
# See the saslauthd man page for information about these options.
#
# Example for postfix users: "-c -m /var/spool/postfix/var/run/saslauthd"
# Note: See /usr/share/doc/sasl2-bin/README.Debian
#OPTIONS="-c"

#make sure you set the options here otherwise it ignores params above and will not work
OPTIONS="-c -m /var/spool/postfix/var/run/saslauthd"
Note: If you prefer, you can use "shadow" instead of "pam". This will use MD5 hashed password transfer and is perfectly secure. The username and password needed to authenticate will be those of the users on the system you are using on the server.
Next, we update the dpkg "state" of /var/spool/postfix/var/run/saslauthd. The saslauthd init script uses this setting to create the missing directory with the appropriate permissions and ownership:

dpkg-statoverride --force --update --add root sasl 755 /var/spool/postfix/var/run/saslauthd

This may report an error that "--update given" and the "/var/spool/postfix/var/run/saslauthd" directory does not exist. You can ignore this because when you start saslauthd next it will be created.
Finally, start saslauthd:
sudo /etc/init.d/saslauthd start

Testing
To see if SMTP-AUTH and TLS work properly now run the following command:
telnet localhost 25
After you have established the connection to your postfix mail server type
ehlo localhost
If you see the lines
250-STARTTLS
250-AUTH
among others, everything is working.
Type quit to return to the system's shell.

Dovecot
Dovecot is a Mail Delivery Agent, written with security primarily in mind. It supports the major mailbox formats: mbox or Maildir. It is a simple and easy to install MDA. This guide explains how to set it up as an IMAP or POP3 server.

Installation
sudo apt-get install dovecot-imapd dovecot-pop3d
Configuration
To configure dovecot, you edit the file /etc/dovecot/dovecot.conf. There are a couple of choices which you need to make.

Once you have chosen, amend the following line in the file /etc/dovecot/dovecot.conf:
protocols = pop3 pop3s imap imaps

This enables those protocols when dovecot is started. Note: if you like, you can enable all the above protocols, or you can choose to enable just one or any number of them. In addition, add the following line in the "protocol pop3" section in the /etc/dovecot/dovecot.conf:
pop3_uidl_format = %08Xu%08Xv
To configure Dovecot for your mailbox format use (for maildir):
mail_location = maildir:~/Maildir
or, for mbox;
mail_location = mbox:~/mail:INBOX=/var/mail/%u

If you have trouble figuring out what you are using, it's most likely mbox. Maildir mails are almost always stored in ~/Maildir/ directory, which contains cur/, new/ and tmp/ subdirectories. In maildir each mail is stored in a separate file, while with the mbox format one file contains all mails in the mailbox. Files in /var/mail/ are nearly always mbox files, one for each user.
Maildir is better overall because it is more scalable and can't get corrupted so easily. So, if you have trouble figuring out what you should be using and have a choice, choose maildir.
To configure Dovecot for your mailbox format use (for maildir):
mail_location = maildir:~/Maildir
or, for mbox;
mail_location = mbox:~/mail:INBOX=/var/mail/%u
Note: You will also need to configure your MTA to transfer the incoming mail to this type of mailbox. (If you installed Postfix with instructions from the previous wiki, then choose mbox.)

Setting up Maildir

Do these steps ONLY if you want Maildir. This setup will put the Maildir in each user's home directory.
If you are using Postfix as your MTA, then add the following line to your /etc/postfix/main.cf file:
home_mailbox = Maildir/
Edit /etc/dovecot/dovecot.conf:
mail_location = maildir:/home/%u/Maildir
It's a good idea to pre-create the Maildir for future users:
sudo maildirmake.dovecot /etc/skel/Maildir
sudo maildirmake.dovecot /etc/skel/Maildir/.Drafts
sudo maildirmake.dovecot /etc/skel/Maildir/.Sent
sudo maildirmake.dovecot /etc/skel/Maildir/.Trash
sudo maildirmake.dovecot /etc/skel/Maildir/.Templates

Then, for an existing user:
sudo cp -r /etc/skel/Maildir /home/myuser/
sudo chown -R myuser:usergroup /home/myuser/Maildir
sudo chmod -R 700 /home/myuser/Maildir

Test
Start dovecot:
/etc/init.d/dovecot start
To check that it is running, type the command
ps -A | grep dovecot
You should see the dovecot service running. If you have enabled imap, or pop3, you can also try to log in with the commands
telnet localhost pop3
or
telnet localhost imap2
If you see something like the following, the installation has been successful.
$ telnet localhost pop3
Trying localhost...
Connected to localhost.
Escape character is '^]'.
+OK dovecot ready.
Or

$ telnet localhost 25
Trying 127.0.0.1...
Connected to localhost.localdomain (127.0.0.1).
Escape character is '^]'.
220 host.example.com ESMTP Postfix>
EHLO testdomain.com
250-host.example.com
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-ENHANCEDSTATUSCODES
250-8BITMIME
MAIL FROM: <user@testdomain.com>
250 2.1.0 Ok

RCPT TO: <local-user@example.com>
250 2.1.5 Ok
DATA
354 End data with <CR><LF>.<CR><LF>
Subject: Hello local-user
Hey local-user,
I just wanted to send some test mail to you :-)
.
250 2.0.0 Ok: queued as B95C8110064
QUIT

SSL
To configure Dovecot to use SSL, edit the file /etc/dovecot/dovecot.conf and amend the following lines (in some cases you may simply have to remove the # symbol from the beginning of the line):
ssl = yes
ssl_cert_file = /etc/ssl/certs/ssl-cert-snakeoil.pem
ssl_key_file = /etc/ssl/private/ssl-cert-snakeoil.key
The cert and key files are created automatically by Dovecot when you install it. (The keys mentioned above are actually the ones created by Postfix, however, but are suitable for use by Dovecot as well). Please note, that these keys are not signed and will give "bad signature" errors when connecting from a client. To avoid this, you can use commercial certificates, or even better, you can use your own SSL certificates. Hopefully, a guide will appear soon on this wiki on how to do this. In the meantime, here are some good ones: this guide on the Linux howto database, and this guide on the Debian Administration website.

Accessing from Outside
In order to access your mail server from another computer, you'll have to configure your firewall or router to allow connections to the server on the necessary ports:
IMAP - 143
IMAPS - 993
POP3 - 110
POP3S - 995
You'll also need to uncomment following line in /etc/dovecot/dovecot.conf:
listen = *
However, this method may cause conflicts with other servers already listening on other ports. The alternative (and probably more desirable) method, then, is to enable the specific listening ports for the protocols that are intended to be used. For example, for IMAP/IMAPS and POP3/POP3S, add to the correct protocol imap and protocol pop3 sections:
protocol imap {
listen = *:143
ssl_listen = *:993
...
}
protocol pop3 {
listen = *:110
ssl_listen = *:995
...
}
Squirrelmail Configuration
#sudo apt-get install squirrelmail

Squirrelmail has a very simple configuration menu. To run it, type:
sudo squirrelmail-configure
Apache Configuration
Squirrelmail comes with a sample apache configuration file in /etc/squirrelmail/apache.conf. You can copy this file to /etc/apache2/sites-available/squirrelmail with the command:
sudo cp /etc/squirrelmail/apache.conf /etc/apache2/sites-available/squirrelmail
then link it to the sites-enabled directory with the command:
sudo ln -s /etc/apache2/sites-available/squirrelmail /etc/apache2/sites-enabled/squirrelmail
Reload Apache Configuration:
sudo /etc/init.d/apache2 force-reload
If you ever wish to disable squirrelmail, you may simply delete the link in the site-enabled directory and Reload Apache's Configuration.

Roundcube

You'll need apache, and mysql installed. If they are not already installed the following command will install them.
$sudo aptitude install apache2
Run the following command to install roundcube
$sudo aptitude install roundcube roundcube-mysql
Configure roundcube
$dpkg-reconfigure roundcube-core
Next create a symbolic link to apache's document root, in this case /var/www
$sudo ln -s /usr/share/roundcube /var/www/roundcube
Restart Apache
$sudo service apache2 restart
Now browse to your machine at http://localhost/roundcube

Using patch and diff commands

2011-06-25T23:52:00.001+05:30

Creating patches with diff

Using diff is simple when you are working with single files. To create a patch for a single .
diff -u file1.txt new.txt > new_file.patch

For the directory, use following command:
diff -rupN directory1/ directory2/ > dir.patch

Apply patch

To apply a patch to a single file, change to the directory where the file is located and call patch:

patch < dir.patch

you can specify the file on the command line:

patch file.txt < dir.patch

To remove a patch, use the -R flag,

patch -R file.txt < file.patch

Network Manager Error : Device not managed (ubuntu)

2011-06-09T23:11:00.001+05:30

I am facing the problem with Network Manager shows error, with Wired and Wireless connection. When I click on tetwork connection, It show "device not managed".

Problem Solve :

> First run command on terminal to see the connection status sudo lshw -C Network

This show ouput like :

sudo lshw -C network

[sudo] password for jagdeep:

*-network DISABLED

description: Wireless interface

product: Centrino Wireless-N 1000

vendor: Intel Corporation

physical id: 0

bus info: pci@0000:03:00.0

logical name: wlan0

version: 00

serial: 8c:a9:82:5e:e4:e2

width: 64 bits

clock: 33MHz

capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless

configuration: broadcast=yes driver=iwlagn driverversion=2.6.38-8-generic firmware=128.50.3.1 build 13488 ip=192.168.1.34 latency=0 link=yes multicast=yes wireless=IEEE 802.11bgn

resources: irq:41 memory:f0500000-f0501fff

*-network DISABLED

description: Ethernet interface

product: AR8152 v1.1 Fast Ethernet

vendor: Atheros Communications

physical id: 0

bus info: pci@0000:04:00.0

logical name: eth0

version: c1

serial: 14:fe:b5:9a:33:ba

capacity: 100Mbit/s

width: 64 bits

clock: 33MHz

capabilities: pm msi pciexpress vpd bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd autonegotiation

configuration: autonegotiation=on broadcast=yes driver=atl1c driverversion=1.0.1.0-NAPI firmware=N/A latency=0 link=no multicast=yes port=twisted pair

resources: irq:44 memory:f0400000-f043ffff ioport:2000(size=128)

> If it Show connection is DISABLED than you need to edit following file /etc/NetworkManager/NetworkManager.conf or /etc/NetworkManager/nm-system-settings.conf

Code :

[main]

plugins=ifupdown, keyfile

[ifupdown]

managed=false

> Changing managed=false to managed=true if You want NM to manage

> Now back in the terminal type sudo killall nm-system-settings or sudo killall NetworkManger.

It works.

Some Basic Network Commands

$sudo /etc/init.d/networking restart

$ping google.com

$plog

$ifconfig

sudo pppoeconf (For setting Dail up Connection with username and password)

lsusb

$lspci

$lsmod

$iwlist

$sudo iwlist eth0 scan

$sudo lshw -C network

$rfkill list all

$rfkill unblock all

$sudo /etc/init.d/networking restart

PHP/MySql : Store file path in database, file in folder

2011-02-15T22:52:00.003+05:30

Create a file : form.html

<form action=addmembers.php method=post enctype="multipart/form-data">
<table border="0" cellspacing="0" align=center cellpadding="3" bordercolor="#cccccc">
<tr>
<td>File:</td>
<td><input type="file" name="filep" size=45></td>
</tr>
<tr>
<td colspan=2><p align=center>
<input type=submit name=action value="Load">
</td>
</tr>
</table>
</form>

Create another file : addmembers.php
<?

if ($_POST["action"] == "Load")
{
$folder = "images/";

move_uploaded_file($_FILES["filep"]["tmp_name"] , "$folder".$_FILES["filep"]["name"]);

echo "<p align=center>File ".$_FILES["filep"]["name"]."loaded...";

$result = mysql_connect("localhost", "****", "****") or die ("Could not save image name Error: " . mysql_error());
mysql_select_db("test") or die("Could not select database");
mysql_query("INSERT into picture (URL) VALUES('".$_FILES['filep']['name']."')");

if($result) { echo "Image name saved into database"; }
else {

//Gives and error if its not
echo "Sorry, there was a problem uploading your file.";
}
}
?>

For Display the file use code :

<?
//Retrieves data from MySQL
mysql_connect("localhost", "****", "*****") or die ("Could not save image name Error: " . mysql_error());
mysql_select_db("test") or die("Could not select database");
$data = mysql_query("SELECT `URL` FROM picture ") or
die(mysql_error());
//Puts it into an array
$file_path = 'http://localhost/test/images/';

while($row = mysql_fetch_assoc( $data ))
{//Outputs the image and other data
$src=$file_path.$row['URL'];
echo "<img src=".$src."> <br>";
}
?>

Comparison of Oracle, MySQL and Postgres DBMS

2010-12-14T23:10:00.003+05:30

Comparison are given below with include all the basic concept :-

Category	Problem	Assessment
Category	Problem	MySQL	Oracle8	Postgres
Elementary features	Basic data types	B	C	A
	SQL	C	B	B
	Declarative constraints	C	A	A
	Programming abstractions	D	A	C
	Generation of ids	C	A	A
	National chars	B	A	B
Transactions	Transactions	D	A	A
	Locks	D	A	A
	Multiuser access	C	A	C
Programming in DB	Stored procedures and triggers	D	A	A
Administration	Access control	A	A	B
	Backup	C	A	C
	Data migration	A	B	A
Portability and scalability	Portability	B	A	B
Portability and scalability	Scalability	B	A	C
Performance and VLDB	Query optimization	B	A	B
	Structures supporting optimization	D	A	B
	Support for OLAP	D	A	D
	Allocation of the disk space	C	A	C
	Size limits	B	A	C
	VLDB implementations	D	A	B
Distributed databases	Access to multiple databases	C	A	C
Distributed databases	Heterogeneous systems support	D	B	D
Special data types	Large objects	B	A	C
	Post-relational extensions	D	A	B
	Support for special data types	D	A	C
Application development and interfaces	Embedded SQL	D	A	B
	Standard interfaces	B	A	B
	Additional interfaces	A	A	A
	Web technology	B	A	B
	XML	D	A	D
	CASE	D	A	D
Reliability	Recovery	C	A	C
Commercial issues	Prices	A	D	A
	Technical support	C	B	D
	Position on the market	D	A	D

Conclusion : Compare your Project requirements with DBMS. It depend on your application or project which is suitable for your project.

TMUX – The Terminal Multiplexer

2010-11-28T01:02:00.004+05:30

tmux is similar to screen as it lets you run numerous TTY’s in the same terminal window. It enables a number of terminals to becreated, accessed, and controlled from a single screen. tmux may be detached from a screen and continue running in the background, then later reattached.

Usecommand for attach after detached to reattached.

$ tmux attach

When tmux is started it creates a new session with a single window and displays it on screen. A status line at the bottom of the screen shows information on the current session and is used to enter interactive

commands.

Advantages

A clearly defined cilent/server model (windows are their own clients which allows flexibility on how you handle windows. You can attach and detach different windows in different sessions without any issues)
Consistent, well-documented command interface. (You can use the same commands interactively as in the .tmux.conf file, more on that later)
Easily scriptable
Multiple paste buffers
Vi & Emacs keybindings
A more usable status line syntax (which also allows you to embed the output of a shell command, handy indeed.

Basic Commands

Ctrl-b c Create new window
Ctrl-b d Detach current client
Ctrl-b l Move to previously selected window
Ctrl-b n Move to the next window
Ctrl-b p Move to the previous window
Ctrl-b & Kill the current window
Ctrl-b , Rename the current window
Ctrl-b % Split the current window into two panes
Ctrl-b q Show pane numbers (used to switch between panes)
Ctrl-b o Switch to the next pane
Ctrl-b ? List all key bindings

Ctrl-b n (Move to the next window)
Ctrl-b p (Move to the previous window)
Ctrl-b l (Move to the previously selected window)
Ctrl-b w (List all windows / window numbers)
Ctrl-b <window number> (Move to the specified window number, the default bindings are from 0 – 9)

Ctrl-b % (Split the window vertically)
Ctrl-b : “split-window” (Split window horizontally)
Ctrl-b o (Goto next pane)
Ctrl-b q (Show pane numbers, when the numbers show up type the key to goto that pane)
Ctrl-b { (Move the current pane left)
Ctrl-b } (Move the current pane right)

Sphinx Auto genrate documentation for Django Project

2010-11-18T11:27:00.002+05:30

Sphinx is a tool that makes it easy to create intelligent and beautiful documentation.

Installing your doc directory

python -c 'import sphinx'

If that fails grab the latest version of and install it with:

> sudo easy_install sphinx

Now you are ready to build a template for your docs, using sphinx-quickstart:

> sphinx-quickstart

accepting most of the defaults. I choose “sampledoc” as the name of my project. cd into your new directory and check the contents:

home:~/tmp/sampledoc> ls
Makefile      _static         conf.py
_build                _templates      index.rst

The index.rst is the master ReST for your project, but before adding anything, let’s see if we can build some html:

make html

If you now point your browser to _build/html/index.html, you should see a basic sphinx site.

This will create your basic documentation project. You should have a file layout something like this:

Makefile
_build
_static
_templates
conf.py
index.rst

.. and you build your documentation simply using the auto-generated build file:
make html

This will now generate a blank skeleton of your documentation ... not really very useful.

Adding some modules

Lets now add some modules for auto-documentation. Lets assume we are have an app called myapp, and we have a models.py module which we want to edit.

In your documentation folder, create a directory called modules, then create a new file called models.rst. e.g.:
mkdir modules
nano modules/models.py

Now edit models.py so that it looks something like this:

myapp.models
==================

.. automodule:: myapp.models
   :members:

now, if we run:
make html

you should get output something like the following:

(test)-bash-3.2$ make html
sphinx-build -b html -d _build/doctrees   . _build/html
Running Sphinx v0.6.3
loading pickled environment... done
building [html]: targets for 0 source files that are out of date
updating environment: 1 added, 0 changed, 0 removed
reading sources... [100%] modules/model
looking for now-outdated files... none found
pickling environment... done
checking consistency... /Users/Me/Projects/MyApp/docs/modules/model.rst:: WARNING: document isn't included in any toctree
done
preparing documents... done
writing output... [100%] modules/model
writing additional files... genindex search
copying static files... done
dumping search index... done
dumping object inventory... done
build succeeded, 1 warning.

Note the warning in bold. We need to add a link to our documentation from a page. so .. open up index.rst in your documentation root dir, and add something like this:

Modules
==================

.. toctree::
   :maxdepth: 2

   modules/model.rst

running it again, you should now get a new error:

/Users/Me/Projects/MyApp/docs/modules/models.rst:4: (WARNING/2) autodoc can't import/find module 'myapp.model', it reported error: "No module named myapp.model", please check your spelling and sys.path

Configuring your django app

We do as above opening my conf.py file, it now looks something like this:

# If extensions (or modules to document with autodoc) are in another directory,
# add these directories to sys.path here. If the directory is relative to the
# documentation root, use os.path.abspath to make it absolute, like shown here.
sys.path.append('/Users/Me/Projects/MyApp/src/myapp')
#setup django
import settings
from django.core.management import setup_environ
setup_environ(settings)

.. and finally, we run:
make html

.. and great success, I now have autodocumented modules in my documentation.

For more Detail Click Here

Django-Cms Installation error "PageAdmin.exclude' refers to field 'created_by' that is missing from"

2010-10-25T21:20:00.004+05:30

Error :

Error "ImproperlyConfigured at / 'PageAdmin.exclude' refers to field 'created_by' that is

missing from the form" 
Problem Solve :
Fixed this error 
by just setting editable=False on created_by and changed_by and removing all fields from

PageAdmin.exclude (the other fields already were editable=False)
Edit two files to fix this error

Edit file: cms/admin/pageadmin.py
Line no. 65 approximately. 
 revision_form_template = "admin/cms/page/revision_form.html"
Change this line
-    exclude = ['created_by', 'changed_by', 'lft', 'rght',

'tree_id', 'level']
by 
+  exclude = []

 mandatory_placeholders = ('title', 'slug', 'parent', 'site',

'meta_description', 'meta_keywords', 'page_title', 'menu_title')

top_fields = [] 
 general_fields = ['title', 'slug', ('published', 'in_navigation')]
     
Edit File : cms/admin/pagemodel.py
line no. 40 approximately 
template_choices = [(x, _(y)) for x,y in settings.CMS_TEMPLATES]
change following lines 
-   created_by = models.CharField(_("created by"), max_length=70)
-    changed_by = models.CharField(_("changed by"), max_length=70)
by 
+    created_by = models.CharField(_("created by"),

max_length=70, editable=False)
+    changed_by = models.CharField(_("changed by"),

 max_length=70, editable=False)
     parent = models.ForeignKey('self', null=True, blank=True,

 related_name='children', db_index=True)
     creation_date = models.DateTimeField(editable=False,

 default=datetime.now)

Python : Virtual Python Environment builder

2010-09-20T22:18:00.001+05:30

Virtual Python Environment builder

virtualenv is a tool to create isolated Python environments.
The basic problem being addressed is one of dependencies and versions, and indirectly permissions. Imagine you have an application that needs version 1 of LibFoo, but another application requires version 2. How can you use both these applications? If you install everything into /usr/lib/python2.4/site-packages (or whatever your platform's standard location is), it's easy to end up in a situation where you unintentionally upgrade an application that shouldn't be upgraded.
Or more generally, what if you want to install an application and leave it be? If an application works, any change in its libraries or the versions of those libraries can break the application.
Also, what if you can't install packages into the global site-packages directory? For instance, on a shared host.
In all these cases, virtualenv can help you. It creates an environment that has its own installation directories, that doesn't share libraries with other virtualenv environments (and optionally doesn't use the globally installed libraries either).

The basic usage is:

$ python virtualenv.py ENV

The --no-site-packages Option
If you build with virtualenv --no-site-packages ENV it will not
inherit any packages from /usr/lib/python2.5/site-packages (or
wherever your global site-packages directory is).  This can be used if
you don't have control over site-packages and don't want to depend on
the packages there, or you just want more isolation from the global
system.
Using Virtualenv without bin/python
Sometimes you can't or don't want to use the Python interpreter
created by the virtualenv.  For instance, in a mod_python or mod_wsgi
environment, there is only one interpreter.

Luckily, it's easy.  You must use the custom Python interpreter to
install libraries.  But to use libraries, you just have to be sure
the path is correct.  A script is available to correct the path.  You
can setup the environment like:


activate_this = '/path/to/env/bin/activate_this.py'
execfile(activate_this, dict(__file__=activate_this))
This will change sys.path and even change sys.prefix, but alsoallow you to use an existing interpreter.  Items in your environmentwill show up first on sys.path, before global items.  However,this cannot undo the activation of other environments, or modules thathave been imported.  You shouldn't try to, for instance, activate anenvironment before a web request; you should activate oneenvironment as early as possible, and not do it again in that process.

Download Link

Using with ModWSGI (Python WSGI adapter module for Apache.)

A virtual Python environment is useful where it is necessary to run multiple WSGI applications which have conflicting requirements as to what version of a Python module or package needs to be installed. They can also be used where Apache and daemon mode of mod_wsgi is used to host WSGI applications for different users and each user wants to be able to separately install their own Python modules and packages.

Baseline Environment

The first step in using virtual environments with mod_wsgi is to point mod_wsgi at a baseline Python environment. This step is actually optional and if not done the main Python installation for the system, usually that which mod_wsgi was compiled for, would be used as the baseline environment.
Although the main Python installation can be used, especially in a shared environment where daemon mode of mod_wsgi is used to host WSGI applications for different users, it is better to make the baseline environment a virgin environment with an effectively empty 'site-packages' directory. This way there is no possibility of conflicts between modules and packages in a users individual Python virtual environment and the baseline environment.
To create a virgin environment using the 'virtualenv' program, the '--no-site-packages' option should be supplied when creating the environment.

$ cd /usr/local/pythonenv
$ virtualenv --no-site-packages BASELINENew python executable in BASELINE/bin/pythonInstalling setuptools............done.


Once the baseline Python environment has been created, the 
WSGIPythonHome directive should be defined within the global part of the
 main Apache configuration files. The directive should refer to the top 
level directory for the baseline environment created by the 'virtualenv'
 script.



WSGIPythonHome /usr/local/pythonenv/BASELINE

This Python environment will now be used as the baseline environment for all WSGI applications running under mod_wsgi, whether they be run in embedded mode or daemon mode.
There is no need to set the WSGIPythonHome directive if you want to use the main Python installation as the baseline environment.

For Applications

As an additional step, the WSGI script file described in the instructions would be modified to overlay the virtual environment for the application on top of the baseline environment. This would be done by adding at the very start of the WSGI script file the following:

import site
site.addsitedir('/usr/local/pythonenv/PYLONS-1/lib/python2.5/site-packages')

Note that in this case the full path to the 'site-packages' directory for the virtual environment needs to be specified and not just the root of the virtual environment.

Django : FileField() or ImageField()

2010-09-10T15:58:00.006+05:30

In Django its very simple to handle images and file field.

First you define the ImageField and FileField in Class.

for example :

Class File(models.Model):

image =models.ImageField(upload_to = 'path')

File =models.FileField(upload_to = 'path')

Using a FileField or an ImageField in a model takes a few steps:

In your settings file, you'll need to define MEDIA_ROOT as the full path to a directory where you'd like Django to store uploaded files. (For performance, these files are not stored in the database.) Define MEDIA_URL as the base public URL of that directory. For Example :MEDIA_ROOT = "/media/" , MEDIA_URL = 'http://localhost/media/'
Add the FileField or ImageField to your model, making sure to define the upload_to option to tell Django to which subdirectory of MEDIA_ROOT it should upload files.
All that will be stored in your database is a path to the file (relative to MEDIA_ROOT). You'll most likely want to use the convenience url attribute provided by Django. For example, if your ImageField is called file, you can get the absolute URL to your image in a template with {{ object.file.url }}.

Facing problem With ImageField() and FileField()
#python manage.py runserver
Error :Unhandled exception in thread started by

<function inner_run at 0x912348c>
Traceback (most recent call last):
  File "/usr/local/lib/python2.6/dist-packages/django/core/management

/commands/runserver.py", line 48, in inner_run
    self.validate(display_num_errors=True)
  File "/usr/local/lib/python2.6/dist-packages/django/core

/management/base.py", line 249, in validate raise CommandError

("One or more models did not validate:\n%s" % error_text)

django.core.management.base.CommandError:

One or more models did not validate:

ukieri.participants: "logo": To use ImageFields,

you need to install the Python Imaging Library.

Need to Install Python Imaging Library in server

Link for Download :http://www.pythonware.com/products/pil/

Second Problem is when i use {{ object.file.url }} in templates

Error in template is :

TemplateSyntaxError at /file/

Caught ValueError while rendering: The 'file' attribute has

no file associated with it.

The problem is solve to use IF statments in template :-

For example :-

{% if object.file %}

     <img src="{{ object.file.url }}" />

{% endif %}

Django application : Contact form

2010-09-04T22:24:00.000+05:30

Make the Contact form in django and also mail is send to admin .

forms.py
from django import forms
class ContactForm(forms.Form):
subject = forms.CharField(max_length=100)
email = forms.EmailField(required=False, label='Your e-mail address')
message = forms.CharField(widget=forms.Textarea)

View.py
from django.core.mail import send_mail
from django.http import HttpResponseRedirect
from django.shortcuts import render_to_response
from mysite.contact.forms import *
from django.template import RequestContext
from django.core.urlresolvers import reverse

def contact(request):
if request.method == 'POST':
form = ContactForm(request.POST)
if form.is_valid():
cd = form.cleaned_data
send_mail(
cd['subject'],
cd['message'],
cd.get('email', 'noreply@example.com'),
['singh.malhi22@gmail.com'],
)
return render_to_response('contact/thanks.html', {'form': form}, context_instance=RequestContext(request))
else:
form = ContactForm()
return render_to_response('contact/contact.html', {'form': form}, context_instance=RequestContext(request))

Template used :
output.html
<html>
<head>
<title>Contact us</title>
</head>
<body>
<link rel="stylesheet" type="text/css" href="/media/css/base.css" />
<h1>Contact us</h1>
<br>
{% if form.errors %}
<p style="color: red;">
Please correct the error{{ form.errors|pluralize }} below.
</p>
{% endif %}

<form action="" method="post">
{% csrf_token %}
<table>
{{ form.as_table }}
</table>
<input type="submit" value="Submit">
</form>
</body>
</html>
thanks.html
<html>
<head>
<title>Thanks</title>
</head>
<link rel="stylesheet" type="text/css" href="/media/css/base.css" />
<body>
<h1>Thanks</h1>
<br>
<h3>
You are in safe hands</h3>
</body>

Django application : Add two number using forms

2010-09-04T22:15:00.001+05:30

In Django its very simple to use the Django forms and create a very simple application using django forms.

Example: Add to number using Djnago forms

forms.py

from django import forms

class Output(forms.Form):

input1 = forms.FloatField()

input2 = forms.FloatField()

View.py

from django.http import HttpResponseRedirect

from django.shortcuts import render_to_response

from mysite.add.forms import *

from django.template import RequestContext

from django.core.urlresolvers import reverse

def add(request):

if request.method == 'POST':

form = Output(request.POST)

if form.is_valid():

cd = form.cleaned_data

input1 = cd['input1']

input2 = cd['input2']

output = input1 + input2

return render_to_response('add/output.html', {'form':form, 'input1': input1, 'input2':input2, 'output':output}, context_instance=RequestContext(request))

else:

form = Output()

return render_to_response('add/add.html', {'form': form}, context_instance=RequestContext(request))

Templates used

add.html

<html>

<head>

<title>Add Numbers</title>

</head>

<body>

<h1>Add Two Number Application </h1>

<br>

{% if form.errors %}

Please correct the error{{ form.errors|pluralize }} below.

</p>

{% endif %}

<h2> Fill Data

{% csrf_token %}

<table>

</table>

</form>

</body>

</html>

Output.html

<html>

<head>

<title>Thanks</title>

</head>

<body>

<h1>Thanks</h1>

<ul>

<li>First Value = {{input1}}

<li>Second Value = {{input2}}

<li> Output = {{output}}

</body>

Script :Find and Replace word from files.

2010-09-04T11:57:00.000+05:30

Script for Replace the One word with another word from all files place in present directory.

And also take backup of old files.

Step to use :

> Copy the below script in file

> Change the permission of file $chmod u+x filename

> Run this ./filename

> FindWord is word to find and replace With ReplaceWord

{

for fl in *.php; do

mv $fl $fl.old

sed 's/FindWord::/ReplaceWord::/g' $fl.old > $fl

done

}

Django Application : Create blog

2010-08-28T22:01:00.005+05:30

Django : A Simple Blog Example

First Create application in Django project directory

#python manage.py startapp blog
Edit your setting.py file and add appilcation code

For example :-

INSTALLED_APPS = (

'django.contrib.auth',

'django.contrib.contenttypes',

'django.contrib.sessions',

'django.contrib.sites',

'django.contrib.messages',

'mysite.blog',

# Uncomment the next line to enable the admin:

'django.contrib.admin',

)

also add Email host to send email.

by default its for locahost, but if your host have not configure EMAIL_HOST then you add this in settings.py

#EMAIL_HOST = "hostname.com"

Edit Urls in url.py main file in project Directory.

Urls.py

from django.conf.urls.defaults import *

from django.contrib import admin

admin.autodiscover()

urlpatterns = patterns('',

(r'^admin/', include(admin.site.urls)),

(r'^blog/', include('mysite.blog.urls')),

)

Edit model.py file in blog directory

Model.py

from django.db import models

from django.contrib.auth.models import User

from django.contrib import admin

from django.core.mail import send_mail

class Post(models.Model):

title = models.CharField(max_length=60)

body = models.TextField()

created = models.DateTimeField(auto_now_add=True)

def __unicode__(self):

return self.title

class Comment(models.Model):

created = models.DateTimeField(auto_now_add=True)

author = models.CharField(max_length=60)

body = models.TextField()

post = models.ForeignKey(Post)

def __unicode__(self):

return unicode("%s: %s" % (self.post, self.body[:60]))

def save(self, *args, **kwargs):

"""Email when a comment is added."""

if "notify" in kwargs and kwargs["notify"] == True:

message = "Comment was was added to '%s' by '%s': \n\n%s" % (self.post, self.author,

self.body)

from_addr = "no-reply@example.com"

recipient_list = ["jagdeepmalhi@gndec.ac.in"]

send_mail( "New comment added", message, from_addr, recipient_list)

if "notify" in kwargs: del kwargs["notify"]

super(Comment, self).save(*args, **kwargs)

Create one more file urls.py file in your blog directory and edit

Urls.py

from django.conf.urls.defaults import *

from mysite.blog.models import *

urlpatterns = patterns('mysite.blog.views',

(r"^(\d+)/$", "post"),

(r"^add_comment/(\d+)/$", "add_comment"),

(r"^delete_comment/(\d+)/$", "delete_comment"),

(r"^delete_comment/$", "delete_comment"),

(r"^month/(\d+)/(\d+)/$", "month"),

(r"", "main"),

)

Create the admin.py file in blog directory and edit file for admin Interface.

Admin.py
from mysite.blog.models import *

from django.contrib import admin

class PostAdmin(admin.ModelAdmin):

search_fields = ['title']

list_display = ("title", "created")

list_filter = ['title']

class CommentAdmin(admin.ModelAdmin):

list_display = ["post", "author", "created"]

list_filter = ['created']

admin.site.register(Post, PostAdmin)

admin.site.register(Comment, CommentAdmin)

Edit the Views.py file for create the user view.

Views.py
# Create your views here.

import time

from django.http import HttpResponseRedirect, HttpResponse

from django.shortcuts import get_object_or_404, render_to_response

from django.contrib.auth.decorators import login_required

from django.core.context_processors import csrf

from django.core.paginator import Paginator, InvalidPage, EmptyPage

from mysite.blog.models import *

from django.forms import ModelForm

class CommentForm(ModelForm):

class Meta:

model = Comment

exclude = ["post"]

def post(request, pk):

"""Single post with comments and a comment form."""

post = Post.objects.get(pk=pk)

comments = Comment.objects.filter(post=post)

d = dict(post=post, comments=comments, form=CommentForm(), user=request.user)

d.update(csrf(request))

return render_to_response("blog/post.html", d)

def delete_comment(request, pk=None):

"""Delete comment(s) with primary key `pk` or with pks in POST."""

if request.user.is_staff:

if not pk: pklst = request.POST.getlist("delete")

else: pklst = [pk]

for pk in pklst:

Comment.objects.filter(pk=pk).delete()

return HttpResponseRedirect(request.META["HTTP_REFERER"])

def add_comment(request, pk):

"""Add a new comment."""

p = request.POST

if p.has_key("body") and p["body"]:

author = "Anonymous"

if p["author"]: author = p["author"]

comment = Comment(post=Post.objects.get(pk=pk))

# save comment form

cf = CommentForm(p, instance=comment)

cf.fields["author"].required = False

comment = cf.save(commit=False)

# save comment instance

comment.author = author

notify = True

if request.user.username == "ak": notify = False

comment.save(notify=notify)

return HttpResponseRedirect("/django/blog/%s/" % pk)

def mkmonth_lst():

"""Make a list of months to show archive links."""

if not Post.objects.count(): return []

# set up vars

year, month = time.localtime()[:2]

first = Post.objects.order_by("created")[0]

fyear = first.created.year

fmonth = first.created.month

months = []

mnames = "January February March April May June July August September October November December"

mnames = mnames.split()

# loop over years and months

for y in range(year, fyear-1, -1):

start, end = 11, -1

if y == year: start = month

if y == fyear: end = fmonth-1

for m in range(start, end, -1):

months.append((y, m, mnames[m]))

return months

def month(request, year, month):

"""Monthly archive."""

posts = Post.objects.filter(created__year=year, created__month=month)

for post in posts:

post.num_comments = Comment.objects.filter(post=post).count()

return render_to_response("blog/list.html", dict(post_list=posts, user=request.user,

months=mkmonth_lst(), archive=True))

def main(request):

"""Main listing."""

posts = Post.objects.all().order_by("-created")

paginator = Paginator(posts, 2)

try: page = int(request.GET.get("page", '1'))

except ValueError: page = 1

try:

posts = paginator.page(page)

except (InvalidPage, EmptyPage):

posts = paginator.page(paginator.num_pages)

for post in posts.object_list:

post.num_comments = Comment.objects.filter(post=post).count()

return render_to_response("blog/list.html", dict(posts=posts, user=request.user,

post_list=posts.object_list, months=mkmonth_lst()))

Now Create the Templates for User and place these file in your templates Directory.

list.html

{% extends "blog/bbase.html" %}

{% block sidebar %}
   <style type="text/css">
   #sidebar { float: right; border: 1px dotted #ccc; padding: 4px; }
   a { margin-left: 15px; }
   </style>
   <div id="sidebar">
   Monthly Archive
   <p>
   {% for month in months %}
   {% ifchanged month.0 %} {{ month.0 }} <br /> {% endifchanged %}
   <a href="/django/blog/month/{{ month.0 }}/{{ month.1 }}/">{{ month.2 }}</a> <br />
   {% endfor %}
   </p>
   </div>
{% endblock %}

{% block content %}
   <style type="text/css">
   .main { margin-left: 25px; margin-top: 30px; }
   .time { font-size: 0.8em; margin-top: 2px; }
   .body { font-size: 1.1em; margin-top: 2px; }
   .commentlink { text-align: right; }
   .step-links a { font-size: 0.89em; }
   .title {
   font-size: 1.4em; margin-top: 20px; border-bottom: 1px solid #ccc;
   padding-left: 4px;
   }
   .messages { margin-left: 20px; }
   </style>
   <div class="main">

   
   {% if messages %}
   <ul class="messages">
   {% for message in messages %}
   <li{% if message.tags %} class="{{ message.tags }}"{% endif %}>{{ message }}</li>
   {% endfor %}
   </ul>
   {% endif %}

   
   <ul>
   {% for post in post_list %}
   <div class="title">{{ post.title }}</div>
   <ul>
   <div class="time">{{ post.created }}</div>
   <div class="body">{{ post.body|linebreaks }}</div>
   <div class="commentlink">
   <a href="/django/blog/{{ post.pk }}/">Comments ({{ post.num_comments }})</a></div>
   </ul>
   {% endfor %}
   </ul>

   
   {% if not archive and posts.object_list and posts.paginator.num_pages > 1 %}
   <div class="pagination" style="margin-top: 20px; margin-left: -20px; ">
   <span class="step-links">
   {% if posts.has_previous %}
   <a href= "?page={{ posts.previous_page_number }}">newer entries << </a>
   {% endif %}

   <span class="current">
    Page {{ posts.number }} of {{ posts.paginator.num_pages }}
   </span>

   {% if posts.has_next %}
   <a href="?page={{ posts.next_page_number }}"> >> older entries</a>
   {% endif %}
   </span>
   </div>
   {% endif %}

   </div>

{% endblock %}

bbase.html

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head> <title>{% block title %}Blog{% endblock %}</title> </head>

<body>
   <div id="sidebar"> {% block sidebar %} {% endblock %} </div>
   <div id="container">
   <div id="menu">
   {% block nav-global %}

   
   <h3>Jagdeep Singh</h3>
   {% if user.is_staff %}
<a href="/django/admin/">Admin</a> <a href="/django/admin/blog/post/add/">Add post</a>
   {% endif %}
   {% endblock %}
   </div>
   <div id="content">
   {% block content %}{% endblock %}
   </div>
   </div>
</body>
</html>

post.html

{% extends "blog/bbase.html" %}

{% block content %}
   <style type="text/css">
   .main { margin-left: 25px; margin-top: 30px; }
   .time { font-size: 0.8em; margin-top: 2px; }
   .comment { border: 1px solid #eee; padding: 4px; margin-bottom: 12px; }
   .body { font-size: 1.1em; margin-top: 2px; }
   .commentlink { text-align: right; }
   .step-links a { font-size: 0.89em; }
   .title {
   font-size: 1.4em; margin-top: 20px; border-bottom: 1px solid #ccc;
   padding-left: 4px;
   }
   .messages { margin-left: 20px; }

   #id_body { width: 500px; height: 250px; }
   #addc {
   width: 508px; background: #f5f5f5; padding: 3px; padding-bottom: 8px;
   border-bottom: 1px dotted #aaa; }
   #cform { background: #f5f5f5; width: 506px; padding: 4px; padding-bottom: 0px; }
   #submit { text-align: right; margin-right: 50px; width: 500px; margin-top: -5px; }

   ul { margin-bottom: 30px; }
   </style>
   <div class="main">

   
   {% if messages %}
   <ul class="messages">
   {% for message in messages %}
   <li{% if message.tags %} class="{{ message.tags }}"{% endif %}>{{ message }}</li>
   {% endfor %}
   </ul>
   {% endif %}

   
   <ul>
   <div class="title">{{ post.title }}</div>
   <ul>
   <div class="time">{{ post.created }}</div>
   <div class="body">{{ post.body }}</div>
   </ul>
   
   {% if comments %}
   <p>Comments:</p>
   {% endif %}

   <form action="/django/blog/delete_comment/" method="POST">{% csrf_token %}
   {% for comment in comments %}
   <div class="comment">
   <div class="time">{{ comment.created }} | {{ comment.author }}</div>
   <div class="body">{{ comment.body|linebreaks }}</div>
   {% if user.is_staff %}
   <input type="checkbox" name="delete" value="{{ comment.pk }}">
   <a href="/django/blog/delete_comment/{{ comment.pk }}/">delete</a>
   {% endif %}
   </div>
   {% endfor %}

   {% if user.is_staff and comments %}
   <p><input type="submit" value="Delete all selected"></p>
   <br />
   {% endif %}
   </form>

   <div id="addc">Add a comment</div>
   
   <form action="/django/blog/add_comment/{{ post.pk }}/" method="POST">{% csrf_token %}
   <div id="cform">
   Name: {{ form.author }}
   <p>{{ form.body|linebreaks }}</p>
   </div>
   <div id="submit"><input type="submit" value="Submit"></div>
   </form>
   </ul>

   </div>

{% endblock %}

Now enjoy your Blog on Django.

Automation Project is approved : Sourceforge.org And Sarovar.org

2010-08-14T10:42:00.002+05:30

Project registration for Automation has been approved.
Sarovar
links:-

http://sarovar.org/projects/automation/

http://automation.sarovar.org/
Sourceforge
links:-
http://automations.sourceforge.net/
http://sourceforge.net/projects/automations/

Check Django version

2010-08-10T15:08:00.000+05:30

Start the interactive Python interpreter
>>> import django

>>> print django.VERSION

Batch resize/Compress all images in a folder.

2010-08-09T23:23:00.001+05:30

Make a new file (not as root):
Run In Terminal
#gedit ~/.gnome2/nautilus-scripts/batch640x480

and then Add
#!/bin/sh
# Use this script to batch resize all images in a folder.
# First open the folder and then use the script.
for file in `ls -l`
do
name=`echo $file | cut -f1 -d.`
convert -geometry 680x500 -quality 65 $file ${name}_680x500.jpg
done

Save this file and make this file executable:
#chmod +x ~/.gnome2/nautilus-scripts/batch640x480
Go to the folder you'd like to resize. Then rightclick and find the 'batch640x480' script.
I use this script for resizing large amounts of photo's for a website

Drupal error : Function ereg() is deprecated

2010-08-08T16:59:00.000+05:30

Its is very simple to solve
open file includes/file.inc in drupal directory
Goto line no in which this error is show

where you can see something like this
elseif ($depth >= $min_depth && ereg($mask, $file))
Now add @ sign before ereg($mask, $file)
copy below line past this line
elseif ($depth >= $min_depth && @ereg($mask, $file))

Its works

Python : CMS

2010-08-05T22:26:00.001+05:30

Plone

A powerful, flexible Content Management solution that is easy to install, use and extend

Plone lets non-technical people create and maintain information for a public website or an intranet using only a web browser. Plone is easy to understand and use — allowing users to be productive in just half an hour — yet offers a wealth of community-developed add-ons and extensibility to keep meeting your needs for years to come.

Click here for further detail

Skeletonz

Skeletonz is a new content management system (CMS) based on Python. It differs from others by being simple, but yet very powerful and extensible. If you need a simple system that you and your users are going love then Skeletonz might be the solution you are looking for! The system is open source and released under GNU GPL.

Click here for further detail

MediaCore Video CMS

MediaCore Video CMS is an open source media focused content management system. It features video & audio support, YouTube & Vimeo integration, podcasting, iTunes RSS generation, user-submitted content, embedded media player, wysiwg edior, search, and is highly customizable. There is both a front-end for users and a back-end for administrators. It is built upon TurboGears, SQLAlchemy, MYSQL and runs with Apache, Fast_CGI or Mod_WSGI.

Click here for more detail

PyLucid

PyLucid is a lightweight CMS written in Python WSGI. No shell account is needed. To run PyLucid you need a standard Web server with Python (at least v2.3), CGI and mySQLdb.

More detail

Django - CMS

Django : Auto-Generate model.py file from PostgreSQL / MySQL / SQLite database

2010-08-04T14:27:00.000+05:30

inspectdb

django-admin.py inspectdb

Introspects the database tables in the database pointed-to by the NAME setting and outputs a Django model module (a models.py file) to standard output.
This feature is meant as a shortcut, not as definitive model generation. After you run it, you'll want to look over the generated models yourself to make customizations. In particular, you'll need to rearrange models' order, so that models that refer to other models are ordered properly.
Primary keys are automatically introspected for PostgreSQL, MySQL and SQLite, in which case Django puts in the primary_key=True where needed.
inspectdb works with PostgreSQL, MySQL and SQLite. Foreign-key detection only works in PostgreSQL and with certain types of MySQL tables.

Example :

Use command

#python manage.py inspectdb >>Models.py

this will automatically convert the django database into Models.py file .

Python : Accesssing a MySQL Database

2010-07-31T21:51:00.001+05:30

The MySQLdb module makes this task extremely easy:

import MySQLdb

# Create a connection object, then use it to create a cursor
Con = MySQLdb.connect(host="127.0.0.1", port=3306, 
    user="joe", passwd="egf42", db="tst")
Cursor = Con.cursor(  )

# Execute an SQL string
sql = "SELECT * FROM Users"
Cursor.execute(sql)

# Fetch all results from the cursor into a sequence and close the connection
Results = Cursor.fetchall(  )
Con.close(  )


Youcan get the MySQLdb module from http://sourceforge.net/projects/mysql-python. It is a plain and
simple implementation of the Python DB API 2.0 that is suitable for all  Python versions from 1.5.2 to2.2.1 and MySQL Versions 3.22 to 4.0. 



As with all other Python DB API implementations, you start by importing the module and calling the
connect function with suitable parameters. The keyword parameters you can pass when calling 
connect depend on the database involved: host (defaulting to the local host), user, passwd (password),
and db (name of the database) are typical. In the recipe, I explicitly pass the default local host's IP 
address and the default MySQL port (3306) to show that you can specify parameters explicitly even 
when you're passing their default values (e.g., to make your source code clearer and more readable 
and maintainable). 


The connect function returns a connection object, and you can proceed to call methods on this object 
until, when you are done, you call the close method. The method you most often call on a connection
object is cursor, which returns a cursor object, which is what you use to send SQL commands to the 
database and fetch the commands' results. The underlying MySQL database engine does not in fact support 
SQL cursors, but that's no problem—the MySQLdb module emulates them on your behalf quite transparently.
Once you have a cursor object in hand, you can call methods on it. The recipe uses the execute method to 
execute an SQL statement and the fetchall method to obtain all results as a sequence of tuples—one tuple 
per row in the result. There are many refinements you can use, but these basic elements of the Python DB 
API's functionality already suffice for many tasks. 



See Also : 


The Python/MySQL interface module (http://sourceforge.net/projects/mysql-python),
the Python DB API (http://www.python.org/topics/database/DatabaseAPI-2.0.html).

Python : Errors and Exceptions

2010-07-25T14:16:00.001+05:30

Until now error messages haven’t been more than mentioned, but if you have tried out the examples you have probably seen some. There are (at least) two distinguishable kinds of errors: syntax errors and exceptions.

Syntax Errors

Syntax errors, also known as parsing errors, are perhaps the most common kind of complaint you get while you are still learning Python:

>>> while True print 'Hello world'
  File "<stdin>", line 1, in ?
    while True print 'Hello world'
                   ^
SyntaxError: invalid syntax

he parser repeats the offending line and displays a little ‘arrow’ pointing at the earliest point in the line where the error was detected. The error is caused by (or at least detected at) the token preceding the arrow: in the example, the error is detected at the keyword print, since a colon (':') is missing before it. File name and line number are printed so you know where to look in case the input came from a script.

Exceptions

Even if a statement or expression is syntactically correct, it may cause an error when an attempt is made to execute it. Errors detected during execution are called exceptions and are not unconditionally fatal: you will soon learn how to handle them in Python programs. Most exceptions are not handled by programs, however, and result in error messages as shown here:

>>> 10 * (1/0)
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
ZeroDivisionError: integer division or modulo by zero
>>> 4 + spam*3
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
NameError: name 'spam' is not defined
>>> '2' + 2
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
TypeError: cannot concatenate 'str' and 'int' objects

Handling Exceptions

It is possible to write programs that handle selected exceptions. Look at the following example, which asks the user for input until a valid integer has been entered, but allows the user to interrupt the program (using Control-C or whatever the operating system supports); note that a user-generated interruption is signalled by raising the KeyboardInterrupt exception.

>>> while True:
...     try:
...         x = int(raw_input("Please enter a number: "))
...         break
...     except ValueError:
...         print "Oops!  That was no valid number.  Try again..."
...

The try statement works as follows.

First, the try clause (the statement(s) between the try and except keywords) is executed.
If no exception occurs, the except clause is skipped and execution of the try statement is finished.
If an exception occurs during execution of the try clause, the rest of the clause is skipped. Then if its type matches the exception named after the except keyword, the except clause is executed, and then execution continues after the try statement.
If an exception occurs which does not match the exception named in the except clause, it is passed on to outer try statements; if no handler is found, it is an unhandled exception and execution stops with a message as shown above.

Raising Exceptions

The raise statement allows the programmer to force a specified exception to occur. For example:

>>> raise NameError('HiThere')
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
NameError: HiThere

The sole argument to raise indicates the exception to be raised. This must be either an exception instance or an exception class (a class that derives from Exception).
If you need to determine whether an exception was raised but don’t intend to handle it, a simpler form of the raise statement allows you to re-raise the exception:

If you need to determine whether an exception was raised but don’t intend to handle it, a simpler form of the raise statement allows you to re-raise the exception:

>>> try:
...     raise NameError('HiThere')
... except NameError:
...     print 'An exception flew by!'
...     raise
...
An exception flew by!
Traceback (most recent call last):
  File "<stdin>", line 2, in ?
NameError: HiThere

Defining Clean-up Actions

The try statement has another optional clause which is intended to define clean-up actions that must be executed under all circumstances. For example:

>>> try:
...     raise KeyboardInterrupt
... finally:
...     print 'Goodbye, world!'
...
Goodbye, world!
KeyboardInterrupt

Predefined Clean-up Actions

Some objects define standard clean-up actions to be undertaken when the object is no longer needed, regardless of whether or not the operation using the object succeeded or failed. Look at the following example, which tries to open a file and print its contents to the screen.

for line in open("myfile.txt"):
    print line

The problem with this code is that it leaves the file open for an indeterminate amount of time after the code has finished executing. This is not an issue in simple scripts, but can be a problem for larger applications. The with statement allows objects like files to be used in a way that ensures they are always cleaned up promptly and correctly.

with open("myfile.txt") as f:
    for line in f:
        print line

Python : Input and Output

2010-07-25T13:55:00.001+05:30

Fancier Output Formatting

So far we’ve encountered two ways of writing values: expression statements and the print statement. (A third way is using the write() method of file objects; the standard output file can be referenced as sys.stdout
Luckily, Python has ways to convert any value to a string: pass it to the repr() or str() functions.
The str() function is meant to return representations of values which are fairly human-readable, while repr() is meant to generate representations which can be read by the interpreter (or will force a SyntaxError if there is not equivalent syntax). For objects which don’t have a particular representation for human consumption, str() will return the same value as repr(). Many values, such as numbers or structures like lists and dictionaries, have the same representation using either function. Strings and floating point numbers, in particular, have two distinct representations.
Some examples:

>>> s = 'Hello, world.'
>>> str(s)
'Hello, world.'
>>> repr(s)
"'Hello, world.'"
>>> str(1.0/7.0)
'0.142857142857'
>>> repr(1.0/7.0)
'0.14285714285714285'

Basic usage of the str.format() method looks like this:

>>> print 'We are the {} who say "{}!"'.format('knights', 'Ni')
We are the knights who say "Ni!"

The brackets and characters within them (called format fields) are replaced with the objects passed into the format() method. A number in the brackets refers to the position of the object passed into the format() method.

>>> print '{0} and {1}'.format('spam', 'eggs')
spam and eggs
>>> print '{1} and {0}'.format('spam', 'eggs')
eggs and spam

Passing an integer after the ':' will cause that field to be a minimum number of characters wide. This is useful for making tables pretty.

>>> table = {'Sjoerd': 4127, 'Jack': 4098, 'Dcab': 7678}
>>> for name, phone in table.items():
...     print '{0:10} ==> {1:10d}'.format(name, phone)
...
Jack       ==>       4098
Dcab       ==>       7678
Sjoerd     ==>       4127

If you have a really long format string that you don’t want to split up, it would be nice if you could reference the variables to be formatted by name instead of by position. This can be done by simply passing the dict and using square brackets '[]' to access the keys

>>> table = {'Sjoerd': 4127, 'Jack': 4098, 'Dcab': 8637678}
>>> print ('Jack: {0[Jack]:d}; Sjoerd: {0[Sjoerd]:d}; '
...        'Dcab: {0[Dcab]:d}'.format(table))
Jack: 4098; Sjoerd: 4127; Dcab: 8637678

Old string formatting

The % operator can also be used for string formatting. It interprets the left argument much like a sprintf()-style format string to be applied to the right argument, and returns the string resulting from this formatting operation. For example:

>>> import math
>>> print 'The value of PI is approximately %5.3f.' % math.pi
The value of PI is approximately 3.142.

Reading and Writing Files

open() returns a file object, and is most commonly used with two arguments: open(filename, mode).

>>> f = open('/tmp/workfile', 'w')
>>> print f
<open file '/tmp/workfile', mode 'w' at 80a0960>

The first argument is a string containing the filename. The second argument is another string containing a few characters describing the way in which the file will be used. mode can be 'r' when the file will only be read, 'w' for only writing (an existing file with the same name will be erased), and 'a' opens the file for appending; any data written to the file is automatically added to the end. 'r+' opens the file for both reading and writing. The mode argument is optional; 'r' will be assumed if it’s omitted.

Methods of File Objects

The rest of the examples in this section will assume that a file object called f has already been created.
To read a file’s contents, call f.read(size), which reads some quantity of data and returns it as a string. size is an optional numeric argument. When size is omitted or negative, the entire contents of the file will be read and returned; it’s your problem if the file is twice as large as your machine’s memory. Otherwise, at most size bytes are read and returned. If the end of the file has been reached, f.read() will return an empty string ("").

>>> f.read()
'This is the entire file.\n'
>>> f.read()
''

f.readline() reads a single line from the file; a newline character (\n) is left at the end of the string, and is only omitted on the last line of the file if the file doesn’t end in a newline. This makes the return value unambiguous; if f.readline() returns an empty string, the end of the file has been reached, while a blank line is represented by '\n', a string containing only a single newline.

>>> f.readline()
'This is the first line of the file.\n'
>>> f.readline()
'Second line of the file\n'
>>> f.readline()
''

f.readlines() returns a list containing all the lines of data in the file. If given an optional parameter sizehint, it reads that many bytes from the file and enough more to complete a line, and returns the lines from that. This is often used to allow efficient reading of a large file by lines, but without having to load the entire file in memory. Only complete lines will be returned.

>>> f.readlines()
['This is the first line of the file.\n', 'Second line of the file\n']

f.write(string) writes the contents of string to the file, returning None.

>>> f.write('This is a test\n')

To write something other than a string, it needs to be converted to a string first:

>>> value = ('the answer', 42)
>>> s = str(value)
>>> f.write(s)

f.tell() returns an integer giving the file object’s current position in the file, measured in bytes from the beginning of the file. To change the file object’s position, use f.seek(offset, from_what). The position is computed from adding offset to a reference point; the reference point is selected by the from_what argument. A from_what value of 0 measures from the beginning of the file, 1 uses the current file position, and 2 uses the end of the file as the reference point. from_what can be omitted and defaults to 0, using the beginning of the file as the reference point.

>>> f = open('/tmp/workfile', 'r+')
>>> f.write('0123456789abcdef')
>>> f.seek(5)     # Go to the 6th byte in the file
>>> f.read(1)
'5'
>>> f.seek(-3, 2) # Go to the 3rd byte before the end
>>> f.read(1)
'd'

When you’re done with a file, call f.close() to close it and free up any system resources taken up by the open file. After calling f.close(), attempts to use the file object will automatically fail.

>>> f.close()
>>> f.read()
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
ValueError: I/O operation on closed file

It is good practice to use the “ with “ keyword when dealing with file objects. This has the advantage that the file is properly closed after its suite finishes, even if an exception is raised on the way. It is also much shorter than writing equivalent try-finally blocks:

>>> with open('/tmp/workfile', 'r') as f:
...     read_data = f.read()
>>> f.closed

The pickle Module

Strings can easily be written to and read from a file. Numbers take a bit more effort, since the read() method only returns strings, which will have to be passed to a function like int(), which takes a string like '123' and returns its numeric value 123. However, when you want to save more complex data types like lists, dictionaries, or class instances, things get a lot more complicated.
Rather than have users be constantly writing and debugging code to save complicated data types, Python provides a standard module called pickle. This is an amazing module that can take almost any Python object (even some forms of Python code!), and convert it to a string representation; this process is called pickling. Reconstructing the object from the string representation is called unpickling. Between pickling and unpickling, the string representing the object may have been stored in a file or data, or sent over a network connection to some distant machine.
If you have an object x, and a file object f that’s been opened for writing, the simplest way to pickle the object takes only one line of code:

pickle.dump(x, f)

To unpickle the object again, if f is a file object which has been opened for reading:

x = pickle.load(f)

PHP String Functions

2010-07-23T23:59:00.001+05:30

explode

Description :

array explode ( string `$delimiter` , string `$string` [, int `$limit` ] )

Returns an array of strings, each of which is a substring of string formed by splitting it on boundaries formed by the string delimiter.

Examples explode()

 <?php
// Example 1
$pizza  = "piece1 piece2 piece3 piece4 piece5 piece6";
$pieces = explode(" ", $pizza);
echo $pieces[0]; // piece1
echo $pieces[1]; // piece2

// Example 2
$data = "foo:*:1023:1000::/home/foo:/bin/sh";
list($user, $pass, $uid, $gid, $gecos, $home, $shell) = explode(":", $data);
echo $user; // foo
echo $pass; // *

?>

substr
Description
string  substr     (  string  $string    ,  int  $start    [,  int  $length   ] )
    Returns the portion of string  specified by the    start and length  parameters.   

Example Basic substr()  usage
 <?php
echo substr('abcdef', 1);     // bcdef
echo substr('abcdef', 1, 3);  // bcd
echo substr('abcdef', 0, 4);  // abcd
echo substr('abcdef', 0, 8);  // abcdef
echo substr('abcdef', -1, 1); // f

// Accessing single characters in a string
// can also be achieved using "square brackets"
$string = 'abcdef';
echo $string[0];                 // a
echo $string[3];                 // d
echo $string[strlen($string)-1]; // f

?>

Work Shop at Drishti School, Ludhiana

2010-07-20T09:24:00.001+05:30

In Drishti School, Near Ludhiana, we give a Workshop . It was very interesting to teach little children and their teachers Linux Softwares and to solve their problems. We are six students with Dr. H.S Rai. Drishti School has bought 40 Linux based Tablet-PC which has default ubuntu 8.10 installed on them. we all gave presentations on different things.

I have given my presentation on KGeography for kids.

KGeography is a Free and open source educational software game that tests students geographical knowledge

Besides for educational purposes, KGeography can be used for evaluating ones knowledge. Right now it has five games:

The game tells you a map division name and you have to click on it
The game tells you a capital and you have to guess the division it belongs to
The game tells you a division and you have to guess its capital
The game shows you a map division flag and you have to guess its name
The game tells you a map division name and you have to guess its flag

Download Presentation Here

Display an image from a MySQL database in a web page via PHP

2010-07-18T23:41:00.000+05:30

Here's a sample HTML page we're going to include an image in:

<html>
<head>
<title>Demo of Database Image in a page</title>
</head>
<body>
Here is your picture:<br>
<img src=picscript.php?imname=potwoods><br>
Example by Well House Consultants
</body>
</html>

Then you need the PHP script - called picscript.php in the same directory in my example:

<?php
mysql_connect("localhost","wellho","xxxxxxx");
mysql_select_db("wellho");
$image = stripslashes($_REQUEST[imname]);
$rs = mysql_query("select * from im_library where filename=\"".
addslashes($image).".jpg\"");
$row = mysql_fetch_assoc($rs);
$imagebytes = $row[imgdata];
header("Content-type: image/jpeg");
print $imagebytes;
?>

Basic Guide lines for python coding

2010-07-12T21:07:00.000+05:30

For Python,  has emerged as the style guide that most projects adhere to; it promotes a very readable and eye-pleasing coding style. Every Python developer should read it at some point; here are the most important points extracted for you:

Use 4-space indentation, and no tabs.
4 spaces are a good compromise between small indentation (allows greater nesting depth) and large indentation (easier to read). Tabs introduce confusion, and are best left out.
Wrap lines so that they don’t exceed 79 characters.
This helps users with small displays and makes it possible to have several code files side-by-side on larger displays.
Use blank lines to separate functions and classes, and larger blocks of code inside functions.
When possible, put comments on a line of their own.
Use docstrings.
Use spaces around operators and after commas, but not directly inside bracketing constructs: a = f(1, 2) + g(3, 4).
Name your classes and functions consistently; the convention is to use CamelCase for classes and lower_case_with_underscores for functions and methods. Always use self as the name for the first method argument .
Don’t use fancy encodings if your code is meant to be used in international environments. Plain ASCII works best in any case.

PHP function for PostGreSQL database

2010-07-11T23:27:00.000+05:30

pg_connect() opens a connection to a PostgreSQL database specified by the connection_string.
If a second call is made to pg_connect() with the same connection_string as an existing connection, the existing connection will be returned unless you pass PGSQL_CONNECT_FORCE_NEW as connect_type.

The old syntax with multiple parameters $conn = pg_connect("host", "port", "options", "tty", "dbname") has been deprecated.

For example :-

$con = pg_connect("host=$dbhost user=$dbuser password=$dbpasswd dbname=$dbname" )

pg_close() closes the non-persistent connection to a PostgreSQL database associated with the given connection resource.

For example :-

pg_close($con);

pg_connection_status() returns the status of the specified connection.

For example :-

<?php
  $dbconn = pg_connect("dbname=publisher") or die("Could not connect");
  $stat = pg_connection_status($dbconn);
  if ($stat === PGSQL_CONNECTION_OK) {
      echo 'Connection status ok';
  } else {
      echo 'Connection status bad';
  }  
?>

pg_fetch_all() returns an array that contains all rows (records) in the result resource.

For example :-

$arr = pg_fetch_all($result);

print_r($arr);

pg_fetch_result() returns the value of a particular row and field (column) in a PostgreSQL result resource.

<?php
$db = pg_connect("dbname=users user=me") || die();

$res = pg_query($db, "SELECT 1 UNION ALL SELECT 2");

$val = pg_fetch_result($res, 1, 0);

echo "First field in the second row is: ", $val, "\n";

?>

pg_fetch_array() returns an array that corresponds to the fetched row (record).
pg_fetch_array() is an extended version of pg_fetch_row(). In addition to storing the data in the numeric indices (field number) to the result array, it can also store the data using associative indices (field name). It stores both indicies by default.

For example :-

$arr = pg_fetch_array($result);
echo $arr["author"] . " <- Row 3 Author\n";
echo $arr[1] . " <- Row 3 E-mail\n";

pg_query() executes the query on the specified database connection.

For example :-

$result = pg_query($con, "SELECT * FROM $tablename where sr_no = 10");

pg_num_rows() will return the number of rows in a PostgreSQL result resource.

For example :-

<?php
$result = pg_query($conn, "SELECT 1");

$rows = pg_num_rows($result);

echo $rows . " row(s) returned.\n";
?>

Basic points about Python

2010-07-08T22:03:00.000+05:30

Python is a high-level, interpreted, interactive and object oriented-scripting language.

Python is Interpreted
Python is Interactive
Python is Object-Oriented
Python is Beginner's Language

Python was developed by Guido van Rossum in the late eighties and early nineties at the National Research Institute for Mathematics and Computer Science in the Netherlands.

Python's Feature highlights include:

Easy-to-learn
Easy-to-read
Easy-to-maintain
A broad standard library
Interactive Mode
Portable
Extendable
Databases
GUI Programming

Scalable

Reserved Words:

The following list shows the reserved words in Python. These reserved words may not be used as constant or variable or any other identifier names.
Keywords contain lowercase letters only.

and exec not
assert finally or
break for pass
class from print
continue global raise
def if return
del import try
elif in while
else is with
except lambda yield

Standard Data Types:

Python has five standard data types:
Numbers
String
List
Tuple
Dictionary

The search Function

This function search for first occurrence of RE pattern within string with optional flags.
Here is the syntax for this function:

re.string(pattern, string, flags=0)
Here is the description of the parameters:

Parameter Description
pattern This is the regular expression to be matched.
string This is the string which would be searched to match the pattern
flags You can specifiy different flags using exclusive OR (|). These are modifiers which are listed in the table below.
The re.search function returns a match object on success, None on failure. We would use group(num) or groups() function of match object to get matched expression.

Match Object Methods Description
group(num=0) This methods returns entire match (or specific subgroup num)
groups() This method return all matching subgroups in a tuple (empty if there weren't any)
Matching vs Searching:
Python offers two different primitive operations based on regular expressions: match checks for a match only at the beginning of the string, while search checks for a match anywhere in the string (this is what Perl does by default).

Search and Replace:

Some of the most important re methods that use regular expressions is sub.

Syntax:
sub(pattern, repl, string, max=0)
This method replace all occurrences of the RE pattern in string with repl, substituting all occurrences unless max provided. This method would return modified string.
Built-In Class Attributes:
Every Python class keeps following built-in attributes and they can be accessed using dot operator like any other attribute:

__dict__ : Dictionary containing the class's namespace.
__doc__ : Class documentation string, or None if undefined.
__name__: Class name.
__module__: Module name in which the class is defined. This attribute is "__main__" in interactive mode.
__bases__ : A possibly empty tuple containing the base classes, in the order of their occurrence in the base class list.

Parameter	Description
pattern	This is the regular expression to be matched.
string	This is the string which would be searched to match the pattern
flags	You can specifiy different flags using exclusive OR (\|). These are modifiers which are listed in the table below.

Match Object Methods	Description
group(num=0)	This methods returns entire match (or specific subgroup num)
groups()	This method return all matching subgroups in a tuple (empty if there weren't any)

Quick Python Tutorial

2010-07-06T22:25:00.000+05:30

Python is an easy to learn, powerful programming language. It has efficient high-level data structures and a simple but effective approach to object-oriented programming. Python’s elegant syntax and dynamic typing, case sensitive , together with its interpreted nature, make it an ideal language for scripting and rapid application development in many areas on most platforms

The Python interpreter is easily extended with new functions and data types implemented in C or C++ (or other languages callable from C). Python is also suitable as an extension language for customizable applications.

Getting Help

Help in Python is always available right in the interpreter. If you want to know how an object works, all you have to do is call help(<object>)! Also useful are dir(), which shows you all the object’s methods, and <object>.doc, which shows you its documentation string:

>>> help(5)
Help on int object: (etc etc)
>>> dir(5)
['__abs__', '__add__', ...]

Syntax

Python has no mandatory statement termination characters and blocks are specified by indentation. Indent to begin a block, dedent to end one. Statements that expect an indentation level end in a colon (:). Comments start with the pound (#) sign and are single-line, multi-line strings are used for multi-line comments. Values are assigned (in fact, objects are bound to names) with the equals sign (”=”), and equality testing is done using two equals signs (”==“). You can increment/decrement values using the += and -= operators respectively by the right-hand amount. This works on many datatypes, strings included. You can also use multiple variables on one line. For example:
>>> myvar = 3
>>> myvar += 2
>>> myvar 5
>>> myvar -= 1
>>> myvar 4
"""This is a multiline comment.
The following lines concatenate the two strings."""
>>> mystring = "Hello"
>>> mystring += " world."
>>> print mystring
Hello world.

DataTypes

The data structures available in python are lists, tuples and dictionaries. Sets are available in the sets library (but are built-in in Python 2.5 and later). Lists are like one-dimensional arrays (but you can also have lists of other lists), dictionaries are associative arrays (a.k.a. hash tables) and tuples are immutable one-dimensional arrays (Python “arrays” can be of any type, so you can mix e.g. integers, strings, etc in lists/dictionaries/tuples). The index of the first item in all array types is 0. Negative numbers count from the end towards the beginning, -1 is the last item. Variables can point to functions. The usage is as follows:

>>> sample = [1, ["another", "list"], ("a", "tuple")]
>>> mylist = ["List item 1", 2, 3.14]
>>> mylist[0] = "List item 1 again"
>>> mylist[-1] = 3.14
>>> mydict = {"Key 1": "Value 1", 2: 3, "pi": 3.14}
>>> mydict["pi"] = 3.15
>>> mytuple = (1, 2, 3)
>>> myfunction = len
>>> print myfunction(mylist)
3

You can access array ranges using a colon (:). Leaving the start index empty assumes the first item, leaving the end index assumes the last item. Negative indexes count from the last item backwards (thus -1 is the last item) like so:

>>>  mylist = ["List item 1",  2, 3.14]
>>> print  mylist[:]
['List item 1', 2, 3.1400000000000001]
>>> print  mylist[0:2]
['List item 1', 2]
>>> print  mylist[-3:-1]
['List item 1', 2]
>>> print  mylist[1:]
[2, 3.14]

Strings

Its strings can use either single or double quotation marks, and you can have quotation marks of one kind inside a string that uses the other kind (i.e. “He said ‘hello’.” is valid). Multiline strings are enclosed in triple double (or single) quotes (”“”). Python supports Unicode out of the box, using the syntax u“This is a unicode string”. To fill a string with values, you use the % (modulo) operator and a tuple. Each %s gets replaced with an item from the tuple, left to right, and you can also use dictionary substitutions, like so:

>>>print "Name: %s\nNumber: %s\nString: %s" % (myclass.name, 3, 3 * "-")
Name: Poromenos
Number: 3
String: ---

strString = """This is
a multiline
string."""

Flow control statements

Flow control statements are `if`, `for`, and `while`. There is no `select`; instead, use if. Use for to enumerate through members of a list. To obtain a list of numbers, use `range(<number>)`. These statements’ syntax is thus:

rangelist = range(10)
>>> print  rangelist
[0, 1,  2, 3, 4, 5, 6,  7, 8, 9]
for number in  rangelist:
    # Check if number is one of
    # the numbers in the tuple.
    if number in (3, 4,  7, 9):
        # "Break" terminates a for without
        # executing the "else" clause.
        break
    else:
        # "Continue" starts the next iteration
        # of the loop. It's rather useless here,
        # as it's the last statement of the loop.
        continue
else:
    # The "else" clause is optional and is
    # executed only if the loop didn't "break".
    pass # Do nothing

if rangelist[1] == 2:
    print "The second item  (lists are 0-based) is 2"
elif rangelist[1] == 3:
    print "The second item  (lists are 0-based) is 3"
else:
    print "Dunno"

while rangelist[1] == 1:
    pass

FunctionsFunctions are declared  with the “def” keyword. Optional arguments are set in the function  declaration after the mandatory arguments by being assigned a default  value. For named  arguments, the name of the argument is assigned a value.  Functions can return a tuple (and using tuple unpacking you can  effectively return multiple  values). Lambda  functions are ad hoc functions that are comprised of a single  statement. Parameters are passed by reference, but immutable types (tuples, ints,  strings, etc) cannot be changed. This is because only the memory location  of the item is passed, and binding another object to a variable discards the  old one, so immutable types are replaced. For example:

# Same as def f(x):  return x + 1
functionvar = lambda x: x + 1
>>> print  functionvar(1)
2

# an_int and a_string are optional, they have default  values
# if one is not passed (2 and "A default string",  respectively).
def passing_example(a_list,  an_int=2, a_string="A  default string"):
    a_list.append("A new item")
    an_int = 4
    return a_list, an_int, a_string

>>> my_list = [1, 2, 3]
>>> my_int = 10
>>> print  passing_example(my_list, my_int)
([1,  2, 3, 'A new item'], 4, "A default string")
>>> my_list
[1, 2,  3, 'A new item']
>>> my_int
10

ClassesPython supports a limited form of multiple inheritance in classes. Private variables and  methods can be declared (by convention, this is not enforced by  the language) by adding at least two leading underscores and at most one  trailing one (e.g. “__spam”). We can also bind arbitrary names to  class instances. An example follows:

class MyClass:
    common = 10
    def __init__(self):
        self.myvariable  = 3
    def myfunction(self, arg1, arg2):
        return self.myvariable

    # This is the class instantiation
>>> classinstance = MyClass()
>>> classinstance.myfunction(1, 2)
3
# This variable is shared by all classes.
>>> classinstance2 = MyClass()
>>> classinstance.common
10
>>> classinstance2.common
10
# Note how we use the class name
# instead of the instance.
>>> MyClass.common  = 30
>>> classinstance.common
30
>>> classinstance2.common
30
# This will not update the variable on the class,
# instead it will bind a new object to the old
# variable name.
>>> classinstance.common  = 10
>>> classinstance.common
10
>>> classinstance2.common
30
>>> MyClass.common  = 50
# This has not changed, because "common" is
# now an instance variable.
>>> classinstance.common
10
>>> classinstance2.common
50

# This class inherits from MyClass. Multiple
# inheritance is declared as:
# class OtherClass(MyClass1, MyClass2, MyClassN)
class OtherClass(MyClass):
    # The "self" argument is passed automatically
    # and refers to the class instance, so you can set
    # instance variables as above, but from inside the  class.
    def __init__(self, arg1):
        self.myvariable  = 3
        print arg1

>>> classinstance = OtherClass("hello")
hello
>>> classinstance.myfunction(1, 2)
3
# This class doesn't have a .test member, but
# we can add one to the instance anyway. Note
# that this will only be a member of classinstance.
>>> classinstance.test  = 10
>>> classinstance.test
10
ExceptionsExceptions in Python are handled with try-except [exceptionname] blocks:

def  some_function():
    try:
        # Division by zero raises an exception
        10 / 0
    except ZeroDivisionError:
        print "Oops,  invalid."
    else:
        # Exception didn't occur, we're good.
        pass
    finally:
        # This is executed after the code block is run
        # and all exceptions have been handled, even
        # if a new exception is raised while handling.
        print "We're done  with that."

>>> some_function()
Oops, invalid.
We're done with that.
ImportingExternal libraries are used with the import [libname]  keyword. You can also use from [libname] import [funcname]  for individual functions. Here is an example:

import random
 from time import clock 
randomint = random.randint(1, 100)
>>> print  randomint
64

File I/OPython has a wide array of libraries built in. As an example, here  is how serializing  (converting data structures to strings using the pickle  library) with file I/O is used:

import pickle
mylist = ["This", "is", 4, 13327]
# Open the file C:\binary.dat for writing. The letter r  before the
# filename string is used to prevent backslash  escaping.
myfile = file(r"C:\binary.dat", "w")
pickle.dump(mylist, myfile)
myfile.close()

myfile = file(r"C:\text.txt", "w")
myfile.write("This is a sample string")
myfile.close()

myfile = file(r"C:\text.txt")
>>> print  myfile.read()
'This is a sample string'
myfile.close()

# Open the file for reading.
myfile = file(r"C:\binary.dat")
loadedlist = pickle.load(myfile)
myfile.close()
>>> print  loadedlist
['This', 'is', 4, 13327]

MiscellaneousConditions can  be chained. 1 < a < 3 checks that a is both  less than 3 and more than 1.
You can use del to delete variables or items in arrays.
List  comprehensions provide a powerful way to create and manipulate  lists. They consist of an expression followed by a for  clause followed by zero or more if or for  clauses, like so:

>>>  lst1 = [1, 2, 3]
>>> lst2 = [3, 4, 5]
>>> print [x * y for  x in lst1 for y in lst2]
[3, 4,  5, 6, 8, 10, 9,  12, 15]
>>> print [x for x in  lst1 if 4 > x > 1]
[2, 3]
# Check if an item has a specific property.
# "any" returns true if any item in the list is true.
>>> any([i % 3  for i in [3, 3,  4, 4, 3]])
True
# This is because 4 % 3 = 1, and 1 is true, so any()
# returns True.

# Check how many items have this property.
>>> sum(1 for  i in [3, 3, 4,  4, 3]  if i == 4)
2
>>> del lst1[0]
>>> print  lst1
[2, 3]
>>> del lst1
Global  variables are declared outside of functions and can be read  without any special declarations, but if you want to write to them you  must declare them at the beginning of the function with the “global”  keyword, otherwise Python will bind that object to a new local variable  (be careful of that, it’s a small catch that can get you if you don’t  know it). For example:

number = 5

def myfunc():
    # This will print 5.
    print number

def anotherfunc():
    # This raises an exception because the variable  has not
    # been bound before printing. Python knows that it  an
    # object will be bound to it later and creates a  new, local
    # object instead of accessing the global one.
    print number
    number = 3

def yetanotherfunc():
    global number
    # This will correctly change the global.
    number = 3

PostgreSQL

2010-07-04T22:45:00.000+05:30

Introduction

PostgreSQL is a powerful object-relational database management system, provided under a flexible BSD-style license.^[1] PostgreSQL contains many advanced features, is very fast and standards compliant.

PostgreSQL has bindings for many programming languages such as C, C++, Python, Java, PHP, Ruby... It can be used to power anything from simple web applications to massive databases with millions of records.

Installation in Ubuntu Server

To install Postgresql you may use the command line and type:

$sudo apt-get install postgresql

Administration

pgAdmin III is a handy GUI for PostgreSQL, it is essential to beginners. To install it, type at the command line:

sudo apt-get install pgadmin3

Basic Server Setup

To start off, we need to change the PostgreSQL postgres user password; we will not be able to access the server otherwise. As the “postgres” Linux user, we will execute the psql command.

Create New User

In a terminal, type:

@-desktop:~$ sudo -s

root@-desktop:~# su - postgres

postgres@-desktop:~$ createuser jagdeep

Shall the new role be a superuser? (y/n) y

Shall the new role be allowed to create databases? (y/n) y

Shall the new role be allowed to create more new roles? (y/n) y

postgres@-desktop:~$ exit

logout

root@-desktop:~# exit

exit

@-desktop:~$ sudo -u postgres psql postgres
psql (8.4.4)
Type "help" for help.

Set a password for the "postgres" database role using the command:

\password postgres

and give your password when prompted. The password text will be hidden from the console for security purposes.

Type Control+D to exit the posgreSQL prompt.

Create database

To create the first database, which we will call "mydb", simply type :

sudo -u postgres createdb mydb

Install phppgadmin for GUI Inter-phase

sudo apt-get install phppgadmin

How to login using phppgadmin

First of all enable login of postgres user via phppgadmin by editing
the /etc/phppgadmin/config.inc.php or {your phppgadmin install
path}/conf/config.inc.php file change the following line-:

$conf['extra_login_security'] = true;
to:
$conf['extra_login_security'] = false;

Now you will be able to login in phppdadmin using postgres username.

After login using postgres or any other superuser account. Create a
new role (by clicking on Roles and then Create role).Give desired
username, password and tick on following checkboxes-:

Inherits privileges?
Can login?

Then press create button to create new user.

Now give the select privilege on the tables to the newly created
user.This can be done by clicking on the table name and grant
permissions under privileges tab.Give select privileges to newly
created user.Now that user can browse through the table and see
individual values.
Logout from superuser account and login again using newly created user
to verify the results.

and	exec	not
assert	finally	or
break	for	pass
class	from	print
continue	global	raise
def	if	return
del	import	try
elif	in	while
else	is	with
except	lambda	yield

JAGDEEP SINGH MALHI

Common Linux log files name and usage

Postfix Flush the Mail Queue commands

Install and Configure Mail Server on Linux System

Using patch and diff commands

Network Manager Error : Device not managed (ubuntu)

PHP/MySql : Store file path in database, file in folder

Comparison of Oracle, MySQL and Postgres DBMS

Conclusion : Compare your Project requirements with DBMS. It depend on your application or project which is suitable for your project.

TMUX – The Terminal Multiplexer

Sphinx Auto genrate documentation for Django Project

Installing your doc directory

Django-Cms Installation error "PageAdmin.exclude' refers to field 'created_by' that is missing from"

Python : Virtual Python Environment builder

The --no-site-packages Option

Using Virtualenv without bin/python

Baseline Environment

Django : FileField() or ImageField()

TemplateSyntaxError at /file/

Django application : Contact form

Make the Contact form in django and also mail is send to admin .

Django application : Add two number using forms

Script :Find and Replace word from files.

Script for Replace the One word with another word from all files place in present directory.

Django Application : Create blog

Django : A Simple Blog Example

Automation Project is approved : Sourceforge.org And Sarovar.org

Check Django version

Batch resize/Compress all images in a folder.

Drupal error : Function ereg() is deprecated

Python : CMS

Plone

A powerful, flexible Content Management solution that is easy to install, use and extend

Django : Auto-Generate model.py file from PostgreSQL / MySQL / SQLite database

inspectdb

Python : Accesssing a MySQL Database

Python : Errors and Exceptions

Syntax Errors

Exceptions

Handling Exceptions

Raising Exceptions

Defining Clean-up Actions

Predefined Clean-up Actions

Python : Input and Output

Fancier Output Formatting

Old string formatting

Reading and Writing Files

Methods of File Objects

The pickle Module

PHP String Functions

explode

Description :

array explode ( string $delimiter , string $string [, int $limit ] )

substr

Description

Work Shop at Drishti School, Ludhiana

Display an image from a MySQL database in a web page via PHP

Basic Guide lines for python coding

PHP function for PostGreSQL database

Basic points about Python

Reserved Words:

Standard Data Types:

Python has five standard data types:

Python has five standard data types:

The search Function

The search Function

Matching vs Searching:

Search and Replace:

Search and Replace:

Syntax:

Syntax:

Built-In Class Attributes:

Quick Python Tutorial

Flow control statements

Flow control statements are if, for, and while. There is no select; instead, use if. Use for to enumerate through members of a list. To obtain a list of numbers, use range(<number>). These statements’ syntax is thus:

Functions

Classes

Exceptions

Importing

File I/O

The `--no-site-packages` Option

Using Virtualenv without `bin/python`

array explode ( string `$delimiter` , string `$string` [, int `$limit` ] )

Flow control statements are `if`, `for`, and `while`. There is no `select`; instead, use if. Use for to enumerate through members of a list. To obtain a list of numbers, use `range(<number>)`. These statements’ syntax is thus: