A Web Developer blog - PHP | JavaScript | MYSQL | Apache | Tool | SEO | Others

Membase

2011-12-09T02:46:00.000-08:00

Membase is high performance key value pair system used for cacheing data. Membase generally provide superset of memcached.

You can use Membase to and configure either "memcached" type or "membase" type buckets. A membase-type bucket provides additional features such as key-value persistence and replication, whereas a memcached-type bucket provides only memory-only caching.

Memcached has it’s limitations. Moving to large+1 machines is going to lose a lot of your data. There is no master to organize the re-balancing of the data.We can avoid data loss using membase bucket type, while adding new server to the clusters.

Moxi

Moxi is the component of Membase that handles the re-routing of requests to other Membase servers when the server receiving the original request is not the one responsible for the data requested.

You can install membase using the instructions here.

testing membase.

you can test it using telnet utility.

shell> telnet localhost 11211 Trying 127.0.0.1... Connected to localhost.localdomain (127.0.0.1). Escape character is '^]'

set test_key 0 0 1 a STORED
or you can run a PHP script to check if membase is installed properly or not.

connect("localhost",11211); // try 127.0.0.1 instead of localhost
                                      // if it is not working

echo "Server's version: " . $memcache->getVersion() . "
\n";

// we will create an array which will be stored in membase serialized
$testArray  = array('horse', 'dog', 'pig');
$tmp         = serialize($testArray);
$memcache->add("key", $tmp);
echo "Data from the cache:
\n";
print_r(unserialize($memcache->get("key")));
?>

Working with memcached

2011-09-22T06:33:00.000-07:00

memcached is a general-purpose distributed memory caching system used to speed up dynamic database driven websites by caching data in RAM to reduce the number of times an external data source to be read.

Here is how memcached can be useful.The system uses a client server architecture. Server maintains associative array in key value pair. the clients populate this array and query it. Keys are up to 250 bytes long and values can be at most 1 MB size. by default server runs on 11211 port. A client should be installed in order to access memcached data. client can connect to multiple server by adding new server to it's pool.gettting data from memcached there are several methods to use memcached. yo can go to official site for more information on memcached.

Using memcached from a script. [I've used PHP in example.]

1. Memcached class should exist if memcached client is installed properly. Create an object of memcached.

$obj = new Memcached();

if object created means memcached service is running. If not then you can start the service from command prompt.using command svc -u path/to/memcached/ [eg: /usr/local/memcache/bin/memcached ]

2. Add the server to the pool.

$obj->addServers($servers); [$servers = array( '172.18.1.69', 11211) where 1st param. is IP of the server and second is port.]

3 Now you can use different methods to add/fetch memcached data. [example get($key),set($key,$value)]. for more information visit php.net site and search for memcached based function.

Checking memcache log.

1. Go to memcashed directory /service/memcached

2.write the following command to get log

tail -f log/main/current | tai64nlocal

Using telnet to connect to memcache server.

1. telnet server_IP port [telnet 127.0.01 11214]

Once connected, you can check if memcache key is set, by typing get memcache_key_name to get the memcached data for the key memcache_key_name and press enter. You can also set and delete key using set and delete.

Well that's all folks. We'll see membase in the next session.

insert query with ampersand in oracle.

2011-06-21T04:26:00.001-07:00

Today I had to insert a query which contains '&' as a character. as usual this is special character in oracle. but to insert data containing '&' in it was not that simple.preceding '&' before any value makes it variables and ask for it's value at the time of execution of query. escape character \& simply didn't work which is working fine in MySQL. So here are the options you can try out to insert data containing '&'.

1) SET DEFINER off;
insert into page(id,URL) values(1,'http:///sample.com?q=1&p=2');

Problem Area : In this case &p won't be treated as variable and will be part of the string value. but suppose if you want variables data also then you can try option below.

2) SET ESCAPE \
insert into page(id,URL) values(1,'http://sample.com?q=1\&p=2');

Problem Area : you may not have permission to set DEFINER or ESCAPE so this option is best suitable.

3) insert into page(id,URL) values(1,'http://sample.com?q=1'||'&'||'p=2');

Courtesy : My senior. (Sanket).

Writing oracle procedure.

2011-06-20T05:40:00.000-07:00

You can write a stored procedure in oracle using any editor. I use sql developer by oracle. I am very new to write procedures in oracle. I found it's syntax way different than the syntax of MySql. I am fond fo opensource projects because of the support and simplicity of the solutions it has. Mysql has very simple ways to extacts rows, have lost's of in built funtions to use which makes it simple to use. After writting few oracle procedures I found how easy and simple mysql is compared to oracle in syntax. Anyway, Oracle has it's own advantage, and I like learning new stuff and the way to write oracle procedure. Here are 2 common requirement which I faced while writting a procedure in oracle.

1) situations where you want to limit number of resultset in range (10-20) in oracle. In mysql you have limit caluse where you simply say

limit start, count

in your query and it's done, but in oracle you don't have this clause.

here is how you go about the same.

suppose you have table emp with coulumn id,name,sal.

CREATE OR REPLACE
PROCEDURE GETEMPLISTING(
var_name VARCHAR2,
var_limit_start IN INTEGER,
var_limit_end IN INTEGER,
page_cur out SYS_REFCURSOR)

AS
var_data_query varchar2(4000) default '';
BEGIN
var_data_query := 'select *
from
( select rownum rnum, a.*
from (SELECT id,name,sal FROM emp WHERE name LIKE ''%'||var_name||'%'') a
where rownum <= '|| var_limit_end ||')
where rnum >= '|| var_limit_start ||'';

OPEN page_cur FOR
var_data_query

2) you want same data but based on ids using IN caluse, In Oracle this is how I've acheived the same.

Declare a new data type

create or replace TYPE "MYNUMTABLE" as table of number;

Declare a function num_list

create or replace FUNCTION "NUM_LIST"
( p_str in varchar2,
p_delim in varchar2 default ',')
return myNumTable
as
l_data myNumTable := myNumTable();
l_str long default p_str || p_delim;
l_n number;
begin
loop
exit when l_str is null;
l_data.extend;
l_n := instr( l_str, p_delim );
l_data( l_data.count ) := substr( l_str, 1, l_n-1 );
l_str := substr( l_str, l_n+1 );
end loop;
return l_data;
end;

now write a procedure

CREATE OR REPLACE
PROCEDURE GETEMPLISTING(
var_ids VARCHAR2,
page_cur out SYS_REFCURSOR)

AS
BEIGIN
OPEN page_cur FOR
SELECT id,name,sal FROM emp WHERE id IN(SELECT * FROM THE
( SELECT CAST( num_list(p_users_id) AS myNumTable
)
FROM dual) a
);

now you can call procedure to get the result expected. page_ids parameter has to be id seperated by comma (,) in this case for example parameter could be 1,2,5,7. which in reutrn shuld give records of the respected emplyee 1,2,5,7.

Well that all for the day. Will cover next learning soon.

running selinium test case using PHP

2010-09-02T04:55:00.000-07:00

Here is the step by step process to run a selenium test case from the PHP program.

Step 1: Download Selenium from the site http://seleniumhq.org/download/

Step 2: unzip it in the document root of the server.In my case it is /var/www/

Step 3: start the selenium server.
seek for the folder selenium-server-1.0.3 [in my case version is 1.0.3].
go to the directory mentioned above and start the server by issuing following command from command line.
java -jar selenium-server.jar
you can see the following output shown in the above picture.

Step 4: run the test program supplied in the zip file.In my case php program GoogleTest.php under the directory selenium-php-client-driver-1.0.1
after running you would be able to see browser open for selenium giving session id for the test and google web page in other browser. [In my case firefox.].see the attached image.

That's it for now.

Mysql Benchmarking tool

2010-06-21T02:35:00.000-07:00

I did a study on the benchmarking tools available for mysql. I found mysqlslap to be the ideal tool for this. You can install mysqlslap by using the following command

$home> sudo apt-get install mysqlslap.

Once install you can use mysqlslap --help to get the argument list and synopsis for how to use it.
you can use number of iteration and concurrency limit for benchmarking performance of mysql.

for example:

mysqlslap -uroot -p -q Desktop/emp.sql -i15000

in this case the sql query written in the file emp.sql will run for 15000 times.

One important note is that mysqlslap only work if all of your tables,views,proc used in the query are under mysqlslap database.

mysql dump

2010-05-06T00:07:00.000-07:00

mysqldump is the client program for the back up of mysql database/tables.

to generate just schema of a table we can use option -d.

to limit the data in mysqldump we can use option --where="true limit 1000" which will give 1000 records.

ex. command is
mysqldump -u -p [] --where="true limit " > filenameforbackup.sql

Remote GUI Activation in Ubuntoo

2010-02-03T04:29:00.000-08:00

you can activate remote GUI from the shell login so that if you try to access any GUI software it get opened up in the terminal where you are connected in.
Here is the command to open evolution.

export DISPLAY=:0.0 && evolution

similarly you can open any GUI software.

Load balancing using Mod_Rewrite and perl

2009-12-21T03:35:00.000-08:00

In computer networking, load balancing is a technique to spread work between two or more computers, network links, CPUs, hard drives, or other to improve the performance.Here is the way to implement load balancing using mod_rewrite.
Proxy Throughput Round-Robin
suppose we want load balancing between 5 different Servers.In this variant we use mod_rewrite and its proxy throughput feature. First we dedicate www0.z-techsoftware.com to be actually www.z-techsoftware.com by using a single entry in DNS.

www    IN  CNAME   www0.foo.com.

Now make this server as proxy server which will redirect requests to all other servers.we first establish a ruleset which contacts a load balancing script lb.pl for all URLs using .htaccess file.

RewriteEngine on
RewriteMap    lb      prg:/path/to/lb.pl
RewriteRule   ^/(.+)$ ${lb:$1}           [P,L]

Then we write lb.pl:

#!/path/to/perl
##
##  lb.pl -- load balancing script
##

$| = 1;

$name   = "www";     # the hostname base
$first  = 1;         # the first server (not 0 here, because 0 is myself)
$last   = 5;         # the last server in the round-robin
$domain = "foo.dom"; # the domainname

$cnt = 0;
while () {
  $cnt = (($cnt+1) % ($last+1-$first));
  $server = sprintf("%s%d.%s", $name, $cnt+$first, $domain);
  print "http://$server/$_";
}

##EOF##

That's it.you are done.Now this server will act as proxy server and pass all requests to other servers one by one.

Tools to make your website work better

2009-12-17T22:26:00.001-08:00

Site-Perf – get an accurate, realistic, and helpful estimation of your site’s loading speed. The script fully emulates natural browser behavior downloading your page with all the images, CSS, JS and other files – just like a regular user. A unique feature is that site-perf.com allows to measure packet loss ratio with reasonable precision.

2. Customer Focus Calculator – will analyze the words on your page and determine if your copy is more about yourself or your customer. This tool will measure if you are we-we-ing all over yourself.

3. BT Buckets – Engage your users with a free segmentation and behavioral targeting tool.

4. 4Q from IPerceptions – developed with web analytics evangelist Avinash Kaushik. When evaluating how you website is doing obviously it helps to get your customers’ opinions. This free tool helps you answer four important questions:

* How satisfied are my visitors?
* What are my visitors at my website to do?
* Are they completing what they set out to do?
* If not, why not?
* If yes, what did they like best about the online experience?

5. What’s the Buzz? – a keyword research tool with one simple aim: to find out who’s talking about a certain keyword. To do that, it does five things:

* It displays the Technorati Blog Popularity Chart, showing how popular the keyword has been blogged about in the past 90 days
* It displays the Google Trends chart for the keyword
* It finds blog posts tagged with the keyword
* It finds blog posts containing the keyword (a straight-forward search)
* It finds social bookmarks tagged with the keywords

6. Bad Neighborhood Link Checker – scan the links on your website, and on the pages that your website is linking to, and flag possible problem areas.

7. Backlink Social Celebrity SEO Tool – discover who bookmarked a webpage and who linked to that webpage. The bookmarks are searched for in the various social bookmarking services, such as del.icio.us, Raw Sugar, and others. The backlinks are found using Google and Yahoo!.

8. Webbed-O-Meter 2.0 – can help track how effective you are at inspiring consumer generated content online, call it buzz marketing, social media marketing or viral marketing.

9. Website Grader – provides a score that incorporates things like website traffic, SEO, social popularity and other technical factors. It also provides some basic advice on how the website can be improved from a marketing perspective.

10. Spider Simulator – help you find out for yourself how a search engine reacts to your pages and what can be done to boost your visibility.

11. Spider Test – Shows the source code of a page, all outbound links, and common words and phrases.

12. Google Analytics – web analytics with new “enterprise features” and a ton of plugins and hacks.

13. Google Website Optimizer – Free A/B and Multivariate Testing

14. Yahoo! Analytics – still in beta, but incredibly powerful. It is currently available with Yahoo! Merchant Solutions Standard, Professional, and Yahoo! Store plans.

15. Microsoft adCenter Analytics – by invitation only, but you can apply at the link provided.

16. Piwik – This is an open source web analytics solution.

17. Linkscape – allows access to link information on more than 30+ billion web pages across 200+ million domains.

18. BacklinkAnalysis – Get a look at what keywords websites are linking to you with.

19. Trifecta – Measures metrics to estimate the relative popularity and importance of Page, Blog or Domain.

20. Firebug – this plugin for Firefox provides a number of development tools. For the purposes of analysis, Firebug will allow you to monitor and debug HTML, CSS, and JavaScript from within your browser.

21. YSlow for Firebug – YSlow will analyze your page to make suggestions for how you can speed up the page. YSlow is integrated with Firebug.

22. Google Webmaster Tools – see which phrases your ranking well for, what pages are causing problems for Google when crawling your site, which pages are getting the most links, rss subscribers, etc.

23. Morgue File – offers free high resolution digital stock photography for either corporate or public use.

24. OpenAds – for sites that want to serve and track advertising.

25. Sitescore – analyzes the quality of incoming and outgoing links, keyword density, page titles, plagiarism, popularity rank, the usage of popups and the effectiveness of site’s structure. Sitescore also grades the printability, readability, spiderability and usability of the page as well as spelling and W3C compliance. This is no longer available for free, sorry.

26. mon.itor.us – use this to monitor uptime, website performance and other hosting abnormalities.

27. Orangoo Spell Check – spell check your website.

28. The Scrutinizer – offers 283 tools to test your website in one place.

29. Product Indexation Check – use this handy tool to check how many of your category or product pages are included in the major search engines.

30. Kamplye – allows your visitors to give feedback on your site, via a little button that sits at the edge of each webpage.

31. Google’s Free Custom Search Engine – create your own custom search engine, indexing your website or add additonal websites as well.

32. Feng-GUI – generates heatmaps for your website (upload a screenshot) by simulating human vision during the first five seconds of viewing your website.

33. Scrutinizer browser – a web browser, based upon the Adobe AIR toolkit and the WebKit browser, that offers a simulation of the human visual system. Using this simulation, you can get a better idea of how users interact with your site design.

UI tools

2009-12-17T22:23:00.000-08:00

There are lots of tools available to help you document and design your web site. It seems that we all need a wireframing or prototyping tool at our fingertips.

It has covered the biggies: OmniGraffle Pro, Visio, Axure RP Pro, iRise Pro, Balsamiq Mockups, ConceptDraw Pro, etc… but he also goes into detail on a few well-known tools that can be used for wireframes and prototypes such as Keynote, PowerPoint, Adobe Fireworks, Adobe Flash and plain ol’ XHTML.

I've used Axure RP Pro and it's amazing to develop wireframe of software/website/web based tools.

MySQL tools

2009-12-17T22:19:00.000-08:00

The most popular and best open source database is MySQL. Simple as that. It is consistently fast , reliabile and very, very easy to use. One of MySQLs main features is its cross-platform support, it will run on almost all operating systems, including Windows, OSX, Linux and many more. So, MySQL is the best database, and we all use it. The question now is which is the best MySQL Admin and Development Tool?

MySQL Workbench
This application is a fully featured visual database design package that includes database design, modeling, creation and maintenance bundled into a single environment for the MySQL database system.

Heidi SQL
Heidi SQL is lightweight and fast with a flexible interface, it allows you to browse and edit your databases databases, manage tables, view and edit records, manage user-privileges, import data from text files, run SQL queries, synchronize tables between two databases and export selected tables to other databases or SQL scripts, and all this from an intuitive Windows interface.

Aqua Data Studio
This complete IDE, has four major areas of functionality: Database query and administration tools; a suite of compare tools for databases, source control and file systems; integrated source control client for Subversion (SVN) and CVS; and a powerful database modeler.

phpMyAdmin
This very popular, feature rich and easy to use free tool, written in PHP (obviusly), has been built to handle the full administration of MySQL. It can create and drop databases, create/drop/alter tables, delete/edit/add fields, execute any SQL statement, manage users and permissions, and manage keys on fields.

SQLyog
SQLyog is another popular SQL management tool that has a couple of useful features such as visual schema designer, visual query builder, intelligent code completion and a data / structure synchronization. It support HTTP / HTTPs / SSH tunneling and SSL connections. You can also specify a job manager, define a scheduled database backup and use a notification service to be reminded when some jobs are finished.

MYSQL Front
This graphical GUI for the MySQL database, is a “real” application, it can offer a more refined user-interface than is possible with systems built on PHP and HTML. Response is immediate, as there is no delay of reloading HTML-pages.

SQL Buddy
This cool lightweight ajax powered database management tool is amazing. It is very, very easy to install, unzip the folder to your server and thats it. As for upgrading, delete the older version and replace with the new version, simple.

Navicat Lite MySQL Admin Tool
Navicat is a fast, reliable and popular (millions of downloads) Database Administration tool purpose-built for simplifying database management and reducing administrative costs.

Toad MySQL
Toad for MySQL is a database development and administration tool that provides productivity features for rapidly creating and executing queries and managing complex database systems. It provides utilities to compare, extract and search for objects, manage projects, import/export data and administer the database.

MyCon – MySQL GUI
MyCon is an extremely powerful windows based graphical user interface, MySQL GUI, for administering and working with MySQL server databases. This easy to use MySQL GUI front-end client includes all the functionality and tools you will need to be productive in MySQL as a DBA, developer, manager, report writer or a general end-user.

MySQL Sidu
MySQL Sidu is a FREE MySQL client that works via your web browser, it is simple, intuitive and an easy database tool to use. Sidu is not as powerful as other similiar tools but packs enough punch to merit its place in this list, its features may be limited but it does do exactly what the name says (Sidu stands for Select Insert Delete Update).

Dummy Data Generator tool

2009-12-17T22:17:00.000-08:00

GenerateData is a free, open source script written in JavaScript, PHP and MySQL that lets you quickly generate large volumes of custom data in a variety of formats for use in testing software, populating databases.

Datagenerator

Datagenerator is a library and GUI for generating rule based test data for various databases like Mysql, Firebird, Interbase, MSSQL, Oracle, SQLite and PostgreSQL.

dgMaster

Data generator tool which supports many data types (primitive data types,but also names,addresses,post codes,etc.) and generates data in various formats (text,xml,db).It provides a GUI and is extensible by means of plugging-in new data-generator classes.

Spawner Data Generator

Spawner is a generator of sample/test data for databases. It can be configured to output delimited text or SQL insert statements. It can also insert directly into a MySQL 5.x database. Includes many field types, most of which are configurable.

DBMonster

DBMonster is a tool that generates random test data and inserts it into SQL database.

PHP Ming

2009-07-08T05:52:00.000-07:00

Ming is a library for generating Macromedia Flash files (.swf), written in C, and includes useful utilities for working with .swf files.You can use this library with PHP,Perl, ruby etc using wrapper.Ming offers a number of advantages over the existing PHP/libswf module. You can use Ming anywhere you can compile the code, whereas libswf is closed-source and only available for a few platforms, Windows not one of them.

Installation PHP
go to command prompt and type the following command

sudo apt-get install php5-ming

Restart web server.That's it folks.

for more info how to use this with php visit

http://in.php.net/manual/en/intro.ming.php

Installing CPAN modules in perl in linux.

2009-06-11T06:08:00.000-07:00

Perl support lots of in built module available under CPAN [Comprehensive Perl Archive Network] which can be install by the following command.

uttam@uttam:/ sudo perl -MCPAN -e shell

after this command you'ill be under cpan shell and you'll see the following text on screen..

cpan shell -- CPAN exploration and modules installation (v1.9205)
ReadLine support available (maybe install Bundle::CPAN or Bundle::CPANxxl?)

cpan[1]>

Now you can install module you want with perl.for example you can type "install DBI" to install DBI modules.

After successful installation you can view the DBI directory under following folder.
/usr/local/lib/perl/5.10.0/.

running perl script in apache

2009-05-28T23:30:00.000-07:00

Perl script can be run as executable files in apache.All you have to do is to follow some basic steps given below.

open your apache.conf file in write mode and add the following line.by default it's under /etc/apache2/ directory.

AddHandler cgi-script .cgi .pl

save the file.

Next, search for the line that says " in the file. It should look something like this:[In this case /var/www/ is the document root.]

 
 Options FollowSymLinks
 AllowOverride None

Add "+ExecCGI" to the options list. The line now looks like this:
Options FollowSymLinks +ExecCGI

generally you can find this in sites-enabled/000-default file.

Restart your apache web server.

test by typing URL of your perl script in web browser.

acessing xml in php sent by other script

2009-05-28T23:18:00.000-07:00

There are several situation where we need to accept xml as input in php file which is sent by other scripts like flash/php/perl etc.

To accept xml as input in php, first you need to check that content-type which is being passed by source script has to be in "text/xml" format.

Now in your PHP script you can accept xml input by the following code.

$xml_str=file_get_contents("php://input");
//where $xml_str will have xml string passed by the source script.

Javascript Key code

2009-05-19T00:09:00.000-07:00

Key Pressed	Key Code
backspace	8
tab	9
enter	13
shift	16
ctrl	17
alt	18
pause/break	19
caps lock	20
escape	27
page up	33
page down	34
end	35
home	36
left arrow	37
up arrow	38
right arrow	39
down arrow	40
insert	45
delete	46
0	48
1	49
2	50
3	51
4	52
5	53
6	54
7	55
8	56
9	57
a	65
b	66
c	67
d	68
e	69
f	70
g	71
h	72
i	73
j	74
k	75
l	76
m	77
n	78
o	79
p	80
q	81
r	82
s	83
t	84
u	85
v	86
w	87
x	88
y	89
z	90
left window key	91
right window key	92
select key	93
numpad 0	96
numpad 1	97
numpad 2	98
numpad 3	99
numpad 4	100
numpad 5	101
numpad 6	102
numpad 7	103
numpad 8	104
numpad 9	105
multiply	106
add	107
subtract	109
decimal point	110
divide	111
f1	112
f2	113
f3	114
f4	115
f5	116
f6	117
f7	118
f8	119
f9	120
f10	121
f11	122
f12	123
num lock	144
scroll lock	145
semi-colon	186
equal sign	187
comma	188
dash	189
period	190
forward slash	191
grave accent	192
open bracket	219
back slash	220
close braket	221
single quote	222

How to get XML/HTML result set with mysql

2009-04-02T07:22:00.000-07:00

you can get directly HTML,XML format of your resultset by just executing the query by following syntax.

uttam@uttam:~$ mysql -u[userName] -p -H -e "[query]" [database]

where -H is to get HTML resultset.you can replace this with -X to get XML output.
-e is to execute the query specified.

go to the shell promt. and thry this example.
mysql -uroot -p -H -e "select * from user" mysql

Google gadget Ads

2009-03-30T23:08:00.000-07:00

Google has come up with new marketing tool google gadget ads.one of the coolest feature among all is that To be sure that your gadget ad has the latest data, you can force a refresh at an interval you specify.

Google also provide Google ad editor to quickly build, test, and validate your gadget ads prior to submitting it for review.

want some more Information for creating a google gadget ad?Click Here

Testing web Application

2009-03-25T02:01:00.000-07:00

Nowadays lot's of effort is gone for testing and quality assurance of the web application which can be minimized by using web based testing tools available on the web.

There are lot's of Ad-ons available for mozila firfox for different kind of the testing which Includes such as iMacros for Firefox, WASP, Fireshot, Window Resizer, Selenium IDE, Web Developer, SwitchProxy, IE Tab, Molybdenum, HackBar, and many more.

Selenium IDE is an integrated development environment for Selenium tests.allows you to record, edit, and debug tests.You can choose to use its recording capability, or you may edit your scripts by hand.

Web Developer The Web Developer extension adds a menu and a toolbar to the browser with various web developer tools. It is designed for Firefox, Flock and Seamonkey, and will run on any platform that these browsers support including Windows, Mac OS X and Linux.

Hackbar allow you to test your web pages against sql injections, XSS holes and site security.It is not used for executing standard exploits.

These are few ad-ons which I use and It help me as a developer/tester to test website more rapidly.

Cerating Firefox Extension

2009-03-23T03:37:00.000-07:00

Keen about Developing/building firefox extensions?.Well ! It's easy to develop extensions for the firefox.You need to have understanding of XUL and Javascript.
Basically, this POST will introduce you how to create your first firefox extension.

Extensions are packaged and distributed in ZIP files, with the XPI (pronounced “zippy”) file extension.
The basic structure of a XPI package is as follows.

emptySidebar.xpi:
    /install.rdf         
    /install.js
    /chrome
       |- emptySidebar.jar

Folder Structure is as follows.
emptySideBar
           /install.rdf         
    /install.js
    /chrome
        |- content
        |    |-login.xul
        |    |-helloworldOverlay.js
        |    |-content.rdf
        |- skin
        |- locale

A folder and two files. install.js was all you used to need for the installation, but now that the extension manager has changed (since Firefox 0.9), the install.rdf is used instead.

Chrome foleder contains another archived file, emptyBar.jar.which has three folder.
content - contains all XUL and related ,JavaScript files and content.rdf file.
skin - contains all layout files like CSS and images used in the XUL files.
locale - contains language specific information.

Once this is done, you are ready to create launcher for your extension.
Step1
go to emptySideBar/chrome/ directory.

zip -r emptySideBar.jar content/ skin/ /locale
cd ..
zip emptySideBar.xpi install.* chrome/captain.jar


Once xpi is created upload it to you server and call it from the firefox mozila.

For more information click here

REST Architecture with PHP

2009-02-25T22:08:00.000-08:00

ROA( Resource Oriented Architecture talks about a set of guidelines of implementation of a REST architecture.REST stands for Representational state transfer.REST architectures can be easily implemented in PHP and has wide popularity among the PHP community since it is based on CURD(CREATE, READ, UPDATE, DELETE) model.here are key REST principle mentioned below.

Give every “thing” an ID
Link things together
Use standard methods
Resources with multiple representations
Communicate statelessly

for more information on REST click here

Confiuring php from source

2009-01-29T22:23:00.000-08:00

There are few steps if you want to compile and configure php from the source code available on php.net website.
1. Download the source code from the site.
2. unzip it to a directory of your choice [for eg. /home/uttam/].
3. go to your shell prompt.
4. run configure with the extension needed to support in php.[for eg. ./configure --with-mysql]
- you may see this type of error while configuring your php.

configure: error: xml2-config not found. Please check your libxml2 installation.

- In this case install libxml2 by using sudo apt-get install libxml2 libxml2-dev

5. You will get a thank you message for using php.
5. run make
6. run make install using command sudo make install.here you will see the following info which tell you directory info of PHP .
Installing PHP CLI binary: /usr/local/bin/
Installing PHP CLI man page: /usr/local/man/man1/
Installing build environment: /usr/local/lib/php/build/
Installing header files: /usr/local/include/php/
Installing helper programs: /usr/local/bin/

7. By default PHP command will be loaded at /usr/local/bin/php directory.you can use /usr/local/bin/php -m to know options and extention available to use with php.

8. Congratulation you have successfully installed PHP.

ADODB with PHP and oracle

2008-12-17T23:21:00.000-08:00

Oracle is the popular commercial database which is being used with the PHP.There are vaious ways to connect to oracle database.ADODB library is one of the fastest way to connect php with the oracle database.It has Has multi-tier design. Simple high-level design for beginners, and also lower-level advanced Oracle functionality.ADODB provide very high speed databse connectivity with catching and fastest database abstaction.It also allow multiple prepare statement.

An example to connect php with oracle using ADODB library is as follows.

include"/path/to/adodb.inc.php";
$db = NewADOConnection("oci8");
$db->Connect($tnsName, "scott", "tiger");

$rs = $db->Execute("select * from emp where empno>:emp order by empno",
                array('emp' => 7900));
while ($arr = $rs->FetchRow())
{
print_r($arr);

}

The Execute( ) function returns a recordset object, and you can retrieve the rows returned using $recordset->FetchRow( ).
You can also query the database using the standard Microsoft ADO MoveNext( ) metaphor. The data array for the current row is stored in the fields property of the recordset object, $rs. MoveNext( ) offers the highest performance among all the techniques for iterating through a recordset:

$rs = $db->Execute("select * from emp where empno>:emp", array('emp' => 7900));
while (!$rs->EOF) {
 print_r($rs->fields);
 $rs->MoveNext();
}

For easy pagination support, we provide the SelectLimit function. The following will perform a select query, limiting it to 100 rows, starting from row 201 (row 1 being the 1st row):

$offset = 200; $limitrows = 100;
$rs = $db->SelectLimit('select * from table', $limitrows, $offset);

Caching

You can define a database cache directory using $ADODB_CACHE_DIR, and cache the results of frequently used queries that rarely change. This is particularly useful for SQL with complex where clauses and group-by's and order-by's. It is also good for relieving heavily-loaded database servers.The following example will cache the following select statement for 7200 seconds

$ADODB_CACHE_DIR = '/var/tmp';
$rs = $db->CacheExecute(7200, "select names from allcountries order by 1");

Using Prepare statements

Prepare( ) is for compiling frequently used SQL statement for reuse. For example, suppose we have a large array which needs to be inserted into an Oracle database. The following will result in a massive speedup in query execution (at least 20-40%), as the SQL statement only needs to be compiled once:

PHP Security

2008-10-10T02:43:00.000-07:00

Now-a-days web security has been a major concern.During development, when the code is being written, it is important to consider illegitimate uses of your application. Often, the focus is on making the application work as intended, and while this is necessary to deliver a properly functioning application, it does nothing to help make the application secure. fact that you are here is evidence that you care about security,

Since PHP is a growing language being used for the web development,It's very important to discuss about PHP security.

Input flaws
most common PHP security flaws is the unvalidated input error. User-provided data simply cannot be trusted and should be validated properly.

register_globals = OFF. The register_globals directive is disabled by default in PHP versions 4.2.0 and greater.Enabling register_globals may cause a security risk.
A common example to explain the problem is as follows.
this example that illustrates how register_globals can be problematic is the following use of include with a dynamic path:

With register_globals enabled, this page can be requested with ?path=http%3A%2F%2Fevil.example.org%2F%3F in the query string in order to equate this example to the following:

Avoid using $_REQUEST[] since as per GPC rule $_GET has higher priorities than $_POST, So $_POST variables may be overwritten.

Always validate input data against maxlength in PHP.you can use array and for each to do this.

50);
foreach($max as $key=>$val)
{
    if(strlen($_POST[$key])>$val)
    {
            //display maxlength error
    }
}
?>

web usabilty

2008-09-29T00:43:00.000-07:00

Usability has it’s own importance in a website.Some dos and don’t s to achieve a good usability are as follows.

Do:
- Use ALT tags for all graphics, especially navigation graphics.
- Use black text on white background whenever possible for optimal legibility.
- Use either plain-color backgrounds or extremely subtle background patterns.
- Make sure text is in a printable color (not white).
- Place navigation in a consistent location on each page of your website.
- Use a familiar location for navigation bars.
- Keep the design from scrolling horizontally.
- Use one axis of symmetry for centered text on a page.
- Encourage scrolling by splitting an image at the fold.
Don’t:
- Allow ALT tags to get clipped (especially an issue for small, fixed width images).
- Display static text in blue or underlined.
- Use boldface or ALL CAPS for long pieces of text. These slow down reading.
- Leave too much white space–reduces scannability.
- Make the user scroll to find critical information, especially transaction buttons and navigation links.
- Use horizontal rules to separate chunks of content.
- Alternate too frequently between centered text and left-aligned text. Most text should be left-aligned.
- Fix pages at larger than 800 x 600 pixels. Larger pages may force users to scroll horizontally.

PHPCamp 2008 learning

2008-09-22T00:25:00.000-07:00

This was the first PHP camp happening in india pune.I have just returned after attending un-organizing India’s biggest php camp.I learned a lots.I shared my knowledge of PHP security there.Overall I enjoyed this camp organized @ persistent system, was attended by over seven hundred interested intellectuals. Nice event, nice ppl..

Actual I was in search of such kind of platform where we all can share our knowledge and our expertise.I think this type of camp should continue for the years ahead....
want to download my presentation on PHP security ?? click here

MYSQL String functions makes life easier

2008-09-12T05:42:00.000-07:00

MYSQL strings function can make your life easier for you.You can use combination of string function to get the complex result needed in some project.String function in mysql helps us to extract what we want from a string and that can avoid lot of code.The common String functions available in MYSQL can be found on the link http://dev.mysql.com/doc/refman/5.1/en/string-functions.html

Use of MYSQL String function.

consider the following table which contains caseId and you have to extract maximum number at the last of caseId, those belong to id 1.

caseId	id	Value
JET/2005-2006/1	1	15
JET/2005-2006/2	1	25
JET/2005-2006/1	2	15
JET/2005-2006/2	1	2
JET/2005-2006/2	2	12
JET/2005-2006/3	1	5

you can use the following query to get the result.

SELECT max(substring(caseId,locate(”/”,caseId,locate(”/”,caseId)+1)+1)) as maxCaseId FROM `test` WHERE id=1

The result of the query is as follows.

maxCaseId
3

This query work as follows.

inner locate function get’s first occurrence of “/” [let's 4].and outer locate function get first occurrence of “/” [let's 17] in the string starting from position 4+1=5.so finally in subString function will give all the string values after position 17+1=18.So by this we will have all numbers those belongs to id 1.now finally max function will get max number within all the numbers found by substring function.

if you want to get the maximum integral value, you got to cast it to an integer - otherwise, on having a caseId value like JET/2005-2006/23, it would still return 3 as maximum & not 23.

SELECT
MAX(0 + SUBSTRING(caseId, LOCATE(’/', caseId, LOCATE(’/', caseId) + 1) + 1)) AS maxCaseId
FROM `test` WHERE id = 1;

SELECT
MAX(0 + RIGHT(caseId, LOCATE(”/”, REVERSE(caseId)) - 1)) AS maxCaseId
FROM `test` WHERE id = 1;

even reversing strings can avoid looping of locate.

SELECT MAX(RIGHT(caseId, LOCATE(”/”, REVERSE(caseId)) - 1)) AS maxCaseId FROM `test` WHERE id = 1

So This is just an example to explain uses of string functions available in MySql. There may be lot’s of other situation where you can use string function provided by mysql and get your work done rather than getting result by writing complex logic in programming.

understanding JSON

2008-09-12T05:38:00.000-07:00

JSON stands for JavaScript Object Notation.It's lightweight data interchange format.It is a text-based, human-readable format for representing object and other data structures and is mainly used to transmit such structured data over a network connection (in a process called serialization).It is based on subset of javascript.

JSON is a self-contained unambiguous data representation format, and since it carries no executable or algorithmic meaning it is inherently secure by itself. However security issues may arise if a program incorrectly processes JSON-formatted data as if it were something else. Since the JSON syntax is by design a subset of the Javascript syntax, most security concerns involve having a Javascript interpreter directly process JSON text as if it were Javascript source code.

The following example shows the JSON representation of an object that describes a employe. The object has string fields for first name and last name,company name,designation contains an object representing the person's address, and contains a list of phone numbers (an array).

   "firstName": "Uttam",

   "lastName": "Kumar",

   “companyName” :”magnet”,

   “designation”:”Sr. web Developer”,

   "address": {

     "streetAddress": "Patankar street",

            "city": "Nsp(w)",

             "state": "MH",

            "postalCode":401203

},

 "phoneNumbers": [ "212 732-1234","646 123-4567"]

Suppose the above text is contained in the JavaScript string variable employee. Since JSON is a subset of JavaScript's object literal notation, one can then recreate the object describing Uttam Kumar with a simple eval() function which is as follows

 var emp = eval("(" + employee + ")");  Now we can access firstName,city,phone number by the following.

emp.firstName //property of object

emp.address.city //sub property of object

emp.phoneNumbers[0]//array

 similerly we can access all the values.

Basic level Interview Questions - PHP

2008-09-12T04:44:00.000-07:00

Difference between session and cookies?

Ans:- 1. session stored at server while cookie get stored at client’s web browser.

2. session are stored as an object on server side on the path specified in the php.in file for session_save path variable while cookies are passed as header and stored on client’s web browser as text file.

3. session variables are exists only when session doesn’t expires while cookies[persistent not session] can be stored for future time also and can be used to handle user’s preference.

what are encryption methods available in php and mysql?Difference between sha1 and md5?

Ans:- some encryption methods available in php are md5,sha1,encrypt,password.Difference between sha1 and md5 encryption is that sha1 take more space than md5 in terms of storing information in the database.Some encryption available in mySql are password,MD5,encrypt.

What is Ajax & how it works?

Ans:- AJAX stands for asynchronous javascript and xml.It’s asynchronous this script doesn’t wait for the response.Regardless of this it can make another request without waiting for the response.Fist of all it creates XMLHttpRequest object by which it makes a request.and when response comes back script handover it to another function which will check for the response readyStatus and returns the response.

Oops principles?

Ans:- Polymorphism [not supported in PHP]

Encapsulation

Abstraction

Dynamic binding

class and Object

for more detail please refer http://in2.php.net/manual/en/language.oop5.php

Mysql Joins?

Ans:- I don’t have idea but know about types.Cross,Left,right,inner and outer join.

Strings and array functions.array_walk,in_array?

Ans:- check function list available on

http://in2.php.net/manual/en/ref.array.php [for array]

http://in2.php.net/manual-lookup.php?pattern=string〈=en [for strings function]

Difference between include,include_once,require,require_once?

Ans:- Unlike include(), require() will always read in the target file, even if the line it’s on never executes. If you want to conditionally include a file, use include(). The conditional statement won’t affect the require(). However, if the line on which the require() occurs is not executed, neither will any of the code in the target file be executed.include() may give warning and proceed further but require() will hault whenever warning/error faced in the script.include_once(),require_once() as name suggest can be used to include a file only one.[useful in case we include a class file]

How can we submit a form without a submit button?

Ans:- you can call a function in javascript onclick event of any form element/link and in the function you amy use document.formName.submit(); to submit the form

What is the difference between mysql_fetch_object, mysql_fetch_rows and mysql_fetch_array?

Ans:- mysql_fetch_object will return an object by which we can access the database fields records while mysql_fetch_aaray and mysql_fetch_rows return array of database records.mysql_fetch_row will not return associative array while mysql_array will return associative array too.

What is the difference between $message and $$message?

$message is used as a variable while $message can be used to assign a value as variable.for eg:

$message=’uttam’;

$message=’kumar’;

in this case $kumar will give you value as ‘uttam’.

What is meant by nl2br()?

Returns string with ‘
’ inserted before all newlines(\n).

$msg=”these are \n interview question”;

$nl2brmsg=nl2br($msg);

$nl2brmsg will return value as “these are
interview question”.