php tutorials

How to add HTML Javascript 2 Blogger template

2012-05-09T23:30:00.000-07:00

Blogger.com is a very popular and powerful online blogging platform. Blogger.com have recently introduced there new interface with lots of new features and enhancements. Whenever there is a change in interface, users might find it difficult to find some options and tool from updated interface.

If you are a blogger user , and wish to add HTML, JavaScript and CSS codes and styles to your blogger template, then you might need to find it because blogger have done some changes in there UI. Because even I face the same problem while editing the template, so I am writing this post which will help you to insert HTML,css and / or JavaScript code to your blogger template.

How To add HTML, CSS and JavaScripts Code in Blogger template?

Go to Blogger >> Your Blog >> Template (Left menu) >> EDIT HTML ( Right Pane ) >> Proceed
How to add CSS
- Search for ]]> With (CTRL+F).
- After you find ]]> just above it paste the css style that you wish to apply to your pages.
- Save your template by pressing Save Template Button.
- Now you can use these css styles in your posts.
How to add JavaScript file
- Search for < / head > With (CTRL+F).
- After you find < / head > just above it paste the following code to add external JavaScript file.
- Save your template by pressing Save Template Button.
How to add custom HTML
- Search for < html > With (CTRL+F).
- After you find < / html > , you can add your HTML code any where. But it may disturb the original template. So do it carefully. Or use the HTML widged.
- Save your template by pressing Save Template Button.

easy jquery form validator absolute message box

2011-07-18T02:20:00.001-07:00

Hey all, I was looking for nice and easy form validator in javascript/ jQuery which displays the error messages as absolute div and not block div. Because the most of validators displays messages next to input element or below them.

The issue with such validators is, some time it becomes very difficult to manage the ui when large no of input elements are there on page and proper space is not there on page. It also makes issues across browsers.

Solution is : Display absolute error messages.
I found a great great jQuery plug in : download from here

This is really very nice form validator in jquery which displays error messages in absolute div. With all best features and customization included.

Here are some custom functions for this plug in.

Allow all ASCII characters with regular expression. - javascript


function checkAsciiValues(field, rules, i, options){
    
    var value  = field.val();
    var length = value.length;

        for(var i = 0; i< length; i++){               if(value.charCodeAt(i) < 1 || value.charCodeAt(i) > 255){
      return "* Please enter only ASCII values.";
     }
        }
          }

____________________________________________________________________

What is polymorphism in php?

2011-02-09T08:37:00.000-08:00

Polymorphism helps a sub class to behave like a parent class. When an object belonging to different data types respond to methods which have a same name, the only condition being that those methods should perform different function.

What is meant by Session Clustering?

2011-02-09T08:24:00.000-08:00

The Session Manager session support allows multiple server instances to share a common pool of sessions, known as a session cluster.

Session clustering setting up methods :

#1)First methods, is to have a NFS shared where session will be store. Setting this is quite easy, just a little modification on php.ini file to change the “session.save_path ? directive to point to the NFS share. The main problem with NFS is on high traffic, NFS share is really slow. So synchronisation and data corruption can arrive and this can be very frustrating.

#2) The Second method is to use a Database to store session datas. This solution suppose to write custom session handler. The only real problem of this method is that will generate a very big amount of the number of connections and database query. And this required a dedicated server and a cron job to clean all unused session datas.

#3)The third method is to use the MCache. MCache is a daemon (a server) that deal with session storing only. It support from RAM storage to data serialization in file/fatabase. It is said that MCache access is native as a session handler in PHP, so it’s just about configuration via php.ini … but I did not investigate yet on how to make it work.

#4)The fourth method is Memcache, another daemon for “distributed memory object caching system ?. Advantage to Memcache, as it’s integrated in PHP as PECL (look at the documentation on how to install). This method can be very interesting as it provide great performance but this will require a single or couple dedicate server of it use.

#5)The last method is commercialized by Zend. The product is the Zend Platform and integrate many component of some previous Zend products (Zend Server, etc.) and some new products (Zend Core…). The Zend Core is a Cluster manager that can handle multiple server. It can be use to remote debugging (from Zend Server), performance monitoring and sessions replication. As described, there are many advantage using Zend Platform so I could only to advise you to use it simply first to profile your application and for session clustering ! But there are a little probleme, session are replicated from a server to the other servers. So if a server crash maybe the Platform could not have the time to replicate session data. It can result to session destruction. But be sure that Zend know the problem and will surely fix this soon or later.

what are the most common caching policy approaches ?

2011-02-09T08:29:00.000-08:00

1)Time triggered caching (expiry timestamp).

2)Content change triggered caching (sensitive content has changed, so cache must be updated).

3)Manually triggered caching (manually inform the application that information is outdated, and force a new cache creation).

what are the database space-saving functions available in php ?

2011-02-09T08:27:00.000-08:00

Use ip2long() and long2ip() to store the IP addresses as Integers instead of storing them as strings, which will reduce the space from 15 bytes to 4 bytes. This will also increase search speed and make it easy to see if a ip falls within a specified range.

# Use gzcompress() and gzuncompress() to reduce the strings before you store them in a database.

The gzcompress can compress plain-text up to 90%. The only reason why you shouldn’t use it is when you need full-text indexing capabilities.

common php questions and answers

2011-01-25T20:38:00.000-08:00

What does a special set of tags do in PHP? - The output is displayed directly to the browser.
What’s the difference between include and require? - It’s how they handle failures. If the file is not found by require(), it will cause a fatal error and halt the execution of the script. If the file is not found by include(), a warning will be issued, but execution will continue.

How do you define a constant? - Via define() directive, like define ("MYCONSTANT", 100);

Explain the ternary conditional operator in PHP? - Expression preceding the ? is evaluated, if it’s true, then the expression preceding the : is executed, otherwise, the expression following : is executed.

How do I find out the number of parameters passed into function? - func_num_args() function returns the number of parameters passed in.

What’s the difference between accessing a class method via -> and via ::? - :: is allowed to access methods that can perform static operations, i.e. those, which do not require object initialization. :: is called as "scope resolution operator".

How do you call a constructor for a parent class? - parent::constructor($value)

What are the two new error levels introduced in PHP5.3? -
E_DEPRECATED

The E_DEPRECATED error level is used to indicate that a function or feature has been deprecated.
E_USER_DEPRECATED

The E_USER_DEPRECATED level is intended for indicating deprecated features in user code, similarly to the E_USER_ERROR and E_USER_WARNING levels.

Twitter result found in google SERP

2009-12-21T21:30:00.001-08:00

I was googling out the keyword "codeignitor" and I got this result in google SERP.
I am not using any monkeyscript in my mozilla browser.

Adjacency List Model and Nested Set Model for hierarchical data in MySQL

2009-11-03T03:42:00.000-08:00

I am working on classifieds website these days. These kind of websites are getting famous these days and they also have average kind of traffic. while working on database designing for websites like classifieds / auction / web directories, we have to take care of few things like

1. This is a tree structure which may have n levels.
2. And there has to a straight way to traverse from top to bottom and from bottom to top.
3. Strong tree traversal algorithm.
4. Retrieving a Single Path between two nodes.
5. Depth of nodes and depth of sub-tree and lots of other things.

For this we need a strong table design and relationship structure. In MySQL we can manage this hierarchical data with two different models.

1. The Adjacency List Model
2. The Nested Set Model

The Adjacency List Model is a very basic table structure which maintain the column lets say "parent" to maintain the parent child relationship. (It actually hold the PK of parent node). But this model again has some disadvantages, described in brief on the link at the bottom.

so,I came across a another hierarchical model called as nested set model. In this type of hierarchical data model parent nodes envelope there children. This is based on algorithm called as preorder tree traversal algorithm. This is a very good concept while working on tree structure tables.

Source of information : http://dev.mysql.com/tech-resources/articles/hierarchical-data.html

Zend framework Captcha-sample image captcha code

2009-04-05T23:11:00.000-07:00

Zend framework is based on number of different components for different purposes. Zend framework has a component ( Zend_Captcha ) for use of captcha in web forms. CAPTCHA stands for "Completely Automated Public Turing test to tell Computers and Humans Apart".

Overview of a component
Component : Zend_Captcha
php extension : gd
use : Can be used as standalone or with Zend_Form
Adapters : Zend_Captcha_Word
Zend_Captcha_Image
Zend_Captcha_Dumb
Zend_Captcha_Figlet
Zend_Captcha_ReCaptcha

Adapter details
1.Zend_Captcha_Word

All word based adapters make use of this adapter. Zend_Captcha_Figlet, Zend_Captcha_Dumb, Zend_Captcha_Image extends this abstract class.

Zend_Captcha_Word is actually a base class for all these word based captcha adapters.

This is an abstract class and cant be instantiated directly.

----------------------------------------------------------------------
2.Zend_Captcha_Image
This also extends Zend_Captcha_Word. This is a very commonly used captcha. And zend really made it easy to use... so take a look at the sample code below...

How to use Zend_Captcha_Image in form? Sample code is here.

$form->addElement('Captcha','captcha',array(
'label' => 'Please enter the 5 letters displayed below:',
'required' => true,
'captcha' => array(
'captcha' => 'image',
'name' => 'foo',
'wordLen' => 6,
'font' => DOC_ROOT.'/html/captcha/arial.ttf',
'fontSize' => 30,
'imgDir' => DOC_ROOT.'/html/captcha',
'imgUrl' => 'http://sagagolf/captcha/',
'timeout' => 300)
));

----------------------------------------------------------------------
3.Zend_Captcha_Figlet

This captcha adapter is also a word based so it extends Zend_Captcha_Word.

This adapter is limited to generate only the characters and no integers.

Take a look at this sample code below, if you want to use the Zend_Captcha_Figlet with Zend_Form. You can write the validations also in this code.

$form->addElement('Captcha','captcha',array(
'label' => 'Please enter the 5 letters displayed below:',
'name' => 'figlet',
'required' => true,
'captcha' => array(
'captcha' => 'figlet',
'wordLen' => 4
)
));
----------------------------------------------------------------------
4.Zend_Captcha_Dumb
Zend_Captcha_Dumb is a very very basic captcha which simply create random string which may consists integers and characters.

This adapter is a word based so it extends Zend_Captcha_Word.

Sample use/code for using Zend_Captcha_Dumb

$form->addElement('Captcha','captcha',array(
'label' => 'Please enter the 5 letters displayed below:',
'name' => 'captcha',
'required' => true,
'captcha' => array(
'captcha' => 'dumb',
'wordLen' => 4,
'timeOut' => 5
)
));

----------------------------------------------------------------------
5.Zend_Captcha_ReCaptcha
The ReCaptcha adapter utilizes Zend_Service_ReCaptcha to generate and validate captchas.
----------------------------------------------------------------------

new php.ini directives in php5

2009-05-19T00:27:00.000-07:00

PHP 5 came up with some new directives in php.ini file. I am writing about all new directives introduced in PHP 5. Heres the list...

1) mail.force_extra_parameters : Force the addition of the specified parameters to be passed as extra parameters to the sendmail binary.

2)register_long_arrays :

configures the php to allow or disallow the registration of long arrays $HTTP_*_VARS

possible values : On / Off

Default:off

Recommended : If you are not using them then its recommended to keep them off for some performance reasons.

3) session.hash_function :
This directive allows us to configure the way of php's session id generation algorithm.
0: MD5 (128 bits)
1: SHA-1 (160 bits)

possible values : 0 / 1

Default : 0

4)session.hash_bits_per_character :
This directive allows us to define how many bits are stored in each character when converting the binary hash data to something readable.

possible values :
'4' (0-9, a-f)
'5' (0-9, a-v)
'6' (0-9, a-z, A-Z, "-", ",")

default : 5

5) zend.ze1_compatibility_mode :
This configuration directive allows us to enable or disable the compatibility with zend engine 1 ( which is a php 4 engine). Its set to Off as default and turning it on may affect cloning,casting. Objects are also passed by value instead of pass by reference.

possible values : On / Off

php functions in details tricks n tips

2009-04-13T01:55:00.000-07:00

I am working with php since more than 3 years and I love this language as this is very powerful servers side programming language. Actually I like the set of php built in functions. Php really has a lots of built in functions for arrays and string manipulation and almost for everything. Here I am trying to write some important things about the php functions and some important tips specially for the peoples who are preparing for some certifications or some php exam.

PHP has
1.User-Defined functions
2.Variable functions
3.Anonymous functions Only php5.3.0 >
-----------------------------------------------------
1.User-Defined functions

function function_name(mixed arg1,.....,mixed argn)
{
// any valid php script
}
Passing arguments to function
a)Default method to pass arguments is pass by value
function takes_array($input)

b)Another method is pass by reference
function takes_array(&$input)

c)default argument values.
In this we can give the default value to the trailing function arguments.
function function_name($arg1,$arglast = "defaultvalue")

d)variable length argument list
We can simply define the function without any argument to it and we can call it and pass random no of arguments at different time. we have to use some built-in functions to implement such kind of function. sample code snippet- thank to codepad.org

-----------------------------------------------------
2.Variable functions
We can simply put the function name in a variable and can execute that function by $varname('function argument if any');
sample code for variable function

[php4 vs php5] - In php5 default values may be passed by reference.

[zce-5]func_get_args() and func_get_arg() works for only arguments which are passed to function and not for the default arguments.

A function can not return multiple values.

To return a reference from a function, use the reference operator & in both the function declaration and when assigning the returned value to a variable.

[zce-5]language constructs : echo(), print(), isset(), unset(), empty(), include(), require(),array(),list(),die(),exit(),eval(), return cant be used with variable functions.

[zce-5] : php functions are not case sensitive.

[php4 vs php5]Anonymous functions are not there in php4.

developing secured web application with php

2009-04-09T02:58:00.000-07:00

Security of a web application

When there is a user interaction in web page and the input data is coming from user inputs and query string etc etc... then I cant trust the behavior of the web page! can you?????

Users can enter the script or some other special characters in query string which can result in to unpredictable behavior...!

some simple things which we should use while developing the application.

1.Input filters more

2.Escape Output
Always use the htmlentities() function to echo the variables.

3. Register Globals
When set to On, the register_globals configuration directive automatically injects variables into scripts. That is, all variables from the query string, posted forms, session store, cookies, and so on are available in what appear to be locally-named variables.

Status of register_globals configuration directive
Before 4.2.0 it was on by default.
Since then it is set as off as default.
In php 6 it will be deprecated.

4.spoof form
Attacker normally go for spoofed form submission. e.g. attacker can simply copy the form to there own local machine change the action with full page url and this way they can change the client side validations and other restrictions.

How to overcome form spoof attacks?
STOPING OFF DOMAIN TRANSACTIONS
Check the REFERER header in $_SERVER superglobal array. The referer has to be your site only.

sample snippet
if (stristr($_SERVER['HTTP_REFERER'], 'http://www.supamu.info') === FALSE ) {
die ( 'Hacking attempt. Your are such a Nooby!.. ' );
**

5.Cross-Site Scripting (XSS)
Its all about stealing the users personal data and values from cookies with the help of some simple JavaScript techniques.

How to overcome form Cross-Site Scripting (XSS) attacks?
Proper output escaping is the only way to make your web pages secure from such attacks.

6.Database Security - SQL injection attack
We normally asks users to fill some data in form elements and we use these user entered data in one of the queries.

How to avoid sql injection attacks?
1. Use the input filters to filter the user data.
Whenever there is a data from outside world just use the php input filters and
sanitize input data, before being used in a sql query.
How to filter the inputs.

2. Always escape your input
PHP has certain built in function which can be used to make database queries safe from outside world.
mysql_escape_string and mysql_real_escape_string.
Mysql_real_escape_string prepends backslashes to the following characters: \x00, \n, \r, \, ', " and \x1a.

Very good article on web security

Are you on shared hosting??
There are variety of security issues while using shared hosting. I cant write much theory here so I am just writing some important things that you should do on shard hosting.
There are 3 very important directives in php configuration file (php.ini)
Disable_functions
This directive in php.ini allows us to disable some functions. We should normally specify the fnctions which are related to security of server. Some of them are
exec,apache_setenv,disk_free_space,diskfreespace,dl,
highlight_file,ini_alter,ini_restore,openlog,passthru,phpinfo,
proc_nice,shell_exec,show_source,symlink,system

---------------------------------------------------------------------------------
open_basedir
---------------------------------------------------------------------------------
disable_classes

Just open the php.ini file and search for these directives. I cant write description better than that..

7.Disable Remote URLs

1. allow_url_fopen to off in php.ini.

2. open_basedir in php.ini to a set of directories that PHP is allowed to perform file operations on

3. safe_mode to on in php.ini. This will prevent the use of the system functions like system(), passthru() and exec(), but will also create other problems as well.

4. Always Use the file_exists() function (which does not work on remote files) to determine the existence of the file to be included on the local filesystem before including it. The safest way to include the files.

Thanks to Aaron Brazell

Best of luck n have secured web applications. Please add your reviews in comments.

Standard PHP Library extension download introduction

2009-05-07T03:13:00.000-07:00

Standard PHP Library

php5 is focused on object oriented strict syntax and object oriented capabilities. Standard php library (SPL) made this job very east. SPL provides all standard set of interfaces for PHP5 to simplify the data access and traverse the aggregate structures. These structures can be anything like directory traversal,database,arrays kind of structures.

simple words : SPL is nothing but a bunch of classes n interfaces which are developed to solve the common problems.

Lets take some examples,
Suppose that you are working on one of the following tasks
1. Database results.
2. Directory traversing n display.
3. Reading file contents.

In all of these tasks we have to iterate the results. Like If we fetch data from database then we have to iterate the result set in order to fetch complete data from result set and same thing with file read and directory traversal task also. In all these cases the programming and coding is same ( fetch the main resource and iterate through the result set), but we have to use different set of php functions to handle different resources( for database we use mysql_fetch_array for directory traversal we use readdir() and so on..)

The classes and interfaces in SPL makes this kind of traversal easy. Lets start with simple DirectoryIterator class.

SPL can work with following data structures.
Arrays
objects
heap
doubly link list
stack
Queues

It provides set of iterators to traverse the objects. List of few iterators
ArrayIterator
IteratorIterator
DirectoryIterator
CachingIterator
RecursiveIteratorIterator
RecusrsiveCachingIterator
RecursiveDirectoryIterator
SimpleXMLIterator
FilesystemIterator
FilterIterator
GlobIterator
ParentIterator
LimitIterator

SPL also provides some Interfaces
SeekableIterator interface
Countable interface

SPL also provides some exceptions and functions. click to read complete details of SPL

--------------------------------------------------------------------------------
Here is one simple example of DirectoryIterator

DirectoryIterator
This is used to iterate through any directory as simple as that.
// sample php code to iterate through any server directory
foreach(new DirectoryIterator('path/to/dir') as $element):
echo $element;
endforeach;
?>
sample Directory iteration with SPL

language construct in php echo print isset unset empty include

2009-05-07T03:02:00.000-07:00

What is language construct?
Language constructs are built in to php and they can be used like a function. But the basic difference between them is the language constructs can't return the anything.

language constructs can be used with or without parentheses.

List of some language constructs in php
echo(), print(), isset(), unset(), empty(), include(), require(),array(),list()

simple file handling functions faster than ctype functions

2009-05-05T06:39:00.000-07:00

Php offers c type functions to handle files. But php also provides some more functions which are simple and faster than all c type functions like fopen() fread() file() etc...

Example 1
readfile() function can be used directly to simply read the file and output its contents to standard output. We can use this function instead of c type functions for better performance.

Example 2
// classic old method
$content = implode("\n", file("filename.txt"));
// it load complete file in memory and large files can make server over load.

// New php 4.3.0 method
$content = file_get_contents("filename.txt");
// in this we can specify the limit to load the file. So at least you have control over memory.

New function in php5.0.0
file_put_contents('file_path','Data to write',MODE);

We can write in to any file in one shot. no need to create any file handle separate.

how to avoid direct access to file protect files in php

2009-05-06T07:24:00.000-07:00

If you don't want users to access some files directly from browser then you can simply use following php script on top of such files.

// this is first code block
if (realpath(__FILE__) == realpath($_SERVER['SCRIPT_FILENAME']))
{
// tell people trying to access this file directly goodbye...
exit('This file can not be accessed directly...');
}
/ protected code below this.
?>

clearstatcache filesystem function clears cached file status

2009-05-06T02:11:00.000-07:00

PHP maintains the status of files in internal cache. If we are using any of the file functions like is_file , is_readable , is_writable, filectime() etc then php stores the information returned by the applied function and if we try to use that same function on the same file in same script then php uses the cached value even if the file status changes in between two calls. But as any php script time is small only, but we have to keep this in mind while working on long running scripts. So if you are really working on such kind of script then you can use the php built in function to clear the php's internal cached information about the files.

Syntax
void clearstatcache(boolean $clear_real_path_cache(default FALSE),string $file_path)

first parameter : To clear real path cache or not.
second parameter : Use only when first parameter is TRUE.

some functions affected by clearstatcache()

programming tips tricks performance improvement

2009-05-06T00:27:00.000-07:00

Here are some of the Tips and tricks which can improve the speed and performance of your php script and may save your resources.(NOTE:I haven't tested all these tips but these are wildly used to improve the performance of the php script.)

Tips while working with strings

string concatenation

echo 'php', 'developer'; // saves overhead time for string concatenation.
echo 'foo' . 'bar'; // slower..

Interpolation

$variable = 'this is '.$another_var.' with me'; // faster
$variable = "this is $another_var with me"; // slower

Tip:
Simply use the single quote instead of double quote.
Avoid the string concatenation with (.) if possible.

Predefined Constants PHP_VERSION _OS _EOL _PREFIX _BINDIR

2009-05-05T02:09:00.000-07:00

Php has lots of predefined constants, Here in this post I am writing about very few constants and there sample output.

[code]
// the use of come special php predefined constants.
echo PHP_VERSION.PHP_EOL;
echo PHP_OS.PHP_EOL;
echo PHP_PREFIX;
echo PHP_EOL;
echo PHP_BINDIR;
echo PHP_EOL;
echo PHP_CONFIG_FILE_PATH;
echo PHP_EOL;
echo PATH_SEPARATOR;
?>
OUTPUT
5.2.5
Linux
/usr
/usr/bin
/etc/httpd
:
[/code]

If you simply look at the constants and there output line by line then you can understand there uses easily , its really straight forward.

List of other constants
http://in.php.net/reserved.constants

custom error handler sample example script

2009-04-20T06:27:00.000-07:00

Error handling in php?? do I really need to put my time on this or php does it automatically??

Errors are the part of every programming language and normally programmers don't want to pay much attention to handling the errors. PHP of course handle the errors and maintain logs also, but we should handle all the errors. PHP has very easy and better facility to create custom error handling system.

Lets first see what type of errors are there in php
1. Parse Errors - compiler error
2. Fatal Errors - execution halts
3. Warnings - execution continues
4. Notices - execution continues

php.ini directives to control errors
There are 3 important directives in php.ini.

display_errors keep it off always on production server.
log_errors keep it on will log errors in server's logs
error_reporting error reporting level setting can be done e.g. E_ALL~E_NOTICE

sample code to create a custom error handler in php
[code]ini_set('display_errors', 'Off');
ini_set('log_errors', 'On');

function UserErrorHandler($errno, $errstr, $errfile, $errline)
{
switch ($errno) {

case E_USER_WARNING:
echo "USER WARNING : [$errno] $errstr\n";
break;

case E_USER_NOTICE:
echo "USER NOTICE : [$errno] $errstr\n";
break;

case E_USER_ERROR:
echo "USER ERROR : [$errno] $errstr\n";
echo "There is a fatal error on line no $errline in script $errfile\n";
echo PHP_VERSION . " on (" . PHP_OS . ")\n";
echo "Execution ends\n";
exit();
break;

default:
echo "Unknown error types: [$errno] $errstr\n";
break;
}
/* you can send email to admin or any other logging system */
return true;
}

set_error_handler("UserErrorHandler",E_ALL);

$x=0;
$y=1;

// division by 0 error
echo $y/$x;
echo "\n\n";

// lets c user generated error
if(0===$x)
trigger_error('X cant be 0',E_USER_ERROR);

?>[code]

Sample custom error handler code

If you look at above sample error handler function , you can understand that the function which is used to create a custom error handler is set_error_handler(). In php5 it starts accepting 2 parameters error handler function name and error type which are handled by that function. In older versions of php this function was accepting only one parameter.

Error handling function : UserErrorHandler is our custom error handling function. This function will get executed whenever there is any error in code. Then its upto you how to handle the errors, you can mail them to administrator or you can keep them in some file log or display it to users.complete freedom to manage the errors in system. This function takes 5 parameters as follows

error_level : e.g. E_ALL , E_NOTICE ..
error_message : error message
error_file : file name in which the error occurred
error_line : line no in which the error occurred
error_context : array of variables in that error context

-- oops way of handling errors is different. We can implement the custom error handler in php with help of php5 default class Exception. Sample php5 custom error handler code

We can also set a exception handler for complete application. I mean a function which can handle all the uncaught exceptions. Just look at following code.
// how to handle error any where in application
function uncaughtexception(Exception $e)
{
echo $e->getMessage()."\n";
echo $e->getCode()."\n";
echo $e->getLine();
}
set_exception_handler('uncaughtexception');

throw new exception('u caught me');

//output
u caught me
0
11
?>

[php4 vs php5]: In php5 set_error_handler() supports second parameter to set the type of error that custom error handler function is going to handle.

oops things to remember about class methods and everything

2009-04-24T00:30:00.001-07:00

Hi all , this post is just to highlight some important facts of oops n php. I am trying to categories them like class / interface / basic etc. Please put your comments if you want to suggest any category. Lets start..

Class
1. When a class defined as final it can no longer extended by other classes and function defined as final then it cant be overridden in child classes.

2. A abstract class cannot be instantiated and it can only be extended.

3. Class constants are public, and accessible from all scopes.

4. class can only extend one parent class, but it can implement multiple
interfaces.

5. In php5 class objects are always passed as reference rather than a value.

6. destructors are introduced in php5 but we cant determine the order of destroying of two different objects in our script.

7. 4 access specifiers are introduced public,private,protected,final.

8. the final specifier can be used for only classes and functions. If class is defined as final then it cant be extended.

9. Member variable can be initialized at the time of declaration.

10. Access to static property of class through the object will produce an notice. where as in php4 it was completely acceptable. Check sample code

11. Class constants are public, and accessible from all scopes.

12. We can implement more than one interfaces in one class.

13. Exceptions are the objects created whenever there is any error in script.
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Methods

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Interface

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access specifiers

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exception handling

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keywords

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setcookie tutorial syntax login example

2009-05-03T23:40:00.000-07:00

setcookie tutorial with login example and syntax of function

setcookie description
It simply sets a cookie to be send with HTTP headers. one cookie is set we can access it later with help of following
$_COOKIE['cookie_name']
$_REQUEST['cookie_name']

setcookie Syntax
Boolean setcookie(string $name,string $value,int $expire,string $path,string $domain,bool $secure,bool $httponly );

Parameters to the function
some tips first.
There is only on parameter which is compulsory that is $name of cookie.
We can skip the parameter by simply putting ("") and 0 for $expire as its a integer.

string $name : Name of cookie

string $value : Value for cookie.

int $expire : Unix timestamp specifying no of seconds the cookie is valid.
one day : time()+60*60*24 .. so simple
If its set to 0 then cookie expires after browser close.

string $path : The cookie will be available to the specified path only(if specified).

string $domain : The domain that the cookie is available.\

bool $secure : If its TRUE then it can be set only on secure connection.

bool $httponly( > php5.2.0) : This option is added in php 5.2.0 and if its set as TRUE then cookie is accessible only through http protocol n not for the external ecripts like javascript. But not supported in all browsers. So use it on your own risk. But it helps against XSS attacks.

example n sample code
setcookie('cookiename','cokievalue',0);
This will set a cookie with name "cookiename" with value cookivalue and will expire on browser close.

This can be access at server side like this
$_COOKIE['cookiename'];

?>

regular expression tutorial basic rules beginners

2009-04-29T03:27:00.001-07:00

I am also new to regular expressions and I am learning to some basic regular expression rules so I am trying to put them here in new post. Please put your comments if I am doing some mistake while explaining.

There are some special characters which are used while developing the regular expression.Here are some ..
Modifiers
Modifiers are used to alters the meaning of the immediately preceding pattern character.

+ : matches 1 or more of the preceding term
a* matches a,aa,aaa n so on
-----------------------------------------------------------------------------
* : matches 0 or more of the preceding term
a* matches '',a,aa,aaa n so on
-----------------------------------------------------------------------------
? : matches 0 or 1 of the preceding term
a* matches '' n a -----------------------------------------------------------------------------
Literal Characters
. : Matches any character including new line.Its called as wildcard.
Example 'a.c' will match 'aec', 'acc', 'a@a' and so on
-----------------------------------------------------------------------------
[ : Set of characters enclosed in [] matches any of the character included in set.
e.g.REGEX [abc] matches with a or b or c
Inclusive Range[a-d]:matches any characters included in range of a - d.
-----------------------------------------------------------------------------
^ : exclusion range[^a-d]:matches the characters not included in range a-d.
The caret loses its special meaning if it is not the first character of the
set.

It marks as start of line so regex "^start" will match any string that starts with "start".
-----------------------------------------------------------------------------
$ : It marks as end of line so regex "end$" will match any string that ends with "end".
-----------------------------------------------------------------------------
()| : Used for grouping of regular expressions.
(REGX1 | REGX2) will match for either REGX1 or REGX2.
-----------------------------------------------------------------------------
{ : Lets take an example : {1,2} matches between 1 and 2 occurrences of the
preceding term. 't{1,3}' will match 't', 'tt' and 'ttt' only.
Whereas
't{2}' will match 'tt' only.
-----------------------------------------------------------------------------
\ : to escape the special character.
-----------------------------------------------------------------------------

type hinting - objects as function parameter in php5.1

2009-04-23T23:55:00.000-07:00

PHP5.1 came up with the type hinting. We can pass the object of any class as function parameter. We just need to write it in the function signature and its done.

We can also pass any array or interface type. Other types such as string, int are not supported in PHP 5.1.

Sample code
[code]
class a
{
public function __construct(b $b)
{
echo $b->v;
}
}
class b
{
public $v;
function __construct($val)
{
$this->v = $val;
}
}
$objb = new b('PHP is best');
$obj = new a($objb);
[code]

php Type hinting sample code

[php4 vs php5] : type hinting is introduced in php5.1
[zce-5] : type hinting only with arrays and class objects.Not with strings and int.