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Friday 28 October 2016

PHP sessions default timeout

Published on: Friday, October 28, 2016 by Unknown - 4 comments

PHP sessions default timeout

We are settind the Session Time out in Php as mentioned as below:

session.gc_maxlifetime = 1440

(1440 seconds = 24 minutes)

differences between InnoDB and MyISAM

Published on: Friday, August 07, 2015 by Unknown - 24 comments

Differences between InnoDB and MyISAM

In MySQL, major difference of InnoDB and MyISAM are given below. MyIsam is supporting the table level locking in database. But InnoDB is supporting the row level locking in the database. MyIsam is supporting the FULL TEXT SEARCH functionality and InnoDB also supporting the FULL TEXT SEARCH after MySQL Version of 5.6.4.

MyISAM Engine :

1. It supporting Table-level Locking
2. It supports FULLTEXT SEARCH functionality
3. It is designed for need of speed
4. It is not supporting foreign key constraints
5. It is storing the data as its tables, data and indexes in diskspace using separate three different files formats. (table.FRM, table.MYD, table.MYI)
6. It is not supporting transactions [ We can't COMMIT and ROLLBACK the comments ]
7. It recovering data by using Requires full repair/rebuild of indexes/tables
8. It is storing the data as no ordering format

INNODB Engine :

1. It is supporting Row-level Locking
2. After MySQL Version 5.6.4 ,Supporting FULL TEXT SEARCH functionality
3. It is designed for maximum performance when processing high volume of data
4. It is supporting foreign key constraints
5. It is supporting transactions [ We can COMMIT and ROLLBACK the comments ]
6. It stores data as tables and indexes in a tablespace
7. It is Auto recovery from crash via replay of logs
8. It is stored the data row as primary key order

CwebP Unsupported Color Conversion Request:

Published on: Tuesday, July 21, 2015 by Unknown - 8 comments

CwebP Unsupported Color Conversion Request:

When i am creating WebP images, that time triggering the error as "cwebp unsupported color conversion request, Error Could not be process file".

Error:

    $imageName = "ilikekaraikudi.jpg";
$webpimgName = "ilikekaraikudi.webp";

   cwebp -q 0 ".$imageName." -o ".$webpimgName.
   Unsupported color conversion request
   Error! Could not process file ilikekaraikudi.jpg
   Error! Cannot read input picture

Solution:

we can try converting to RBG color-space via ImageMagick (convert) or any other image-editor tool.

exec("convert -colorspace RGB ".$imageName." ".$webpimgName . " ");

   1. how to create webp image in php
   2. fedex shipping integration
   3. 413 “Request Entity Too Large” error with uploading a file
   4. How to blink text in html for various browsers
   5. Difference between cookies and sessions in php

How to create a .webp image in PHP

Published on: Thursday, July 16, 2015 by Unknown - 20 comments

WebP:

WebP is an image file type that was created in 2010 and is created by Google. This image format provides lossless and lossy compression to images on the server. Big social media websites are using WebP image process are Google, Facebook and EBay.

WebP images natively supporting to the following browsers are Chrome, Opera, Opera Mini, Android Browser and Chrome for Android browsers only. It is not supported any other browsers like Firefox, IE and Safari,etc.

    WebP lossless image files are 26% smaller than PNGs.
    WebP lossy images files are 25-34% smaller than JPEG images at equivalent SSIM index.
    WebP supports lossless transparency (also known as alpha channel) with just 22% more bytes.

WebP images creating process in php:

you can use following php commands,to get the webp images

$imgName = "codingslovers.jpg";
$webPName = "codingslovers.webp";

Syntax:

cwebp [quality qualitypercentage] [source image] -o [destination]

exec("cwebp -q 0 ".$imgName." -o ".$webPName." ");

Another Method:

exec("convert -colorspace RGB ".$imgName." ".$webPName . " ");

Exec : executes the given command in php

http://php.net/manual/en/function.exec.php

Advantages of WebP:

Smaller file size
Different compression algorithm
Smoother color gradations
Alpha channel mask

Disadvantages of WebP:

Weak browser support
Artifacting has plastic appearance
Poor exporting interface

Browserwise WebP Performance:

WebP Supporting Browsers

Abstract Class in Php

Published on: Monday, July 06, 2015 by Unknown - 3 comments

Abstract class in PHP:

Abstract Class contains only declare the method's signature, they can't define the implementation.

Abstraction class are defined using the keyword abstract .
Abstract Class is not possible to implement multiple inheritance.
Latest version of PHP 5 has introduces abstract classes and methods.
Classes defined as abstract , we are unable to create the object ( may not instantiated ).

we can extend the Abstract class, by using extends operator.
we can inherit only one abstract class at one time extending.
Any class that contains one abstract method must also be declare as abstract.
All methods marked as abstract in the parent's class, declaration must be defined by the child.
Additionally, these methods must be defined with the same (or a less restricted) visibility (Public,Protected & private).
Type hint & number of parameter must be match between parent & child class.

JSON with Php, javascript and ajax

Published on: Wednesday, May 13, 2015 by Unknown - 17 comments

What is JSON?

JavaScript Object Notation (JSON) is a lightweight data-interchange format inspired by the object literals of JavaScript.

JSON values can consist of:

objects (collections of name-value pairs)
arrays (ordered lists of values)
strings (in double quotes)
numbers
true, false, or null

JSON is language independent.

JSON with PHP?

After PHP Version 5.2.0, JSON extension is decodes and encodes functionalities as default.

Json_encode - returns the JSON representation of values
Json_decode - Decodes the JSON String
Json_last_error - Returns the last error occured.

JSON Syntax and Rules?

JSON syntax is derived from JavaScript object notation syntax:

Data is in name/value pairs
Data is separated by commas
Curly braces hold objects
Square brackets hold arrays

JSON Example

This example is simple phone number validation and once phone number has validated , it will be sent this php page, there we are using the json format related encode data.

Html Page:

<html>
<head>
<title>JSON Example in Php</title>
<script src="js/jquery-1.11.0.min.js"></script>
</head>
<body>
<h1>Json Basic Example</h1>
<form name="phone-form" method="post" onsubmit="return validation();">
 <input type="text" name="phone" id="phone" value="" >
 <input type="submit" value="submit" >
</form>
<div id="outputDisplay"></div>

Javascript Function

<script>
function validation(value){ 
 //Phone Number Validations
 var phone   = $('#phone').val();
 var specialDigitPattern  = /[~`!@#\$%\^&\*()\-_\+=|\\{}\[\]:;"'<>,\?\/\.0123456789]/;
 //var mailvalidateregex  = /^([a-zA-Z0-9_.+-])+\@(([a-zA-Z0-9-])+\.)+([a-zA-Z0-9]{2,4})+$/;  email validation
 if(phone == ""){
  alert("Please enter the phone ");
  return false;
 }else if(isNaN(phone)){
  alert('Please Enter Valid Phone Number');
  return false;
 }
 
 var postdata  = 'phone='+phone;
 var url   = 'testphone.php?phone='+phone;
 
 $.ajax({
  type  : "POST",
  url   : url, 
  data  : postdata,
  dataType : "json",
  success  : phonestatus_check,
 });
 return false;
}

function phonestatus_check(response){
 if(response.status == 1){
  alert('success');
  $("#outputDisplay").css("color","green");
  $("#outputDisplay").html(response.message);
 }else{
  alert('failure');
  return false;
 }
}
//ends
</script>

Php Page:

<?php
 if(isset($_POST['phone'])){
  $phonenumber = $_POST['phone'];
  $responsearray = array();$responsestatus = '1';
  if($responsestatus == 1){
      $responsearray = array('status' => 1,'message'=> 'Thanks for submitting the Phone Number');
  }else{
   $responsearray = array('status' => 0,'message'=> 'failure');
  }
  echo json_encode($responsearray);
  /* $json = json_encode($responsearray);
  if($_GET['jsoncallback'])
   exit("{$_GET['jsoncallback']}($json)"); */
 }
?>

413 “Request Entity Too Large” error with uploading a file

Published on: Friday, May 01, 2015 by Unknown - 18 comments

Nginx: 413 Request Entity Too Large Error and Solution

My application is running nginx as a frond end to php based Apache server. My applicatio lets user upload images upto 2MB in size. When users trying to upload 1.5MB+ size image file using nginx reverse proxy, they are getting the following error on screen:

Nginx 413 Request Entity Too Large

You need to configure both nginx and php to allow upload size.

Nginx configuration:

The client_max_body_size directive assigns the maximum accepted body size of client 
 request, indicated by the line Content-Length in the header of request.

If size is greater the given one, then the client gets the error "Request Entity Too Large" 
(413). To fix this issue edit your nginx.conf.
  
Open the Terminal or login to the remote server using ssh client. 
Type the following command to edit your nginx.conf using a text editor such as vi or joe:

# vi /etc/nginx/nginx.conf

OR

# vi /usr/local/nginx/conf/nginx.conf
Add the following line to http or server or location context to increase 
 the size limit 
 in nginx.conf, enter:

# set client body size to 2M #
client_max_body_size 2M;
 

Save and close the file. Reload the nginx webserver, enter:
# /usr/local/nginx/sbin/nginx -s reload
OR
# /sbin/nginx -s reload
OR use the following on RHEL/CentOS/Debian/Ubuntu Linux:
# service nginx reload

PHP configuration (optional):



Your php installation also put limits on upload file size. 

Edit php.ini and set the following directives

;This sets the maximum amount of memory in bytes that a script is allowed 

to allocate
memory_limit = 32M
 
;The maximum size of an uploaded file.
upload_max_filesize = 2M
 
;Sets max size of post data allowed.This setting also affects file upload.

To upload large files, this value must be larger than upload_max_filesize
post_max_size = 3M
 

Save and close the file. Make sure you reload/restart back-end apache or 

nginx web server as per your setup

Difference between cookies and sessions in php

Published on: Wednesday, April 01, 2015 by Unknown - 14 comments

Cookies are stored in browser as a text file format.It is stored limit amount of data.It is only allowing 4kb[4096bytes].It is not holding the multiple variable in cookies.

we can accessing the cookies values in easily.So it is less secure.The setcookie() function must appear BEFORE the <html> tag.

Sessions are stored in server side.It is stored unlimit amount of data.It is holding the multiple variable in sessions. we cannot accessing the cookies values in easily.So it is more secure.

Cookies	Sessions
Cookies are stored in browser as text file format.	Sessions are stored in server side.
It is stored limit amount of data. It is only allowing 4kb[4096bytes]	It is stored unlimit amount of data.
It is not holding the multiple variable in cookies.	It is holding the multiple variable in sessions.
we can accessing the cookies values in easily. So it is less secure. The setcookie() function must appear BEFORE the <html> tag	we cannot accessing the cookies values in easily. So it is more secure.
Destroy Cookies: 1. if we Closing the browsers at the time cookies values destoryed. 2. setting the cookie time to expire the cookie.	Destroy Sessions : 1. using unset() session,we will destroyed the sessions. 2. using session_destory(), we we will destroyed the sessions.
Example: <?php setcookie(name, value, expire, path,domain, secure, httponly); $cookie_uame = "codingslover"; $cookie_uvalue= "website"; //set cookies for 1 hour time setcookie($cookie_uname, $cookie_uvalue, 3600, "/"); //expire cookies setcookie($cookie_uname,"",-3600); ?>	Example: <?php session_start(); //session variable $_SESSION['testvaraible'] = 'Codings'; //destroyed the entire sessions session_destroy(); //Destroyed the session variable "testvaraible". unset($_SESSION['testvaraible']); ?>

How to expire PHP session after a period of time

Published on: Wednesday, February 25, 2015 by Unknown - 32 comments

Expire the session after some peiod of time by using in php.

Basically, two methods are available to destory the sessions.

1. session_destroy()
2. unset($_SESSION['testvaraible'])
3. setting the time out for this session

1.session_destroy()

if we will call the session_destroy(), it will destroy all the SESSION variable.It is no need any other parameters.

<?php
 session_destroy();
?>

2. unset($_SESSION['testvaraible'])

When we will call the unset() ,it will destroyed the particular variable.
Example:

<?php 
 // Destroyed the session variable "testvaraible".
 unset($_SESSION['testvaraible']);

?>

3. setting the time out for this session

<?php

if isset($_SESSION['LAST_MINITUte_ACTIVITY']) && 
(time() - $_SESSION['LAST_MINITUte_ACTIVITY'] > 1800)) {
    // last request was more than 30 minutes ago

    session_unset();     // unset $_SESSION variable for the run-time
    session_destroy();   // destroy session data in storage
}

// update last activity time stamp
$_SESSION['LAST_MINITUte_ACTIVITY'] = time(); 

/*

You can also use an additional time stamp to regenerate the session ID 
periodically,to avoid attacks on sessions like session fixation:

*/

if (!isset($_SESSION['CREATED'])) {
    $_SESSION['CREATED'] = time();

} else if (time() - $_SESSION['CREATED'] > 1800) {

    // session started more than 30 minutes ago
    // change session ID for the current session
    // an invalidate old session ID
    session_regenerate_id(true);    

    $_SESSION['CREATED'] = time();  // update creation time
}

4.session.gc_maxlifetime()

By using php ini_set session.gc_maxlifetime also we will expire the session.

<?php
 ini_set session.gc_maxlifetime
?>

How to resolved when Logged out sessions get restored by back button?

Published on: Saturday, January 10, 2015 by Unknown - 3 comments

How to resolved when Logged out sessions get restored by back button?

When we log out the sessions , We clear the cookies in browser. But when we press the back button after logging out the session gets restored.

Link :
http://www.codingslover.com/2015/01/How-to-resolved-when-Logged-out-sessions-get-restored-by-back-button.html

Solution:

 header("Cache-Control: no-cache, must-revalidate"); // HTTP/1.1
 header("Expires: Sat, 26 Jul 1997 05:00:00 GMT"); // Date in the past

what are the differences between json and jsonp?

Published on: Monday, November 03, 2014 by Unknown - 5 comments

JSON (Javascript Object Notation) is a convenient way to transport data between applications, especially when the destination is a Javascript application.

Example :

Here is a minimal example that uses JSON as the transport for the server response. The client makes an ajax request with the JQuery shorthand function $.getJSON. The server generates a hash, formats it as JSON and returns this to the client. The client formats this and puts it in a page element.

Server:

get '/json' do
 content_type :json
 content = { :response  => 'Sent via JSON',
            :timestamp => Time.now,
            :random    => rand(10000) }
 content.to_json
end

Client:

var url = host_prefix + '/json';
$.getJSON(url, function(json){
  $("#json-response").html(JSON.stringify(json, null, 2));
});

Output:

  {
   "response": "Sent via JSON",
   "timestamp": "2014-06-18 09:49:01 +0000",
   "random": 6074
  }

JSONP (JSON with Padding)

JSONP is a simple way to overcome browser restrictions when sending JSON responses from different domains from the client. The only change on the Client side with JSONP is to add a callback parameter to the URL.

Server:

get '/jsonp' do
 callback = params['callback']
 content_type :js
 content = { :response  => 'Sent via JSONP',
            :timestamp => Time.now,
            :random    => rand(10000) }
 "#{callback}(#{content.to_json})"
end

Client:

var url = host_prefix + '/jsonp?callback=?';
$.getJSON(url, function(jsonp){
  $("#jsonp-response").html(JSON.stringify(jsonp, null, 2));
});

Output:

 {
  "response": "Sent via JSONP",
  "timestamp": "2014-06-18 09:50:15 +0000",
  "random": 364
}

Friday 28 October 2016

Friday 7 August 2015

Differences between InnoDB and MyISAM

MyISAM Engine :

INNODB Engine :

Tuesday 21 July 2015

CwebP Unsupported Color Conversion Request:

When i am creating WebP images, that time triggering the error as "cwebp unsupported color conversion request, Error Could not be process file".

Error:

Solution:

we can try converting to RBG color-space via ImageMagick (convert) or any other image-editor tool.

Related Posts:

Thursday 16 July 2015

WebP:

WebP images creating process in php:

Syntax: cwebp [quality qualitypercentage] [source image] -o [destination]exec("cwebp -q 0 ".$imgName." -o ".$webPName." ");

Another Method:

Advantages of WebP:

Disadvantages of WebP:

Browserwise WebP Performance:

Monday 6 July 2015

Abstract class in PHP:

Related Posts:

Wednesday 13 May 2015

What is JSON?

Friday 1 May 2015

Wednesday 1 April 2015

Cookies

Sessions

Wednesday 25 February 2015

4.session.gc_maxlifetime()

Saturday 10 January 2015

How to resolved when Logged out sessions get restored by back button?

Monday 3 November 2014

JSONP (JSON with Padding)

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Syntax:

cwebp [quality qualitypercentage] [source image] -o [destination]

exec("cwebp -q 0 ".$imgName." -o ".$webPName." ");