VIKIWEBS

Saturday, September 1, 2012

How to Prevent SQL injections by adding slashes to Query String (GET / POST Parameters)

<?php
//create array to temporarily grab variables
$input_arr = array();
//grabs the $_POST variables and adds slashes
foreach ($_POST as $key => $input_arr) {
    $_POST[$key] = addslashes($input_arr);
}
//create array to temporarily grab variables
$input_arr = array();
//grabs the $_POST variables and adds slashes
foreach ($_GET as $key => $input_arr) {
    $_GET[$key] = addslashes($input_arr);
}
//create array to temporarily grab variables
$input_arr = array();
//grabs the $_POST variables and adds slashes
foreach ($_REQUEST as $key => $input_arr) {
    $_REQUEST[$key] = addslashes($input_arr);
}

?>

How to do Paging in PHP MYSQL ?

<?php
///////database connection here
include("../include/database.php");
?>
<?php
$currentPage = $_SERVER["PHP_SELF"];
////////////no. of pages to display $maxRows_profile = 5;////////////////////////edit here
$pageNum_profile = 0;
if (isset($_GET['pageNum_profile'])) {
$pageNum_profile = $_GET['pageNum_profile'];
}
$startRow_profile = $pageNum_profile * $maxRows_profile;
$colname_profile = "-1";
if (isset($_GET['Id'])) {
$colname_profile = (get_magic_quotes_gpc()) ? $_GET['Id'] : addslashes($_GET['Id']);
}
/////////////////////your query goes here
$query_profile ="SELECT * FROM student where STUDENT_NAME like '%".$_GET['Id']."%'"; /////////////edit here
$query_limit_profile = sprintf("%s LIMIT %d, %d", $query_profile, $startRow_profile, $maxRows_profile);
$profile = mysql_query($query_limit_profile) or die(mysql_error());
$row_profile = mysql_fetch_assoc($profile);
/////////////////////////////////////////////PAGING LOGIC STARTS HERE ///////////////////////////////
///////////!!!!!!!!!!DO NOT EDIT BELOW THIS!!!!!!!!!!!/////////////
if (isset($_GET['totalRows_profile'])) {
$totalRows_profile = $_GET['totalRows_profile'];
} else {
$all_profile = mysql_query($query_profile);
$totalRows_profile = mysql_num_rows($all_profile);
}
$totalPages_profile = ceil($totalRows_profile/$maxRows_profile)-1;
//////////////////////////////////////////////////////////Paging
$queryString_profile = "";
if (!empty($_SERVER['QUERY_STRING'])) {
$params = explode("&", $_SERVER['QUERY_STRING']);
$newParams = array();
foreach ($params as $param) {
    if (stristr($param, "pageNum_profile") == false &&
        stristr($param, "totalRows_profile") == false) {
      array_push($newParams, $param);
    }
}
if (count($newParams) != 0) {
    $queryString_profile = "&" . htmlentities(implode("&", $newParams));
}
}
$queryString_profile = sprintf("&totalRows_profile=%d%s", $totalRows_profile, $queryString_profile);
///////////////////////////////////////////////////////////////////PAGING END LOGIC////////////////////////////////////
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>My Document</title>
</head>

<body>

<p> 
Records <?php echo ($startRow_profile + 1) ?> to <?php echo min($startRow_profile + $maxRows_profile, $totalRows_profile) ?> of <?php echo $totalRows_profile ?> </p>


<table border="1">
<tr>
    <td>Id</td>
    <td>Child_Name</td>
    <td>Gender</td>
</tr>
<?php do { ?>
    <tr>
      <td><?php echo $row_profile['MD5']; ?></td>
      <td><?php echo $row_profile['STUDENT_NAME']; ?></td>
      <td><?php echo $row_profile['SURNAME']; ?></td>
    </tr>
    <?php } while ($row_profile = mysql_fetch_assoc($profile)); ?>
</table>

<table border="0" width="42%" >
<tr>
    <td width="23%" align="center"><?php if ($pageNum_profile > 0) { // Show if first page ?>
          <a href="<?php printf("%s?pageNum_profile=%d%s", $currentPage, 0, $queryString_profile); ?>"><<First</a>
          <?php } else { echo '<<First'; }   ?>
    </td>
    <td width="31%" align="center"><?php if ($pageNum_profile > 0) { // Show if not first page ?>
          <a href="<?php printf("%s?pageNum_profile=%d%s", $currentPage, max(0, $pageNum_profile - 1), $queryString_profile); ?>"><Previous</a>
          <?php }else   { echo '<Previous'; }   ?>
    </td>
    <td width="23%" align="center"><?php if ($pageNum_profile < $totalPages_profile) { // Show if not last page ?>
          <a href="<?php printf("%s?pageNum_profile=%d%s", $currentPage, min($totalPages_profile, $pageNum_profile + 1), $queryString_profile); ?>">Next></a>
          <?php } else { echo 'Next>'; }     ?>
    </td>
    <td width="23%" align="center"><?php if ($pageNum_profile < $totalPages_profile) { // Show if last page ?>
          <a href="<?php printf("%s?pageNum_profile=%d%s", $currentPage, $totalPages_profile, $queryString_profile); ?>">Last>></a>
          <?php } else { echo 'Last>>'; }   ?>

    </td>
</tr>
</table>

</body>
</html>
<?php
mysql_free_result($profile);
?>

How to use PHP MYSQL and AJAX together

index.php

Code listing:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Untitled Document</title>
<script src="ajax.js"></script>
</head>

<body>
<form action="" method="get">
<p> Enter no </p>
<p>
<input name="no" type="text" onkeyup="sq(this.value)" />
</p>
<p><div id="res"></div></p>
</form>
</body>
</html>

result.php

Code listing:

<?php
echo $_REQUEST['no']*$_REQUEST['no'];

?>

ajax.php

Code listing:

var xmlhttp

function sq(str)
{

xmlhttp=GetXmlHttpObject();
if (xmlhttp==null)
{
alert ("Your browser does not support XMLHTTP!");
return;
}
var url="result.php";
url=url+"?no="+str;
url=url+"&sid="+Math.random();
xmlhttp.onreadystatechange=stateChanged;
xmlhttp.open("GET",url,true);
xmlhttp.send(null);
}

function stateChanged()
{
if (xmlhttp.readyState==4)
{
document.getElementById("res").innerHTML=xmlhttp.responseText;
}
else
{
document.getElementById("res").innerHTML="PROCESSING..<img src='images/3.gif' />";
}
}

function GetXmlHttpObject()
{
if (window.XMLHttpRequest)
{
// code for IE7+, Firefox, Chrome, Opera, Safari
return new XMLHttpRequest();
}
if (window.ActiveXObject)
{
// code for IE6, IE5
return new ActiveXObject("Microsoft.XMLHTTP");
}
return null;
}

How to use PHP MYSQL and AJAX together

index.php

Code listing:

result.php

Code listing:

<?php
echo $_REQUEST['no']*$_REQUEST['no'];

?>

ajax.php

Code listing:

PHP HTML DOM PARSER

Description, Requirement & Features

A HTML DOM parser written in PHP5+ let you manipulate HTML in a very easy way!
Require PHP 5+.
Supports invalid HTML.
Find tags on an HTML page with selectors just like jQuery.
Extract contents from HTML in a single line.

How to get HTML Element
// Create DOM from URL or file
$html = file_get_html('http://www.google.com/');

// Find all images
foreach($html->find('img') as $element)
echo $element->src . '<br>';

// Find all links
foreach($html->find('a') as $element)
echo $element->href . '<br>';

How to modify HTML element

// Create DOM from string
$html = str_get_html('<div id="hello">Hello</div><div id="world">World</div>');

$html->find('div', 1)->class = 'bar';

$html->find('div[id=hello]', 0)->innertext = 'foo';

echo $html; // Output: <div id="hello">foo</div><div id="world" class="bar">World</div>

Extract Content from HTML
// Dump contents (without tags) from HTML
echo file_get_html('http://www.google.com/')->plaintext;

Scrapping Slashdot
// Create DOM from URL
$html = file_get_html('http://slashdot.org/');

// Find all article blocks
foreach($html->find('div.article') as $article) {
    $item['title']     = $article->find('div.title', 0)->plaintext;
    $item['intro']    = $article->find('div.intro', 0)->plaintext;
    $item['details'] = $article->find('div.details', 0)->plaintext;
    $articles[] = $item;
}

print_r($articles);

Sample uses
// Include the library
include('simple_html_dom.php');

// Retrieve the DOM from a given URL
$html = file_get_html('http://davidwalsh.name/');

// Find all "A" tags and print their HREFs
foreach($html->find('a') as $e)
    echo $e->href . '<br>';

// Retrieve all images and print their SRCs
foreach($html->find('img') as $e)
    echo $e->src . '<br>';

// Find all images, print their text with the "<>" included
foreach($html->find('img') as $e)
    echo $e->outertext . '<br>';

// Find the DIV tag with an id of "myId"
foreach($html->find('div#myId') as $e)
    echo $e->innertext . '<br>';

// Find all SPAN tags that have a class of "myClass"
foreach($html->find('span.myClass') as $e)
    echo $e->outertext . '<br>';

// Find all TD tags with "align=center"
foreach($html->find('td[align=center]') as $e)
    echo $e->innertext . '<br>';

// Extract all text from a given cell
echo $html->find('td[align="center"]', 1)->plaintext.'<br><hr>';

AJAX Multiple request / Load Multiple Pages Simlultaneously in Ajax

In this example we are loading first.php, second.php and third.php asynchronously in the same page simultaneously by making multiple ajax function calls.

index.html

<head>

<title>Ajax Multiple Calls</title>

function loader(){

f=GetXmlHttpObject();

vloader(f,'first.php','con1');

s=GetXmlHttpObject();

vloader(s,'second.php','con2');

t=GetXmlHttpObject();

vloader(t,'third.php','con3');

}</script>

</head>

<h1>First.php</h1>

<h1>Second.php</h1>

<h1>Third.php</h1>

</body>

</html>

Content loader.js

function vloader(xmlhttp,url,container)

{

//alert('hi'+url+container);

if(xmlhttp==null)

{alert ("Your browser does not support XMLHTTP!");return;}

if(url.indexOf("?")>= 0){}

else{url=url+"?";}

url=url+"&sid="+Math.random();

xmlhttp.onreadystatechange= function (){

if (xmlhttp.readyState==4)

{ document.getElementById(container).innerHTML=xmlhttp.responseText; } else

{ document.getElementById(container).innerHTML="<img src='loader.gif' />"; } };

xmlhttp.open("GET",url,true);

xmlhttp.send(null);

}

/////////////////////////////////////////////////////////////////////////////////////////////

function GetXmlHttpObject()

{

if (window.XMLHttpRequest)

{

return new XMLHttpRequest();

}

if (window.ActiveXObject)

{

return new ActiveXObject("Microsoft.XMLHTTP");

}

return null;

}

first.php

<?php

for($i=0;$i<1000000;$i+=0.1);/////just to show animated loading gif

echo 'First.php..loaded';

second.php

<?php

for($i=0;$i<1000000;$i+=0.1);/////just to show animated loading gif

echo 'second.php..loaded';

third.php

<?php

for($i=0;$i<1000000;$i+=0.1);/////just to show animated loading gif

echo 'third.php..loaded';

How to run c and c++ program in gcc on linux platform

Running C Program in gcc on Linux Platform:

Steps:
1. Create a file demo.c with a C code inside it.
$gedit <filename>
$gedit demo.c

- It will create and open demo.c file in gedit text editor where you can type your c code, save and close it. e.g.,
#include<stdio.h>
void main()
{
printf("Hello C");
}

2. Compile demo.c
      $gcc <source file name>
      $gcc demo.c
                 - It will compile C program and create a.out executable binary file.
3. Running demo.c
      $./<executable file name>
      $./a.out

Note: If you are dealing with multiple c files at a time, then it is favorable to specify a name executable which can be done as below during compile time.
   $gcc <Source file name> -o <output file name>
   $gcc demo.c -o demoout
    now you can run it as
    $./demoout

Running C++ Program in gcc on Linux Platform:

Steps:

1. Install the 'build-essential' package.
$ sudo apt-get install build-essential                         { For Ubuntu }

2. Create a file demo.cpp with a CPP code inside it.
      $gedit <filename>
      $gedit demo.cpp

- It will create and open demo.cpp file in gedit text editor where you can type your cpp code, save and close it. e.g.,
#include <iostream>
using namespace std;

int main()
{
cout << "Hello C++";
return 0;
}

3. Compile demo.cpp
      $g++ <source file name> -o <output file name>
      g++ demo.cpp -o hellocpp
                 - It will compile C program and create a.out executable binary file.
4. Running demo.cpp
      $./<executable file name>
     $ ./hellocpp

Debugging C Program in GCC on Linux platform:

Create C program as below

$ gedit demo.c

type your code in this demo.c file
example:

#include<stdio.h>
void main()
{
   int i=0;
while(i<10)
{
      printf("\n %d",i);
      i++;
}
}

Compile this program with -g option so that compiler can embed debugging information in executable.
$gcc -g demo.c -o demo
Next to start debugger run below given command.
$gdb demo
gdb --- debugger gets loaded.
Now make us of below commands for various operations.
Important gdb commands

help [gdb-command]
run args

Run the program till breakpoint / end

break [function-name | line-number]

Insert breakpoint at specific line.
You can have one or more breakpoints.

delete [bp-number]

To delete breakpoint.

next [N]

Debugger will execute the next line as single instruction.
next 3, jumps 3 lines.

step [N]

Same as next, but does not treats function as a single instruction, instead goes into the function and executes it line by line.

finish

run till end.

continue

continue until next breakpoint.

where

Same as next, but does not treats function as a single instruction, instead goes into the function and executes it line by line.

quit

quit debugger.