Maribol Labs » PHP

Using AJAX and PHP together

Samuel Marian — Sun, 14 Aug 2011 18:21:58 +0000

In this tutorial i’ll show you how to use PHP and AJAX together and get the results that you need.

Here’s an example of a function that executes a ajax request

function execAjax(type){
   $.ajax({
      url: 'ajax.php?type='+type,
      dataType: 'json',
      success: function( data ) {
         var items = [];
 
         $.each(data, function(key, val) {
            items.push('+ key + '">' + val + '
');
         });
 
         $('#results').html(
            $('', {
               'class': 'results-list',
               html: items.join('')
            })
         );
      }
   });
}

This function should add a list with all the items resulted from the request.

Example of use:

View Code HTML

fruits
vegetables
furniture

And the ajax.php return an array encoded in json.

View Code PHP

$results = array(
   'fruits' => array(
      'apple',
      'bannana',
      'orange'
   ),
   'vegetables' => array(
      'potato',
      'carrot',
      'onion'
   ),
   'furniture' => array(
      'chair',
      'desk'
   )
);
 
$type = $_GET['type'];
 
echo json_encode($results[$type]);

If we’ve clicked on the “fruits” link, will get a result like:

View Code JSON

["apple","bannana","orange"]

This encoded array will be transformed in list with the “each” function from jquery and the result that you should see is:

View Code HTML


   
      apple
      bannana
      orange

Security Tutorial #2: Are you protected against sql injections?

Samuel Marian — Sat, 16 Jul 2011 12:34:42 +0000

There are alot of websites that are vulnerable to sql injections.
In this tutorial i’ll give you some examples with methods to protect you website.

Make your id from url (int)

Let’s assume that you get the id like this:

View Code PHP

   $id = $_GET['id'];

Well with this, your site may be vulnerable.

But if you use like this it will never be vulerable from this variable:

View Code PHP

   $id = (int)$_GET['id'];

Basically this will make your id an id, i mean the value returned is always numeric.

Use the mysql_real_escape_string function
This function may help you alot!

View Code PHP

$city = $_GET['city'];
$sql = mysql_query('SELECT firstname, lastname FROM people WHERE city="'.mysql_real_escape_string($city).'" ');

Note: if magic_quotes_gpc is enabled you should use:

View Code PHP

$city = stripslashes($_GET['city']);
$sql = mysql_query('SELECT firstname, lastname FROM people WHERE city="'.mysql_real_escape_string($city).'" ');

Security Tutorial #1: Password hashing

Samuel Marian — Thu, 14 Jul 2011 15:10:23 +0000

In the past two years i’ve used many methods to hash a password. The best method i used is by adding a salt and then encrypting with md5.

If you encrypt a password without a salt is more easily (but almost impossible) to find the password.

It’s important to know that if you want to make a login system you have to chose a salt and never change it.

An example how to encrypt:

View Code PHP

$string = 'password';
$salt = '!@#$%^&*()_+';
echo md5($string.$salt)

This code should result and md5 string like:
bbadaec5c53ce3065d14cbe938640088

This is the first tutorial in a series of tutorials dedicated to your site security

Transform image to Base64

Samuel Marian — Thu, 23 Jun 2011 18:36:57 +0000

Lately i’ve seen very often in email newsletters images embed with base64.
If you send email newsletters containing image, this is the best way to send.

First we try to open the file.

View Code PHP

   $file_path = 'my-image.jpg';
   if($fp = fopen($file,"rb", 0)){
   }else{
      echo 'Can\'t open file';
   }

If the file exist and we have all the rights we need to open it, we read the binary data.

View Code PHP

   $picture = fread($fp,filesize($file));
   fclose($fp);

After we have the binary data of the image wi’ll encode it to base64 and then break it into chunks according to RFC 2045 semantics and we display the html code in a textarea.

View Code PHP

   $base64 = chunk_split(base64_encode($picture));
   $tag = '<span style="color: #339933;">.</span><span style="color: #000088;">$base64</span><span style="color: #339933;">.</span><span style="color: #0000ff;">'"  />';
   echo $tag;

..and the final code:

View Code PHP

   $file_path = 'my-image.jpg';
   if($fp = fopen($file,"rb", 0)){
      $picture = fread($fp,filesize($file));
      fclose($fp);
      $base64 = chunk_split(base64_encode($picture));
      $tag = '<span style="color: #339933;">.</span><span style="color: #000088;">$base64</span><span style="color: #339933;">.</span><span style="color: #0000ff;">'"  />';
      echo $tag;
   }else{
      echo 'Can\'t open file';
   }

How to make a search engine on your site. The good method.

Samuel Marian — Tue, 31 May 2011 18:35:58 +0000

Okay, so many people think that if you make a search engine on your site with query like the one below, it’s okay.

View Code SQL

SELECT id,name,post FROM posts WHERE name LIKE '%my key%'

But it’s not!

Because:
Let’s assume that you have a post called: My little post name

If you make a search in your database like:

View Code SQL

SELECT id,name,post FROM posts WHERE name LIKE '%little post%'

you will get a result.

But if you make a search in your database like:

View Code SQL

SELECT id,name,post FROM posts WHERE name LIKE '%my post%'

you will not get any result.

Okay so the method i use is like this:

View Code SQL

SELECT id,name,post FROM posts WHERE (name LIKE '%my%' AND name LIKE '%post%')

and this query will get a result.

How to do:

First we split the string by space with the explode() function and the result is an array with two items.

View Code PHP

$query = 'my post';
$query_items = explode(' ', trim($string))

After that, we use the implode() function to create the condition

View Code PHP

$addToQuery = '';
foreach($query_items as $item){
	$addToQuery .= ' AND name LIKE "%'.$item.'%"';
}
$addToQuery .= '';

The above code should result something like:

View Code SQL

 AND name LIKE "%my%" AND name LIKE "%post%"

Now we have to add this string to SQL Query:

View Code PHP

$sql = 'SELECT id,name,post FROM posts WHERE 1 '.$addToQuery.' ORDER BY id DESC';

How to increase memory limit

Samuel Marian — Sat, 23 Apr 2011 16:25:20 +0000

Recently i needed to increase memory limit for executing a PHP script.
And i think there are many of you who don’t know how to do it.

Here is a simple an example:

View Code PHP

ini_set('memory_limit', '128M');

How to transform arrays to objects and object to arrays

Samuel Marian — Tue, 19 Apr 2011 08:00:35 +0000

I haven’t wrote any tutorial since two months (i’ve been very busy lately).

Anyway, now i’ll show you a simple way to transform arrays to objects and objects to arrays.

Let’s start with transformation from arrays to objects.

View Code PHP

   function ArrayToObject($array){
      foreach($array as $key=>$value){
         if(is_array($value)){
            $new_object->$key = ArrayToObject($value);
         }else{
            $new_object->$key = $value;
         }
      }
      return $new_object;
   }

Function explained:

View Code PHP

foreach($array as $key=>$value)

Using the foreach function we create a loop with $key and $value for each array item that we get from the function parram $array.

Now that we are in the loop we have to check if the item value is array so that we can pass it again to ArrayToObject() function.

View Code PHP

if(is_array($value))

If this function returns true, we call the ArrayToObject() and we start over again but with other value.
If returns false, we create a variable in the new object.

After all the loops are executed we return the object with:

View Code PHP

return $new_object;

How to use it:

View Code PHP

   $array = array(
      array(
         array('a','b'),
         array('a','b'),
         array('a','b'),
         array('a','b'),
         array('a','b'),
         array('a','b'),
         array('a','b'),
         array('a','b')
      ),
      array('a','b'),
      array('a','b', array('a','b'), array('a','b'), array('a','b'), array('a','b',array('dsa')))
   );
   $object = ArrayToObject($array);
   print_r($object);

The function for transforming objects to array is:

View Code PHP

   function ObjectToArray($object){
      foreach($object as $key=>$value){
         if(is_object($value)){
            $new_array[$key] = ObjectToArray($value);
         }else{
            $new_array[$key] = $value;
         }
      }
      return $new_array;
   }

You can use this function exactly like the ArrayToObject function but you send an object instead of array.

Video Tutorial: How to create a Like/Unlike button with jQuery and PHP

Samuel Marian — Fri, 18 Feb 2011 21:50:41 +0000

Hi here!

In this video tutorial you’ll see how to create a simple like/unlike button using jQuery and PHP.

Download the code here: http://etiny.info/ynjtqc
Download the database here: http://etiny.info/yxhczc

Using PHP cookies

Samuel Marian — Sun, 06 Feb 2011 13:44:09 +0000

Awhile ago we’ve talked about handling sessions in PHP witch is used to store data for a short time.

Now i’ll show you how to use cookies.

The cookies are like sessions in a way. Cause they store data to, but for a long time (for how much you set) unlike sessions who’s deleted after browser is closed.

Creating a cookie and set it to expire in 1 hour:

View Code PHP

setcookie("myFirstCookie", 'some value', time()+3600);

Creating a cookie and set it to expire in 30 days:

View Code PHP

setcookie("myFirstCookie", 'some value', time()+60*60*24*30);

Reading a cookie:
So the variable $myCookie will content “some value” (the value that we’ve set above)

View Code PHP

$myCookie = $_COOKIE['myFirstCookie'];
echo $myCookie;

Deleting a cookie:
To delete a cookie you will set it to one hour ago.

View Code PHP

setcookie ("myFirstCookie", "", time() - 3600);

Good 2 know: Sometines IE6 doesn’t get the null cookie so you will have to set a value.

Create a file using PHP

Samuel Marian — Sat, 05 Feb 2011 13:03:50 +0000

Now i’ll show you how to create a file using PHP’s function fopen()

Example:

View Code PHP

$fileName = 'myFirstFile.txt';
$fh = fopen($fileName, 'w') or die("can't open file");
fclose($fh);

Explain:

View Code PHP

$fileName = 'myFirstFile.txt';

This is the file name and extension we will create.

View Code PHP

$fh = fopen($fileName, 'w') or die("can't open file");

This function will open file but if the file doesn’t exist he will create it because we’ve put the write mode (w)

View Code PHP

fclose($fh);

We close the file that was opened above.