Category: PHP

PHP

Changing Font Style in PHP Generated Image

Post author By masnun
Post date June 11, 2010

To change the font style, you need to use different fonts. You can use the imagettftext() function to draw text on a php generated image using GD. Here’s a code snippet:

<?php
header('Content-type: image/png');
$im = imagecreatetruecolor(400, 300);
$white = imagecolorallocate($im, 255, 255, 255);
$grey = imagecolorallocate($im, 128, 128, 128);
$black = imagecolorallocate($im, 0, 0, 0);
imagefilledrectangle($im, 0, 0, 399, 299, $white);
$text = 'maSnun';
$font = '/usr/share/fonts/truetype/freefont/FreeMonoBold.ttf';
imagettftext($im, 50,180, 300, 130, $black, $font, $text);
imagepng($im);
imagedestroy($im);
?>

<?php

header('Content-type: image/png');

$im = imagecreatetruecolor(400, 300);

$white = imagecolorallocate($im, 255, 255, 255);

$grey = imagecolorallocate($im, 128, 128, 128);

$black = imagecolorallocate($im, 0, 0, 0);

imagefilledrectangle($im, 0, 0, 399, 299, $white);

$text = 'maSnun';

$font = '/usr/share/fonts/truetype/freefont/FreeMonoBold.ttf';

imagettftext($im, 50,180, 300, 130, $black, $font, $text);

imagepng($im);

imagedestroy($im);

Have a look at the function’s doc on php.net to learn more. http://www.php.net/imagettftext 🙂

It’s not that hard! Put the file in the www directory of a ubuntu LAMP server and visit the url on a web browser 🙂

PHP

Text based Captcha with PHP

Post author By masnun
Post date May 18, 2010
1 Comment on Text based Captcha with PHP

I needed text based captcha for my mobile web application to stop automated registrations. The mobile application was developed targeting the WAP devices without any fancy JS or iFrame support. So, I was forced to put some text based captcha. I set one up earlier which didn’t require any database but it was just an eye wash. If anyone examined the HTML source, s/he would know how to break it through.

This time I have come up with something better, something more effective. It is quite simple. Have a look at the source code and you’ll understand yourself.

The SQL for the Table:

CREATE TABLE IF NOT EXISTS `masnun_text_captcha` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `captcha` varchar(255) NOT NULL,
  `time` int(11) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 ;

CREATE TABLE IF NOT EXISTS `masnun_text_captcha` (

`id` int(11) NOT NULL AUTO_INCREMENT,

`captcha` varchar(255) NOT NULL,

`time` int(11) NOT NULL,

PRIMARY KEY (`id`)

) ENGINE=MyISAM DEFAULT CHARSET=latin1 ;

The TextCaptcha Class :

<?php


class TextCaptcha {
    public function getCaptcha($id) {
        $res = mysql_fetch_assoc(mysql_query("select captcha from masnun_text_captcha where id='{$id}'"));
        return $res['captcha'];
    }

    public function verifyCaptcha($id,$captcha) {
        $captchaFromId = $this->getCaptcha($id);
        if ( !empty ( $captchaFromId ) && $captchaFromId == $captcha ) {
            mysql_query("delete from masnun_text_captcha where id='{$id}'");
            return true;
        } else {
            return false;
        }
    }

    public function createNew() {
        $time = time();
        $salt = "mZs45#";
        $rand = rand(0,100);
        $hash = md5($time.$salt.$rand);
        $string = substr($hash, 0, 5);
        mysql_query("insert into masnun_text_captcha (captcha,time) values('$string','$time')");
        $id = mysql_insert_id();
        $data['id'] = $id;
        $data['captcha'] = $string;
        return (object) $data;
    }
}

?>

<?php

class TextCaptcha {

public function getCaptcha($id) {

$res = mysql_fetch_assoc(mysql_query("select captcha from masnun_text_captcha where id='{$id}'"));

return $res['captcha'];

}

public function verifyCaptcha($id,$captcha) {

$captchaFromId = $this->getCaptcha($id);

if ( !empty ( $captchaFromId ) && $captchaFromId == $captcha ) {

mysql_query("delete from masnun_text_captcha where id='{$id}'");

return true;

} else {

return false;

}

public function createNew() {

$time = time();

$salt = "mZs45#";

$rand = rand(0,100);

$hash = md5($time.$salt.$rand);

$string = substr($hash, 0, 5);

mysql_query("insert into masnun_text_captcha (captcha,time) values('$string','$time')");

$id = mysql_insert_id();

$data['id'] = $id;

$data['captcha'] = $string;

return (object) $data;

}

You might notice that I haven’t used the “time” field. It will be used to delete unused captcha via cron or in some other way. Didn’t get the time to code that.

And how to use it:

<?php
include 'textCaptcha.class.php';

// We must have an already open mysql connection to the database
mysql_connect("localhost","masnun","masnun");
mysql_select_db("text_captcha");


$TextCaptcha = new TextCaptcha(); # Construct the object
$captcha = $TextCaptcha->createNew(); # Create a new Captcha Object

/*
 * The Captcha Object has two properties:
 * id --> The ID of the Captcha. You use it as an identifier.
 * captcha --> The Text that is matched with the id to verify
 *
 */

$bool = $TextCaptcha->verifyCaptcha($captcha->id, $captcha->captcha);
var_dump($bool); // Always true :) Alter the code to play yourself
?>

<?php

include 'textCaptcha.class.php';

// We must have an already open mysql connection to the database

mysql_connect("localhost","masnun","masnun");

mysql_select_db("text_captcha");

$TextCaptcha = new TextCaptcha(); # Construct the object

$captcha = $TextCaptcha->createNew(); # Create a new Captcha Object

* The Captcha Object has two properties:

* id --> The ID of the Captcha. You use it as an identifier.

* captcha --> The Text that is matched with the id to verify

$bool = $TextCaptcha->verifyCaptcha($captcha->id, $captcha->captcha);

var_dump($bool); // Always true :) Alter the code to play yourself

Have fun! If you don’t get anything, please place a question below.

PHP

Using the Facebook Graph API

Post author By masnun
Post date April 30, 2010
11 Comments on Using the Facebook Graph API

I caught viral fever and decided to take the day off from work. To pass my leisure I decided to play with the Facebook APIs. I noticed that Facebook Platform has changed a lot. They have released the new “php-sdk” to let the devlopers integrate facebook into their own sites. Actually, they have released SDKs for other languages too (namely Python and JS). For playing with the toys at hand, I picked up the php-sdk and started browsing through the docs. Amazingly, Facebook has launched OAuth support. I am very happy about that. I no longer need to run my applications inside the facebook frame. Rather I can customize my contents for the facebook users. This is plain cool!

I downloaded the php-sdk and started off. But soon, I faced problem. The php-sdk is not well documented (in my opinion) and I had a very hard time figuring things out. It became even worse when I failed to test some of the features which are tightly integrated deep inside facebook. For example, I couldn’t find a way to construct some advanced URLs and also the sdk was not suitable for my debugging needs. The sdk is not poor, I later found it out to be strong but the main problem is it’s not much documented.

So, to try out things and to figure out how the Facebook OAuth works, I started writing my own codes. That helped though I struggled a bit to setup permissions. When I saw that the code is working fine, I chose to pack it up in a class file and rewrite the testing environment.

It took me 30 minutes to rewrite everything up. The package now contains the library and a console to test different methods.

You can download it from: http://masnun.googlecode.com/files/facebook-graph_API-oauth.zip

Extract it into a directory on your website. Register a facebook application. Go through the traditional setup. Please remember to add your domain name on the Connect tab of the application you created 🙂 Edit the config.php and visit the index.php using your browser. You’ll be redirected to Facebook without a word. When you authorize and return, you get a fine console to test things out and see for yourself! 😀

Lets see a quick intro to the library (facebook.php) 🙂

Facebook requires you to redirect the user to an authorization URL with your client id and the callback url. So, we first do this:

// Construct a Facebook object with your app id and secret
$facebook = new Facebook($client_id, $client_secret);
// Get the authorization url. $perms is an array of extended permission. See config.php
$url = $facebook->getAuthorizeUrl($callback_url, $perms);
// Redirect the user to that url
header("Location: {$url} ");

// Construct a Facebook object with your app id and secret

$facebook = new Facebook($client_id, $client_secret);

// Get the authorization url. $perms is an array of extended permission. See config.php

$url = $facebook->getAuthorizeUrl($callback_url, $perms);

// Redirect the user to that url

header("Location: {$url} ");

You have to ask for permissions on Authorization. I couldn’t get to make the user extend permissions on the post authorization phase. So, I have included **ALL** available permissions in the config.php. Permission is what I suffered with most. If you use my library, it’ll ask the user for all permissions so that you can test everything out. I know you won’t need all those permissions in production environment. Just comment out the ones you don’t want!

Facebook returns the user to the $callback_url with a GET parameter named “code” with others. By using this code with the application secret and callback url, we can get the access_token for the user 🙂 We can do that easily using the client :

$facebook = new Facebook($client_id, $client_secret);
$data = $facebook->getAccessToken($callback_url, $code);
$facebook->setAccessToken($data['access_token']);
$response = $facebook->call_api("/me/feed", "post", "message=Hello, Facebook!");
print_r($response);

$facebook = new Facebook($client_id, $client_secret);

$data = $facebook->getAccessToken($callback_url, $code);

$facebook->setAccessToken($data['access_token']);

$response = $facebook->call_api("/me/feed", "post", "message=Hello, Facebook!");

print_r($response);

getAccessToken() retrieves the access_token from the facebook server. setAccessToken() adds the token to the facebook object and makes it ready to make api calls.

The $data is an array with the keys – access_token and expires. After we set the access token, we can make API calls from the client. For the details on API Paths, please visit: http://developers.facebook.com/docs/api 🙂

I really liked the new structure of the facebook API. The previous API was bloated and sometimes very hard to implement. I do thank Facebook very much for making things easy for the developers!

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