Emran Hasan's Blog » Web Development

To me design is…

Emran Hasan — Sun, 15 Jan 2012 16:16:59 +0000

A great compilation by Vostok Studios on what great designers think about design.

Painless Ruby and Rails installation on Ubuntu/Mint

Emran Hasan — Fri, 03 Jun 2011 05:28:16 +0000

It took me an hour to properly install the latest versions of ruby, rails and its mysql binder. Although its less than a 5 mins task, I had to search in forums, blogs to deal with the various errors. So just posting this so its easy for someone else to get done with this in 5 mins.

1. Open Terminal and install RVM (Ruby Version Manager)

bash < <(curl -s https://rvm.beginrescueend.com/install/rvm)

2. Enter the following in ~/.bash_profile and/or ~/.bashrc (replace YOUR USER NAME with the username you’re logged in with):

[[ -s "/home/YOUR USER NAME/.rvm/scripts/rvm" ]] && source "/home/YOUR USER NAME/.rvm/scripts/rvm" # This loads RVM into a shell session.

3. Install Ruby 1.9.2

rvm install 1.9.2

4. Set it as the ruby version to use through rvm:

rvm use 1.9.2

5. Install latest version of Rails:

gem install rails

6. Install mysql bindings:

sudo apt-get install libmysql-ruby libmysqlclient-dev
gem install mysql

7. Now you should be able to create a rails project with mysql binding:

rails new hello
bundle install

Enjoy!

Developing better PHP projects

Emran Hasan — Sat, 06 Nov 2010 14:45:25 +0000

I presented this talk yesterday on the phpXperts seminar 2010 – the largest PHP group in Bangladesh. My objective was to give a quick overview on project structure, development practices and use of tools to improve the overall quality of the PHP projects.

So here goes the presentation:

Quick start on new Facebook PHP SDK (IFrame based)

Emran Hasan — Mon, 03 May 2010 20:39:46 +0000

This post is more than 1 year old. It solved the issues when the SDK was first released and facebook had lack of documentation. However, now facebook has very rich set of documnetation and you should follow that instead!

The new Facebook API has already spread over the application developers and if you’re like me, you’ve already got your hands dirty to see how this new thing works. If you have tried to follow the documentation to authorize/get session in your canvas application, it is likely you have already hit roadblocks. Well, I am no savior but I have glued together a few clues and got it working for myself.

I am assuming that you have already created your application by following the Getting Started section from the official documentation. Also, this is for IFrame based applications only.

Enough talking, let’s get some code.

Step 1: Get the new SDK

Download the new SDK from github. We will only need the facebook.php file from the src folder. In our project directory, let’s create a folder called “lib” and put the file there.

Step 2: A configuration file

Let’s now create a configuration file to store our facebook configuration. Let’s name it config.php. Here goes the source:

define("FACEBOOK_APP_ID", '113795715321151');
define("FACEBOOK_API_KEY", '064baf5fb98de050cd7b9a001ca1988b');
define("FACEBOOK_SECRET_KEY", '430f43c01f6dfe02c284b4545976f9ce');
define("FACEBOOK_CANVAS_URL", 'http://apps.facebook.com/emran-test-app/');

Step 3: Application Main Page

This file will be the main entry point to our facebook application. It just instantiates the facebook object, sets the configuration and checks for a valid session. If it does not find a valid session, it redirects to the login page. For first time visitors, it will be the authorization page. On later requests, the operation will occur in the background – without any user interaction.

include_once 'lib/facebook.php';
include_once 'config.php';

$facebook = new Facebook(array(
'appId' => FACEBOOK_APP_ID,
'secret' => FACEBOOK_SECRET_KEY,
'cookie' => true,
'domain' => 'phpfour.com'
));

$session = $facebook->getSession();

if (!$session) {

$url = $facebook->getLoginUrl(array(
'canvas' => 1,
'fbconnect' => 0
));

echo "";

} else {

try {

$uid = $facebook->getUser();
$me = $facebook->api('/me');

$updated = date("l, F j, Y", strtotime($me['updated_time']));

echo "Hello " . $me['name'] . "
";
echo "You last updated your profile on " . $updated;

} catch (FacebookApiException $e) {

echo "Error:" . print_r($e, true);

}
}

You might be wondering – it’s pretty straight-forward, so what’s the catch ? Well, to be honest, the documentation does not have the “canvas” parameter mentioned anywhere which does the primary magic here. Also, if you do not use the javascript trick, then you end up with an authorization dialog with full facebook UI within the iframe itself (see below).

CodeIgniter Version

Here is the CodeIgniter version of the above example. The significance is that CodeIgniter removes the values from the $_GET super global – which is required for the library to work. We thus re-populate it on the constructor ourselves and start a session to share data among subsequent page visits.

include_once APPPATH . 'libraries/facebook-php-sdk/facebook.php';

class Test extends Controller
{
private $facebook;

public function __construct()
{
parent::__construct();
parse_str($_SERVER['QUERY_STRING'], $_GET);
session_start();
}

public function index()
{
$this->facebook = new Facebook(array(
'appId' => $this->config->item('facebook_app_id'),
'secret' => $this->config->item('facebook_secret_key'),
'cookie' => true,
'domain' => 'phpfour.com'
));

$session = $this->facebook->getSession();

if (!$session) {

$url = $this->facebook->getLoginUrl(array('canvas' => 1, 'fbconnect' => 0));
echo "";

} else {

try {

$uid = $this->facebook->getUser();
$me = $this->facebook->api('/me');

$updated = date("l, F j, Y", strtotime($me['updated_time']));

echo "Hello " . $me['name'] . "
";
echo "You last updated your profile on " . $updated;

} catch (FacebookApiException $e) {

echo "Error:" . print_r($e, true);

}
}
}
}

Hope I am able to help a few people.

Cheers!

Enterprise PHP

Emran Hasan — Tue, 16 Feb 2010 12:11:13 +0000

I presented this talk on the Soft Expo 2010 – the largest software fair in Bangladesh. The intention was to clear some of the misconception about PHP, the growth of PHP, how it can fit in the enterprise now, etc.

After these, I shed light on some topics that a company/developer should keep in mind in order to write good software in PHP. This was followed by live session on caching, mysql query optimization, use of Xdebug, etc.

So here goes the presentation:

And a big thanks to Ivo Jansch’s “PHP in the real wolrd” presentation, from where I took inspiration.

Cheers!

Changing the default controller naming convention in CodeIgniter

Emran Hasan — Mon, 21 Sep 2009 06:23:04 +0000

CodeIgniter is one of my favorite framework and I often use it for developing application quickly. Although it is very flexible in most cases, I find its naming convention to be strict. Many times I have faced this problem when my controller’s class name and a model/library’s class names are the same – a Fatal error is inevitable and I have to forcefully change the name of the conflicting class to something less desirable (say from Users to UsersModel). Today I wanted to end this problem.

So I extended the CI_Router core class and made change to the _validate_request method. Now I can name my controller classes in this fashion: UsersController and it resides on the file system as controllers/UsersController.php. If you’ve tried other established frameworks, you should notice that this naming convention is widely used. So, if you have the same need, then just download the MY_Router.php file and put it on your application/libraries folder. That’s it.

Here is how your controller would start:

class UsersController extends Controller
{
public function __construct()
{
parent::__construct();
}
}

If you’d like to have a look at the code, here is the source for quick view:

if ( ! defined('BASEPATH')) exit('No direct script access allowed');

/*
* MY_Router
*
* Extended the core CI_Router class in order to force a different naming
* convention for controllers.
*
*/
class MY_Router extends CI_Router
{
/*
* Suffix in controller name
*
* @var String
*/
private $_suffix = "Controller";

/*
* Call the parent constructor
*
* This is a requirement for extending base CI core class. Just abiding by
* the rules.
*
* @access public
* @return void
*/
public function MY_Router()
{
parent::CI_Router();
}

/**
* Validates the supplied segments. Attempts to determine the path to
* the controller.
*
* @access private
* @param array
* @return array
*/
function _validate_request($segments)
{
// Retain the original segments
$orgSegments = array_slice($segments, 0);

// Add suffix to the end
$segments[0] = ucfirst($segments[0]) . $this->_suffix;

// Does the requested controller exist in the root folder?
if (file_exists(APPPATH.'controllers/'.$segments[0].EXT))
{
return $segments;
}

// OK, revert to the original segment
$segments[0] = $orgSegments[0];

// Is the controller in a sub-folder?
if (is_dir(APPPATH.'controllers/'.$segments[0]))
{
// Set the directory and remove it from the segment array
$this->set_directory($segments[0]);
$segments = array_slice($segments, 1);

if (count($segments) > 0)
{
// Add suffix to the end
$segments[0] = ucfirst($segments[0]) . $this->_suffix;

// Does the requested controller exist in the sub-folder?
if ( ! file_exists(APPPATH.'controllers/'.$this->fetch_directory().$segments[0].EXT))
{
show_404($this->fetch_directory().$segments[0]);
}
}
else
{
// Add suffix to the end
$this->default_controller = ucfirst($this->default_controller) . $this->_suffix;

$this->set_class($this->default_controller);
$this->set_method('index');

// Does the default controller exist in the sub-folder?
if ( ! file_exists(APPPATH.'controllers/'.$this->fetch_directory().$this->default_controller.EXT))
{
$this->directory = '';
return array();
}

}

return $segments;
}

// Can't find the requested controller...
show_404($segments[0]);
}
}

Cheers!

Facebook Developer Garage Dhaka – Open Stream API

Emran Hasan — Mon, 24 Aug 2009 03:26:05 +0000

The first ever “Facebook Developer Garage” took place in Dhaka, Bangladesh and I am proud to be a part of it. I was one of the speakers of this spectacular event organized by Facebook and IBT bangladesh. I spoke about the recently released Open Stream API from Facebook. It was more of an overview rather than a detail one. Here goes the slides:

I have created a quick start example which outlines both Facebook Connect and the Open Stream API. You can check that here. A blog post covering the steps is coming soon in 3-4 days.

Stay tuned if you have interest in them.

Cheers

phpXperts ’09 seminar

Emran Hasan — Sun, 17 May 2009 12:29:25 +0000

At last the phpXperts seminar on “Current Web Trends” have taken place and I was one of the speakers there. Among all the topics, mine was a bit suggestive and naturally a bit less exciting. I spoke about how to become a PHP ninja – what are the characteristics they posses, what are the tools they use, what are the paths they follow etc. It’s actually a follow-up of one of my blog posts: “Becoming a kick-ass PHP ninja“.

Here goes the slides:

All the other slides, pictures, and videos are available here.

Enjoy!

PHP Payment Library for Paypal, Authorize.net and 2Checkout

Emran Hasan — Sat, 21 Feb 2009 20:03:27 +0000

If you are like me, whenever you need to work with a 3rd party API or a gateway, you’d first search in Google for a possible wrapper for it in PHP. When it comes to supporting payment gateways, you get bunch of libraries in the search results who are fundamentally different. Some of them are old PHP 3/4 ones, some are new, some may need PEAR, etc.

As they were not required together in one single project, I used them whenever needed. But in one project, I needed them all. I thoughts it’s a chance and decided to stop using them and wrote my own ones where I can use the same methods for all the gateways.

So, here is an abstract PaymentGateway library which is being extended to be used for three popular payment gateways (Paypal, Authorize.net, and 2Checkout) in order to provide you with a similar way of using them. Note that the libraries are for basic usage only and do not contain options for recurring payments. Without much babble, let’s see a few examples of how you can use them.

Download

You can straight-away download the Payment library with all the libraries, examples, and readme.

Paypal

In order to process payments using Paypal, you’ll need to follow these steps:

1. Send the required information to Paypal (snippet 1). Be sure to specify your Paypal email where you want to receive the funds, the success and failure pages, the IPN page, and the product information. The example has the test mode ON, which you will not need in real scenario.

2. Create a payment success page where Paypal will send your customer after payment.

3. Create a payment failure page where Paypal will send your customer after failed payment.

4. Create a IPN page where Paypal will send payment notification in the background. Make sure you use/remove the test mode in conjunction with step 1. (snippet 2)

// Include the paypal library
include_once ('Paypal.php');

// Create an instance of the paypal library
$myPaypal = new Paypal();

// Specify your paypal email
$myPaypal->addField('business', 'YOUR_PAYPAL_EMAIL');

// Specify the currency
$myPaypal->addField('currency_code', 'USD');

// Specify the url where paypal will send the user on success/failure
$myPaypal->addField('return', 'http://YOUR_HOST/payment/paypal_success.php');
$myPaypal->addField('cancel_return', 'http://YOUR_HOST/payment/paypal_failure.php');

// Specify the url where paypal will send the IPN
$myPaypal->addField('notify_url', 'http://YOUR_HOST/payment/paypal_ipn.php');

// Specify the product information
$myPaypal->addField('item_name', 'T-Shirt');
$myPaypal->addField('amount', '9.99');
$myPaypal->addField('item_number', '001');

// Specify any custom value
$myPaypal->addField('custom', 'muri-khao');

// Enable test mode if needed
$myPaypal->enableTestMode();

// Let's start the train!
$myPaypal->submitPayment();

Snippet 1

// Include the paypal library
include_once ('Paypal.php');

// Create an instance of the paypal library
$myPaypal = new Paypal();

// Log the IPN results
$myPaypal->ipnLog = TRUE;

// Enable test mode if needed
$myPaypal->enableTestMode();

// Check validity and write down it
if ($myPaypal->validateIpn()) {
if ($myPaypal->ipnData['payment_status'] == 'Completed') {
file_put_contents('paypal.txt', 'SUCCESS');
}
else {
file_put_contents('paypal.txt', "FAILURE\n\n" . $myPaypal->ipnData);
}
}

Snippet 2

Authorize.net

In order to process payments using Authorize.net, you’ll need to follow these steps:

1. Send the required information to Authorize.net(snippet 3). Be sure to specify your Authorize.net login and secret key, the success/failure pages, the IPN page, and the product information. The example has the test mode ON, which you will not need in real scenario.

2. Create a payment success/failure page where Authorize.net will send your customer after payment.

3. Create a IPN page where Authorize.net will send payment notification in the background. Make sure you use/remove the test mode in conjunction with step 1. (snippet 4)

4. In order to set the secret key, log into your authorize.net merchant account. Go to “MD5 Hash” menu and set a secret word to desired values and use that in the “setUserInfo” function showed in the example.

// Include the paypal library
include_once ('Authorize.php');

// Create an instance of the authorize.net library
$myAuthorize = new Authorize();

// Specify your authorize.net login and secret
$myAuthorize->setUserInfo('YOUR_LOGIN', 'YOUR_SECRET_KEY');

// Specify the url where authorize.net will send the user on success/failure
$myAuthorize->addField('x_Receipt_Link_URL', 'http://YOUR_HOST/payment/authorize_success.php');

// Specify the url where authorize.net will send the IPN
$myAuthorize->addField('x_Relay_URL', 'http://YOUR_HOST/payment/authorize_ipn.php');

// Specify the product information
$myAuthorize->addField('x_Description', 'T-Shirt');
$myAuthorize->addField('x_Amount', '9.99');
$myAuthorize->addField('x_Invoice_num', rand(1, 100));
$myAuthorize->addField('x_Cust_ID', 'muri-khao');

// Enable test mode if needed
$myAuthorize->enableTestMode();

// Let's start the train!
$myAuthorize->submitPayment();

Snippet 3

// Include the paypal library
include_once ('Authorize.php');

// Create an instance of the authorize.net library
$myAuthorize = new Authorize();

// Log the IPN results
$myAuthorize->ipnLog = TRUE;

// Specify your authorize login and secret
$myAuthorize->setUserInfo('YOUR_LOGIN', 'YOUR_SECRET_KEY');

// Enable test mode if needed
$myAuthorize->enableTestMode();

// Check validity and write down it
if ($myAuthorize->validateIpn()) {
file_put_contents('authorize.txt', 'SUCCESS');
} else {
file_put_contents('authorize.txt', "FAILURE\n\n" . $myPaypal->ipnData);
}

Snippet 4

2Checkout

In order to process payments using 2Checkout, you’ll need to follow these steps:

1. Send the required information to 2Checkout(snippet 5). Be sure to specify your 2Checkout vendor id, the return page, and the product information. Please note that 2Checkout does not send IPN in the background, so you will need to handle the payment data in the return page. The example has the test mode ON, which you will not need in real scenario.

2. Create a return page where 2Checkout will send your customer after payment. This is also where you will need to retrieve and use the payment data. Make sure you use/remove the test mode in conjunction with step 1. (snippet 6)

3. In order to set the secret key, log into your 2checkout.com account and go to “Look and Feel” section. At the bottom enter the “Secret Word” and use it in the IPN verification process as shown in the example.

// Include the paypal library
include_once ('TwoCo.php');

// Create an instance of the authorize.net library
$my2CO = new TwoCo();

// Specify your 2CheckOut vendor id
$my2CO->addField('sid', 'YOUR_VENDOR_ID');

// Specify the order information
$my2CO->addField('cart_order_id', rand(1, 100));
$my2CO->addField('total', '9.99');

// Specify the url where authorize.net will send the IPN
$my2CO->addField('x_Receipt_Link_URL', 'http://YOUR_HOST/payment/twoco_ipn.php');
$my2CO->addField('tco_currency', 'USD');
$my2CO->addField('custom', 'muri-khao');

// Enable test mode if needed
$my2CO->enableTestMode();

// Let's start the train!
$my2CO->submitPayment();

Snippet 5

// Include the paypal library
include_once ('TwoCo.php');

// Create an instance of the authorize.net library
$my2CO = new TwoCo();

// Log the IPN results
$my2CO->ipnLog = TRUE;

// Specify your authorize login and secret
$my2CO->setSecret('YOUR_SECRET_KEY');

// Enable test mode if needed
$my2CO->enableTestMode();

// Check validity and write down it
if ($my2CO->validateIpn()) {
file_put_contents('2co.txt', 'SUCCESS');
} else {
file_put_contents('2co.txt', "FAILURE\n\n" . $my2CO->ipnData);
}

Snippet 6

Hope this will help you integrate the payment gateways in an easy manner. If you have any questions, or find any bug, have a suggestion, feel free to post them as comment here. Btw, this library is released under the MIT license.

Cheers!

Code Updates (HTTP class, Extended CodeIgniter Model, Cross-domain AJAX transport)

Emran Hasan — Wed, 18 Feb 2009 21:27:47 +0000

Greetings to all the readers of my blog.

Many of you have been writing to me in the last couple days when I took the site down. The main objective was to add the new theme and push a few code updates of the existing libraries. I really appreciate your concern and would like to reassure you that the site is up and will be up as usual Now, besides the slightly customized theme from Elegant Themes, I have put a few code updates. They are detailed below:

Extended Model for CodeIgniter

The original version of the Extended Model for CodeIgniter has been serving many people well. Although most users loved the nifty functions of the Model, many (including me) didn’t like the hacking of CI core to get this functionality. With the release of CodeIgniter 1.7, we can avoid that as we can now overload the Model class of CI like the other libraries. Follow this instruction:

1. Download the updated version from here
2. Put it in your application/libraries folder
3. In your model files, use it this way: class Product extends MY_Model
4. Everything else is same just like the original one

HTTP Class

There is not much update in this class except for a few bug fixes (thanks to you guys). Also, I have included a license file in the package as many of you have asked. It’s released under the MIT license. The original post is here for reference.

Download the update from here and the API reference is here.

Cross-domain AJAX calls using PHP

A minor bug fix in the code. Thanks to a few of you who pointed them out. Original post is here. Download the update from here.

I have accelerated plans for the blog in 2009 so stay tuned for some worthy posts in this month. And do write to me if you feel you have any questions/ideas/suggestions.

Cheers!