How to make a custom Magento payment extension for an external gateway

Magento is a great open source e-commerce platform and has emerged as the market leader in the recent past. However, it still has a steep learning curve and although the community is growing exponentially, I was not able to find a simple tutorial on how to make a Magento payment extension which links up to an external payment gateway.

In this tutorial, I’m going to attempt to show you how to make a bare-minimum extension, which you’ll need to complete because different payment gateways have different APIs, hooks and functionality. This is by no means a definitive guide, but my attempt to try and get you started. Please note this tutorial assumes that you already know how to build a simple custom extension and have average knowledge of Magento, MVC architecture and of course, PHP. This tutorial is for Magento versions 1.4 and above.

I have created a bare-minimum version of the extension which you need to download from the steps that follow. I hope the code will be self-explanatory. For information from Magento’s wiki click here.

Step #1: Click here to download the ZIP archive for this step. Extract it to app\code\local

Step #2: Click here to download the ZIP archive for this step. Extract it to app\design\frontend\base\default\template

Step #3: Click here to download the ZIP archive for this step. Extract it to app\etc\modules

Once you have done this, you need to follow the following steps to get it working:

1. Open app\code\local\Myname\Mygateway\controllers\PaymentController.php and read through the inline comments carefully. The URL that the payment gateway needs to redirect to on your web site after processing the customer’s payment (based on the naming we’ve used in this example) should be: http://www.yourwebsite.com/mygateway/payment/response . This URL will trigger the responseAction() function in the PaymentController, where we will need to validate the response sent by the gateway (to make sure it’s really from there), and if validated, process the order. The validation code is generally provided by the payment gateway.
2. Open app\design\frontend\base\default\template\mygateway\redirect.phtml . This is where we post our values to our external gateway. We can retrieve any order information and pass it on as hidden form fields, which is submitted via JavaScript.
3. Log into your Magento admin, clear your cache, and make sure the extension is enabled and working fine by navigating to System -> Configuration -> Sales -> Payment Methods and checking if you can see it there.

It is extremely important to go through all the files to get a perfect understanding of the extension. I figured the best way to learn this is to look at a working example. This took me a long time to figure out and I hope this saves a lot of effort for someone. Happy coding!

What web technology to use on my site?

Biggest Piece of the Cake

I think this should have been one of my first posts. If you’re making a web site for your business to showcase your company, etc. you will use XHTML-CSS and JavaScript for best SEO results.

But what if you have a bigger plan? What if you want to build a larger web application? What server-side language will you use?

The only person who can answer that is you. But you must get guidance from an unbiased source. Web developers tend to become fanatics of the language they are used to working with. It turns into a kind of patriotism. People will recommend a lot of web languages and frameworks and pull clients into what they are comfortable working with, as opposed to what the need really is.

You know you’ve picked the right technology to use on your web site if:

• It works without any hitches
• There is tons of help available on the Internet (documentation, forums, communities, open source)
• There are tons of companies / individuals who can take over half-way through the project
• It is the most popular

The last point is stressed because the more popular a technology is, the lesser the chance of you getting into trouble. We don’t want something that, only the person who developed your application and a handful of others know about, do we? We want something that everyone knows about, so we have more options to choose from.

In my opinion, the technology that falls under this category is PHP. This has nothing to do with the fact that I am a PHP developer. I migrated to PHP from ASP.NET because of all of the above mentioned. There are many skeptics and articles all over the Internet that might disagree, but I don’t want to end up red-faced in front of my clients who want more flexibility in developers, and scalability. The fact everyone will agree on, whatever the reasons might be for it, is that the number of PHP developers in the world outnumber any server side language by a HUGE number.

If you are looking to use a web technology in India, you can bet on PHP because it is about to become the largest PHP development community in the world. This means unlimited support and flexibility.

There are newer languages that boast better features, but don’t come close to the market share of PHP.

The closest example I can think of is: Would you pick a Windows PC with all its vulnerabilities and viruses for your office or a Linux-based computer? I’ve used Ubuntu Linux. I’ve never been a bigger Windows fan. I admit Ubuntu is far superior to Windows, but I felt isolated and let-down because Windows boasts a larger market share and all major software run on it perfectly.

In short, it all comes down to:  support and market share. If, in the future, some other technology can boast such a market share, I will migrate to it and recommend it.

Easy Clean URLs with Apache’s mod_rewrite

First of all I would like to get the following out of my system:

Tutorials are supposed to be EASY! How on earth do you expect someone who is just learning to understand regular expressions, you jerk!

That felt good. Now lets move on, shall we?

You’ve seen it being used everywhere. What is a “Clean URL” and why is it so important today?

1. It’s better for Search Engine Optimization (SEO) because it fools the search engine into thinking that the page is actually a folder or a file (depending on how you’ve written it), rather than a long URL with a thousand variables which even a regular person would think twice about crawling.
2. It demonstrates knowledge on part of the developer. Since this is slowly becoming a standard of sorts, it’s a must-know for developers.
3. It looks nice and clean

Okay, now what do you need to make this work?

1. An Apache server with mod_rewrite function on. The following technique works ONLY on an Apache server with mod_rewite enabled. That’s right. If you use a Windows server:
   1. You’d better be using some Microsoft Technology like ASP, ASP.NET, etc. or you’re wasting your money!
   2. Here is an article to get clean URLs on the Windows (IIS) server.
2. The ‘.htaccess’ file

That’s it!

Now, lets start. Assuming you have a web site called http://www.mywebsite.com and you have a page URL that looks like: http://www.mywebsite.com/index.php?page=green

UGLY!

Here is how you achieve clean URLs:

1. Open the .htaccess file on your root folder. If you don’t already have one, make one in Notepad or whatever, but make sure you name it ‘.htaccess’ (so that’s no name with the file extension ‘htaccess’) and upload it to your root folder (this is usually www or public_html)

2. If your .htaccess file already existed and you have some code in it already, do not overwrite it.

3. Take a backup of the .htaccess file (in case something goes wrong) . Paste the following code:

RewriteEngine on
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteRule ^([a-z\-]+)$ index.php?page=$1 [L]
</IfModule>

Note: If the line RewriteEngine on already exists in your .htaccess file, don’t paste that again.

Voila! You now have a clean URL. Now if you navigate to http://www.mywebsite.com/green , you get your page!

How does this work? The text following “RewriteRule”  is called a regular expression. It tells Apache to match a condition and if a match is found, redirect (rewrite) internally to a page.

It’s really simple:

^([a-z\-]+)$ : This part is the matching part. This means that lowercase letters a through z and the hyphen (-) are accepted. In our case, “green” falls under this category, so its counted as a “match”

index.php?page=$1 [L] : This is the part that is executed if a match is found. It tells Apache that whatever you found before the “$” is now $1. If you have two conditions, the first one would be $1 and the second $2 and so on. In our case we just matched one, so that’s stored in $1. So now $1 = green. And the page is directed to index.php?page=green .

Sweet! But what’s that [L]? It tells Apache that this is the last statement it needs to execute if a match is found and to stop right there. Just to save on time.

So basically, this entire thing is made up of:

1. A condition which checks for a set. (Cause)
2. A result statement which does something when a match is found. (Effect)

For more in-depth reading on this subject, click here. For another simple tutorial, click here.

Problems:

“My page loads with mod_rewrite but my style sheets and/or images don’t work!”

Obviously! Now that your browser believes that http://www.mywebsite.com/green is an actual folder, it tries to link it up from there.

Quite simply, if your code on your page for your style sheet is: <link href=”assets/css/style.css” /> it looks for it under http://www.mywebsite.com/green/assets/css/style.css , which doesn’t exist.

Simple solution:

Right after your <html> tag, insert this: <base href = “http://www.mywebsite.com/&#8221; />

Now you’re telling the browser, “Hey, from now on all links to resources on my page are to start from my base URL, okay?”

So now the browser  loads http://www.mywebsite.com/(the base URL)assets/css/style.css

Problem solved.

“This just doesn’t work!”

Make sure you are running an Apache server with mod_rewrite on. If you’re not sure, contact your web hosting company.