#advanced php and database issue

[lodiwayoflearning]

The Portability of Web Services

By Felipe Lodi

Object Oriented Programming (or simply OOP) is an important concept in application development. Usually a well structured application (all type of application) had on its development a great effort during the modeling. Although optional, the developer can basically create classes that have properties and execute tasks. They can interact against each other, they can be extended, inherited and instantiated.

It means that classes, their properties and methods can be used and reused, can be saved in memory, on disk and on the database. The developer usually decides (after planning) which class to use for determined achievement and when he does that, he creates an object. An object is an instance of the class and it is used taking a copy of the class usually without interfering on the original class. “A class is a blueprint for an object” interestingly states Adrian O’Neill (O'Neill, 2011)

OOP creates portability to the application. The business rules are all put on the Object Model as well as the developer has on his side, depending on the language he is developing with, countless classes to be instantiate for a determined purpose. Again depending on the language, these classes can be categorized, grouped and optionally compiled, thus becoming portable.

It becomes portable because it can be moved, shared, used and reused. It becomes portable because of its interoperability, because the possibility to use these classes across different platforms (it is not that simple) such as Java accessing .Net (Luminis, n.d.) The very same compiled class can be shared between a Web Application and a Desktop Application. It can be used for a local application and at the same time exposed to the Web.

This is the concept of Web Service, a class exposed by an URL. The developer still has to instantiate the class in order to borrow a “copy” of the class, but he does that so, making reference to a Web address. “Web Services can convert your application into a Web-application, which can publish its function or message to the rest of the world.” (W3Schools, 2011)

Being exposed through a Web address, the class can technically be accessed from everywhere in the world (most of the Web services exposed on the Web, have authentication though) and therefore the portability of these small components becomes shareable. Meaning by that, Web services can be accessed at the same time, by a Website, by a Desktop Application, by a Mobile, by an automobile and by a kitchen appliance.

The statement that the development on Web will be made with componentization it is indeed true. Small pieces of software are already spread on the Web for either free, paid or restrict usage. Companies can also expose part of their databases on the web using Web services. Services on the Web already expose (and enable) interaction via Web services.

For instance, developers intended to create interactivity with Facebook have at their disposal, Web services to do that. (Facebook, 2011) The Website WebserviceX.NET, expose for free several Web services for developers such as Currency Converter and Global Weather. (WebserviceX.NET, n.d.)

And this is the point: developers that need to convert currency on their projects do not need to develop this functionality, the same happens if they want to show current global climate. They just have to decide how to display and embed this since the data they are already able to gather from the available Web services. It is indeed easy to envisage applications using all this shared information. Web services are also ready to avail data that would be difficult to produce such as the examples above.

In my conclusion, applications will be using even more shared data. By shared I do not say the data will be free or visible to the world. By shared I mean the data is technically possible to be accessed by different devices, different companies and different users. At the same time as it was never possible before.

REFERENCES LIST

Facebook, 2011. Facebook for Websites. [Online] Available at: http://developers.facebook.com/docs/guides/web/ [Accessed 15 April 2011].

Luminis, n.d. Java.Net interoperability. [Online] Available at: http://lsd.luminis.nl/java-net-interoperability/ [Accessed 15 April 2011].

O'Neill, A., 2011. Classes. [Online] Available at: http://www.aonaware.com/OOP4.htm [Accessed 15 April 2011].

W3Schools, 2011. Web Services Tutorial. [Online] Available at: http://www.w3schools.com/webservices/default.asp [Accessed n.d. April 2011].

WebserviceX.NET, n.d. Web Services. [Online] Available at: http://www.webservicex.net/ws/wscatlist.aspx [Accessed 15 April 2011].

[lodiwayoflearning]

Welcome to Smarty

By Felipe Lodi

In my recent professional past, I built several applications using a CMS (Content Management System) called Xoops (xoops.org). Apart of all nice things that could be done with this amazing tool, one of the things that I liked the most is a MVC Framework used by Xoops called Smarty.

The Smarty pattern is a lightweight framework that separates the development of User Interfaces from the Business Model. Moreover, it nearly creates a different syntax for PHP having as benefit the merging coding between HTML and PHP usually done by developers. This merging sometimes can be hard to be done, though the development tools such as Eclipse help a lot, as developer you find yourself opening and closing the PHP tag every time you need to switch from HTML to PHP.

And that is what Smarty does. Smarty insulates PHP from the presentation with a “much simpler tag-based syntax.” (Smarty, 2010) And the creators also state that no PHP experience is needed in order to start working with Smarty. Analyzing the code comparison below, Smarty saves the developer from typing 113 characters in a single “foreach” statement.

First the code example from PHP containing 300 characters:

=$bar['zag']?>

=$bar['zag2']?>

=$bar['zag3']?>

There were no rows found.

(Smarty, 2010)

Now the same instruction written using the Smarty pattern containing 187 characters:

{foreach $foo as $bar}

{$bar.zag}

{$bar.zag2}

{$bar.zag3}

{foreachelse}

There were no rows found.

{/foreach}

(Smarty, 2010)

It can be observed that several PHP tags () could be avoided when using the Smarty Framework. But given the level of instructions and code snippets an IDE (Integrated Development Environment) can provide nowadays, I don’t see too much benefit on using another pattern just to avoid opening and closing PHP tags. However, the benefits of using Smarty transcend the typing savings.

Smarty on its latest version 3, works with Template Inheritance, bringing the flexibility and scalability from the Objected Oriented Programming to the combination of PHP and HTML. Inherited commands can be extended and code within these templates can also be overridden. These templates therefore can receive parameters that will be evaluated on its context in order to render or not a determinate piece of code. And this code can be simply HTML or a complex routine interacting with Database in PHP.

The Module Project proposed could be really improved by using the Smarty Framework in my opinion. Without any efforts I can see where many replicated code could be replaced by Smarty statements as well as the PHP layer about to be developed. For instance our Project has a JavaScript menu across the top. Using HTML pages, this piece of code is copied in all pages and every time there is a new change on the links or new pages are created, all pages have to be updated just because of this link.

In an educational project this is suitable, since we need to get an overview of bad and good practices but on the professional world, the practice above, would be strictly reproved. By using Smarty my idea is that a page template would be created in order to store this JavaScript menu. Such solution would be also possible using only PHP (e.g. include instruction). However, given the possibility of having different menu options for different users, type or state, this template built using Smarty would also be able to receive and manage parameters and therefore, render a different set of options per group of users.

Without going deep into Smarty and PHP, the example below shows the call to this kind of template and a parameter that will render only part of the menu options:

{extends file="menu.tpl"}

{block name=set_of_options}USER_GROUP_1{/block}

Still without going further into the template code, the parameter USER_GROUP_1 would also be fed by a PHP routine. In the end several lines of code would be avoided as well as the gains in flexibility and scalability would be huge. New options, new pages, updates would be managed to be made only on the menu.tpl file.

That is the point on using MVC (Model View Controller). Besides splitting the development of interface, object model (and databases) and the gain of having different teams working in different streams, the interfacing could also be extended into having inheritance and parameterization. (Juday, 2004) The former brings flexibility to User Interfaces as they do not need to be redeveloped and replicated along the source code, and the latter uses attributes to conditionally render the code within these templates.

Welcome to MVC and be “Smarty”!

REFERENCES LIST

Juday, J.T., 2004. Reap the benefits of design patterns in software development. [Online] Available at: http://www.techrepublic.com/article/reap-the-benefits-of-design-patterns-in-software-development/5173591 [Accessed 14 April 2011].

Smarty, 2010. Template Syntax: Smarty vs PHP. [Online] Available at: http://www.smarty.net/syntax_comparison [Accessed 14 April 2011].