Mojavi Project

Creating Your First Module
A work in progress

This tutorial is a work in progress, so you may find parts that don’t completely fit together.
Module

The module is where the Model and View takes place in the MVC model. For this first example, we will create a very simple module that will move data from a Action to a View and display it on the screen, through a template.

The module is contained within a directory that carries the name of the module. This resides in the modules directory of the webapp directory. Inside the module directory are sub-directories holding the classes that make up the module. Here is the directory hierarchy:

webapp
|
|—modules
|
|—moduleName
|
|—actions
|
|— config
|
|— lib
|
|— models
|
|— templates
|
|— validate
|
|— views

Minimally, you need the actions, config, templates and views directories. However, I prefer to have a blank module created and just copy and rename it. You can get a copy of the blank module (link to be added). I have chosen to call this module Test

Each module must have a module.ini file in the config directory. Here is the module.ini for Test

; +—————————————————————————-+
; | This file is part of the Mojavi package. |
; | Copyright (c) 2003, 2004 Sean Kerr. |
; | |
; | For the full copyright and license information, please view the LICENSE |
; | file that was distributed with this source code. You can also view the |
; | LICENSE file online at http://www.mojavi.org. |
; | ————————————————————————– |
; | MODULE INFORMATION FILE |
; +—————————————————————————-+

[module]

ENABLED = “On”

TITLE = “Getting Started Test Module”

VERSION = “0.1″

NAME = “TestModule”

AUTHOR = “Richard D Shank”

HOMEPAGE = “http://www.mojavi.org”

DESCRIPTION = “A test module”

The module is pretty self explanitory. It is necessary to have ENABLED property set to “On” for the module to be used by Mojavi. Now that we have the module set up, we can work on the classes.
Action

The Action class handles the request for the module. It can be as simple as handling a static html template or a full blown multi-page wizard style form. Just a note to Mojavi 2 users, a significant change from Mojavi 2 to Mojavi 3 is that it is not longer necessary to pass the controller, request and user classes in on many of the methods. These are now accessed through a context class. More on that later.

This is a list of the methods you can use in an Action and an explanation of what they do
execute ()

Note: This method is required in your Action class.

This will execute any application/business logic for the action. This method is reached only after the request methods have been checked and any of the parameters have been validated.

When leaving, the execute() method should tell the controller what view is to be used. This is done by returning a string containing the view name associated with the action or an array of the parent module for the view to be executed, parent action for the view and the name of the view. I will show an example of return both in a later tutorial.
getCredential ()

This is a new feature in Mojavi 3. Basically, a credentials are a privilege array that describes any level of security. They work hand in hand with the security aspects of the User class. For Mojavi 2 users, note that this replaces the old Privileges. But it is also important to know that it can do more than just handle privileges. I will handle the usage of creditials in a later section. For now, it is sufficient to know that we set the creditial requirements for the action inside this method and that it is set to NULL by default.
getDefaultView ()

This is the view that will be executed when a given request is not served by the action. This could happen when a form being displayed for the first time or if we are displaying a static page.

Again, just as with the execute() methoad, a string with a view name or an array of a module/action/view is passed back to the controller. By default it will pass back View::INPUT
getRequestMethods ()

This method will determine what types of requests will be recognized. There are 4 choices:

* Request::GET - Indicates that this action serves only GET requests.
* Request::POST - Indicates that this action serves only POST requests.
* Request::NONE - Indicates that this action serves no requests.

You can also select both GET and POST requests by using Request::GET | Request::POST
handleError ()

Execute any post-validation error application logic.

It also returns the view through a string of the view name or the array of a module/action/view. By default, it passes View::ERROR.
initialize ($context)

You can set up the Action in the initialize() method. In a later tutorial, I’ll give an example of doing this. NOTE: It is worth to note that you must handle the context in the initialize() method. You should do this by

parent::initialize($context);

You also need to return a TRUE or FALSE based on the success of the initialization. By default it is TRUE.
isSecure ()

Does the action require security? TRUE if you do, FALSE otherwise. It is FALSE by default.
validate ()

This is used to manually validate input parameters instead of using a pre-progammed validator. This will also be explain later in the tutorial on validation.
Creating Your First Action

Now that we have an overview of the Action class, we can move forward to creating our first Action. For this example, there isn’t any request to be handled so we can set up a minimal Action.

In naming an action you must use this format Actionname Action.class.php where Actionname is what you are calling this particular action. When you declare your class, it also must have the class name in the same format Actionname Action. For this example, I chose to call this FirstAction.

When creating a new action, at the very least, there has to be an execute() method, even if it does nothing. Also, since we are displaying a non-request page, we don’t need to process any request. We tell the controller this with the getRequestMethods() method, by setting the return value to Request::NONE. Finally, we also need to tell the controller what the default view is going to be. We do this by returning View::SUCCESS in getDefaultView().

Here is what my FirstAction.class.php looks like. I basically just took my BLANKAction.class.php, renamed it to FirstAction.class.php, renamed the class to FirstAction, removed the methods I didn’t need and set the remaining 3 methods to match my needs.

class FirstAction extends Action
{
/**
* Execute any application/business logic for this action.
*/
public function execute ()
{
// we don’t need any data here because this action doesn’t serve
// any request methods, so the processing skips directly to the view
}

// ————————————————————————-

/**
* Retrieve the default view to be executed when a given request is not
* served by this action.
*/
public function getDefaultView ()
{
return View::SUCCESS;
}

// ————————————————————————-

/**
* Retrieve the request methods on which this action will process
* validation and execution.
*/
public function getRequestMethods ()
{
return Request::NONE;
}

You can also return a view from another module. You do this by passing an array with the view information intead of the standard View::INPUT. When you use this you create a two element array. The first element is the module name. The second element is which view you want. It cannot be just the Action name, but the Action name with the specific view.

Here’s an example:

class MyClass extends Action
{
…

function execute()
{
…

$returnView[0] = MyModule;
$returnView[1] = DoSomethingInput;
-or-
$returnView[1] = DoSomethingError;
-not-
$returnView[1] = DoSomething;

return $returnView
}
}

View

I’ll add more to this later, describing the View class.

For now, all we need to use is the execute() method.
Creating the View

The class name should be in this format ActionnameViewtype View. Again Actionname is the name of the action in the module. Viewtype is the view type that was passed to the controller in the action. Both Actionname and Viewtype are capitialized. This is a list of the predefined view file types and their naming convention.
Internal Name Class and File Name
ALERT Alert
ERROR Error
INPUT Input
SUCCESS Success

Mojavi 2 users ; the naming convention on the file has changed slightly. Before there was an underscore between Actionname and Viewtype. Now, there is no underscore in between, and the Viewtype is capitialized.

For this example, I called my view FirstSuccessView and named the file FirstSuccessView.class.php.

Here’s the code

class FirstSuccessView extends PHPView
{
/**
* Execute any presentation logic and set template attributes.
*/
public function execute ()
{

// set our template
$this->setTemplate(’FirstSuccess.php’);

// set the title
$this->setAttribute(’title’, ‘Getting Started First Test Page’);

// set the message that is to be passed
$this->setAttribute(’passedData’, ‘Hello World!’);

}

}

Template

You also need a template to display the information. I stayed with the naming convention and called my file FirstSuccess.php.

Here is the code for that

Global Templating - The Decorator Pattern

* Enter Decorator
* Insert Here: Slots
* Let’s Decorate!
o Creating a Global Template
o Putting the ornaments up

Ever since Mojavi 3 was released earlier this year, people have been looking to create a flexible global templating solution. From using post filters to page controllers, people have been looking for a way to create simple and managable global templates that will allow for a great deal of flexibility without compromising the need for larges amount of duplicated code.
Enter Decorator

The Decorator design pattern, like every other pattern, is nothing more than a way to talk about a resuable concept, or pattern, that a programmer might encounter while coding applications. The Decorator pattern’s strength is it’s ability to serve as a wrapper for that particular object, while leaving objects like it in tact.

The Decorator pattern has been implemented in the View class, providing a number of new methods:

public function setSlot ($attributeName, $moduleName, $actionName)
public function setDecoratorDirectory ($directory)
public function isDecorator ()
protected function & getSlots ()
public function getDecoratorTemplate ()
public function getDecoratorDirectory ()
protected function & decorate (&$content)

Now a brief explanation of what each of these do:

* setSlot - Creates a slot entry based upon the results of a specially controlled controller->forward()
* setDecoratorTemplate - Sets the template that you’re going to use for your decorator. This method also automatically turns the decorator switch to true
* isDecorator - returns true is setDecoratorTemplate has been called, otherwise false.
* getSlots - Returns an array of the slots.
* getDecoratorTemplate - Returns the decorator template.
* getDecoratorDirectory - Returns the decorator directory.
* decorate - A method that must be implemented in derivate Views.

Note: these functions are in View, so all derivates of View (ie PHPView) have access.
Insert Here: Slots

Slots is a new name for an old concept. More or less, slots serve as placeholders that can be populated by the results of a $controller->foward($mod, $act) call. And, as you can see, the setSlot method takes three parameters:

public function setSlot ($attributeName, $moduleName, $actionName)

The first parameter, $attributeName, serves as the name of the slot. The next two parameters will be used to get the results of that Action, put it in a buffer, and place it into the internal $slots memeber variable.
Let’s Decorate!

The usage pattern of Views changes little with the implementation of the decorator pattern at the module level (though secondary View authors, ie SmartyView et al, do have a few things to play with).

Now let’s look at what you’re going to need to do implement the new, and NEW decorator features of Mojavi.
Creating a Global Template

First off, we’re going to need a great big christma..ehh..template to decorate. While I won’t get into breaking down and factoring our global template, keep in mind that this is not the only way to do this.

Example 2: The Christmas Tree (myGlobalTemplate.php)

Side note: Sometimes you’ll have issues with that <?xml [....] ?> declaration, an easy
workaround is to disable short tags in your php.ini file, or to use ini_set() to disable
it.

<?xml version=”1.0″ encoding=”iso-8859-1″?>
<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.1//EN” “http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd”>
<html xmlns=”http://www.w3.org/1999/xhtml” xml:lang=”en-us”>

<head>

<title><?php echo $template['title']; ?></title>

<meta http-equiv=”Content-Type” content=”application/xhtml+xml; charset=utf-8″/>
<style type=”text/css” media=”all”>

<!–Css slot–>
<?php echo $template['css']; ?>

</style>

</head>

<body>

<!–menu slot–>
<div id=”menu”>

<?php echo $template['menu']; ?>

</div>

<!–main content slot–>
<div id=”main”>

<?php echo $template['content']; ?>

</div>

</body>
</html>

Putting the ornaments up

So now that we have our decorator template, we need to decorate it. The decorating process is fairly simple, and consists of the following simple steps:

* Setting the decorator directory using setDecoratorDirectory() (Optional)
* Setting the decorator template using setDecoratorTemplate()
* Setting slots setSlot()

For example,

Example 3: In the View (IndexSuccessView.class.php)

class IndexSuccessView extends PHPView
{

public function execute ()
{

// set our template
$this->setTemplate(’IndexSuccess.php’);

//setup our decorator template
$this->setDecoratorDirectory(MO_TEMPLATE_DIR);
$this->setDecoratorTemplate(’myGlobalTemplate.php’);

//setup our slots
//(SlotName, Module, Action)
$this->setSlot(’menu’, ‘Content’, ‘PopulateMenu’);
$this->setSlot(’css’, ‘Content’, ‘PopulateCss’);

// set the title
$this->setAttribute(’title’, ‘Default Action’);

}

}

Now you might be wondering where the content slot is being populated. Well, content is a reserved slot that is automatically populated with the output of the originally requested Action/View pair.

To be Continued….

Migrating From Mojavi 2.0

Moved To: Migrating From Mojavi 2

By Tyler Tompkins

Note: This document will be changing frequently as I add more information, and rearrange to create a more logical order and progression of the said information.

* Prerequisites
* First Things First
* The Context
* Translating your Renderer
* View
* Actions
* Configuration
* References

Prerequisites

You should have a decent grasp of Mojavi2 and PHP5 before trying to upgrade to Mojavi3.

If you want a quick crash course of Mojavi 3, see Creating Your First Module 2.
First Things First

Before you begin transferring your applications over from Mojavi2, make sure whatever host you’re using supports PHP5. You can figure out if your host supports PHP5 by running

phpinfo();

Furthermore, you need to download and install the Mojavi3 package, which can be attained by going to this location.
The Context

Probably the most important new and powerful aspect of Mojavi3 is the Context object. Once I figured out what this thing did, I fell in love with it. Basically, it is a sort of catalyst/storage object that allows you to access:

* The $request object via getRequest()
* The $controller object via getController()
* The $user object via getUser()
* The Current Action/Module names via getModuleName() and getActionName()
* And finally the Current module’s directory

More or less, most classes that are exposed to the user/developer (you) are going to have a getContext() function, which will allow you to access this object. And with the recent addition of cascading calls, you can perform operations that you were unable to in php4, for example:

The Old Way:

$obj =& $request->getAttribute(’myobj’);
$anotherobj =& $obj->doSomethingSpecial();
$anotherobj -> execute();

The New Way:

$this->getContext()->getRequest()->getAttribute(’myobj’)->doSomethingSpecial()->execute();

Okay, so maybe that wasn’t the best example, as it is rather lengthy, but you get my point, 1 line vs 3 lines, and no possible mistakes when dealing with large objects like copying them over without references, etc.

This subsection is to be continued….
Translating your Renderer

Mojavi2 used ‘renderers’ to translate the API of one templating system into a generic API that would easily allow a developer to switch out one templating system for another. For example, the Smarty templating engine uses $smarty->assign() to allow you to set a variable, while patTemplate, another templating system, uses $pat->addVar(). In Mojavi 2, you would then write or use an existing renderer, which you would then invoke to display your output.

Note: This was done typically through a filter, which would create the renderer object, then assign it to your $request via

$request->setAttribute(’MyRenderer’,$rendererObj))

Mojavi3 uses largely the same methodology, but instead of getting the renderer directly from the $request object within each of your views, it simply extends the View class.

For example:

abstract class SmartyView extends View
{
…..

function __construct()
{
$this->engine = $this->getContext()->getRequest()->getAttribute(’MySmartyObj’);
}

public function setAttribute($name, $value)
{
$this->engine->assign($name, $value);
}

…..
}

Note: the use of

$this->engine = $this->getContext()->getRequest()->getAttribute(’MySmartyObj’);

was simply the best solution I could come up with for getting any object from within the view, you could also have done the following just as easily:

$this->engine = new Smarty();

View

The Mojavi3 View is mostly an abstract class, which provides a skeleton of functions to work with, thus providing the unified API as was achieved in Mojavi2 (It’s unified because you are forced to comply with the naming conventions implemented by the abstract class View.)

Now, instead of intitializing your Renderer object (as you would in Mojavi2) you simply extend View, and initialize that. Like shown above:

abstract class SmartyView extends View
{
…

is what our new View would look like. To put this new View type into action, we extend it when declaring views for our modules. For example:

class DoSomeActionSuccessView extends SmartyView
{
…
}

As you can see, this is much more fluid than pulling the renderer out of $request with every new View, it’s also a lot less code that you have to copy and paste, and thus less code to maintain. You may also have noticed that the naming scheme is different for the Views, instead of naming the file DoSomeActionView_success.class.php you would now name it DoSomeActionSuccessView.class.php, and name the class likewise(In Mojavi2 we just named our view classes DoSomeActionView, in Mojavi3 it’s DoSomeActionSuccessView replacing ‘Success’ with your application’s state).

This subsection is to be continued….
Actions

Actions in Mojavi3 are fairly similiar to those of Mojavi2, with a few enhancement and semantic tweaks here and there. Listed Below:

* When returning a VIEW_SUCCESS in Mojavi2, now return the View class constant corresponding to your application state, ie: View::Success, or View::Error
* When checking for view types supporting execution (getRequestMethods) instead of returning REQ_POST etc, return Request::Post etc.
* There is a new return type for getRequestMethods(), Request::All, which serves all request methods.
* The root Action class which all your actions extend now has a getContext() method, which allows you access to the context object.

Configuration

Mojavi3 configurations are done, by default, using .ini files. This simple and straightforward configuration makes configuring mojavi very easy. The base syntax of these ini files is as follows:

[SECTION]

; a comment…..
ConfigKey = “%MO_APP_DIR%/my/config/value”

Because some people might not like ini files, Mojavi3 was created in such a way that you could write your own configuration handlers. For example, if you wanted to use xml files to configure your mojavi, you could write a configuration handler, plug it in, and start using your custom configuration styles.

This subsection is to be continued….
References

To find out more about PHP5 in general go here: Where can I go to learn more?