rawebone/ViewModel

This library provides an MVVM approach to view layers with am emphasis on testability and documentation

ViewModel

View Models provide an abstraction between Models, structures holding data in your Domain Layer, and Views, the interpolation of data into a User Interface. This abstraction exists to reduce the amount of logic required to markup the UI and to enable testing of the core presentation logic without having to compare the entire output markup. In addition, should your template system change the logic should be very simplistic to migrate.

This library provides:

• A basic implementation of the MVVM pattern
• Adapters for a number of Templating Engines
• A system for documenting View Models so that the information can be passed on to designers/product managers

Usage

View Models

A View Model consists of a class, defining the logic, and a template defining the markup of the output:

<?php
namespace My\App\Views;

// src/My/App/Views/Model.php

use Rawebone\ViewModel\AbstractViewModel;

class Model extends AbstractViewModel
{
    // Define your logic/constructors here

    public function name()
    {
        return "John";
    }
}

<?php

// src/My/App/Views/Model.view.php

echo $model->name() . "\n";

Engines

The library supports a number of Templating Systems by default:

• Rawebone\ViewModels\Engines\BasicPhpEngine
• Rawebone\ViewModels\Engines\MustacheEngine
• Rawebone\ViewModels\Engines\PhlyMustacheEngine
• Rawebone\ViewModels\Engines\TwigEngine

Usage of the engines is quite straight forward:

$engine = new \Rawebone\ViewModel\Engine\BasicPhpEngine();
echo $engine->render(new \My\Project\Views\Model()); // John

By convention, all of the Engine adapters will expose a single variable in their contexts called "model". In addition, each engine appends on their specific file extension to the file name provided by the ViewModel (i.e. ".twig", ".php").

The TwigEngine, MustacheEngine and PhlyMustacheEngine all accept two constructor parameters with the first being the encapsulated engine and the second being a boolean specifying whether the file should be passed through or whether the contents of the file should be passed through.

Documentation

You may find yourself working with design teams who do not know the internals of the application or wondering what data can be consumed by a template. This library provides a tool to document the View Models in your system easily so that you can output the information in whatever format you require.

$meta = new \Rawebone\ViewModel\MetaData\Providers\ZeptechMetaDataProvider():

$model = $meta->collateFor(new \My\Project\Views\Model());

foreach ($model as $exposed) {
    echo "Type: " . ($exposed->isProperty() ? "Property" : "Method") . "\n" .
         "Name: " . $exposed->name() . "\n" . 
         "Returns:" . $exposed->returnType() . "\n" .
         "Example: " . $exposed->example() . "\n";
}

The model can then be annotated as:

namespace My\Project\Views;

use Rawebone\ViewModel\AbstractViewModel;

class Model extends AbstractViewModel
{
    /**
     * @vmExpose
     * @vmReturn string
     * @vmExample JOHN
     */
    public $upper;

    /**
     * @vmExpose
     * @vmReturn string
     * @vmExample John
     */
    public function name()
    {
        return "John";
    }
}