I've picked up PHPTAL (after coming from PHPMustache), and I'm trying to inject a ViewModel class Mustache-style into my template. Let me explain ..
controller
$viewmodel = new \Viewmodel\Home();
$template = new \PHPTAL('application/views/home.html');
$template->viewmodel = $viewmodel;
echo $template->execute();
home.html <- template
<p>Hello <strong>${viewmodel/test}</strong>.</p>
Home.php <- viewmodel class
namespace Viewmodel;
class Home {
function test() {
return "world";
}
}
The above works, but how do I avoid prefixing every variable reference with "viewmodel/"?
With Mustache, your variable context could be a single class. eg. echo $template->render($html, $viewmodel);. Prefixing is not necessary. All the meat is inside a loosely coupled viewmodel. I'd like to enforce this behaviour with PHPTAL without having to explicitly assign the whole class to a variable name.
In short, no.
There's no equivalent to JavaScript's with(model){} operator. You're supposed to be explicit what variables you declare via $context->set() and use models explicitly, e.g. ${user/name} rather than ${name}. The latest version (in GitHub) supports closures, so you can use that for lazily computed variables.
If you're not giving direct access to models and you want to proxy all data through the viewmodel, then that looks like impedance mismatch with Moustache design philosophy.
In PHPTAL's approach to MVC you have business logic handled by model/controller (e.g. customer's account balance stored/manipulated) and any view-specific logic (e.g. if balance is negative then display it in red) goes into the template.
There's no in-between object to mediate that communication to add expressiveness to the template, because the template language is more expressive, and can be extended with TALES expressions:
<strong tal:condition="customer/isInDebt"/>
<strong tal:condition="isNegative:customer/balance"/>
Related
Usually an AEM component is retrieving its data from a JCR node, but I was wondering whether it's possible to pass data to it in HTL. Sure, there's data-sly-resource, but as far as I know this way you can only pass a JCR node.
So in an actual case I've got data in a model that's retrieved from elsewhere. Yet I'd like to use existing components. I'm aware that the data must at least match the component-types' model.
But what if the component I'd like to use is using an model that got its data injected like
#Inject
#Optional
String[] itemList;
So in my stubborn thoughts it should be possible to somehow pass a string array like
<div data-sly-resource="${myModel.aStringArray # resourceType='my/component' }"></div>
But like mentioned above this seems to be meant for passing nodes only.
Is there any way to accomplish passing data directly to a component (other than creating a template)?
You can pass additional information in the form of request attributes or selectors
Selectors
Selectors are the most straight forward of passing simple information. This is an array of strings that can be passed. This is quite useful to data that can act as flags ex:
Variant/Mode of the component
index of the component in a list if it is being included in a loop.
ID of the parent when building things like accordion, tabs
This approach is an abuse of selectors, but IMHO as long as you know what you are doing this shouldn't be a major concern.
<article data-sly-resource="${'path/to/resource' # selectors=['s1', 's2']}"></article>
You can add, replace or remove selectors while including the component. Checkout the documentation for the syntax. https://docs.adobe.com/content/help/en/experience-manager-htl/using/htl/block-statements.html#resource
Request Attributes
This option allows you to add custom request attributes to the component request. This can be used to pass objects as parameters to the component while including them.
These are standard http request attributes with convince of scoping them to a particular instance of script/resource inclusion. To use this you will end up needing a model class or use-js as there is little support to compose the data to be passed along in sightly.
<sly data-sly-use.settings="com.adobe.examples.htl.core.hashmap.Settings"
data-sly-include="${ 'productdetails.html' # requestAttributes=settings.settings}" />
https://docs.adobe.com/content/help/en/experience-manager-htl/using/htl/block-statements.html#request-attributes
There is another way. You can pass additional parameters to the Sling Model on initialization using data-sly-use. For example:
<div data-sly-use.model="${'com.model.Teaser' # test='abc'}"
You can read then the variable "test" in model from request:
#PostConstruct
private void initModel() {
String value = request.getAttribute("test");
// value is 'abc'
}
In order this to work correctly you need to make sure your Sling Model is adaptable from request #Model(adaptables = SlingHttpServletRequest.class}
I've been refactoring my app to make more components stateless/pure components; i.e., they're just functions. However, I noticed that some components will need to connect with the redux store via mapStateToProps. Which causes me to do something like this:
const someComp = (props) => {
const {
funcFromReduxStore,
} = props;
return (
...
<SomeComponent
func={ funcFromReduxStore(myArgs) }
...
);
};
This will not work because I am executing funcFromReduxStore. An easy solution is to wrap the prop in an arrow function. However, this causes many unnecessary re-renders b/c the function won't be bound.
The question then becomes: How do I bind a function in a stateless component?
Is it still stateless if I make it a class, without a constructor, and create a class instance field as so:
class someComp extends React.Component {
const {
funcFromReduxStore,
} = this.props,
wrapper = (x) => funcFromReduxStore(x) // equivalent way to bind w/ ES8+
render() {
...
<SomeCompnent
func={ wrapper(myArgs) }/>
...
}
}
I don't have a constructor, nor state. I want to keep the comopnent stateless, but I also want to bind the function to avoid unncessary re-renders. I also want to continue to keep it stateless b/c React has stated there will be performance benefits for stateless comopnents. Does this qualify as a workaround?
Short answer, no. Stateless functional components need to be simple functions.
You should take a look at the Recompose library for some really cool helpers that allow you to beef up your SFCs.
If you're trying to prevent unnecessary re-renders, you could look into onlyUpdateForKeys() or pure().
EDIT: So, I've been thinking about this a bit more and found this really great article on React component rendering performance. One of the key points in that article that pertains to your question:
Stateless components are internally wrapped in a class without any optimizations currently applied, according to Dan Abramov.
From a tweet in July 2016
So it appears that I was wrong. "Stateless Functional Components" are classes...for now. The confusing thing is that there have been performance improvements theorized:
In the future, we’ll also be able to make performance optimizations specific to these components by avoiding unnecessary checks and memory allocations.
At this point, I think the answer to your question becomes largely subjective. When you make a class that extends a React Component, any instances of your class get the setStateprototype method. Meaning you have the ability to set state. So does that mean it's stateful even if you're not using state? Thanks to #Jordan for the link to the code. SFCs only get a render method on the prototype when they are wrapped in a class by React.
To your point about wanting to bind functions, there's only two reasons I can think of that you'd want to bind the function:
To give the function access to this (the instance of the component). From your example, it doesn't seem like you need that.
To ensure that the function passed as a prop to a child component always retains the same identity. The wrapper function in your example seems unnecessary. The identity of the function is determined by the parent component (or mapStateToProps, or whatever HOC).
You should also take a look at React's PureComponent which does the same kind of shallow checking that the pure() HOC from recompose does.
I know there are view controllers and action controllers. I think that view helpers can be used from views and action helpers used from actions in controllers.
I need a class that at bootstrap or wherever, it initializes a number of configuration options, arrays for things like convert month numbers to their names and role numbers to their names.
How can this be achieved?
Put them in a model and use it anywhere you like by instantiating it and calling its helper methods. All model files are auto loaded whenever you call them.
Have a model Constants.php:
<?php
class Constants {
public static function convertMonth($month) {
doLogic();
return $something;
}
}
?>
In your controller or view:
Constants::convertMonth(12);
You could build a Resource Plugin and then add it to yout bootstrap class.
The Constants class or Resource approaches both work nicely. However, I recently had to undo/upgrade a Constants class based solution to meet new requirements, so you might want to consider your future plans before going down those paths.
Specifically, if you ever intend to support multiple languages, or even different words for the constants in different contexts, check out Zend_Translate API docs, Zend_Translate example, or this blog post.
How can I eliminate to write $object = new Application_Model_Database() in every controller?
For example for an article controller, I have to type $articles = new Application_Model_Articles() for every controller. Should I put it under viewer controller, action helpers, or any other way?
Your question almost sounds like an OOP best practices question as opposed to a Zend Framework specific question. Regardless of whether or not I'm using a framework, and regardless of what framework I choose, I base when and where I create new objects on testability how many times I have to write $object = new My_Random_Object();.
Speaking specifically to the Zend Framework: Objects I'm going to use everywhere, or almost everywhere, get created in Bootstrap.php. These objects generally include a database adapter, logger, view object, and any plugins I might use. To access these across the application, I'll create private properties in the appropriate controllers and assign the objects to those properties in the controller's init() method.
class ExampleController extends Zend_Controller_Action
{
public function init()
{
$bootstrap = $this->getInvokeArg('bootstrap');
$this->_db = $bootstrap->getResource('db');
$this->_log = $bootstrap->getResource('log');
// and so on, and so forth
}
}
Ideally, models, services, daos, etc, will all be relatively tightly grouped by controller and by action. In my experience, and this is speaking generally, if I have the same model or service class showing up across all of the controllers in my application, I have an organization problem. That being said, any model that shows up in only one action gets created in that action. If it's across actions in a controller, it gets created in the init() method and assigned to a property. If it shows up across multiple controllers, it gets created in my Bootstrap.php.
(Ideally, everything gets created in the Bootstrap.php, so you can swap out that bootstrap for testing purposes. Sadly, I don't always do that, and I most often use the principles I outlined above.)
Well do you really need it in every controllers? Because that's pretty much by design. You implement models when you need them. Its not that much code really.
Now if its to be used across actions from a controller you could always:
class MyController extends Zend_Controllers{
$protected $_articleModel;
...
and in your constructor or __init() function initialize it so you can use it in every action thru $this->_articleModel
If you REALLY want it everywhere in your application just initialize it in your bootstrap and store it in the registry.
public function __initModels(){
$articles = new Application_Model_Articles()
Zend_Registry::set('articles', $articles );
}
And access it in your controllers like so:
Zend_Registry::get('articles')->fetchAll();
But then your still writing a couple of characters.
Hope this help!
IF you want to use models in the controllers you must call it..anyway some shortcuts are here
1.You can initialize it in the init section of your controller like
public function init(){
$this->object = new Application_Model_Database();
}
So that the this->object is available in all the actions of that particular controller
2.Use Zend_registry as suggested in the above answer
Another possibility is to use a Dependency Injection container, such as the Symfony DI component. It takes care of instantiating your objects, and you get some additional benefits:
Separation of concerns. You have a component devoted to create your object tree.
Easier testability of the objects.
Last, but not least, the performance benefits given by lazy instantiation (objects are created only when you ask for them). Thus, if some object is not used by the particular controller serving your request, it's not instantiated).
It's a bit more laborious than the above solutions, but much more flexible if you need to maintain and extend your application in the future.
Hope that helps,
If you are using this object to just display data in your view and are using your controller to grab the data and assign it to your view, like so:
//someControllerAction
$object = new Application_Model_Articles();
$object->fetchAll();
//assign to view
$this->view->articles = $object;
You might be better off making a view helper similar to:
//Articles.php put in /application/views/helpers
class Zend_View_Helper_Articles extends Zend_View_Helper_Abstract {
public function Articles() {
$articles = new Application_Model_Articles();
$articles->fetchAll();
//return rowset object
return $articles;
Then in your view (phtml) you could do something like:
//someView.phmtl
<?php $articles = $this->Articles(); ?>
<h1><?php echo $this->escape($articles->title); ?></h1>
<p><?php echo $this->escape($articles->body); ?></p>
building a view helper allows you to bypass the controller completely if you just need to display data from the model. This is a very simple example and can be used with partials and partialLoops.
REF:ZF reference Custom View Helper
ZF partial view helper reference
Does ASP.NET MVC offer any simple way to get model binding to work when you have model classes that inherit from others?
In my scenario I have a View that is strongly typed to List<Person>.
I have a couple of classes that inherit from Person, namely PersonTypeOne and PersonTypeTwo.
I have three strongly typed partial views with names that match these class names (and render form elements for the properties of their respective models).
This means that in my main View I can have the following code:
<% for(int i = 0; i < Model.Count; i++)
{
Html.RenderPartial(Model[i].GetType().Name, Model[i]);
} %>
This works well, apart from when the user submits the form the relevant controller action method just gets a List<Person>, rather than a list of Person, PersonTypeOne and PersonTypeTwo.
This is pretty much as expected as the form submission doesn't contain enough information to tell the default model binder to create any instances of PersonTypeOne and PersonTypeTwo classes.
So, is there any way to get such functionality from the default model binder?
You should just create separate models to bind to your input. Your ViewModels and EditModels are truly distinct responsibilities and thus deserve their own objects.