Is there a way to load a controller from a view ?
Here is what i am affter..
I want to use one view multiple times, but this view is being loaded by separate controller that gives the view, information from the db.So becouse of that information from the model i can't just set $this-load->view(); and etc. Is there a way to do this thing, or it has a better way ?
I think a lot of sites face similar challenges, including one I'm working on that loads the same db content into the sidebar on almost every page in the site. I implemented this with the combination of a library and a helper:
Put the data logic into the library (mine is named common.php). In addition to interfacing with the database, you may want the library to store the data in a local variable in case you want to reference it multiple times on a single load.public function get_total_items()
{
if ($this->_total_items === NULL)
{
$row = $this->ci->db->query("SELECT COUNT(*) FROM items")->row();
$this->_total_items = $row[0];
}
return $this->_total_items;
}
Create a helper to load the library. (Don't load libraries within a view!) I have MY_text_helper that loads the library and returns the data:function total_items()
{
$CI =& get_instance();
return $CI->common->get_total_items();
}
Call the helper function from within the view.<p> Total items: <?php echo total_items(); ?> </p>
Simply put, you can't and shouldn't load a controller from a view. That sad, I understand your frustration because you want to re-use the model-pulling/acting logic in the controller across multiples views.
There are various ways of doing this;
Re-use the models. Your models should be very simple to select data from, and should be sleek, but if you're doing the same thing over and over it does seem stupid. In which case...
Use a controller as a "main container" and extend upon it from any logic you need. So your basically using the controller as a template, which pulls data down from the model, loads the appropriate view.
MVC doesn't work that way ... Just re-use the model - that's why it's separate from the controller. If that doesn't fit your needs, you should probably implement a library that does the logic.
I would use a library.
That way you can wrap up the data retrieval in a reusable package that you can call from any controller you like.
just do this
if you controller named controller1
put a link in view just like that
http://your-site.com/index.php/controller1/
if you want specific function add it to your url
http://your-site.com/index.php/controller1/myfunction
that's it
Related
In a MVC pattern, what's the best way to handle when a single view could have multiple actions of the same type (e.g POST)?
Say for instance in a TODO list application. You might allow a user to create multiple lists. Each list could have multiple items. So a user navigates to site.com/list/1 which shows them all the items on the 1st list (1 is a GET parameter). There are then 2 forms (POST) on this page to allow a user to:
Create a new item
Delete an existing item
Should the bootstrap create a "listcontroller", inspect the POST variables and then call the appropriate method similar to :
$lc = new ListController();
if(strtolower($request->verb) === 'post'):
if(isset($_POST['title'])) :
$data = $lc->newItem($_POST);
$load->view('newitem.php', $data);
else if(isset($_POST['delete']) && isset($_POST['id'])):
$data = $lc->deleteItem($_POST);
$load-view('deleteitem.php', $data);
endif;// End if post title
else:
//GET request here so show view for single list
endif; //
Or is it better to just do something like
$lc = new ListController();
if(isset($_POST)):
//controller handles logic about what function to call
$data = $lc->PostAction($_POST);
// $data could also potentially hold correct view name based on post
$load->view();
else:
//again just show single list
endif;
I'm just struggling how best to have a controller potentially handle multiple different actions, as there's potentially quite a few nested if/else or case statements to handle different scenarios. I know these would have to sit somewhere, but where is cleanest?
I know that there are many frameworks out there, but I'm going through the whole "want to understand best practice" behind it phase. Or is this totally the wrong way to do it? Should the controllers actually be structured differently?
To begin with, I actually really like, how you are dealing with implementation of MVC. None of that rails-like parody, where view is managed inside the controller.
Here is what I think is the root of your problem: you are still using a "dumb view" approach.
View is not supposed to be a synonym for "template". Instead it should be a full object, which has knowledge-of and ability-to deal with multiple templates. Also, in most of MVC-inspired design patterns, the view instances are able to request information from model layer.
In your code the issue can be traced back to view's factory ( the $load->view() method ), which only gets what controller sends it. Instead controller should only change the name of the view, and maybe send something that would change the state of view.
The best solution for you would be to create full-blown view implementation. Such that view itself could request data from model layer and , based on data it received, decide which template(s) to use and whether to require additional information from model layer.
I think you're somewhat on the right track with the latter approach. However, you should not hard code the calling of actions in your bootstrap. The bootstrap should interpret the URL and call the action methods dynamically through the use of a function like call_user_func_array.
Also, I would suggest that you leave the rendering of views up to the action code so the action logic is self sufficient and flexible. That would allow the action to analyse the input for correctness and render errors or views appropriately. Also, you've got the method 'deleteItem' on your controller, but that should really be the work of a model. Perhaps you should read up some more on MVC and try to work with an existing framework to understand the concepts better before you try to implement your own framework (I would suggest the Yii framework for that).
Here's an example of how I think your logic should be implemented in a good MVC framework.
class ListController extends BaseController
{
public function CreateAction($title){
if(ctype_alnum($title))
{
$list = new List();
$list->Title = $title;
if($list->insert())
{
$this->render_view('list/create_successful');
}
else
{
$this->render_view('list/create_failed');
}
}
else
{
$this->render_view('list/invalid_title');
}
}
public function DeleteAction($id){
$list = List::model()->getById($id);
if($list == null)
{
$this->render_view('list/errors/list_not_found');
}
elseif($list->delete())
{
$this->render_view('list/delete_successful');
}
else
{
$this->render_view('list/delete_failed');
}
}
}
here is a great tutorial on how to write your own MVC framework
I am currently involved in the development of a larger webapplication written in PHP and based upon a MVC-framework sharing a wide range of similarities with the Zend Framework in terms of architecture.
When the user has logged in I have a place that is supposed to display the balance of the current users virtual points. This display needs to be on every page across every single controller.
Where do you put code for fetching sidewide modeldata, that isn't controller specific but needs to go in the sitewide layout on every pageview, independently of the current controller? How would the MVC or ZF-heads do this? And how about the rest of you?
I thought about loading the balance when the user logs in and storing it in the session, but as the balance is frequently altered this doesn't seem right - it needs to be checked and updated pretty much on every page load. I also thought about doing it by adding the fetching routine to every controller, but that didn't seem right either as it would result in code-duplication.
Well, you're right, having routines to every controller would be a code-duplication and wouldn't make your code reusable.
Unlike suggested in your question comments, I wouldn't go for a a base controller, since base controllers aren't a good practice (in most cases) and Zend Framework implements Action Helpers in order to to avoid them.
If your partial view is site-wide, why don't you just write your own custom View Helper and fetch the data in your model from your view helper? Then you could call this view helper directly from your layout. In my opinion, fetching data through a model from the view doesn't break the MVC design pattern at all, as long as you don't update/edit these data.
You can add your view helpers in /view/helpers/ or in your library (then you would have to register your view helper path too):
class Zend_View_Helper_Balance extends Zend_View_Helper_Abstract
{
public function balance()
{
$html = '';
if (Zend_Auth::getInstance()->hasIdentity()) {
// pull data from your model
$html .= ...;
}
return $html;
}
}
Note that you view helper could also call a partial view (render(), partial(), partialLoop()) if you need to format your code in a specific way.
This is a pretty simple example, but to me it's enough is your case. If you want to have more control on these data and be able to modify it (or not) depending on a particular view (or controller), then I recommend you to take a look on Placeholders. Zend has a really good example about them here on the online documentation.
More information about custom view helpers here.
When you perform such a task, consider using the Zend_Cache component too, so you won't have to query the database after each request but let's say, every minute (depending on your needs).
What you are looking for is Zend_Registry. This is the component you should use when you think you need some form of global variable. If you need this on EVERY page, then you are best adding it to your bootstrap, if you only need it in certain places add it in init method of relavent controllers.
application/Bootstrap.php
public _initUserBalance()
{
$userId = Zend_Auth::getInstance()->getIdentity()->userId;
$user = UserService::getUser($userId);
Zend_Registry::set('balance', $user->getBalance());
}
application/layouts/default.phtml
echo 'Balance = ' . Zend_Registry::get('balance');
That wee snippet should give you the right idea!
In this case, I usually go with a front controller plugin with a dispatchLoopShutdown() hook that performs the required data access and adds the data to the view/layout. The layout script then renders that data.
More details available on request.
[UPDATE]
Suppose you wanted to display inside your layout the last X news items from your db (or web service or an RSS feed), independent of which controller was requested.
Your front-controller plugin could look something like this in application/plugins/SidebarNews.php:
class My_Plugin_SidebarNews
{
public function dispatchLoopShutdown()
{
$front = Zend_Controller_Front::getInstance();
$view = $front->getParam('bootstrap')->getResource('view');
$view->sidebarNews = $this->getNewsItems();
}
protected function getNewsItems()
{
// Access your datasource (db, web service, RSS feed, etc)
// and return an iterable collection of news items
}
}
Make sure you register your plugin with the front controller, typically in application/configs/application.ini:
resource.frontController.plugins.sidebarNews = "My_Plugin_SidebarNews"
Then in your layout, just render as usual, perhaps in application/layouts/scripts/layout.phtml:
<?php if (isset($this->sidebarNews) && is_array($this->sidebarNews) && count($this->sidebarNews) > 0): ?>
<div id="sidebarNews">
<?php foreach ($this->sidebarNews as $newsItem): ?>
<div class="sidebarNewsItem">
<h3><?= $this->escape($newsItem['headline']) ?></h3>
<p><?= $this->escape($newsItem['blurb']) ?></p>
</div>
<?php endforeach; ?>
</div>
<?php endif; ?>
See what I mean?
For a project I used some logic in my view, this is not the way to go so I want to get it out.
The problem is that it can't be done from a class method of my model because Zend will make 10000 of queries from 10000 of instances to the database and it becomes very slow.
So I have to do it on a way that it loads all data at once, then processes it and returns the data back to the view. In my view it works the way I do it, the only problem is that it is IN the viewfiles.
What is the way to go? Just make a class in the model that inputs the values and returns required data?
Thanks
Here is the way i would go to display data from a MVC perspective
Controller
function someAction(){
$someTable = new Model_DbTable_SomeTable();
$allData = $someTable->fetchAll();
$arrayFormattedData = DataProcessor::process($allData);
$this->view->data = $arrayFormattedData;
}
You have to do your logic processing in a model (in the example above its done in the static class DataProcessor throught the process method (Not neccessarly the way to go, but it could be a good start)
View
echo $this->dataParser($this->data); // using a view helper to parse data to be displayed
or
echo $this->partialLoop('partialLoop.phtml', $this->data); // using the partial loop view helper built in in ZF
Finally, you should try to make your models as flexible as possible to make them reusable which is the key in oop development.
I'm about to write a admin panel for my CMS written in CodeIgniter. There will be some user information visible at all time - both in the layout's header section and the sidebar. I'm used to do it in a way that I personally hope and think could be done a lot easier, since I'm tired of sending the same parametres to the view over and over again, when it's dynamic data that needs to be displayed on every page anyways (such as unread messages, username, name, status, etc).
I'll need controllers and models, I know that, but do I have to pass, just for an example, the user's username, unread messages etc. every time I need to load a view? Should I do some kind of library for this?
Now my question is: How would I do it when it comes to best practice and for making it easy to maintain in the future?
I hope my question is understandable :)
Personally, I would extend the Controller library (create a MY_Controller by following the guidance at the bottom of Creating Libraries at codeigniter.com).
You would use your model etc as normal. Then you would create a private function in your MY_Controller class to get the relevant "global" data and call
$this->load->vars('everywhere_data', $data_from_relevant_models);
which would make the data available to all views called from that point on as $everywhere_data. Then add a reference to that function in the constructor of MY_Controller, perhaps with a conditional checking for the user to be actually logged in.
If it's complex to collect and get all that data, you might write a library to handle it for you, but the 'controller' part would still be done by MY_Controller: i.e. to get the data and then use load->vars() to publish it to the view.
As a quick and untested example, MY_Controller would start something like as follows:
<?php
class MY_Controller extends Controller
{
private $logged_in_user;
function MY_Controller()
{
parent::Controller();
if( $this->_logged_in_userid() > 0 )
{
$this->logged_in_user = $this->_get_user( $this->logged_in_userid() );
$this->load->vars('logged_in_username', $this->logged_in_user->username );
} else {
$this->logged_in_user = false;
}
}
...
}
Note that things like _logged_in_userid() would access the session for you (e.g. return $this->session->userdata('logged_in_userid');), and _get_user() would access the relevant models.
Finally, you would have a view that accesses $logged_in_username (or everywhere_data in my first example) which you would call into your headers etc. This leaves your normal controllers uncluttered so that they can focus on delivering their specific functionality, stops you rewriting your code several times AND maintains the MVC ideals.
You could create a View just to hold the information and get it from a $_SESSION variable in the View itself if you want to keep it all in one place.
I have a CakePHP application that in some moment will show a view with product media (pictures or videos) I want to know if, there is someway to include another view that threats the video or threats the pictures, depending on a flag. I want to use those "small views" to several other purposes, so It should be "like" a cake component, for reutilization.
What you guys suggest to use to be in Cake conventions (and not using a raw include('') command)
In the interest of having the information here in case someone stumbles upon this, it is important to note that the solution varies depending on the CakePHP version.
For CakePHP 1.1
$this->renderElement('display', array('flag' => 'value'));
in your view, and then in /app/views/elements/ you can make a file called display.thtml, where $flag will have the value of whatever you pass to it.
For CakePHP 1.2
$this->element('display', array('flag' => 'value'));
in your view, and then in /app/views/elements/ you can make a file called display.ctp, where $flag will have the value of whatever you pass to it.
In both versions the element will have access to all the data the view has access to + any values you pass to it. Furthermore, as someone pointed out, requestAction() is also an option, but it can take a heavy toll in performance if done without using cache, since it has to go through all the steps a normal action would.
In your controller (in this example the posts controller).
function something() {
return $this->Post->find('all');
}
In your elements directory (app/views/element) create a file called posts.ctp.
In posts.ctp:
$posts = $this->requestAction('posts/something');
foreach($posts as $post):
echo $post['Post']['title'];
endforeach;
Then in your view:
<?php echo $this->element('posts'); ?>
This is mostly taken from the CakePHP book here:
Creating Reusable Elements with requestAction
I do believe that using requestAction is quite expensive, so you will want to look into caching.
Simply use:
<?php include('/<other_view>.ctp'); ?>
in the .ctp your action ends up in.
For example, build an archived function
function archived() {
// do some stuff
// you can even hook the index() function
$myscope = array("archived = 1");
$this->index($myscope);
// coming back, so the archived view will be launched
$this->set("is_archived", true); // e.g. use this in your index.ctp for customization
}
Possibly adjust your index action:
function index($scope = array()) {
// ...
$this->set(items, $this->paginate($scope));
}
Your archive.ctp will be:
<?php include('/index.ctp'); ?>
Ideal reuse of code of controller actions and views.
For CakePHP 2.x
New for Cake 2.x is the abilty to extend a given view. So while elements are great for having little bits of reusable code, extending a view allows you to reuse whole views.
See the manual for more/better information
http://book.cakephp.org/2.0/en/views.html#extending-views
Elements work if you want them to have access to the same data that the calling view has access to.
If you want your embedded view to have access to its own set of data, you might want to use something like requestAction(). This allows you to embed a full-fledged view that would otherwise be stand-alone.
I want to use those "small views" to
several other purposes, so It should
be "like" a cake component, for
reutilization.
This is done with "Helpers", as described here. But I'm not sure that's really what you want. The "Elements" suggestion seems correct too. It heavily depends of what you're trying to accomplish. My two cents...
In CakePHP 3.x you can simple use:
$this->render('view')
This will render the view from the same directory as parent view.