I am working with an MVC for the first time and developing a library app for personal dev. I am using the php login found here. I am new to php and sql so apologies for any amateur coding, I have taught myself php.
I have been reading for the past two weeks and trying to get my head around how to do the simplest of tasks. Maybe it's the MVC I am working with or it's just my inability to figure it out. I find myself copying chunks of code from one model/view/controller to the next in order to achieve my desired results, however this isn't ideal as I would like to know what the code does or I won't be learning.
I have been doing a lot of independent reading and following tutorials online however most of them are aimed towards CodeIgniter or CakePhp, therefore the syntax is different. I know that once I finally get my head around the syntax and logics then I won't have any issues.
I will use a simple example for reference below. Hopefully somebody will be able to shed some light on this for me and help me out.
I have been trying all day today to select the number of rows in my table and display this on a user profile page as "You have this number of favourites: x".
As I understand, I create the query in my model which is favouriteTotal(). I then reference this is the controller and render the view? Using PDO to connect to db.
login.php (model)
class LoginModel
{
public function favouriteTotal()
{
$query = $this->db->prepare("SELECT COUNT(*) FROM favourite");
$query->execute();
$count = $query->rowCount()
}
}
login.php (controller)
class Login extends Controller
{
function showProfile()
{
$login_model = $this->loadModel('Login');
$login_model->favouriteTotal();
$this->view->render('login/showprofile');
}
}
showprofile.php (view)
<div>
Your have this number of favourites: <? NUMBER OF FAVS HERE ?>
</div>
This is kind of a general answer about how it often works... Please tell us what framework you are using if you want a specific answer.
Many MVC applications use a ViewBag, a 'Container' of sorts, that gets passed along to the view that's being rendered.
(Updated the code below to reflect how the used framework passes data to the view)
login.php (controller)
class Login extends Controller
{
function showProfile()
{
$login_model = $this->loadModel('Login');
$this->view->count = $login_model->favouriteTotal();
$this->view->render('login/showprofile');
}
}
showprofile.php (view)
<div>
Your have this number of favourites: <?php echo $this->count; ?>
</div>
So, in the controller you assign the value of $login_model->favouriteTotal() to $this->view->count. Then you render the view. In that view, you call $this->count to access the previously sent data.
Related
I'm trying to understand MVC, and learning CI framework. I've some questions about MVC and some basic questions about CI.
1)Views are visual part of application as i read from tutorials, my question is: e.g There is a button "Login" but if user already logged in button will be "Logout". Where will that login check be? On controller or on view? i mean
//this is view//
<?php if($_SESSION('logged') == true):?>
Logout
<?php else: ?>
login
<?php endif; ?>
or
//this is controller//
if($_SESSION('logged') == true)
$buttonVal = 'logout';
else
$buttonVal = 'login';
//and we pass these value to view like
$this->view->load('header',$someData);
//this time view is like
<?=$somedata['buttonVal']?>
i just write theese codes as an example i know they wont work, they are imaginary codes, but i guess you got what i mean. Login check should be on controller or on view?
2)Should models contain only codes about data and return them to controller? For example there is a math, we get 2 value from database and multiply them and display them. Model will multiply or controller will do it?
here we load data with model and do math on controller:
//model
$db->query(....);
$vars=$db->fetchAll();
return $vars;
//controller
$multi = $vars[0] * $vars[1];
$this-load->view('bla.php',$mutli);
here we load data with model and do math on model too, controller just passes data from model to view:
//model
$db->query(....);
$vars=$db->fetchAll();
$multi = $vars[0] * $vars[1];
return $multi;
//controller
$multi = $this->model->multiply();
$this-load->view('bla.php',$mutli);
i mean with that, models should do only database works and pass data to controllers, controller do rest of work and send view to render? Or models do work, controllers get them and send them to view?
3)This is about codeigniter, i have a header which has to be in every page, but it has javascripts,css depending to page i'm using
<?php foreach ($styles as $style): ?>
<link id="stil" href="<?= base_url() ?>/css/<?= $style ?>.css" rel="stylesheet" type="text/css" />
<?php endforeach; ?>
this will be on every page, so in every controller i have
$data['styles'] = array('css1','css2');
$this->load->view('header', $headers);
i'm thinking to make a main controller, write this in it, and all my others controllers will extend this, i see something MY_Controller on CI wiki, is this MY_Controller same with what i'm doing? Are there any other ways to do this?
Sorry for bad English and dummy questions. Thanks for answers.
This is absolutely view logic, the correct way to do it in my opinion:
<?php if($logged_in):?>
Logout
<?php else: ?>
login
<?php endif; ?>
The value of $logged_in would probably be retrieved from a call to a library method:
<?php if ($this->auth->logged_in()): ?>
Authentication is one of those things you'll want access to globally, so you may be calling $this->auth->logged_in() in controller or views for different reasons (but probably not in models).
In every controller i have
$data['styles'] = array('css1','css2');
$this->load->view('header', $headers);
Yes you could extend the controller class with MY_Controller, but you're better off keeping this in the view/presentation layer. I usually create a master template:
<html>
<head><!-- load assets --></head>
<body id="my_page">
<header />
<?php $this->load->view($view); ?>
<footer />
</body>
</html>
And write a little wrapper class for loading templates:
class Template {
function load($view_file, $data) {
$CI = &get_instance();
$view = $CI->load->view($view_file, $data, TRUE);
$CI->load->view('master', array('view' => $view));
}
}
Usage in a controller:
$this->template->load('my_view', $some_data);
This saves you from loading header/footer repeatedly. In my opinion, presentation logic like which CSS file to load or what the page title should be belongs in the view whenever possible.
As far as models go, you want them to be reusable - so make them do what you need and keep it strictly related to data manipulation (usually just your database). Let your controller decide what to do with the data.
Not related to MVC, but in general you want to write as little code as possible. Redundancy is a sign that you could probably find a better solution. These are broad tips (as is your question) but hopefully it helps.
1) View logic should be simple and mostly if-then statements, if needed. In your example, either case would work but use the logic in the view. However, if you were checking for login and redirecting if not logged in, then that would occur in a controller (or a library).
2) Think of Codeigniter models as ways to access database functions - Create, Retrieve, Update, Delete. My (loose) rule of thumb is for Codeigniter models is to return results from update, delete or insert queries or a result set from a fetch query. Any applicable math can then occur in the controller. If this is a math operation that occurs EVERY time, consider adding it to a library function. See below...
3) Extending the controller is the proper and best way to accomplish this.
*) Not to add more to your plate, but also be sure to learn about Codeigniter Libraries. For example, in your controller you could load your library. You then call your library function from your controller. The library function calls a model which retrieves your database result. The library function then performs math on that function and returns the result to the controller. The controller is left with little code but a lot is accomplished due to the library and model.
The user lo-gin check should be in the controller.
This should be the first function that need to be invoked in the constructor.
Below i have given the sample code which redirects the user to the login page if he is not logged in, hope this would give you some idea,
<?php
class Summary extends Controller {
function Summary() {
parent::Controller();
$this->is_logged_in();
}
function is_logged_in() {
$logged_in = $this->session->userdata('logged_in');
if (!isset($logged_in) || $logged_in != true) {
$url = base_url() . 'index.php';
redirect($url);
exit();
}
}
?>
The button change can be implemented in the view by checking the session variable in view and making decisions accordingly.
Please take look at this link
Okay, so I'm laying face down on the pavement looking up at the ATK4 learning curve...
I'm trying to set up a simple page much like the Agile demo here: http://codepad.agiletoolkit.org/autocomplete using my own db tables.
So, the problem I have is that the database record primary key 'id' is showing up in the autocomplete box. Data all shows properly, but, obviously, I want the complex name (complex_name) column data to show, not the id. I see nowhere to define which column to display, and it appears that agile is deciding that? Can I set it? What am I doing wrong?
Something so simple, but I've been banging my head with no clue how to set this in ATK4 for so many hours now that I could tear my hair out. I have searched and looked at code examples.
Here is my code:
<?php
class page_index extends Page {
function init(){
parent::init();
$page=$this;
$form=$this->add('Form');
$name=$form->addField('autocomplete','complex_name','Complex Lookup/Add')->setModel('Complex');
$form->getElement('complex_name')->js('change',$form->js()->submit());
$form2=$this->add('MVCForm');
$model = $form2->setModel('Complex');
if($_GET['id'])$model->loadData($_GET['id']);
$form2->addSubmit();
if($form2->isSubmitted()){
$form2->update();
$form2->js()->reload()->execute();
}
if($form->isSubmitted()){
$form2->js()->reload(array('id'=>$form->get('complex_name')))->execute();
}
}
}
<?php
class Model_Complex extends Model_Table {
public $entity_code='condo_complexes';
function init(){
parent::init();
$this->addField('complex_name');
$this->addField('complex_address1');
$this->addField('complex_city');
$this->addField('complex_zip');
}
}
Thank you for any help.
Check out this add-on: https://github.com/atk4/autocomplete
It's not fully finished, but it's in development stage.
Maybe you'll also be interested to follow ATK4 hangouts.
Visit ATK4 homepage and get more info.
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?
I'm new to zend so I'm not sure what's the best way to organize what I'm trying to do. I direct the user to a series of quizzes.
mysite.com/quiz1
mysite.com/quiz2
mysite.com/quiz3
mysite.com/quiz4
When the user answers the first quiz, he is forwarded to a page that tells him if his answer is correct, and on the same page he can choose to answer another quiz. If he answers it, he again will be taken to a page where he is told if his answer was correct and presented with the third quiz.
From the architecture side of things, are each of these quiz1, quiz2, etc. pages considered a controller of their own? Their path says they may be, but doesn't make sense to me if they are. Is there a way to have them at those same paths but bundle them in the same controller. As I said I'm new to Zend so would appreciate some feedback about the right way to do this.
I would do a Quiz controller that will have actions like showQuiz(), validateQuiz() that will read the quiz parameter. This way you will reuse most of the code. The quizes will be entries in the db and there you can also build paths or connections with them.
class QuizController extends Zend_Controller_Action
{
public function showAction()
{
// you can play this in routes but it could be basically something like this
// localhost/quiz/id/1
$quiz_id = $this->_request->getParam('id');
$this->view->quiz = $this->getQuizTable()->find($quiz_id);
}
public function validateAction()
{
$quiz_id = $this->_request->getParam('id');
$quiz = $this->getQuizTable()->find($quiz_id);
$quiz->validate(); // build your own validator function
}
}
I'm trying to understand the MVC pattern. Here's what I think MV is:
Model:
<?php
if($a == 2){
$variable = 'two';
}
else{
$variable = 'not two';
}
$this->output->addContent($variable);
$this->output->displayContent();
?>
View:
<?php
class output{
private $content;
public function addContent($var){
$this->content = 'The variable is '.$var;
}
public function displayContent(){
include 'header.php';
echo $content;
include 'footer.php';
}
}
?>
Is this right? If so, what is the controller?
The controller is your logic, the model is your data, and the view is your output.
So, this is the controller:
$model = new UserDB();
$user = $model->getUser("Chacha102");
$view = new UserPage($user->getName(), $user->getEmail());
echo $view->getHTML();
The model is the UserDB class which will give me my data. The view is the UserPage that I give the data from the model to, and it will then output that page.
As you can see, the controller doesn't do much in this example, because you are simply getting user data and displaying it. That is the beauty of MVC. The controller doesn't have to deal with the User SQL or HTML stuff, it just grabs the data and passes it to the view.
Also, the view doesn't know anything about the model, and the model doesn't know anything about the view. Therefore, you can chance the implementation of either, and it won't affect the other.
Relating more to your example, you have the view correct, but you have mixed your controller and model.
You could relieve this by:
Controller:
$model = new NumberToWord();
$word = $model->getWord($a);
$this->output->addContent($word);
$this->output->displayContent();
Model:
class NumberToWord{
public function getWord($number)
{
if($number == 2){
return 'two';
}
else{
return 'not two';
}
}
}
And keep your same output
Controllers receive user requests - usually there is some kind of router that takes a URL and routes the request to the appropriate controller method.
Models are used by a controller to query data to/from a database (or other data source).
Views are called from a controller to render the actual HTML output.
If all you want to do is create a simple template system, you might aswell go with:
$content = 'blaba';
$tpl = file_get_contents('tpl.html');
echo str_replace('{content}',$content,$tpl);
With a template file like:
<html>
<head><title>Whatever</title></head>
<body>{content}</body>
</html>
In your example, it's more like you've split a Controller into a Model and a View.
Model: Business logic / rules and typically some sort of database to object relational mapping
Controller: Responds to url requests by pulling together the appropriate Model(s) and View(s) to build an output.
View: The visual structure the output will take. Typically a "dumb" component.
It can be confusing when you first encounter MVC architecture for a web app, mainly because most web frameworks are not MVC at all, but bear a much closer resemblance to PAC. In other words, the Model and View don't talk, but are two elements pulled together by the context the Controller understands from the given request. Check out Larry Garfield's excellent commentary on the subject for more information:
http://www.garfieldtech.com/blog/mvc-vs-pac
Also, if you are interested in the MVC pattern of development, I suggest you download one of the many frameworks and run through a tutorial or two. Kohana, CodeIgnitor, CakePHP, and Zend should be enough to kick-start a Google-a-thon!
Zend Framework: Surviving The Deep End has some good sections explaining MVC. Check out the MCV Intro and especially this seciton on the model.
There are numerous interpretations of the Model but for many programmers the Model is equated with data access, a misconception most frameworks inadvertently promote by not obviously acknowledging that they do not provide full Models. In our buzzword inundated community, many frameworks leave the definition of the Model unclear and obscured in their documentation.
To answer "where's the controller":
Controllers must define application behaviour only in the sense that they map input from the UI onto calls in Models and handle client interaction, but beyond that role it should be clear all other application logic is contained within the Model. Controllers are lowly creatures with minimal code who just set the stage and let things work in an organised fashion for the environment the application operates in.
I think you'll fine it (and his references of other articles and books) a good read.
Here is a very simple example of MVC using PHP. One thing missing is THE router. It selects one of the controller to do the job. We have only one controller, the customer.
If we compare it with 3 tiers
Model: The database
View: Client
Server:Controller
Router:It selects a controller
When you select something from an application on web browser, the request goes to router, from router it goes to controller. Controller asks from model and make a view. View is rendered to you.
Only model can talk to controller back and forth.
1- Model.php
<?php
class Model
{
private $con=null;
private $r=null;
function connect()
{
$host="localhost";
$db="mis";
$user="root";
$pass="";
$this->con=mysqli_connect($host,$user,$pass) or die(mysqli_error());
if(!$this->con){
echo die(mysqli_error());
}
else mysqli_select_db($this->con,$db);
}
function select_all()
{
$this->connect();
$sql="select * from customers";
$this->r=mysqli_query($this->con,$sql) or die(mysqli_error());
return $this->r;
}
function display_all()
{
$i=0;
echo "aaaaaaaaaa";
$this->r=$this->select_all();
while($q=mysqli_fetch_array($this->r))
{
$i++;
echo $i."-Id:".$q['id']."</br>";
echo $i."-Name:".$q['name']."</br>";
echo $i."-Phone:".$q['phone']."</br></br>";
}
}
}
?>
2. Controller: There may may be many controllers.
<?php
class Customers extends Model
{
function select_all1()
{
//echo "aaaaaaa";
$this->display_all();
}
}
?>
3. View: There may be many views
<?php
include("model.php");
include("customers.php");
?>
<html>
<head><title>Customers</title></head>
<body>
<?php
$c=new Customers();
echo $c->select_all1();
?>
</body>
</html>