I'm new to MVC and I'm introducing myself through the Codeigniter framework. As a practice application I'm creating a simple blog application that gives the ability to create, view, edit, and delete posts.
For the "edit post" page, I'm using the same view file as my "create new post" and simply populating the form fields with the data I'm getting from my model when the user is editing an old post.
This seems all fine and dandy but I'm a bit confused on what logic is stored in the Controller vs. View. I obviously need some logic that tells the form to pre-populate the form fields (if I'm editing a post) or to leave everything blank (if it's a new post). There's also other things such as the view page needs to know what title to display at the top of the page: "Create New Post" or "Edit Post".
Where does this logic go? Does it go in the View? Or does it go in the Controller? and Why? I started putting all that logic inside the view file because I've read that I should keep the controller code minimal, however I now have a big php code block at the top of my view file that's dealing with variables and I'm not sure if this is the correct approach.
Any advice would be much appreciated!
I obviously need some logic that tells the form to pre-populate the form fields (if I'm editing a post) or to leave everything blank (if it's a new post).
Check out the set_value() function in the Form Helper. You can do something like this in your view:
<input type="text" name="subject" value="<?php echo set_value('subject', $subject); ?>" size="50" />
If it's a new post, pass empty string as $subject when loading the View from the Controller.
If it's editing, pass the subject of the post that is being edited as $subject.
Also, if a user submits the form and there are errors and you need to reload the form, set_value() will return what the user just posted (i.e. $_POST['subject']).
There's also other things such as the view page needs to know what title to display at the top of the page: "Create New Post" or "Edit Post".
Just pass a variable named $page_title from your Controller to your View, and set the value accordingly. This is pretty common, especially when you start building reusable templates.
Where does this logic go? Does it go in the View? Or does it go in the Controller? and Why?
There should be almost no logic in the View. Maybe simple if/else statements if you must, and loops to iterate through arrays of data.
Even Controller should not have much logic in it. It is mainly responsible for acting as a middle-man between the Models, the Views and the libraries.
I've read that I should keep the controller code minimal
That has to do with Controllers vs. Models, not the Views. It is good practice to keep Controllers smaller, and put as much of the logic as possible into the Models and the libraries. Also referred to as "Skinny Controllers, Fat Models".
Related
I'm a developer and I am very confident with MVC pattern and have already developed a lot of webapp from scratch using php framework like symfony or yii.
I'm a little bit confused about joomla mvc and terminology and after googling a lot, read joomla book extensions guide, read on joomla website my doubt are still there.
What is confusing for me is the component mvc structure and how I have to set up "my way of think" about joomla mvc, for doing the things in the joomla way.
In particular I am used to reasoning in terms of controller/action (like in symfony and yii framework)
So the final list of all my webapp url will be
controller1/action1
controller1/action2
controller1/action3
controller2/action1
controller2/action2
Each controller's action will decide what view to render and what layout to use for showing the view.
In particular in these frameworks, the definition of a layout is exactly the mean of a layout. And the view is the "core part" of the page.
So I can have a view with a list of users and I can put this view inside a mobile layout or a desktop layout, or to build a view for mobile and put it only in the mobile layout and so on.
The final result about directory structure in my webapp is something similar to the following:
controllers/
controller1
controller2
controller3
models/
modelForTableA
modelForTableB
views/
controller1/
viewForAction1
viewForAction2
layouts/
mobileLayout.php
desktopLayout.php
and for me is very clear to understand.
So finally my questions are:
how would be the directory structure in joomla?
what are in joomla the definition of view, layout and task?
I need to clarify that I do not need an explaination about MVC works in general, but if I would achieve the same result as before, how I have to organize my code and my work?
Suppose that I want to build a component with the following "url"
userController/addUser
userController/editUser
userController/listUsers
userController/viewUserDetail
anotherController/addOperation
anotherController/editOperation
anotherController/myNonCrudOperation
Thank you very much
Routing in Joomla is slightly different. The SEF URLs are built from menu items, which in turn point to a View/Layout combination.
This turns things around: a controller is not bound to a specific View/Layout.
Let's make an example of the flow with the addUser functionality you mentioned as an example; I'll be referring to these files (but you'll have plenty more):
/controllers/user.php
/models/user.php
/views/useradd/view.html.php
/views/useradd/tmpl/default.php
/views/useradd/tmpl/default.xml
/controller.php
/router.php
As you can see the layouts are inside each view's tmpl folder.
router.php
Let's start from this last file: router.php defines our custom SEF rules so, after Joomla passes the call to our component (usually with the params
?option=com_componentname) we can takeover and interpret the URL as we wish. It is a bit hard to get started with but does provide the most flexibility and power. We don't really need to implement it at all for this simple example: so back to our registration now.
First step: show the "new user" form.
You would typically bind this to a menu item, pointing to the /views/useradd/tmpl/default.php; the /views/useradd/tmpl/default.xml contains the definition of the layout so it's available in the menu manager. Very often there is only one layout per view.
Control is passed to the view /views/useradd/view.html.php , and the view will then load an instance of its own model (automatically chosen based on the view name, you can load other models of course) to gather any initialization data.
The view then renders the layout, and presents it to the user.
The layout's responsibility includes generating a form with an appropriate action (endpoint) and security tokens if appropriate:
<form action="index.php?option=com_mycomponent">
<input type="hidden" task="user.save">
<?php echo JHtml::_('form.token');?>
as you see it doesn't really matter if you want to use <input or params on the url, and you can most often mix them.
Form interaction
For autocompletion the form may need to invoke some backend controller methods, i.e. the method emailAvailable() in the /controllers/user.php
It does not make sense to have such functionality indexed, so we'll invoke the method directly with a non-SEF url:
index.php?option=com_ourcomponent&task=user.emailAvailable
followed by any other parameter. This will work in both get and post.
The controller /controllers/user.php's emailAvailable() method will return a json structure and then invoke exit() as we don't want the CMS to kick in at all. An alternative solution is to add the param &format=json in the call.
{"email":"johndoe#example.com", "available":true}
Saving the data
When the user submits the form, processing is first handled by the controller since a task is specified. (see above task=user.save). Joomla will invoke the method save() in the controller /controllers/user.php.
This time, however, our controller is responsible for returning information to the user. After processing the data, it may choose to re-render the registration form showing an error, or a thank you page. In either case the controller simply sets the redirect, letting Joomla handle the rendering when appropriate.
$this->setRedirect(JRoute::_('index.php?option=com_yourcomponent&view=useradd', false));
More control
Each time a controller task is not specified, the display() method of the main controller is invoked. You can add custom logic there.
Joomla fires several events during a view rendering; these can be intercepted by a system plugin or - if you add in the calls - other kinds of plugins as well. You may even create your own types of plugins. Do not try to instantiate a view manually from a controller, as this may inhibit plugin firing.
Small insight,
1) Directory Structure
controllers/
controller1
controller2
controller3
models/
modelForTableA
modelForTableB
views/
layout1
2) View and layout and task
check this answer
3) More routing techniques with SEF.
Hope it helps.
solved with this. I cannot delete this question because there already exists other answer.
Could any moderator close or delete this? Thank you
https://joomla.stackexchange.com/questions/18774/joomla-terminology-view-layout-task-and-component-development/18799#18799
I am looking for the way to refresh a template inside a view rendered from another controller than the template's controller, I mean:
I got two controllers AdminController & UserController. And two gsps /admin/listUsers & /user/_searchResult.
Then a want to render view listUsers who have inside the template _searchResult and all right.
Now, i want to refresh the template _searchResult, but cant find how. I tryed calling render(view:"/admin/listUsers", template:"/user/_searchResult", model:[searchResult:result])
AdminController.groovy
#Secured(['ROLE_ADMIN'])
def listUsers(){
//...
}
UserController.groovy
#Secured(['ROLE_ADMIN'])
def search(){
//search users for the givven params and send result by chain if there's an action or update a template if it's needed
//in my case this method need to update the template _searchResult
}
#Secured(['ROLE_ADMIN'])
def searchResult(){
//...
[searchResult:result]
}
listUsers.gsp
//...
<formRemote name="searchForm" url="[action:"search", controller:"user"]">
//Some fields for the search
//I need to place here some hidden inputs to send which
//template i want to update or action to redirect
</formRemote>
<g:render template="/user/_searchResult"/>
//...
_searchResult.gsp
//Just itterate and print the search result in a table
I hope I have explained the problem correctly, thanks!
I don't think I entirely understand your question, but I think the source of your confusion is that the way you are naming things doesn't follow regular conventions and you're not using the right tools for the job. Let me explain...
The methods on Controllers are called Actions. They send some data (the Model) to a View to be rendered into HTML. Views can be composed from smaller, reusable fragments called Templates. (sorry if I sound like I'm being condescending here, but I'm just trying to make sure we're all on the same page).
Now, what you've called templateA is actually a View, not a Template. You're correct that templateA (your View) can call templateB to render some markup, but then having the templateB try to call a method on another Controller doesn't make sense. That's not how things flow.
If you have some logic that needs to be executed after you've sent your Model to the View, you want to use a Tag Library (http://grails.org/doc/latest/guide/theWebLayer.html#taglibs).
To summarise, here's a quick recap.
A request should only call one Action, which sends the model to only one view.
If you need to reuse logic between Controllers, move that code to a Service.
If you need to reuse markup between Views, move that markup to a Template.
If you have logic that you want to have executed after you've sent the Model to the View, use a Tag Library.
Hopefully this will point you in the right direction.
--- UPDATE ---
OK, with the real code I can see better what you're trying to achieve. Firstly, as you're using the <g:formRemote> tag, you should have a good read of the docs at http://grails.org/doc/latest/ref/Tags/formRemote.html to understand what it does.
What you will have here is 2 separate requests. The first will be a regular page load by your browser, which is handled by the listUsers() action. Once the page is then finished loading, the user will enter a search term and hit the submit button. This will fire off a second ajax request, which will be handled by the search() action. This action could use the _searchResult.gsp template to render a HTML table to display the search results. When the browser get this, it will insert it into the DOM where you've told it to put it using the "update" attribute of the <g:formRemote> tag.
The important thing here is that from the server's perspective, these are 2 separate requests that are completely independent. They both first call an action, then send a model (a Map containing some data) to a view, which renders/merges the data with HTML and sends it back to the browser.
The difference between the 2 is that the first is a complete page load by the browser, whereas for the second request, the browser only loads a small chunk of HTML (the search results table) and updates the page content without reloading it.
So your code would look more like this...
AdminController.groovy
#Secured(['ROLE_ADMIN'])
def listUsers() {
render(view:"/admin/listUsers")
}
listUsers.gsp
<g:formRemote name="searchForm" update="insertSearchResultsHere"
url="[controller: 'user', action:'search']">
<input name="searchTerm" type="text" />
</g:formRemote>
<div id="insertSearchResultsHere"></div>
UserController.groovy
#Secured(['ROLE_ADMIN'])
def search() {
// use the search term to get a List<User>
render(template: "/user/searchResult", model: [users: users])
}
_searchResult.gsp
<table>
<g:each var="user" in="${users}">
%{-- Iterate through your search results --}%
</g:each>
</table>
I solved it by placing the attribute update and rendering the template alone:
gsp:
<formRemote name="searchForm" url="[action:"search", controller:"user"]" update="divToUpdate">
//Some fields for the search
</formRemote>
<div id="divToUpdate">
<g:render template="/user/_searchResult"/>
</div>
Controller:
def search(){
render(template:"/user/_searchResult", model:[searchResult:result])
}
When i asked this question, i was new on Grails community and i was confused with the use of remoteFunction and tags that use it like remoteForm. But i had this confusion because of i had not read the documentation. So in my case, the solution was search for documentation about how to use remote tags and render. Thanks to #AndrewW for show me the way.
I have a C#.Net web app and I am trying to access one of the HTML/ASP Text Boxes in the Controller for the Edit View of my Proposal model. In a non-MVC app, I was able to do this using Control.ControlCollection.Find(). Is there an equivalent for a MVC3 project?
You ask for an equivalent of Control.ControlCollection.Find() in MVC?
In MVC your controller is not aware of controls.
The controller just receives data via parameters and returns data via the function result.
What do you want to do with the control in your controller code?
If you want to access the value, you should bind it to a parameter:
View:
<input name="MyControl" type="text" />
Controller:
public ActionResult MyAction(string MyControl) {
// MyControl contains the value of the input with name MyControl
}
The MVC pattern was designed to keep things separated.
The View has no knowledge of the controller at all
The Controller only knows that a view exists and what kind of data that it needs. It do not know how the data is render.
Hence, you can never get information about controls/tags in the view from the controller. You need to use javascript/jQuery in the view and invoke the proper action in the controller.
In an MVC-application you don't have controls like in a webform-application.
In MVC you collect your required data in the controller and pass it to the view.
Typicaly the view is a HTML-page with embedded code.
In opposite to controls in webforms which produce HTML and handles the post-backs in MVC you have to do all this manually. So you don't have controls with properties and events wich you can access easily in the controller and you have to handle all your posts with your own code.
Thats sounds as it is a lot of more work - and indeed it could be if you implement the behaviour of complex controls - but MVC applications are much better to maintain and you have 100% influence to the produced HTML.
Well probably i am late for this but it should help others in future...u can store ur value in hidden field in view and then access that value in controller by following code..
Request.Form["hfAnswerOrder"].ToString();
Point - hfAnswerOrder is the ID of the hidden field
My Control in cshtml page..
#Html.Hidden("hfAnswerOrder", Model.Answers.ToList()[0].AnswerOrder)
Imagine I have a form (Page1.cshtml) with 1 link (LinkBrands). I also have a controller for Page1 (Page1Controller) and one for brands (BrandController). When the user clicks the link what is better to do:
LinkBrands-->Page1Controller-->BrandController (Page1Controller's action will redirect to BrandController)
OR
LinkBrands-->BrandController
Not sure what route is better. Any suggestions?
Usually you don't have a single controller per view. You would use multiple views or partial views all calling actions on the same related controller. I assume Brand is a separate entity from whatever else Page1 is trying to display, therefore it should probably use the BrandController directly but since there really isn't enough information to go on with your example as to what page1's function is I couldn't say what you are trying to relate.
If you need to capture information from the brand link as it relates to page1 then sure have it collect that in page1controller first before redirecting to brandcontroller to display a new view.
What does your Page1Controller do?? It seems as though you are defeating the purpose of the Model-View-Controller architecture and trying to form it back to the WebForms method with code-behind.
So without seeing what exactly your controllers are doing, I'd say your second option is best.
It all depends.
If you have to execute any logic in Page1Controller (saving data for instance) before displaying the second page, then you need to go by Page1Controller, and then go to BrandController:
LinkBrands-->Page1Controller-->BrandController
In case you just need to redirected to the second page (you do not need anything from Page1Controller, you do not need it to perform any action, and you can create a the model for second page in BrandController) then go with the second option:
LinkBrands-->BrandController
Hope this helps.
I've been using Codeigniter in order to get accustomed to the Model-View-Controller architecture, and to try and speed up the process of making and implementing sites.
I keep seeing references to "Partial Views" but can't find a definition for the term.
Can anyone tell me what a partial view is, and where it is used?
A partial view is just a sub-view that you can include in a parent view. Let's take a look at a common example:
// Controller:
$data['myvar'] = array('element1', 'element2', 'element3');
$this->load->view('myview', $data);
// Myview:
<ul>
foreach ($myvar as $var) {
$this->load->view('partialview', array('var', $var));
}
</ul>
// Partialview:
<li><?= $var ?></li>
This is useful to repeat content according to a list.
Note that nothing differs between a view and a partialview, it's just the way you include it that defines the term.
The best way to describe a "partial view" is to think of it as a template, it displays a chunk of html with Model data passed to it.
Good examples of where to use one would be where you plan on displaying the same html over and over, like a menu or a page header or even better yet use them to display content requested using ajax.
Basically you call an action on the controller that returns the partial view from lets say jQuery and then put the returned markup into a select or div tag. Here is an example of doing that from my blog easy ajax with aspnet mvc and jquery, yes I know it asp.net mvc not php and codeigniter, but the principal is the same.