Controllers and Actions in MVC

[Jeff Mott]

I agree that injecting a templating library/component is definitely the best option. Though, I expect the view would still need to decide for itself which template to render, because the template may need to vary depending on the user input (a result from the controller). For instance, if user input doesn't validate, then the view may need to render a form with errors. Or if the input does validate, then the view may need to render a success message or perhaps a redirect response. Though, I definitely don't think the model should be involved with the templates in any way, shape or form. The model is supposed to be about domain logic, and templates are about presentation.

[markbrown4]

For what it's with worth(not much) I find these discussions interesting but no MVC framework that I've come across is even a close contender to the elegant simplicity of Rails.
So, if I were using PHP I would try to implement the conventions and methods of Rails because I think they make a lot of sense.

I'd try to implement code that looked something like this.. lots of psedo code and I haven't written php in years.
--

I would set up routes somewhere which map HTTP to a controller and action

# routes

method url                 controller#action  helper_method
GET    /users              users#index        users_path
POST   /users              users#create       users_path
GET    /users/new          users#new          new_user_path
GET    /users/:id/edit     users#edit         edit_user_path(user)
GET    /users/:id          users#show         user_path(user)
POST   /users/:id          users#update       user_path(user)
POST   /users/:id/delete   users#delete       delete_user_path(user)

The model should contain the validations
# models/user.php

class User extends ApplicationModel {
  public $name = ''
  public $email = ''
 
  public function validate() {
    $errors = [];
    if ($this->name == '') {
      $errors['name'] = 'Name cannot be blank';
    }
    if (!filter_var($this->$email, FILTER_VALIDATE_EMAIL)) {
      $errors['email'] = 'Email is invalid';
    }
    return $errors
  }
}

The controller should expose methods to the view to consume data as well as handling params to the actions and deciding what to do
# controllers/users_controller.php

class UsersController extends ApplicationController {
 
    // expose an api to the views
    public function users {
      return User.all()
    }
 
    public function user {
      if (params('id')) {
        return User.find(params('id'))
      }
      else {
        $user = new User
        if (params('user')) {
          $user.attributes(params('user'))
        }
        return $user
      }
    }
 
    // actions
    public function create() {
      if (user().save()) {
        flash('success', 'User created!');
        redirect_to(users_path());
      }
      else {
        flash('error', 'Errors');
        render('new');
      }
    }
 
    public function update() {
      if (user().save()) {
        flash('success', 'User created!');
        redirect_to(users_path());
      }
      else {
        flash('error', 'Errors');
        render('new');
      }
    }
 
    public function delete() {
      user().delete()
      flash('success', 'User deleted!');
      redirect_to(users_path());
    }
}

The view should have access to the exposed methods of the controller and helper methods like named routes and flash
# views/users/index.php

<h1>Users</h1>
<ul>
<?php foreach (users() as $user) { ?>
  <li><?php echo $user.name ?></li>
<?php } ?>
</ul>

# views/users/show.php

<h1><?php echo user().name ?></h1>
<p>Email: <?php echo user().email ?></p>

# views/users/new.php

<h1>New User</h1>
<form action="<?php echo users_path() ?>" method="post">
  <?php render('form') ?>
  <input type="submit" value="Create">
</form>

# views/users/edit.php

<h1>Edit User</h1>
<form action="<?php echo user_path(user()) ?>" method="post">
  <?php render('form') ?>
  <input type="submit" value="Update">
</form>

# views/users/_form.php

<div>
  <label for="user_name">Name</label>
  <input id="user_name" name="user[name]" value="<?php params('user[name]') ?>">
</div>
<div>
  <label for="user_email">Email</label>
  <input id="user_email" name="user[email]" value="<?php params('user[email]') ?>">
</div>

I'd have an application layout which renders the views
# views/layouts/application.php

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>untitled</title>
</head>
<body>
<?php if (flash('error')) {
  <div id="error"><?php echo flash('error') ?></div>
<?php } ?>
<?php if (flash('success')) {
  <div id="success"><?php echo flash('success') ?></div>
<?php } ?>
<div id="content">
  <?php render_view() ?>
</div>
</body>
</html>

I'd abstract everything that you want to be able to reuse across your models controllers and views into a separate part of the app.

# framework/application_model.php

class ApplicationModel {
 
  public static function all() {
    // select * from <pluralised lowercased __CLASS__>;
  }
 
  public static function find($id) {
    // select * from table where id=$id;
  }
 
  public function save() {
    $errors = $this->validate()
    if ($errors.length == 0) {
      // UPDATE table where id=$id
    }
    else {
      return false;
    }
  }
 
  public function delete() {
      // DELETE FROM table where id=$id
  }
 
  public function attributes($attributes) {
    foreach($attributes as $attr => $value) {
      $this->$attr = $value
    }
  }
 
}

# framework/application_controller.php

class ApplicationController {
  public function params($key) {
    // map nested params ?user[name]=mark&user[email]=markbrown4@gmail.com
    // params('user') == { name: 'mark', email: 'markbrown4@gmail.com' }
    // params('user[email]') == 'markbrown4@gmail.com'
  }
 
  public function redirect_to($url, $flash) {}
 
  public function flash($key, $value) {
    // set a short lived variable in session
  }
 
  public function render($view) {
    // render a view from a controller
  }
 
  // 7 rest actions
  public function index() {}
  public function show() {}
  public function new() {}
  public function edit() {}
  public function create() {}
  public function update() {}
  public function delete() {}
}

# framework/application_view.php

class ApplicationView {
  public function flash($key) {
 
  }
  public function render($partial) {
    // render '_$partial.php'
  }
 
  public function render_view() {
  }
}

I just thought this may give you some ideas to play with.

[oddz]

For what it's with worth(not much) I find these discussions interesting but no MVC framework that I've come across is even a close contender to the elegant simplicity of Rails.

I was going to say… it looks like you just provided pseudo code for replicating a rails like interface in PHP. Not that it's a bad thing…

So, if I were using PHP I would try to implement the conventions and methods of Rails because I think they make a lot of sense.

Bingo, we can debate all day that rails is not true MVC but the fact of the matter is the web based derivation of MVC exists because it works very well in a none persistent environment using http.

I'd try to implement code that looked something like this.. lots of psedo code and I haven't written php in years.

I would recommend the op use Symfony 2 instead re-inventing this wheel. Not to mention Symfony 2 goes way beyond MVC providing strategies for managing dependencies to promoting package management (similar to gems) using composer. Though if the op really has an itch to reinvent the wheel more power to them I guess…

[markbrown4]

I would recommend the op use Symfony 2 instead re-inventing this wheel. Not to mention Symfony 2 goes way beyond MVC providing strategies for managing dependencies to promoting package management (similar to gems) using composer. Though if the op really has an itch to reinvent the wheel more power to them I guess…

Aye, I'm not familiar with any of the PHP MVC frameworks out there, I'd heard Cake was Rails inspired but I haven't explored it.
You're right, those frameworks should be a heck of a lot better than something you can write from scratch - It sounded like the OP was wanting to try to do that though, "what is a good way to implement MVC in PHP?"

What is the least and most expressive code you can write to get the task done?

[Hall of Famer]

I think it depends on what you wish to accomplish here. Reinventing the wheel is not recommended for working on a project with a strict timeline, especially for commercial project. However, if your primary goal is to learn the basics behind MVC and true OOP, building your own framework will help you a lot.

[Lemon Juice]

Yes, I'm experimenting with the concept to understand how it works in detail and if it proves to be worthwhile I'll start implementing it in my projects. That's why I'm starting from scratch. The other reason is that it's hard to find a ready-made framework that would be pure MVC - and because I have already worked with frameworks that are MVC-like to a greater or lesser extent (including my own that works very well for commercial projects) I have no intention dabbling with them. It's not that I find them bad, I just want to see how MVC plays out in its purest possible implementation and possibly simplest as well. Most frameworks are huge, I want something simple but good and add to it over time as my requirements grow.

[markbrown4]

Yes, I'm experimenting with the concept to understand how it works in detail and if it proves to be worthwhile I'll start implementing it in my projects. That's why I'm starting from scratch. The other reason is that it's hard to find a ready-made framework that would be pure MVC - and because I have already worked with frameworks that are MVC-like to a greater or lesser extent (including my own that works very well for commercial projects) I have no intention dabbling with them. It's not that I find them bad, I just want to see how MVC plays out in its purest possible implementation and possibly simplest as well. Most frameworks are huge, I want something simple but good and add to it over time as my requirements grow.

You will learn a lot doing that, I'd encourage you to focus on the API and DRY, how much code can you get away with not writing.
I'm curious why you're interested in a 'pure' implementation. Surely it's more valuable to have the best implementation