Working with the BaseController class

What is the BaseController class?

The BaseController class provides foundational functionality for all controllers in the application. It handles dependency injection, view rendering, and HTTP redirects with a focus on educational clarity and simplicity.

This guide demonstrates how to use the BaseController class methods in your Slim MVC application controllers.

Creating a Controller Class

Extend BaseController to create your own controllers. The constructor should call the parent constructor with the Container instance.

<?php

namespace App\Controllers;

use DI\Container;
use Psr\Http\Message\ResponseInterface as Response;
use Psr\Http\Message\ServerRequestInterface as Request;

class UserController extends BaseController
{
    public function __construct(Container $container)
    {
        parent::__construct($container);
    }

    // Your controller methods here...
}

Available BaseController Methods

render() - Render View Templates

The render() method processes view templates and returns HTTP responses with proper headers.

Method Signature:

protected function render(Response $response, string $view_name, array $data = []): Response

Parameters:

$response - PSR-7 response object to modify
$view_name - Name of the view template file
$data - Associative array of data to pass to the view

redirect() - HTTP Redirects

The redirect() method creates HTTP redirect responses to named routes with support for parameters and query strings.

Method Signature:

protected function redirect(
    Request $request,
    Response $response,
    string $route_name,
    array $uri_args = [],
    array $query_params = []
): Response

Parameters:

$request - PSR-7 request object for route context
$response - PSR-7 response object to modify
$route_name - Named route to redirect to (e.g., ‘user.profile’, ‘articles.index’)
$uri_args - Associative array for route placeholders (e.g., [‘id’ => 123] for /users/{id})
$query_params - Query string parameters

Important: Understanding $uri_args vs $query_params

$uri_args - Replaces route placeholders like {id} in route patterns (e.g., /users/{id} becomes /users/123)
$query_params - Adds query string parameters to any URL (e.g., ?tab=settings&page=2)
Only use $uri_args when your target route has {placeholders} - otherwise use empty array []

Basic View Rendering

public function index(Request $request, Response $response, array $args): Response
{
    return $this->render($response, 'home/index.php');
}

Passing Data to Views

Pass data to views using the $data parameter. This is an associative array of data to pass to the view.

public function show(Request $request, Response $response, array $args): Response
{
    $userId = (int) $args['id'];

    $data = [
        'user' => [
            'id' => $userId,
            'name' => 'John Doe',
            'email' => 'john@example.com'
        ],
        'title' => 'User Profile'
    ];

    return $this->render($response, 'user/profile.php', $data);
}

Complex Data Structures

A complex data structure can be passed to the view as an associative array.

public function dashboard(Request $request, Response $response, array $args): Response
{
    $data = [
        'page_title' => 'Dashboard',
        'user' => [
            'name' => 'Jane Smith',
            'role' => 'Administrator'
        ],
        'stats' => [
            'total_users' => 1250,
            'active_sessions' => 89,
            'recent_logins' => 45
        ],
        'notifications' => [
            ['message' => 'System update completed', 'type' => 'success'],
            ['message' => 'New user registered', 'type' => 'info']
        ]
    ];

    return $this->render($response, 'dashboard/index.php', $data);
}

Conditional Rendering

public function profile(Request $request, Response $response, array $args): Response
{
    $user = $this->getCurrentUser(); // Assume this method exists

    if (!$user) {
        return $this->render($response, 'errors/unauthorized.php', [
            'message' => 'Please log in to view your profile'
        ]);
    }

    $data = [
        'user' => $user,
        'title' => 'My Profile'
    ];

    return $this->render($response, 'user/profile.php', $data);
}

Basic Redirect (No Parameters)

public function logout(Request $request, Response $response, array $args): Response
{
    // Clear session data
    session_destroy();

    // Redirect to home page (no parameters needed)
    return $this->redirect($request, $response, 'home.index');
}

Redirect with Route Parameters

// For route: /users/{id}
public function updateProfile(Request $request, Response $response, array $args): Response
{
    $userId = (int) $args['id'];

    // Process form data
    $this->updateUserData($userId, $request->getParsedBody());

    // Redirect to user profile with ID parameter (replaces {id} placeholder)
    return $this->redirect($request, $response, 'user.profile', ['id' => $userId]);
}

Redirect with Query Parameters Only

// For route: /search (no placeholders)
public function search(Request $request, Response $response, array $args): Response
{
    $searchTerm = $request->getQueryParams()['q'] ?? '';
    $category = $request->getQueryParams()['category'] ?? 'all';

    if (empty($searchTerm)) {
        // Redirect back to search form (use flash messages for errors instead)
        return $this->redirect($request, $response, 'search.index');
    }

    // Redirect to results with search parameters
    return $this->redirect($request, $response, 'search.results', [], [
        'q' => $searchTerm,
        'category' => $category,
        'page' => 1
    ]);
}

Redirect with Both Route Parameters and Query Strings

// For route: /users/{id}/edit
public function editUser(Request $request, Response $response, array $args): Response
{
    $userId = (int) $args['id'];
    $currentTab = $request->getQueryParams()['tab'] ?? 'general';

    // Validate user exists
    if (!$this->userExists($userId)) {
        // Redirect to user list (use flash messages for errors instead)
        return $this->redirect($request, $response, 'user.list');
    }

    // Process form submission
    if ($request->getMethod() === 'POST') {
        $this->updateUser($userId, $request->getParsedBody());

        // Redirect back to same tab: ['id' => $userId] replaces {id}, query params add ?tab=...
        return $this->redirect($request, $response, 'user.edit', ['id' => $userId], [
            'tab' => $currentTab
        ]);
    }

    // Show edit form
    return $this->render($response, 'user/edit.php', [
        'user' => $this->getUser($userId),
        'active_tab' => $currentTab
    ]);
}

Post-Redirect-Get Pattern

public function createUser(Request $request, Response $response, array $args): Response
{
    if ($request->getMethod() === 'POST') {
        $userData = $request->getParsedBody();

        try {
            // Create user
            $userId = $this->userService->create($userData);

            // Redirect to prevent form resubmission (PRG pattern)
            // Use flash messages for success notifications
            return $this->redirect($request, $response, 'user.profile', ['id' => $userId]);

        } catch (ValidationException $e) {
            // Redirect back to form (use flash messages for errors)
            return $this->redirect($request, $response, 'user.create');
        }
    }

    // Show create form
    return $this->render($response, 'user/create.php');
}

Best Practices

1. Data Validation

Always validate data before passing to views:

public function userProfile(Request $request, Response $response, array $args): Response
{
    $userId = filter_var($args['id'], FILTER_VALIDATE_INT);

    if (!$userId) {
        // Use flash messages for errors instead
        return $this->redirect($request, $response, 'user.list');
    }

    // Continue with valid ID...
}

2. Error Handling

Handle errors gracefully with appropriate redirects:

public function processForm(Request $request, Response $response, array $args): Response
{
    try {
        $this->processUserData($request->getParsedBody());
        return $this->redirect($request, $response, 'success.page');

    } catch (ValidationException $e) {
        // Use flash messages for errors instead
        return $this->redirect($request, $response, 'form.page');
    }
}

3. Consistent Naming

Use descriptive view names that match your controller actions:

// Good - clear mapping
return $this->render($response, 'user/profile.php', $data);
return $this->render($response, 'articles/edit.php', $data);

// Avoid - unclear purpose
return $this->render($response, 'page1.php', $data);

4. Data Structure

Organize view data logically:

$data = [
    'meta' => [
        'title' => 'Page Title',
        'description' => 'Page description'
    ],
    'user' => $currentUser,
    'content' => $pageContent,
    'sidebar' => $sidebarData
];

Route Integration

use App\Controllers\UserController;
use App\Controllers\ArticleController;

return static function (Slim\App $app): void {
    // User routes
    $app->get('/users', [UserController::class, 'index'])->setName('user.list');
    $app->get('/users/{id}', [UserController::class, 'show'])->setName('user.profile');
    $app->get('/users/{id}/edit', [UserController::class, 'edit'])->setName('user.edit');
    $app->post('/users/{id}', [UserController::class, 'update']);

    // Article routes
    $app->get('/articles', [ArticleController::class, 'index'])->setName('articles.index');
    $app->get('/articles/{id}', [ArticleController::class, 'show'])->setName('articles.show');
};