Understanding MVC Pattern in Laravel: Architecture Mastery

Understanding MVC Pattern in Laravel: Architecture Mastery

Understanding MVC Pattern in Laravel: Architecture Mastery

Expert Guide by Alaa Amer – Professional Web Developer & Applications Designer

The MVC (Model-View-Controller) pattern is the backbone of Laravel's architecture. Master this pattern to build maintainable, scalable, and professional applications.

2️⃣ Models: The Data Powerhouse

Advanced Model Implementation:

<?php
// app/Models/Post.php
namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\SoftDeletes;
use Illuminate\Database\Eloquent\Relations\{BelongsTo, HasMany, BelongsToMany};

class Post extends Model
{
    use HasFactory, SoftDeletes;

    // === MASS ASSIGNMENT PROTECTION ===
    protected $fillable = [
        'title', 'slug', 'content', 'excerpt', 'featured_image',
        'status', 'published_at', 'user_id', 'category_id'
    ];

    protected $guarded = ['id', 'created_at', 'updated_at'];

    // === DATA CASTING ===
    protected $casts = [
        'published_at' => 'datetime',
        'meta' => 'array',
        'is_featured' => 'boolean',
        'settings' => 'json'
    ];

    // === RELATIONSHIPS ===
    public function author(): BelongsTo
    {
        return $this->belongsTo(User::class, 'user_id');
    }

    public function category(): BelongsTo
    {
        return $this->belongsTo(Category::class);
    }

    public function tags(): BelongsToMany
    {
        return $this->belongsToMany(Tag::class)
                    ->withTimestamps()
                    ->withPivot(['added_by']);
    }

    public function comments(): HasMany
    {
        return $this->hasMany(Comment::class);
    }

    public function approvedComments(): HasMany
    {
        return $this->comments()->where('status', 'approved');
    }

    // === QUERY SCOPES ===
    public function scopePublished($query)
    {
        return $query->where('status', 'published')
                    ->where('published_at', '<=', now());
    }

    public function scopeFeatured($query)
    {
        return $query->where('is_featured', true);
    }

    public function scopeByAuthor($query, $authorId)
    {
        return $query->where('user_id', $authorId);
    }

    public function scopeInCategory($query, $categorySlug)
    {
        return $query->whereHas('category', function($q) use ($categorySlug) {
            $q->where('slug', $categorySlug);
        });
    }

    public function scopePopular($query, $timeframe = 30)
    {
        return $query->withCount(['comments', 'likes'])
                    ->where('created_at', '>=', now()->subDays($timeframe))
                    ->orderBy('likes_count', 'desc')
                    ->orderBy('comments_count', 'desc');
    }

    // === ACCESSORS (Getters) ===
    public function getTitleAttribute($value)
    {
        return ucfirst($value);
    }

    public function getExcerptAttribute($value)
    {
        return $value ?: Str::limit(strip_tags($this->content), 150);
    }

    public function getReadingTimeAttribute()
    {
        $wordCount = str_word_count(strip_tags($this->content));
        return ceil($wordCount / 200); // Average 200 words per minute
    }

    public function getIsPublishedAttribute()
    {
        return $this->status === 'published' &&
               $this->published_at &&
               $this->published_at->isPast();
    }

    public function getUrlAttribute()
    {
        return route('posts.show', $this->slug);
    }

    // === MUTATORS (Setters) ===
    public function setTitleAttribute($value)
    {
        $this->attributes['title'] = $value;
        $this->attributes['slug'] = Str::slug($value);
    }

    public function setContentAttribute($value)
    {
        $this->attributes['content'] = $value;
        // Auto-calculate reading time
        $wordCount = str_word_count(strip_tags($value));
        $this->attributes['reading_time'] = ceil($wordCount / 200);
    }

    // === BUSINESS LOGIC METHODS ===
    public function publish()
    {
        $this->update([
            'status' => 'published',
            'published_at' => now()
        ]);
    }

    public function unpublish()
    {
        $this->update(['status' => 'draft']);
    }

    public function incrementViews()
    {
        $this->increment('views_count');
    }

    public function isOwnedBy(User $user)
    {
        return $this->user_id === $user->id;
    }

    public function canBeEditedBy(User $user)
    {
        return $this->isOwnedBy($user) || $user->hasRole('editor');
    }

    public function getRelatedPosts($limit = 4)
    {
        return static::published()
                    ->where('category_id', $this->category_id)
                    ->where('id', '!=', $this->id)
                    ->inRandomOrder()
                    ->limit($limit)
                    ->get();
    }

    // === MODEL EVENTS ===
    protected static function boot()
    {
        parent::boot();

        static::creating(function ($post) {
            if (empty($post->slug)) {
                $post->slug = Str::slug($post->title);
            }
        });

        static::updating(function ($post) {
            if ($post->isDirty('title')) {
                $post->slug = Str::slug($post->title);
            }
        });

        static::deleting(function ($post) {
            // Clean up related data
            $post->comments()->delete();
            $post->tags()->detach();
        });
    }
}

// === SEPARATE BUSINESS LOGIC INTO SERVICES ===
// app/Services/PostService.php
namespace App\Services;

class PostService
{
    public function createPost(array $data, User $author)
    {
        $post = new Post($data);
        $post->user_id = $author->id;
        $post->save();

        // Handle tags
        if (isset($data['tags'])) {
            $post->tags()->sync($data['tags']);
        }

        // Handle featured image
        if (isset($data['featured_image'])) {
            $post->addMediaFromRequest('featured_image')
                 ->toMediaCollection('featured');
        }

        return $post;
    }

    public function getPopularPosts($timeframe = 7, $limit = 10)
    {
        return Post::published()
                  ->popular($timeframe)
                  ->with(['author', 'category'])
                  ->limit($limit)
                  ->get();
    }
}

4️⃣ Controllers: Request Orchestrators

Professional Controller Implementation:

<?php
// app/Http/Controllers/PostController.php
namespace App\Http\Controllers;

use App\Models\{Post, Category};
use App\Services\PostService;
use App\Http\Requests\{StorePostRequest, UpdatePostRequest};
use Illuminate\Http\{Request, RedirectResponse};
use Illuminate\View\View;

class PostController extends Controller
{
    public function __construct(
        private PostService $postService
    ) {
        $this->middleware('auth')->except(['index', 'show']);
        $this->middleware('verified')->only(['create', 'store']);

        // Apply rate limiting
        $this->middleware('throttle:60,1')->only(['store', 'update']);
    }

    /**
     * Display paginated list of posts
     */
    public function index(Request $request): View
    {
        $query = Post::with(['author:id,name,avatar', 'category:id,name,slug'])
                    ->withCount(['comments', 'likes'])
                    ->published();

        // Apply filters
        $query = $this->applyFilters($query, $request);

        // Apply search
        if ($request->filled('search')) {
            $query->where(function($q) use ($request) {
                $searchTerm = $request->search;
                $q->where('title', 'LIKE', "%{$searchTerm}%")
                  ->orWhere('content', 'LIKE', "%{$searchTerm}%");
            });
        }

        // Sort options
        $sort = $request->get('sort', 'latest');
        match($sort) {
            'popular' => $query->orderBy('likes_count', 'desc'),
            'oldest' => $query->oldest('published_at'),
            default => $query->latest('published_at')
        };

        $posts = $query->paginate(12)->withQueryString();

        return view('posts.index', [
            'posts' => $posts,
            'categories' => Category::withCount('posts')->get(),
            'currentFilters' => $request->only(['category', 'search', 'sort'])
        ]);
    }

    /**
     * Show individual post
     */
    public function show(Post $post): View
    {
        // Security check
        abort_unless(
            $post->isPublished() || $post->canBeEditedBy(auth()->user() ?? new User()),
            404
        );

        // Eager load relationships
        $post->load([
            'author:id,name,email,avatar,bio',
            'category:id,name,slug',
            'tags:id,name,slug',
            'comments' => fn($query) => $query->approved()
                                             ->with('user:id,name,avatar')
                                             ->latest()
        ]);

        // Get related posts
        $relatedPosts = $post->getRelatedPosts(4);

        // Track view (async job recommended)
        $post->incrementViews();

        return view('posts.show', compact('post', 'relatedPosts'));
    }

    /**
     * Show create form
     */
    public function create(): View
    {
        $this->authorize('create', Post::class);

        return view('posts.create', [
            'categories' => Category::active()->orderBy('name')->get(),
            'post' => new Post() // For form model binding
        ]);
    }

    /**
     * Store new post
     */
    public function store(StorePostRequest $request): RedirectResponse
    {
        $this->authorize('create', Post::class);

        $post = $this->postService->createPost(
            $request->validated(),
            $request->user()
        );

        return redirect()
               ->route('posts.show', $post)
               ->with('success', 'Post created successfully!');
    }

    /**
     * Show edit form
     */
    public function edit(Post $post): View
    {
        $this->authorize('update', $post);

        return view('posts.edit', [
            'post' => $post,
            'categories' => Category::active()->orderBy('name')->get()
        ]);
    }

    /**
     * Update existing post
     */
    public function update(UpdatePostRequest $request, Post $post): RedirectResponse
    {
        $this->authorize('update', $post);

        $this->postService->updatePost($post, $request->validated());

        return redirect()
               ->route('posts.show', $post)
               ->with('success', 'Post updated successfully!');
    }

    /**
     * Delete post
     */
    public function destroy(Post $post): RedirectResponse
    {
        $this->authorize('delete', $post);

        $post->delete();

        return redirect()
               ->route('posts.index')
               ->with('success', 'Post deleted successfully!');
    }

    /**
     * Toggle like status
     */
    public function toggleLike(Post $post)
    {
        $user = auth()->user();

        if ($post->isLikedBy($user)) {
            $post->unlike($user);
            $liked = false;
        } else {
            $post->like($user);
            $liked = true;
        }

        return response()->json([
            'liked' => $liked,
            'likes_count' => $post->likes()->count()
        ]);
    }

    /**
     * Apply filters to query
     */
    private function applyFilters($query, Request $request)
    {
        if ($request->filled('category')) {
            $query->whereHas('category', function($q) use ($request) {
                $q->where('slug', $request->category);
            });
        }

        if ($request->filled('tag')) {
            $query->whereHas('tags', function($q) use ($request) {
                $q->where('slug', $request->tag);
            });
        }

        return $query;
    }
}

// === FORM REQUEST VALIDATION ===
// app/Http/Requests/StorePostRequest.php
namespace App\Http\Requests;

use Illuminate\Foundation\Http\FormRequest;

class StorePostRequest extends FormRequest
{
    public function authorize(): bool
    {
        return auth()->check();
    }

    public function rules(): array
    {
        return [
            'title' => 'required|string|max:255|unique:posts,title',
            'content' => 'required|string|min:100',
            'excerpt' => 'nullable|string|max:500',
            'category_id' => 'required|exists:categories,id',
            'tags' => 'nullable|array',
            'tags.*' => 'exists:tags,id',
            'featured_image' => 'nullable|image|mimes:jpeg,png,jpg|max:2048',
            'status' => 'required|in:draft,published',
            'published_at' => 'nullable|date|after_or_equal:now'
        ];
    }

    public function messages(): array
    {
        return [
            'title.unique' => 'A post with this title already exists.',
            'content.min' => 'Post content must be at least 100 characters.',
            'featured_image.max' => 'Image size should not exceed 2MB.'
        ];
    }
}

💡 MVC Best Practices

1. Fat Models, Skinny Controllers

// ❌ Bad - Business logic in controller
class PostController extends Controller
{
    public function publish(Post $post)
    {
        $post->status = 'published';
        $post->published_at = now();
        $post->save();

        // Send notifications
        $post->author->notify(new PostPublishedNotification($post));

        return redirect()->back();
    }
}

// ✅ Good - Business logic in model/service
class Post extends Model
{
    public function publish()
    {
        $this->update([
            'status' => 'published',
            'published_at' => now()
        ]);

        $this->author->notify(new PostPublishedNotification($this));

        return $this;
    }
}

class PostController extends Controller
{
    public function publish(Post $post)
    {
        $post->publish();
        return redirect()->back()->with('success', 'Post published!');
    }
}

2. Single Responsibility Principle

// ❌ Bad - Controller doing too much
class PostController extends Controller
{
    public function store(Request $request)
    {
        // Validation
        $validated = $request->validate([...]);

        // Image processing
        if ($request->hasFile('image')) {
            $path = $request->file('image')->store('posts');
            // Resize image
            // Create thumbnails
            // Optimize image
        }

        // Create post
        $post = Post::create($validated);

        // Send notifications
        // Update search index
        // Clear caches

        return redirect()->route('posts.show', $post);
    }
}

// ✅ Good - Separated responsibilities
class PostController extends Controller
{
    public function store(StorePostRequest $request, PostService $service)
    {
        $post = $service->createPost($request->validated());
        return redirect()->route('posts.show', $post);
    }
}

class PostService
{
    public function __construct(
        private ImageService $imageService,
        private NotificationService $notificationService
    ) {}

    public function createPost(array $data): Post
    {
        if (isset($data['image'])) {
            $data['featured_image'] = $this->imageService->process($data['image']);
        }

        $post = Post::create($data);

        $this->notificationService->notifyPostCreated($post);

        return $post;
    }
}

Next Steps

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