<?php

namespace App\Http\Controllers;

use App\Http\Requests\StorePostRequest;
use App\Http\Requests\UpdatePostRequest;
use App\Models\Post;
use Illuminate\Http\RedirectResponse;

class PostController extends Controller
{
    public function store(StorePostRequest $request): RedirectResponse
    {
        // Validation happens automatically
        $validated = $request->validated();

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

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

    public function update(UpdatePostRequest $request, Post $post): RedirectResponse
    {
        $post->update($request->validated());

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

<?php

namespace App\Http\Requests;

use Illuminate\Foundation\Http\FormRequest;

class StorePostRequest extends FormRequest
{
    public function authorize(): bool
    {
        return $this->user()->can('create', Post::class);
    }

    public function rules(): array
    {
        return [
            'title' => ['required', 'string', 'max:255'],
            'body' => ['required', 'string', 'min:100'],
            'category_id' => ['required', 'exists:categories,id'],
            'tags' => ['nullable', 'array'],
            'tags.*' => ['exists:tags,id'],
            'published_at' => ['nullable', 'date', 'after:now'],
        ];
    }

    public function messages(): array
    {
        return [
            'body.min' => 'The post body must be at least 100 characters.',
        ];
    }
}

<?php

namespace App\Services;

use App\Models\User;
use App\Models\Post;
use App\Events\PostPublished;
use Illuminate\Support\Facades\DB;

class PostService
{
    public function __construct(
        private readonly NotificationService $notifications,
    ) {}

    public function publish(Post $post): Post
    {
        return DB::transaction(function () use ($post) {
            $post->update([
                'published_at' => now(),
                'status' => 'published',
            ]);

            event(new PostPublished($post));

            $this->notifications->notifyFollowers($post->author, $post);

            return $post->fresh();
        });
    }
}

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Database\Eloquent\Relations\BelongsToMany;
use Illuminate\Database\Eloquent\Builder;

class Post extends Model
{
    use HasFactory;

    protected $fillable = [
        'title',
        'slug',
        'body',
        'category_id',
        'published_at',
    ];

    protected $casts = [
        'published_at' => 'datetime',
    ];

    // 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();
    }

    // Scopes
    public function scopePublished(Builder $query): Builder
    {
        return $query->whereNotNull('published_at')
            ->where('published_at', '<=', now());
    }

    public function scopeByCategory(Builder $query, int $categoryId): Builder
    {
        return $query->where('category_id', $categoryId);
    }

    // Accessors & Mutators
    protected function title(): Attribute
    {
        return Attribute::make(
            set: fn (string $value) => ucfirst($value),
        );
    }
}

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    public function up(): void
    {
        Schema::create('posts', function (Blueprint $table) {
            $table->id();
            $table->foreignId('user_id')->constrained()->cascadeOnDelete();
            $table->foreignId('category_id')->constrained()->cascadeOnDelete();
            $table->string('title');
            $table->string('slug')->unique();
            $table->text('body');
            $table->timestamp('published_at')->nullable();
            $table->timestamps();

            // Indexes for common queries
            $table->index(['user_id', 'published_at']);
            $table->index('category_id');
        });
    }

    public function down(): void
    {
        Schema::dropIfExists('posts');
    }
};

// N+1 Problem
$posts = Post::all();
foreach ($posts as $post) {
    echo $post->author->name;  // Query per post
}

// Eager loading — only 3 queries total
$posts = Post::with(['author', 'category', 'tags'])->get();
foreach ($posts as $post) {
    echo $post->author->name;  // No additional queries
}

// Nested eager loading
$posts = Post::with([
    'author.profile',
    'comments.user',
    'tags',
])->get();

// Constrained eager loading
$posts = Post::with([
    'comments' => fn ($query) => $query->latest()->limit(5),
])->get();

rules/arch-service-classes.md
rules/eloquent-eager-loading.md
rules/validation-form-requests.md
rules/_sections.md