Laravel Service-Repository Pattern

In this article, you’ll learn about:
• Main benefits of using Repository Pattern
• How to implement a PHP Repository Pattern in Laravel?
• We will show you how to start code and implement it in the Laravel based App.

What Important – Why we need a design pattern?

Service-Repository design pattern is clean and sustainable. The concept of repositories and services ensures that you write reusable code and helps to keep your controller as simple as possible making them more readable.

The main idea to use Repository Pattern in a Laravel application is to create a bridge between models and controllers. In other words, to decouple the hard dependencies of models from the controllers.

Repositories are usually a common wrapper for your model and the place where you would write different queries in your database. A service on the other hand is a layer for handling all your application’s logic.

Based on experience, it’s really conducive to separate the logic and the wrapper of the model especially when you’re working on team or big projects.

The use of Repository Pattern has many benefits, below is a list of the most important ones:
• It centralizes data logic or business logic and service logic.
• It gives a substitution point for the unit tests.
• Provides a flexible architecture.
• Reduces duplication of code
• A lower chance for making programming errors.

Let’s start with code and implement it in your Laravel app!

Now you know the benefits of the repository pattern in Laravel, so let’s implement them in your application! 

Repository

In the beginning, we will start with a folder structure. Laravel does not have a repository command. You have to do it manually. We should start by creating a Repositories folder into our app folder. Then add PostRepository file. So the final file structure should look like this:

-- app
---- Repositories
--------PostRepository.php

We call the Post model in the constructor of our class. So the PostRepository class will look like this:

<?php

namespace App\Repositories;

use App\Models\Post;

class PostRepository
{
    /**
     * @var Post
     */
    protected $post;

    /**
     * PostRepository constructor.
     *
     * @param Post $post
     */
    public function __construct(Post $post)
    {
        $this->post = $post;
    }

    /**
     * Get all posts.
     *
     * @return Post $post
     */
    public function getAll()
    {
        return $this->post
            ->get();
    }

    /**
     * Get post by id
     *
     * @param $id
     * @return mixed
     */
    public function getById($id)
    {
        return $this->post
            ->where('id', $id)
            ->get();
    }

    /**
     * Save Post
     *
     * @param $data
     * @return Post
     */
    public function save($data)
    {
        $post = new $this->post;

        $post->title = $data['title'];
        $post->description = $data['description'];

        $post->save();

        return $post->fresh();
    }

    /**
     * Update Post
     *
     * @param $data
     * @return Post
     */
    public function update($data, $id)
    {
        
        $post = $this->post->find($id);

        $post->title = $data['title'];
        $post->description = $data['description'];

        $post->update();

        return $post;
    }

    /**
     * Update Post
     *
     * @param $data
     * @return Post
     */
    public function delete($id)
    {
        
        $post = $this->post->find($id);
        $post->delete();

        return $post;
    }

}

Service

Like repository, laravel doesn’t have a service command. We should start by creating a Services folder into our app folder. Then add PostService file. So the final file structure should look like this:

-- app
---- Services
--------PostService.php

<?php

namespace App\Services;

use App\Models\Post;
use App\Repositories\PostRepository;
use Exception;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\Validator;
use InvalidArgumentException;

class PostService
{
    /**
     * @var $postRepository
     */
    protected $postRepository;

    /**
     * PostService constructor.
     *
     * @param PostRepository $postRepository
     */
    public function __construct(PostRepository $postRepository)
    {
        $this->postRepository = $postRepository;
    }

    /**
     * Delete post by id.
     *
     * @param $id
     * @return String
     */
    public function deleteById($id)
    {
        DB::beginTransaction();

        try {
            $post = $this->postRepository->delete($id);

        } catch (Exception $e) {
            DB::rollBack();
            Log::info($e->getMessage());

            throw new InvalidArgumentException('Unable to delete post data');
        }

        DB::commit();

        return $post;

    }

    /**
     * Get all post.
     *
     * @return String
     */
    public function getAll()
    {
        return $this->postRepository->getAll();
    }

    /**
     * Get post by id.
     *
     * @param $id
     * @return String
     */
    public function getById($id)
    {
        return $this->postRepository->getById($id);
    }

    /**
     * Update post data
     * Store to DB if there are no errors.
     *
     * @param array $data
     * @return String
     */
    public function updatePost($data, $id)
    {
        $validator = Validator::make($data, [
            'title' => 'bail|min:2',
            'description' => 'bail|max:255'
        ]);

        if ($validator->fails()) {
            throw new InvalidArgumentException($validator->errors()->first());
        }

        DB::beginTransaction();

        try {
            $post = $this->postRepository->update($data, $id);

        } catch (Exception $e) {
            DB::rollBack();
            Log::info($e->getMessage());

            throw new InvalidArgumentException('Unable to update post data');
        }

        DB::commit();

        return $post;

    }

    /**
     * Validate post data.
     * Store to DB if there are no errors.
     *
     * @param array $data
     * @return String
     */
    public function savePostData($data)
    {
        $validator = Validator::make($data, [
            'title' => 'required',
            'description' => 'required'
        ]);

        if ($validator->fails()) {
            throw new InvalidArgumentException($validator->errors()->first());
        }

        $result = $this->postRepository->save($data);

        return $result;
    }

}

We inject the PostRepository dependency into the constructor of our PostService class. Now that we are done with the repository-service setup. 

PostController -> PostService -> PostRepository

So we can use makinglogic like this in the controller:

<?php

namespace App\Http\Controllers;

use App\Services\PostService;
use Exception;
use Illuminate\Http\Request;

class PostController extends Controller
{
    /**
     * @var postService
     */
    protected $postService;

    /**
     * PostController Constructor
     *
     * @param PostService $postService
     *
     */
    public function __construct(PostService $postService)
    {
        $this->postService = $postService;
    }

    /**
     * Display a listing of the resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function index()
    {
        $result = ['status' => 200];

        try {
            $result['data'] = $this->postService->getAll();
        } catch (Exception $e) {
            $result = [
                'status' => 500,
                'error' => $e->getMessage()
            ];
        }

        return response()->json($result, $result['status']);
    }

    /**
     * Show the form for creating a new resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function create()
    {
        //
    }

    /**
     * Store a newly created resource in storage.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return \Illuminate\Http\Response
     */
    public function store(Request $request)
    {
        $data = $request->only([
            'title',
            'description',
        ]);

        $result = ['status' => 200];

        try {
            $result['data'] = $this->postService->savePostData($data);
        } catch (Exception $e) {
            $result = [
                'status' => 500,
                'error' => $e->getMessage()
            ];
        }

        return response()->json($result, $result['status']);
    }

    /**
     * Display the specified resource.
     *
     * @param  id
     * @return \Illuminate\Http\Response
     */
    public function show($id)
    {
        $result = ['status' => 200];

        try {
            $result['data'] = $this->postService->getById($id);
        } catch (Exception $e) {
            $result = [
                'status' => 500,
                'error' => $e->getMessage()
            ];
        }
        return response()->json($result, $result['status']);
    }

    /**
     * Show the form for editing the specified resource.
     *
     * @param  Post $post
     * @return \Illuminate\Http\Response
     */
    public function edit(Post $post)
    {
        //
    }

    /**
     * Update post.
     *
     * @param Request $request
     * @param id
     * @return \Illuminate\Http\Response
     */
    public function update(Request $request, $id)
    {
        $data = $request->only([
            'title',
            'description'
        ]);

        $result = ['status' => 200];

        try {
            $result['data'] = $this->postService->updatePost($data, $id);

        } catch (Exception $e) {
            $result = [
                'status' => 500,
                'error' => $e->getMessage()
            ];
        }

        return response()->json($result, $result['status']);

    }

    /**
     * Remove the specified resource from storage.
     *
     * @param $id
     * @return \Illuminate\Http\Response
     */
    public function destroy($id)
    {
        $result = ['status' => 200];

        try {
            $result['data'] = $this->postService->deleteById($id);
        } catch (Exception $e) {
            $result = [
                'status' => 500,
                'error' => $e->getMessage()
            ];
        }
        return response()->json($result, $result['status']);
    }
}

That’s it! You have implemented a repository pattern in your app. Now you can add new repositories for the other models you are using in your application.

By Ami