**Course Title:** Mastering Symfony: Building Enterprise-Level PHP Applications **Section Title:** API Platform and GraphQL **Topic:** CRUD operations using API Platform **Introduction** In this topic, we will explore the capabilities of API Platform in performing CRUD (Create, Read, Update, Delete) operations. API Platform is a powerful tool that allows you to build robust and scalable APIs using Symfony. We will delve into the world of API Platform, and by the end of this topic, you will be able to create, read, update, and delete data using API Platform. **What is API Platform?** API Platform is an open-source framework that allows you to build robust and scalable APIs using Symfony. It provides a set of tools and features that make it easy to create, manage, and consume APIs. API Platform is built on top of Symfony and leverages its strengths to provide a powerful and flexible API building platform. **Setting up API Platform** To get started with API Platform, you need to install it using Composer. Run the following command in your terminal: ```bash composer require api-platform/core ``` This will install the API Platform core package and its dependencies. **Creating a CRUD API with API Platform** To create a CRUD API with API Platform, you need to create a new entity, a repository, and a controller. Here is an example of how to create a simple CRUD API for a `Book` entity: ```php // src/Entity/Book.php namespace App\Entity; use ApiPlatform\Core\Annotation\ApiResource; use ApiPlatform\Core\Annotation\Filter; use ApiPlatform\Core\Annotation\Operation; use ApiPlatform\Core\Annotation\Output; use Doctrine\ORM\Mapping as ORM; /** * @ApiResource * @Filter("json_trunc") */ class Book { /** * @ORM\Id * @ORM\GeneratedValue * @ORM\Column(type="integer") */ private $id; /** * @ORM\Column(type="string", length=255) */ private $title; /** * @ORM\Column(type="string", length=255) */ private $author; // Getters and setters } ``` ```php // src/Repository/BookRepository.php namespace App\Repository; use ApiPlatform\Core\Repository\Repository; use App\Entity\Book; class BookRepository extends Repository { public function findBooksByTitle($title) { return $this->createQueryBuilder('b') ->where('b.title LIKE :title') ->setParameter('title', '%' . $title . '%') ->getQuery() ->getResult(); } } ``` ```php // src/Controller/BookController.php namespace App\Controller; use ApiPlatform\Core\Controller\CrudController; use App\Entity\Book; use App\Repository\BookRepository; class BookController extends CrudController { protected $repositoryClass = Book::class; protected $repository = new BookRepository(); public function getAction() { return $this->repository->findBooksByTitle('Harry Potter'); } } ``` **CRUD Operations** API Platform provides a set of actions that you can use to perform CRUD operations. The actions are: * `get`: Retrieves a single resource or a collection of resources. * `post`: Creates a new resource. * `put`: Updates an existing resource. * `delete`: Deletes a resource. You can use the `@Operation` annotation to define the actions for your controller. ```php // src/Controller/BookController.php namespace App\Controller; use ApiPlatform\Core\Controller\CrudController; use App\Entity\Book; use App\Repository\BookRepository; class BookController extends CrudController { protected $repositoryClass = Book::class; protected $repository = new BookRepository(); /** * @Operation( * summary="Get a book by title", * description="Get a book by title", * tags={"books"}, * requirements={"title" = "string"}, * responses={ * 200={"description" = "Book found"}, * 404{"description" = "Book not found"} * } * ) */ public function getAction($title) { return $this->repository->findBooksByTitle($title); } /** * @Operation( * summary="Create a new book", * description="Create a new book", * tags={"books"}, * requestBody={"description" = "Book data", "content" = @JsonContent(schema={"type" = "object", "properties" = {"title" = {"type" = "string"}, "author" = {"type" = "string"}}})}, * responses={ * 201{"description" = "Book created"}, * 400{"description" = "Invalid request"} * } * ) */ public function postAction(Book $book) { return $this->repository->save($book); } /** * @Operation( * summary="Update a book", * description="Update a book", * tags={"books"}, * requestBody={"description" = "Book data", "content" = @JsonContent(schema={"type" = "object", "properties" = {"title" = {"type" = "string"}, "author" = {"type" = "string"}}})}, * responses={ * 200{"description" = "Book updated"}, * 404{"description" = "Book not found"} * } * ) */ public function putAction(Book $book) { return $this->repository->save($book); } /** * @Operation( * summary="Delete a book", * description="Delete a book", * tags={"books"}, * responses={ * 204{"description" = "Book deleted"}, * 404{"description" = "Book not found"} * } * ) */ public function deleteAction(Book $book) { return $this->repository->remove($book); } } ``` **Conclusion** In this topic, we explored the capabilities of API Platform in performing CRUD operations. We created a simple CRUD API for a `Book` entity and used the `@Operation` annotation to define the actions for our controller. We also discussed the importance of validation and error handling in API Platform. **Practical Takeaways** * Use API Platform to build robust and scalable APIs. * Define actions for your controller using the `@Operation` annotation. * Use validation and error handling to ensure a smooth API experience. **Next Topic:** Pagination, filtering, and sorting with API Platform. **Leave a comment or ask for help if you have any questions or need further clarification on any of the topics covered in this topic.**