Tutorial 2

In this tutorial, you will learn how to develop high quality standards-based REST (Hypermedia) applications using the following tools.

• Define a JSON schema and use it for validation and documentation Json Schema
• Hypermedia types HAL (Hypertext Application Language)
• A DB migration tool developed by CakePHP Phinx
• Binding PHP interfaces to SQL statement execution Ray. MediaQuery

Let’s proceed with the commits found in tutorial2.

Create the project

Create the project skeleton.

composer create-project bear/skeleton MyVendor.Ticket

Enter the vendor name as MyVendor and the project name as Ticket.

Migration

Install Phinx.

composer require --dev robmorgan/phinx

Configure the DB connection information in the .env.dist file in the project root folder.

TKT_DB_HOST=127.0.0.1:3306
TKT_DB_NAME=ticket
TKT_DB_USER=root
TKT_DB_PASS=''
TKT_DB_SLAVE=''
TKT_DB_DSN=mysql:host=${TKT_DB_HOST}

The .env.dist file should look like this, and the actual connection information should be written in .env. ^1]

Next, create a folder to be used by Phinx.

mkdir -p var/phinx/migrations
mkdir var/phinx/seeds

Set up var/phinx/phinx.php to use the .env connection information we have set up earlier.

<?php
use BEAR\Dotenv\Dotenv;

require_once dirname(__DIR__, 2) . '/vendor/autoload.php';

(new Dotenv())->load(dirname(__DIR__, 2));

$development = new PDO(getenv('TKT_DB_DSN'), getenv('TKT_DB_USER'), getenv('TKT_DB_PASS'));
$test = new PDO(getenv('TKT_DB_DSN') . '_test', getenv('TKT_DB_USER'), getenv('TKT_DB_PASS'));
return [
    'paths' => [
        'migrations' => __DIR__ . '/migrations',
    ],
    'environments' => [
        'development' => [
            'name' => $development->query("SELECT DATABASE()")->fetchColumn(),
            'connection' => $development
        ],
        'test' => [
            'name' => $test->query("SELECT DATABASE()")->fetchColumn(),
            'connection' => $test
        ]
    ]
];

setup script

Edit bin/setup.php for easy database creation and migration.

<?php
use BEAR\Dotenv\Dotenv;

require_once dirname(__DIR__) . '/vendor/autoload.php';

(new Dotenv())->load(dirname(__DIR__));

chdir(dirname(__DIR__));
passthru('rm -rf var/tmp/*');
passthru('chmod 775 var/tmp');
passthru('chmod 775 var/log');
// db
$pdo = new \PDO('mysql:host=' . getenv('TKT_DB_HOST'), getenv('TKT_DB_USER'), getenv('TKT_DB_PASS'));
$pdo->exec('CREATE DATABASE IF NOT EXISTS ' . getenv('TKT_DB_NAME'));
$pdo->exec('DROP DATABASE IF EXISTS ' . getenv('TKT_DB_NAME') . '_test');
$pdo->exec('CREATE DATABASE ' . getenv('TKT_DB_NAME') . '_test');
passthru('./vendor/bin/phinx migrate -c var/phinx/phinx.php -e development');
passthru('./vendor/bin/phinx migrate -c var/phinx/phinx.php -e test');

Next, we will create a migration class to create the ticket table.

./vendor/bin/phinx create Ticket -c var/phinx/phinx.php

Phinx by CakePHP - https://phinx.org.

...
created var/phinx/migrations/20210520124501_ticket.php

Edit var/phinx/migrations/{current_date}_ticket.php to implement the change() method.

<?php
use Phinx\Migration\AbstractMigration;

final class Ticket extends AbstractMigration
{
    public function change(): void
    {
        $table = $this->table('ticket', ['id' => false, 'primary_key' => ['id']]);
        $table->addColumn('id', 'uuid', ['null' => false])
            ->addColumn('title', 'string')
            ->addColumn('date_created', 'datetime')
            ->create();
    }
}

In addition, edit .env.dist like the following.

 TKT_DB_USER=root
 TKT_DB_PASS=
 TKT_DB_SLAVE=
-TKT_DB_DSN=mysql:host=${TKT_DB_HOST}
+TKT_DB_DSN=mysql:host=${TKT_DB_HOST};dbname=${TKT_DB_NAME}

Now that we are done with the setup, run the setup command to create the table.

composer setup

> php bin/setup.php
...
All Done. Took 0.0248s

The table has been created. The next time you want to set up a database environment for this project, just run composer setup.

For more information about writing migration classes, see Phinx Manual: Writing Migrations.

Module

Install the module as a composer.

composer require ray/identity-value-module ray/media-query -w

Install the package with AppModule.

src/Module/AppModule.php

<?php
namespace MyVendor\Ticket\Module;

use BEAR\Dotenv\Dotenv;
use BEAR\Package\AbstractAppModule;
use BEAR\Package\PackageModule;

use BEAR\Resource\Module\JsonSchemaModule;
use Ray\AuraSqlModule\AuraSqlModule;
use Ray\IdentityValueModule\IdentityValueModule;
use Ray\MediaQuery\DbQueryConfig;
use Ray\MediaQuery\MediaQueryModule;
use Ray\MediaQuery\Queries;
use function dirname;

class AppModule extends AbstractAppModule
{
    protected function configure(): void
    {
        (new Dotenv())->load(dirname(__DIR__, 2));
        $this->install(
            new AuraSqlModule(
                (string) getenv('TKT_DB_DSN'),
                (string) getenv('TKT_DB_USER'),
                (string) getenv('TKT_DB_PASS'),
                (string) getenv('TKT_DB_SLAVE')
            )
        );
        $this->install(
            new MediaQueryModule(
                Queries::fromDir($this->appMeta->appDir . '/src/Query'), [
                   new DbQueryConfig($this->appMeta->appDir . '/var/sql'),
                ]
            )
        );
        $this->install(new IdentityValueModule());
        $this->install(
            new JsonSchemaModule(
                $this->appMeta->appDir . '/var/schema/response',
                $this->appMeta->appDir . '/var/schema/request'
            )
        );
        $this->install(new PackageModule());
    }
}

SQL

Save the three SQLs for the ticket in var/sql.¹

var/sql/ticket_add.sql

/* ticket add */
INSERT INTO ticket (id, title, date_created)
VALUES (:id, :title, :dateCreated);

var/sql/ticket_list.sql

/* ticket list */
SELECT id, title, date_created
  FROM ticket
 LIMIT 3;

var/sql/ticket_item.sql

/* ticket item */
SELECT id, title, date_created
  FROM ticket
 WHERE id = :id

Make sure that the SQL will work on its own when you create it.

PHPStorm includes a database tool, DataGrip, which has all the necessary features for SQL development such as code completion and SQL refactoring. Once the DB connection and other setups are made, SQL files can be executed directly in the IDE. ²³

JsonSchema.

Create new files that will represent the resource Ticket (ticket item) and Tickets (ticket item list) with JsonSchema:

var/schema/response/ticket.json

{
  "$id": "ticket.json",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "Ticket",
  "type": "object",
  "required": ["id", "title", "date_created"],
  "properties": {
    "id": {
      "description": "The unique identifier for a ticket.",
      "type": "string",
      "maxLength": 64
    },
    "title": {
      "description": "The unique identifier for a ticket.",
      "type": "string",
      "maxLength": 255
    },
    "date_created": {
      "description": "The date and time that the ticket was created",
      "type": "string",
      "format": "datetime"
    }
  }
}

var/schema/response/tickets.json

Tickets is a Ticket array.

{
  "$id": "tickets.json",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "Tickets",
  "type": "object",
  "required": ["tickets"],
  "properties": {
    "tickets": {
      "type": "array",
      "items":{"$ref": "./ticket.json"}
    }
  }
}

• $id - specifies the file name, but if it is to be published, it should be a URL.
• title - This will be treated in the API documentation as an object name.
• examples - specify examples as appropriate. You can also specify the entire object.

In PHPStorm, you will see a green check in the upper right corner of the editor to indicate that everything is OK. You should also validate the schema itself when you create it.

Query Interface

We will create a PHP interface that abstracts access to the infrastructure.

• Read Ticket resources TicketQueryInterface.
• Create a Ticket resource TicketCommandInterface.

src/Query/TicketQueryInterface.php

<?php

namespace MyVendor\Ticket\Query;

use Ray\MediaQuery\Annotation\DbQuery;

interface TicketQueryInterface
{
    #[DbQuery('ticket_item']
    public function item(string $id): Ticket|null;

    /** @return array<Ticket> */
    #[DbQuery('ticket_list']
    public function list(): array;
}

src/Query/TicketCommandInterface.php

<?php

namespace MyVendor\Ticket\Query;

use DateTimeInterface;
use Ray\MediaQuery\Annotation\DbQuery;

interface TicketCommandInterface
{
    #[DbQuery('ticket_add')]
    public function add(string $id, string $title, DateTimeInterface $dateCreated = null): void;
}

Specify an SQL statement with the #[DbQuery] attribute. You do not need to write any implementation for this interface. An object that performs the specified SQL query will be created automatically.

The interface is divided into two concerns: command which has side effects, and query which returns a value. It can be one interface and one method as in ADR pattern. The application designer decides the policy.

Entity

If you specify array for the return value of a method, you will get the database result as it is, an associative array, but if you specify an entity type for the return value of the method, it will be hydrated to that type.

``php #[DbQuery(‘ticket_item’) public function item(string $id): array // you get an array.

```php
#[DbQuery('ticket_item')].
public function item(string $id): ticket|null; // yields a Ticket entity.

For multiple rows (row_list), use /** @return array<Ticket>*/ and phpdoc to specify that Ticket is returned as an array.

/** @return array<Ticket> */
#[DbQuery('ticket_list')].
public function list(): array; // yields an array of Ticket entities.

The value of each row is passed to the constructor by name argument. ⁴

<?php

declare(strict_types=1);

namespace MyVendor\Ticket\Entity;

class Ticket
{
    public function __construct(
        public readonly string $id,
        public readonly string $title,
        public readonly string $dateCreated
    ) {}
}

Resources

The resource class depends on the query interface.

Ticket resource

Create a ticket resource in src/Resource/App/Ticket.php.

<?php

declare(strict_types=1);

namespace MyVendor\Ticket\Resource\App;

use BEAR\Resource\Annotation\JsonSchema;
use BEAR\Resource\ResourceObject;
use MyVendor\Ticket\Query\TicketQueryInterface;

class Ticket extends ResourceObject
{
    public function __construct(
        private TicketQueryInterface $query
    ){}
    
   #[JsonSchema("ticket.json")]
   public function onGet(string $id = ''): static
    {
        $this->body = (array) $this->query->item($id);

        return $this;
    }
}

The attribute #[JsonSchema] indicates that the value output by onGet() is defined in the ticket.json schema. It is validated for each request by AOP.

Let’s try to request a resource by entering a seed. ⁵

% mysql -u root -e "INSERT INTO ticket (id, title, date_created) VALUES ('1', 'foo', '1970-01-01 00:00:00')" ticket

% php bin/app.php get '/ticket?id=1'

200 OK
Content-Type: application/hal+json

{
    "id": "1",
    "title": "foo",
    "date_created": "1970-01-01 00:00:01",
    "_links": {
        "self": {
            "href": "/ticket?id=1"
        }
    }
}

MediaQuery

With Ray.MediaQuery, an auto-generated SQL execution object is injected from the interface without the need to code boilerplate implementation classes. ⁶

A SQL statement can contain multiple SQLs separated by ;, and multiple SQLs are bound to the same parameter by name, and transactions are executed for queries other than SELECT.

If you want to generate SQL dynamically, you can use an SQL execution class that injects the query builder instead of Ray. For more details, please see Database in the manual.

Embedded links

Usually, a website page contains multiple resources. For example, a blog post page might contain recommendations, advertisements, category links, etc. in addition to the post. Instead of the client getting them separately, they can be bundled into one resource with embedded links as independent resources.

Think of HTML and the <img> tag that is written in it. Both have independent URLs, but the image resource is embedded in the HTML resource, and when the HTML is retrieved, the image is displayed in the HTML. These are called hypermedia types Embedding links(LE), and the resource to be embedded is linked.

Let’s embed the project resource into the ticket resource, and prepare the Project class.

src/Resource/App/Project.php

<?php

namespace MyVendor\Ticket\Resource\App;

use BEAR\Resource\ResourceObject;

class Project extends ResourceObject
{
    public function onGet(): static
    {
        $this->body = ['title' => 'Project A'];

        return $this;
    }
}

Add the attribute #[Embed] to the Ticket resource.

+use BEAR\Resource\Annotation\Embed;
+use BEAR\Resource\Request;
+
+   #[Embed(src: '/project', rel: 'project')]
    #[JsonSchema("ticket.json")]
    public function onGet(string $id = ''): static
    {
+        assert($this->body['project'] instanceof Request);
-        $this->body = (array) $this->query->item($id);
+        $this->body += (array) $this->query->item($id);

The request for the resource specified by the #[Embed] attribute src will be injected into the rel key of the body property, and will be lazily evaluated into a string representation when rendered.

For the sake of simplicity, no parameters are passed in this example, but you can pass the values received by the method arguments using the URI template, or you can modify or add parameters to the injected request. See resource for details.

If you make the request again, you will see that the status of the project resource has been added to the property _embedded.

% php bin/app.php get '/ticket?id=1'

{
    "id": "1",
    "title": "2",
    "date_created": "1970-01-01 00:00:01",
+    "_embedded": {
+        "project": {
+            "title": "Project A",
+        }
    },

Embedded resources are an important feature of the REST API. It gives a tree structure to the content and reduces the HTTP request cost. Instead of letting the client fetching it as a separate resource each time, the relationship can be represented in server-side. ⁷

tickets resource

Create a tickets resource in src/resource/App/Tickets.php that can be created with POST and retrieved with GET for a list of tickets.

<?php

declare(strict_types=1);

namespace MyVendor\Ticket\Resource\App;

use BEAR\Resource\Annotation\JsonSchema;
use BEAR\Resource\Annotation\Link;
use BEAR\Resource\ResourceObject;
use Koriym\HttpConstants\ResponseHeader;
use Koriym\HttpConstants\StatusCode;
use MyVendor\Ticket\Query\TicketCommandInterface;
use MyVendor\Ticket\Query\TicketQueryInterface;
use Ray\IdentityValueModule\UuidInterface;
use function uri_template;

class Tickets extends ResourceObject
{
    public function __construct(
        private TicketQueryInterface $query,
        private TicketCommandInterface $command,
        private UuidInterface $uuid
    ){}

    #[Link(rel: "doPost", href: '/tickets')]
    #[Link(rel: "goTicket", href: '/ticket{?id}')]
    #[JsonSchema("tickets.json")]
    public function onGet(): static
    {
        $this->body = [
            'tickets' => $this->query->list()
        ];
        
        return $this;
    }

    #[Link(rel: "goTickets", href: '/tickets')]
    public function onPost(string $title): static
    {
        $id = (string) $this->uuid;
        $this->command->add($id, $title);

        $this->code = StatusCode::CREATED;
        $this->headers[ResponseHeader::LOCATION] = uri_template('/ticket{?id}', ['id' => $id]);

        return $this;
    }
}

The injected $uuid can be cast to a string to get the UUID. Also, #Link[] represents a link to another resource (application state).

Notice that we don’t pass the current time in the add() method. If no value is passed, it will not be null, but the MySQL current time string will be bound to the SQL. This is because the string representation of the current time DateTime object bound to the DateTimeInterface (current time string) is bound to SQL.

public function add(string $id, string $title, DateTimeInterface $dateCreated = null): void;

It saves you the trouble of hard-coding NOW() inside SQL and passing the current time to the method every time. You can pass a DateTime object, or in the context of a test, you can bind a fixed test time.

In this way, if you specify an interface as an argument to a query, you get that object using DI, and its string representation is bound to SQL. For example, login user IDs can be bound and used across applications. ⁸

Hypermedia API test

The term REST (representational state transfer) was introduced and defined by Roy Fielding in his doctoral dissertation in 2000, and is intended to give an idea of “the behavior of a properly designed web application”. It is a network of web resources (a virtual state machine) where the user selects a resource identifier (URL) and a resource operation (application state transition) such as GET or POST to proceed with the application, resulting in the next representation of the resource (the next application state) being forwarded to the end user. application state) is transferred to the end user for use.

– Wikipedia (REST)

In a REST application, the following actions are provided by the service as URLs, and the client selects them.

HTML web applications are completely RESTful. The only operations are “Go to the provided URL (with a tag, etc.)” or “Fill the provided form and submit”.

The REST API tests are written in the same way.

<?php

declare(strict_types=1);

namespace MyVendor\Ticket\Hypermedia;

use BEAR\Resource\ResourceInterface;
use BEAR\Resource\ResourceObject;
use Koriym\HttpConstants\ResponseHeader;
use MyVendor\Ticket\Injector;
use MyVendor\Ticket\Query\TicketQueryInterface;
use PHPUnit\Framework\TestCase;
use Ray\Di\InjectorInterface;
use function json_decode;

class WorkflowTest extends TestCase
{
    protected ResourceInterface $resource;
    protected InjectorInterface $injector;

    protected function setUp(): void
    {
        $this->injector = Injector::getInstance('hal-api-app');
        $this->resource = $this->injector->getInstance(ResourceInterface::class);
        $a = $this->injector->getInstance(TicketQueryInterface::class);
    }

    public function testIndex(): static
    {
        $index = $this->resource->get('/');
        $this->assertSame(200, $index->code);

        return $index;
    }

    /**
     * @depends testIndex
     */
    public function testGoTickets(ResourceObject $response): static
    {

        $json = (string) $response;
        $href = json_decode($json)->_links->{'goTickets'}->href;
        $ro = $this->resource->get($href);
        $this->assertSame(200, $ro->code);

        return $ro;
    }

    /**
     * @depends testGoTickets
     */
    public function testDoPost(ResourceObject $response): static
    {
        $json = (string) $response;
        $href = json_decode($json)->_links->{'doPost'}->href;
        $ro = $this->resource->post($href, ['title' => 'title1']);
        $this->assertSame(201, $ro->code);

        return $ro;
    }

    /**
     * @depends testDoPost
     */
    public function testGoTicket(ResourceObject $response): static
    {
        $href = $response->headers[ResponseHeader::LOCATION];
        $ro = $this->resource->get($href);
        $this->assertSame(200, $ro->code);

        return $ro;
    }
}

You will also need a route page as a starting point.

src/Resource/App/Index.php

<?php

declare(strict_types=1);

namespace MyVendor\Ticket\Resource\App;

use BEAR\Resource\Annotation\Link;
use BEAR\Resource\ResourceObject;

class Index extends ResourceObject
{
    #[Link(rel: 'goTickets', href: '/tickets')]
    public function onGet(): static
    {
        return $this;
    }
}

• setUp creates a resource client, and testIndex() accesses the root page.
• The testGoTickets() method, which receives the response, makes a JSON representation of the response object and gets the link goTickets to get the next list of tickets.
• There is no need to write a test for the resource body. * No need to write tests for the resource body, just check the status code, since it is guaranteed that the JsonSchema validation of the response has passed.
• Following the uniform interface of REST, the next request URL to be accessed is always included in the response. Inspect them one after another.

Uniform Interface

REST is defined by four interface constraints: identification of resources; manipulation of resources through representations; self-descriptive messages; and, hypermedia as the engine of application state.⁹

Let’s run it.

./vendor/bin/phpunit --testsuite hypermedia

Hypermedia API tests (REST application tests) are a good representation of the fact that REST applications are state machines, and workflows can be described as use cases. Ideally, REST API tests should cover how the application will be used.

HTTP Testing

To test the REST API over HTTP, inherit the whole test and set the client to the HTTP test client with setUp.

class WorkflowTest extends Workflow
{
    protected function setUp(): void
    {
        $this->resource = new HttpResource('127.0.0.1:8080', __DIR__ . '/index.php', __DIR__ . '/log/workflow.log');
    }
}

This client has the same interface as the resource client, but the actual request is made as an HTTP request to the built-in server and receives the response from the server. The first argument is the URL of the built-in server. When new is executed, the built-in server will be started with the bootstrap script specified in the second argument.

The bootstrap script for the test server will also be changed to the API context.

tests/Http/index.php

-exit((new Bootstrap())('hal-app', $GLOBALS, $_SERVER));
+exit((new Bootstrap())('hal-api-app', $GLOBALS, $_SERVER));

Let’s run it.

./vendor/bin/phpunit --testsuite http

HTTP Access Log

The actual HTTP request/response log made by curl will be recorded in the resource log of the third argument.

curl -s -i 'http://127.0.0.1:8080/'

HTTP/1.1 200 OK
Host: 127.0.0.1:8080
Date: Fri, 21 May 2021 22:41:02 GMT
Connection: close
X-Powered-By: PHP/8.0.6
Content-Type: application/hal+json

{
    "_links": {
        "self": {
            "href": "/index"
        },
        "goTickets": {
            "href": "/tickets"
        }
    }
}

curl -s -i -H 'Content-Type:application/json' -X POST -d '{"title":"title1"}' http://127.0.0.1:8080/tickets

HTTP/1.1 201 Created
Host: 127.0.0.1:8080
Date: Fri, 21 May 2021 22:41:02 GMT
Connection: close
X-Powered-By: PHP/8.0.6
Location: /ticket?id=421d997c-9a0e-4018-a6c2-9b8758cac6d6

The actual recorded JSON is useful for checking, especially if it has a complex structure, and is also good to check along with the API documentation. The HTTP client can also be used for E2E testing.

API documentation

In ResourceObjects, method signatures are the input parameters to the API, and responses are schema-defined. Because of its self-descriptiveness, API documentation can be generated automatically.

Let’s create it. The documentation will be output to the docs folder.

composer doc

It reduces the effort of writing IDL (Interface Definition Language), but more valuable is that the documentation follows the latest PHP code and is always accurate. It is a good idea to include it in your CI so that your code and API documentation are always in sync.

You can also link to related documentation. See ApiDoc for more details on configuration.

Code examples

The following code example is also available.

• TestModulethat adds a Test context and clears the DB for each test. 4e9704d
• entity option for #[DbQuery] that returns a hydrated entity class instead of an associative array in DB queries 29f0a1f
• Query builder synthesizing static and dynamic SQL 9d095ac

REST framework

There are three styles of Web APIs.

• Tunnels (SOAP, GraphQL)
• URI (Object, CRUD)
• Hypermedia (REST)

In contrast to the URI style, where resources are treated as just RPCs ¹⁰, what we learned in this tutorial is REST, where resources are linked. ¹¹ Resources are connected by LOs (outbound links) in #Link to represent workflows, and LEs (embedded links) in #[Embed] to represent tree structures.

BEAR.Sunday emphasizes clean, standards-based code.

JsonSchema over framework-specific validators, standard SQL over proprietary ORM, IANA registered standard¹² media type JSON over proprietary structure JSON.

Application design is not about “free implementation”, but about “free choice of constraints”. Applications should aim for evolvability without breaking development efficiency, performance, and backward compatibility based on the constraints.

(This manual has been prepared through deepL automated translation.)

The comment is not only descriptive, but also makes it easier to identify the SQL in the slow query log, etc.