Getting started with XPSR

This tutorial builds a small tasks API: three endpoints, an API-key middleware, a console command, and tests. Then it switches the router adapter without touching any route. Every step was run in a freshly created project; the commands and files below are the ones that were tested.

You need PHP 8.4 or newer and Composer 2. On Linux and macOS, php xpsr serve also needs the pcntl extension.

1. Create a project

composer create-project crystoline/xpsr my-app
cd my-app

To try unreleased changes, create a project from a clone of the XPSR repository instead:

php scripts/export-skeleton.php /tmp/xpsr-skeleton
composer create-project crystoline/xpsr my-app 0.3.x-dev --add-repository \
  --repository='{"type":"path","url":"/tmp/xpsr-skeleton","options":{"symlink":false,"versions":{"crystoline/xpsr":"0.3.x-dev"}}}' \
  --repository='{"type":"path","url":"'"$PWD"'/packages/*","options":{"symlink":false,"versions":{"crystoline/xpsr-framework":"0.3.x-dev","crystoline/xpsr-router-fastroute":"0.3.x-dev","crystoline/xpsr-router-sunrise":"0.3.x-dev"}}}'
cd my-app

Composer creates .env from .env.example. Now choose the router and preset. This tutorial builds an API, so it uses the api preset, which loads only routes/api.php:

php xpsr setup --router=fastroute --preset=api

Router: fastroute. Preset: api.
Write config/routing.php to load routes/api.php.
Bootstrap check passed: 1 route(s); 1 without placeholders matched by Crystoline\Xpsr\Router\FastRoute\FastRouteRouter.

Start the development server and keep it running in another terminal:

php xpsr serve          # http://127.0.0.1:3001
curl http://127.0.0.1:3001/hello

2. Add a controller and routes

php xpsr make:controller TaskController

Replace the generated app/Http/Controller/TaskController.php. There is no database integration yet, so the tasks are a constant:

<?php

declare(strict_types=1);

namespace App\Http\Controller;

use Crystoline\Xpsr\Http\Response\ResponseBuilder;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;
use Crystoline\Xpsr\Http\Exception\BadRequestHttpException;
use Crystoline\Xpsr\Http\Exception\NotFoundHttpException;

final class TaskController
{
    private const TASKS = [
        1 => ['id' => 1, 'title' => 'Read the XPSR docs'],
        2 => ['id' => 2, 'title' => 'Build an endpoint'],
    ];

    public function __construct(private readonly ResponseBuilder $responses) {}

    public function index(ServerRequestInterface $request): ResponseInterface
    {
        return $this->responses->json(array_values(self::TASKS));
    }

    public function show(ServerRequestInterface $request): ResponseInterface
    {
        $id = (int) $request->getAttribute('id');

        return $this->responses->json(self::TASKS[$id] ?? throw new NotFoundHttpException("Task {$id} does not exist."));
    }

    public function store(ServerRequestInterface $request): ResponseInterface
    {
        $data = $request->getParsedBody();
        $title = is_array($data) && is_string($data['title'] ?? null) ? trim($data['title']) : '';
        if ($title === '') {
            throw new BadRequestHttpException('A task needs a title.');
        }

        return $this->responses->json(['id' => 3, 'title' => $title], 201);
    }
}

Things to notice:

Injection: the constructor's ResponseBuilder is supplied by the container. Controllers need no registration.
Route parameters: the {id} placeholder arrives as a request attribute.
Request bodies: JSON is already decoded in getParsedBody(), by the body-parsing middleware the skeleton enables.
Errors: throwing one of XPSR's HTTP exceptions (Crystoline\Xpsr\Http\Exception\*) produces that status code. API clients get {"message": "Bad Request"}; the detailed message appears only with APP_DEBUG=true.

Add the routes to routes/api.php:

<?php

declare(strict_types=1);

use App\Http\Controller\TaskController;
use App\Http\Middleware\RequireApiKey;
use Crystoline\Xpsr\Http\Response\ResponseBuilder;
use Crystoline\Xpsr\Routing\RouteCollection;
use Psr\Http\Message\ResponseInterface;

return static function (RouteCollection $routes): void {
    $routes->get('/hello', static function (): ResponseInterface {
        return app()->get(ResponseBuilder::class)->json(['helloooooooo']);
    })->name('hello');

    $routes->get('/tasks', [TaskController::class, 'index'])->name('tasks.index');
    $routes->get('/tasks/{id}', [TaskController::class, 'show'])->where('id', '\d+')->name('tasks.show');
    $routes->post('/tasks', [TaskController::class, 'store'])->name('tasks.store')->middleware(RequireApiKey::class);
};

where('id', '\d+') makes /tasks/abc a 404 instead of reaching the controller. The POST route uses a middleware you create next.

3. Protect a route with middleware

php xpsr make:middleware RequireApiKey

Replace app/Http/Middleware/RequireApiKey.php:

<?php

declare(strict_types=1);

namespace App\Http\Middleware;

use Crystoline\Xpsr\Configuration;
use Crystoline\Xpsr\Http\Response\ResponseBuilder;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Server\MiddlewareInterface;
use Psr\Http\Server\RequestHandlerInterface;

final class RequireApiKey implements MiddlewareInterface
{
    public function __construct(
        private readonly Configuration $config,
        private readonly ResponseBuilder $responses,
    ) {}

    public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
    {
        $expected = (string) $this->config->get('tasks.api_key', '');
        if ($expected === '' || !hash_equals($expected, $request->getHeaderLine('X-Api-Key'))) {
            return $this->responses->json(['message' => 'A valid X-Api-Key header is required.'], 401);
        }

        return $handler->handle($request);
    }
}

Returning a response without calling $handler stops the request before it reaches the controller. The key comes from configuration rather than straight from the environment. Each config/*.php file becomes a configuration section, so create config/tasks.php:

<?php

declare(strict_types=1);

return [
    'api_key' => env('TASKS_API_KEY', ''),
];

Then add the key to .env:

echo "TASKS_API_KEY=secret-key" >> .env

Try it:

curl http://127.0.0.1:3001/tasks
# [{"id":1,"title":"Read the XPSR docs"},{"id":2,"title":"Build an endpoint"}]

curl -H 'Accept: application/json' http://127.0.0.1:3001/tasks/99
# {"message":"Not Found"}

curl -X POST -H 'Content-Type: application/json' -H 'X-Api-Key: secret-key' \
     -d '{"title":"Ship it"}' http://127.0.0.1:3001/tasks
# {"id":3,"title":"Ship it"}   (201)

curl -X POST -H 'Content-Type: application/json' -d '{"title":"Ship it"}' http://127.0.0.1:3001/tasks
# {"message":"A valid X-Api-Key header is required."}   (401)

4. Add a console command

php xpsr make:command TaskCountCommand

The generator names the command app:task-count and prints the lines needed to register it. Replace the execute() body in app/Console/Commands/TaskCountCommand.php, and set the description:

protected function configure(): void
{
    $this->setDescription('Show how many tasks exist.');
}

protected function execute(InputInterface $input, OutputInterface $output): int
{
    $output->writeln('There are 2 tasks.');

    return self::SUCCESS;
}

Commands are registered explicitly, with no directory scanning. Add it to app/Registry/CommandServiceRegistry.php:

<?php

declare(strict_types=1);

namespace App\Registry;

use App\Console\Commands\GreetCommand;
use App\Console\Commands\TaskCountCommand;
use Crystoline\Xpsr\Console\CommandRegistry;
use Crystoline\Xpsr\ServiceContainer\ServiceRegistry;

final class CommandServiceRegistry extends ServiceRegistry
{
    public function register(): void
    {
        $this->container->bind(GreetCommand::class);
        $this->container->bind(TaskCountCommand::class);
    }

    public function boot(): void
    {
        $commands = $this->container->get(CommandRegistry::class);
        $commands->register('app:greet', GreetCommand::class, 'Example application command with constructor injection.');
        $commands->register('app:task-count', TaskCountCommand::class, 'Show how many tasks exist.');
    }
}

php xpsr app:task-count     # There are 2 tasks.
php xpsr route:list         # the four routes, with the middleware on POST /tasks

5. Write tests

tests/TestCase.php sends requests through the full HTTP kernel (middleware, routing, error rendering) without a web server, and runs console commands. PHPUnit sets APP_ENV=testing, which loads overrides from config/testing/. Give the tests a known key in config/testing/tasks.php:

<?php

declare(strict_types=1);

return [
    'api_key' => 'test-key',
];

Create tests/Application/TaskTest.php:

<?php

declare(strict_types=1);

namespace Tests\Application;

use Tests\TestCase;

final class TaskTest extends TestCase
{
    public function testListsTasks(): void
    {
        $response = $this->get('/tasks');

        self::assertSame(200, $response->getStatusCode());
        self::assertCount(2, json_decode((string) $response->getBody(), true));
    }

    public function testShowsOneTaskOrNotFound(): void
    {
        self::assertSame(['id' => 1, 'title' => 'Read the XPSR docs'], json_decode((string) $this->get('/tasks/1')->getBody(), true));
        self::assertSame(404, $this->get('/tasks/99', ['Accept' => 'application/json'])->getStatusCode());
        self::assertSame(404, $this->get('/tasks/abc')->getStatusCode(), 'The id must be numeric.');
    }

    public function testCreatingATaskNeedsTheApiKey(): void
    {
        self::assertSame(401, $this->postJson('/tasks', ['title' => 'Ship it'])->getStatusCode());

        $response = $this->request('POST', '/tasks', ['X-Api-Key' => 'test-key', 'Accept' => 'application/json'], ['title' => 'Ship it']);
        self::assertSame(201, $response->getStatusCode());
        self::assertSame(['id' => 3, 'title' => 'Ship it'], json_decode((string) $response->getBody(), true));
    }

    public function testATaskNeedsATitle(): void
    {
        $response = $this->request('POST', '/tasks', ['X-Api-Key' => 'test-key', 'Accept' => 'application/json'], ['title' => '  ']);

        self::assertSame(400, $response->getStatusCode());
        self::assertSame(['message' => 'Bad Request'], json_decode((string) $response->getBody(), true));
    }

    public function testTaskCountCommand(): void
    {
        [$status, $output] = $this->console('app:task-count');

        self::assertSame(0, $status);
        self::assertSame("There are 2 tasks.\n", $output);
    }
}

composer test
# OK (9 tests, 20 assertions)   (these 5 plus the skeleton's 4 examples)

request() sends an array body as JSON. console() takes arguments by name, for example $this->console('app:greet', ['name' => 'Ada']). swap($id, $replacement) replaces a service for the rest of a test, for example a fake HTTP client in place of Psr\Http\Client\ClientInterface. freezeTime('2026-01-31 09:00:00') stops the application clock; see CONTAINER.md.

6. Switch the router adapter

Routes are declared once and matched by an adapter. Switch to Sunrise:

php xpsr setup --router=sunrise --install-dependencies

Router: sunrise. Preset: api.
Installed crystoline/xpsr-router-sunrise:^0.3.
Set ROUTER_ADAPTER=sunrise in .env.
Bootstrap check passed: 4 route(s); 3 without placeholders matched by Crystoline\Xpsr\Router\Sunrise\SunriseRouter.

Run composer test again: the same 9 tests pass without changing a route or controller. Switch back with php xpsr setup --router=fastroute.

Next steps

HTTP.md: request bodies, errors, logging, and how responses are sent.
ROUTING.md: groups, named URLs (UrlGeneratorInterface), constraints, and HEAD/OPTIONS behavior.
CONTAINER.md: bindings, factories, and service providers (php xpsr make:provider).
CONSOLE.md: every command and generator.
EVENTS.md: dispatching events and writing listeners.
Optional packages: the cache, the HTTP client, and database connections and migrations.
DEPLOYMENT.md: running an XPSR application in production.