Openapi Data Mocker Server Middleware

PSR-15 HTTP Server Middleware to create mock responses from OpenAPI Schemas(OAS 3.0). This package was an enhancement of PHP Slim4 server in OpenAPI Generator project, but it easier to maintain it in separated repo.

Requirements

• PHP ^7.3

Important notice! While PHP 8.0 declared in composer.json this package hasn't been tested against it.

Installation via Composer

Run in terminal:

composer require ybelenko/openapi-data-mocker-server-middleware

Constructor Arguments

1. $mocker: OpenApiDataMockerInterface
   • is mocker class instance. To create custom data mocker extend OpenAPIServer\Mock\OpenApiDataMockerInterface.
2. $responses: array
   • Array with OAS3 response definitions of applied route. Check examples/get_mock_responses.php file.
3. $responseFactory: ResponseFactoryInterface
   • Any PSR-17 compliant response factory. PSR-17: HTTP Factories - 2.2 ResponseFactoryInterface
4. $getMockStatusCodeCallback: callable|null = null
   • is callback before mock data generation. Below example shows how to enable mock feature for only requests with X-OpenAPIServer-Mock: ping HTTP header. Adjust requests filtering to fit your project requirements. This function must return single response schema from $responses array parameter. Mock feature is disabled when callback returns anything beside existent key from $responses array, eg 'default' or 200.
5. $afterCallback: callable|null = null
   • is callback executed after mock data generation. Most obvious use case is append specific HTTP headers to distinguish real and fake responses. This function must always return response instance.

Usage Example

require_once __DIR__ . '/vendor/autoload.php';

use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Message\ResponseInterface;
use Slim\Factory\AppFactory;
use Slim\Factory\ServerRequestCreatorFactory;
use OpenAPIServer\Mock\OpenApiDataMockerRouteMiddleware;
use OpenAPIServer\Mock\OpenApiDataMocker;

// initiate Slim app or any other PSR-15 compliant framework
$app = AppFactory::create();

// create new mocker instance
$mocker = new OpenApiDataMocker();

// responses OAS3.0 definition of GET /mock operation
// check examples/get_mock_responses.php file
$responsesForGetMockRoute = require_once(__DIR__ . '/get_mock_responses.php');

// initiate any PSR-17 compliant response factory
$responseFactory = AppFactory::determineResponseFactory();

// optional response schema selector
$getMockStatusCodeCallback = function (ServerRequestInterface $request, $responses) {
    // check if client clearly asks for mocked response
    if (
        $request->hasHeader('X-OpenAPIServer-Mock')
        && $request->getHeader('X-OpenAPIServer-Mock')[0] === 'ping'
    ) {
        $responses = (array) $responses;
        if (array_key_exists('default', $responses)) {
            return 'default';
        }

        // return first response key
        reset($responses);
        return key($responses);
    }
    return false;
};

// optional after middleware callback
$afterCallback = function (ServerRequestInterface $request, ResponseInterface $response) {
    // mark mocked response to distinguish real and fake responses
    return $response->withHeader('X-OpenAPIServer-Mock', 'pong');
};

// create middleware itself
$mw = new OpenApiDataMockerRouteMiddleware(
    $mocker,
    $responsesForGetMockRoute,
    $responseFactory,
    $getMockStatusCodeCallback,
    $afterCallback
);

// this package is route middleware, apply it to route as described in Slim docs:
// https://www.slimframework.com/docs/v4/concepts/middleware.html#route-middleware
$app->get('/mock', function (ServerRequestInterface $request, ResponseInterface $response) {
    $response->getBody()->write('Hello ');

    return $response;
})->add($mw);

$app->run();

// let's assume you started builtin PHP server
// which you MUST NOT use on production:
// $ php -S localhost:8888 examples/slim_example.php

// finally you can check output with curl library
// $ curl http://localhost:8888/mock
// Hello

// $ curl http://localhost:8888/mock -H 'X-OpenAPIServer-Mock: ping'