Component: OpenAPI

Jane OpenAPI is a library to generate, in PHP, an HTTP client and its associated models and serializers from a OpenAPI specification: version 2 or 3. Jane supports both OpenAPI v2 & v3. Depending on your OpenAPI version, the command line will detect which version to use and if this version is actually installed in your dependencies.

Installation

Jane supports both OpenAPI v2 & v3. Depending on your OpenAPI version, the command line will detect which version to use and if this version is actually installed in your dependencies.

You have to add the generation library as a dev dependency. This library contains a lot of dependencies, to be able to generate code, which are not needed on runtime. However, the generated code depends on other libraries and a few classes that are available through the runtime package. It is mandatory to add the runtime dependency as a requirement. Choose your library depending on OpenAPI version you need (you can even install both if you want):

# OpenAPI 2
composer require --dev jane-php/open-api-2
composer require jane-php/open-api-runtime

# OpenAPI 3
composer require --dev jane-php/open-api-3
composer require jane-php/open-api-runtime

With Symfony ecosystem, we created a recipe to make it easier to use Jane. You just have to allow contrib recipes before installing our packages:

composer config extra.symfony.allow-contrib true

Then when installing jane-php/open-api-*, it will add all the required files:

  • bin/open-api-generate: a binary file to run JSON Schema generation based on config/jane/open-api.php configuration;
  • config/jane/open-api.php: your Jane configuration (see “Configuration file”);
  • config/packages/open-api.yaml: Symfony Serializer configured to be optimized for Jane.

By default, generated code is not formatted, to make it compliant to PSR2 standard and others coding style formats, you can add the PHP CS Fixer library to your dev dependencies (and it makes it easier to debug!):

composer require --dev friendsofphp/php-cs-fixer

Generating a Client

This library provides a PHP console application to generate the Model. You can use it by executing the following command at the root of your project:

php vendor/bin/jane-openapi generate

This command will try to read a config file named .jane-openapi located on the current working directory. However, you can name it as you like and use the --config-file option to specify its location and name:

php vendor/bin/jane-openapi generate --config-file=jane-openapi-configuration.php

Note

If you are using Symfony recipe, this command is embbeded in the bin/open-api-generate binary file, you only have to run it to make it work 🎉

Note

No others options can be passed to the command. Having a config file ensure that a team working on the project always use the same set of parameters and, when it changes, give vision of the new option(s) used to generate the code.

Hint

If you have a really big specification and want to optimize your generation time, you can disable garbage collector during generation, you can read more about it on Scrutinizer blog post . To do that, use Jane as following: php -d zend.enable_gc=0 vendor/bin/jane-openapi generate.

Configuration file

The configuration file consists of a simple PHP script returning an array:

<?php

return [
    'openapi-file' => __DIR__ . '/open-api.json',
    'namespace' => 'Vendor\Library\Generated',
    'directory' => __DIR__ . '/generated',
];

This example shows the minimum configuration required to generate a client:

  • openapi-file: Specify the location of your OpenApi file, it can be a local file or a remote one https://my.domain.com/my-api.json. It can also be a yaml file.
  • namespace: Root namespace of all of your generated code
  • directory: Directory where the code will be generated

Given this configuration, you will need to add the following configuration to composer, in order to load the generated files:

"autoload": {
    "psr-4": {
        "Vendor\\Library\\Generated\\": "generated/"
    }
}

Options

Other options are available to customize the generated code:

  • reference: A boolean which indicate to add the support for JSON Reference into the generated code.

  • date-format: A date format to specify how the generated code should encode and decode \DateTime object to string

  • date-format: A date-time format to specify how the generated code should encode and decode \DateTime object to string. This option is only for format date-time.

  • full-date-format: A date format to specify how the generated code should encode and decode \DateTime object to string. This option is only for format date.

  • date-prefer-interface: The \DateTimeInterface is the base of every \DateTime related action. This makes it more compatible with other DateTime libraries like Carbon. This option replace \DateTime returns with \DateTimeInterface, it’s disabled by default.

  • date-input-format: During denormalization (from array to object), we may have a different format than the output format. This option allows you to specify which format you want. By default it will take date-format configuration.

  • strict: A boolean which indicate strict mode (true by default), not strict mode generate more permissive client not respecting some standards (nullable field as an example) client.

  • use-fixer: A boolean which indicate if we make a first cs-fix after code generation, is disabled by default.

  • fixer-config-file: A string to specify where to find the custom configuration for the cs-fixer after code generation, will remove all Jane default cs-fixer default configuration.

  • clean-generated: A boolean which indicate if we clean generated output before generating new files, is enabled by default.

  • use-cacheable-supports-method: A boolean which indicate if we use CacheableSupportsMethodInterface interface to improve caching performances when used with Symfony Serializer.

  • skip-null-values: When having nullable properties, you can enforce normalization to skip theses properties even if they are nullable. This option allows you to not have theses properties when they’re not set (null). By default it is enabled.

  • skip-required-fields: If your model has required fields, this option allows you to skip the required behavior that forces them to be present during denormalization. By default it is disabled

  • whitelisted-paths: This option allows you to generate only needed endpoints and related models. Be carefull, that option will filter models used by whitelisted endpoints and generate model & normalizer only for them. Here is some examples about how to use it:

    <?php
    
    return [
        // your usual configuration ...
        'whitelisted-paths' => [
            '\/foo$',
            ['\/foo\/(bar|baz)'],
            ['\/foo$', 'GET'],
            ['\/foo$', ['POST']],
            ['\/foo$', ['POST', 'PUT']]
        ],
    ];
    

    There is many ways to use it, first you atleast need a regex defining which endpoint is whitelisted. This endpoint can be either a string or in an array. If you don’t provide any HTTP method, we will just accept any methods, but you can provide either a string or array as second argument to specify which method you accept.

  • endpoint-generator: Generator Class which can specify custom endpoint interface & corresponding trait (this class should extends \Jane\Component\OpenApi3\Generator\EndpointGenerator)

  • custom-query-resolver: This option allows you to customize the query parameter normalizer for each of the API endpoint with a userland callback. Here is all possible combinations:

    <?php
    
    use App\BoolCustomQueryResolver;
    use App\IntCustomQueryResolver;
    use App\BarCustomQueryResolver;
    use App\BazCustomQueryResolver;
    
    return [
        // your usual configuration ...
        'custom-query-resolver' => [
            '__type' => [
                'bool' => BoolCustomQueryResolver::class,
                'int' => IntCustomQueryResolver::class,
            ],
            '/foo' => [
                'get' => [
                    'bar' => BarCustomQueryResolver::class,
                    'baz' => BazCustomQueryResolver::class,
                ],
                'post' => [
                    'bar' => BarCustomQueryResolver::class,
                ],
            ],
        ],
    ];
    

    There are many ways to use it. You can either use the __type key to specify a custom query normalizer for a given type (bool, int, string, …) and give it your class that contains the custom normalizer by extending the generated runtime CustomQueryResolver class. You can also filter the usage of your custom normalizer by giving the exact path, method and parameter name where you want to apply it.

  • throw-unexpected-status-code: Will return a UnexpectedStatusCodeException if nothing has been matched during the transformation of the Endpoint body (including described exceptions). By default, it’s disabled.

Using a generated client

Generating a client will produce same classes as the Component: JSON Schema library:

  • Model files in the Model namespace
  • Normalizer files in the Normalizer namespace
  • A JaneObjectNormalizer class in the Normalizer namespace

Furthermore, it generates:

  • Endpoints files in the Endpoint namespace, each API Endpoint will generate a class containing all the logic to go from Object to Request, and from Response to Object with the generated Normalizer
  • Client file in the root namespace containing all API endpoints

Creating the API Client

Generated Client class have a static method create which act like a factory to create your Client:

<?php

$apiClient = Vendor\Library\Generated\Client::create();

Note

If you are using Symfony recipe, the client will be autowired. So you can use it anywhere by using your Client class

Note

Optionally, you can pass a custom HttpClient respecting the PSR18 Client standard. If you which to use the constructor to reuse existing instances, sections below describe the 4 services used by it and how to create them.

Creating the Http Client

The main dependency on the Client class is an HTTP client respecting the PSR18 client standard. We highly recommend you to read the PSR18 specification. This HTTP client MAY redirect on a 3XX responses (depend on your API), but it MUST not throw errors on 4XX and 5XX responses, as this can be handle by the generated code directly.

Recommended way of creating an HTTP Client is by using the discovery library to create the client:

<?php

$httpClient = Http\Discovery\Psr18ClientDiscovery::find();

This allows user of the API to use any client respecting the standard.

Hint

You can use clients such as Symfony HttpClient as PSR18 client.

Creating the Request Factory

The generated endpoints will also need a factory to transform parameters and object of the endpoint to a PSR7 Request.

Like the HTTP Client, it is recommended to use the discovery library to create it:

<?php

$requestFactory = Http\Discovery\Psr17FactoryDiscovery::findRequestFactory();

Creating the Serializer

Like in Component: JSON Schema, creating a serializer is done by using the JaneObjectNormalizer class:

<?php

$normalizers = [
    new \Symfony\Component\Serializer\Normalizer\ArrayDenormalizer(),
    new \Vendor\Library\Generated\Normalizer\JaneObjectNormalizer(),
];

$serializer = new \Symfony\Component\Serializer\Serializer($normalizers, [new \Symfony\Component\Serializer\Encoder\JsonEncoder()]);
$serializer->deserialize('{...}');

With Symfony ecosystem, you just have to use the recipe and all the configuration will be added automatically. This serializer will be able to encode and decode every data respecting your OpenAPI specification thanks to autowiring of the generated normalizers.

Creating the Stream Factory

The generated endpoints will also need a service to transform body parameters like resource or string into PSR7 Stream when uploading file (multipart form).

Like the HTTP Client and Request Factory, it is recommended to use the discovery library to create it:

<?php

$streamFactory = Http\Discovery\Psr17FactoryDiscovery::findStreamFactory();

Using the API Client

Generated code has complete PHPDoc comment on each method, which should correctly describe the endpoint. Method names for each endpoint depends on the operationId property of the OpenAPI specification. And if not present it will be generated from the endpoint path:

<?php

$apiClient = Vendor\Library\Generated\Client::create();
// Operation id being listFoo
$foos = $apiClient->listFoo();

Also depending on the parameters of the endpoint, it may have 2 to more arguments.

Last parameter of each endpoint, allows to specify which type of data the method must return. By default, it will try to return an object depending on the status code of your response. But you can force the method to return a PSR7 Response object:

$apiClient = Vendor\Library\Generated\Client::create();
// First argument is an empty list of parameters, second one being the return type
$response = $apiClient->listFoo([], Vendor\Library\Generated\Client::FETCH_RESPONSE);

This allow to do custom work when the API does not return standard JSON body.

Host and basePath support

Jane OpenAPI will never generate the complete url with the host and the base path for an endpoint. Instead, it will only do a request on the specified path.

If host and/or base path is present in the specification it is added, via the PluginClient, AddHostPlugin and AddPathPlugin thanks to php-http plugin system when using the static create.

This allow you to configure different host and base path given a specific environment / server, which may defer when in test, preprod and production environment.

Jane OpenAPI will always try to use https if present in the scheme (or if there is no scheme). It will use the first scheme present if https is not present.

Having custom plugins

If you want to support more behavior such as authentication or other stuff that need a plugin, you can pass them through the second argument of the static create method.

Authentication

We do generate a plugin for each authentication method declared in your scheme. It does support:

  • apiKey in header & query for both OpenAPI v2 & v3
  • HTTP Basic & Bearer for OpenAPI v3

Quick example of how your authentication definition could look (OpenAPI v3):

components:
  securitySchemes:
    BasicAuth:
      type: http
      scheme: basic
    BearerAuth:
      type: http
      scheme: bearer
    ApiKeyAuth:
      type: apiKey
      in: header
      name: X-API-Key

When your OpenAPI definition contains it, Jane will generate a Authentication namespace that contains all plugins you need for your API. Then you give all your authentication plugins to Jane\Component\OpenApiRuntime\Client\Plugin\AuthenticationRegistry. And finally you can pass it to your Jane Client (only if you let Jane make a HTTP Client for you, otherwise this second parameters is ignored).

An example Authentification directory:

../_images/authentication.png

This AuthenticationRegistry class is used to match security scopes in your API, if an Endpoint require a certain authentication method, then it will use it. You need to have security fields correctly made in your scheme in order to use this class. If they’re not set, you can simply pass the authentication plugin to your Jane Client.

Here is how you can use it:

$authenticationRegistry = new AuthenticationRegistry([new ApiKeyAuthentication($this->apiKey)]);
$client = Client::create(null, [$authenticationRegistry]);
$foo = $client->foo();

You can replace Client::create first argument with your custom HttpClient if needed as usual.

Extending the Client

Some endpoints need sometimes custom implementation that were not possible to generate through the OpenAPI specification. Jane OpenAPI try to be nice with this and each specific behavior of an API call has been seprated into different methods which are public or protected.

As an exemple you may want to encode in base64 a specific query parameter of an Endpoint. First step is to create your own Endpoint extending the generated one:

<?php

namespace Vendor\Library\Generated\Endpoint;

use Vendor\Library\Generated\Endpoint\FooEndpoint as BaseEndpoint;
use Symfony\Component\OptionsResolver\Options;
use Symfony\Component\OptionsResolver\OptionsResolver;

class FooEndpoint extends BaseEndpoint
{
    protected function getQueryOptionsResolver(): OptionsResolver
    {
        $optionsResolver = parent::getQueryOptionsResolver();
        $optionsResolver->setNormalizer('bar', function (Options $options, $value) {
            return base64_encode($value);
        });

        return $optionsResolver;
    }
}

Once this endpoint is generated, you need to tell your Client to use yours endpoint instead of the Generated one. For that you can extends the generated client and override the method that use this endpoint:

<?php

namespace Vendor\Library\Generated;

use Vendor\Library\Generated\Client as BaseClient;
use Vendor\Library\Generated\Endpoint\FooEndpoint;

class Client extends BaseClient
{
    public function getFoo(array $queryParameters = [], $fetch = self::FETCH_OBJECT)
    {
        return $this->executePsr7Endpoint(new FooEndpoint($queryParameters), $fetch);
    }
}

Then you will need to use your own client instead of the generated one. To extends other parts of the endpoint you can look at the generated code.