The efficient and elegant, PSR-7 compliant JSON:API client library for PHP
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README.md

Woohoo Labs. Yang

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Woohoo Labs. Yang is a PHP framework which helps you to communicate with JSON:API servers more easily.

Table of Contents

Introduction

JSON:API specification reached 1.0 on 29th May 2015 and we also believe it is a big day for RESTful APIs as this specification makes APIs more robust and future-proof than they have ever been. Woohoo Labs. Yang (named after Yin-Yang) was born to bring efficiency and elegance to your JSON:API clients, while Woohoo Labs. Yin is its server-side counterpart.

Features

  • 100% PSR-7 compatibility
  • 99% JSON:API 1.0 conformance (approximately)
  • Provides a Request Builder to setup JSON:API request more easily
  • Provides easy-to-use HTTP clients via HTTPlug
  • Supports hydrators out-of-the-box in order to easily convert API responses to objects

Install

The only thing you need before getting started is Composer.

Install HTTP client and message implementations:

Because Yang requires a HTTP client implementation (a package which provides the php-http/client-implementation virtual package), you must install one first. You may use Guzzle 6 Adapter or any other library of your preference as long as it also provides the psr/http-message-implementation virtual package:

$ composer require php-http/guzzle6-adapter

Install Yang:

To install the latest version of this library, run the command below:

$ composer require woohoolabs/yang

Note: The tests and examples won't be downloaded by default. You have to use composer require woohoolabs/yang --prefer-source or clone the repository if you need them.

Yang requires PHP 7.1 at least. You may use Yang 1.2 for PHP 7.0 and 0.9 for PHP 5.6.

Basic Usage

Yang can help you in 3 ways to communicate with JSON:API servers. The following subsections will cover these topics.

Request builder

Yang comes with a powerful request builder with which you are able to setup PSR-7 Request objects. For this purpose, you may use the JsonApiRequestBuilder class as it can be seen in the following example.

use GuzzleHttp\Psr7\Request;
use WoohooLabs\Yang\JsonApi\Request\JsonApiRequestBuilder

// Instantiate an empty PSR-7 request
$request = new Request("", "")

// Instantiate the request builder
$requestBuilder = new JsonApiRequestBuilder($request);

// Setup the request with general properties
$requestBuilder
    ->setProtocolVersion("1.1")
    ->setMethod("GET")
    ->setUri("https://www.example.com/api/users")
    ->setHeader("Accept-Charset", "utf-8");

// Setup the request with JSON:API specific properties
$requestBuilder
    ->setJsonApiFields(                                         // To define sparse fieldset
        [
            "users" => ["first_name", "last_name"],
            "address" => ["country", "city", "postal_code"]
        ]
    )
    ->setJsonApiIncludes(                                       // To include related resources
        ["address", "friends"]
    )
    ->setJsonApiIncludes(                                       // Or you can pass a string instead
        "address,friends"
    )
    ->setJsonApiSort(                                           // To sort resource collections
        ["last_name", "first_name"]
    )
    ->setJsonApiPage(                                           // To paginate the primary data
        ["number" => 1, "size" => 100]
    )
    ->setJsonApiFilter(                                         // To filter the primary data
        ["first_name" => "John"]
    );

// Setup the request body
$requestBuilder
    ->setJsonApiBody(                                           // You can pass the content as a JSON string
        '{
           "data": [
             { "type": "user", "id": "1" },
             { "type": "user", "id": "2" }
           ]
         }'
    )
    ->setJsonApiBody(                                           // or you can pass it as an array
        [
            "data" => [
                ["type" => "user", "id" => 1],
                ["type" => "user", "id" => 2],
            ]
        ]
    )
    ->setJsonApiBody(                                           // or as a ResourceObject instance
        new ResourceObject("user", 1)
    );

// Get the composed request
$request = $requestBuilder->getRequest();

If you do not want to use the built-in Request Builder, you can freely setup any PSR-7 RequestInterface instances in order to proceed with the next steps:

$request = new Request("", "");
$request = $request
    ->withProtocolVersion("1.1")
    ->withUri(new Uri("https://example.com/api/users?fields[users]=first_name,last_name"))
    ->withHeader("Accept", "application/vnd.api+json")
    ->withHeader("Content-Type", "application/vnd.api+json");

HTTP clients

The library comes with support for HTTPlug which is a clever HTTP client abstraction so you can choose how you want to send your requests. If you installed the php-http/guzzle6-adapter package, then you will be able to use Guzzle to do so:

use Http\Adapter\Guzzle6\Client;

// Instantiate the Guzzle HTTP Client
$guzzleClient = Client::createWithConfig([]);

// Instantiate the syncronous JSON:API Client
$client = new JsonApiClient($guzzleClient);

// Send the request syncronously to retrieve the response
$response = $client->sendRequest($request);

// Instantiate the asyncronous JSON:API Client
$client = new JsonApiAsyncClient($guzzleClient);

// Send the request asyncronously to retrieve a promise
$promise = $client->sendAsyncRequest($request);

// Send multiple request asyncronously to retrieve an array of promises
$promises = $client->sendConcurrentAsyncRequests([$request, $request]);

Of course, you can use any available HTTP Clients or create a custom HTTP Client thanks to HTTPlug.

Response

As soon as you have retrieved the server response, you can start querying it. Yang uses the PSR-7 compatible JsonApiResponse class for this purpose. If you used a HTTP client introduced above, you will automatically get an object of this type, otherwise you have to take care of instantiating it with the right dependencies.

// Instantiate a JSON:API response from a PSR-7 response with the default deserializer
$response = new JsonApiResponse($psr7Response);

The JsonApiResponse class - above the ones defined by PSR-7 - has some methods to make the handling of JSON:API responses easier:

// Checks if the response contains a JSON:API Document
$hasDocument = $response->hasDocument();

// Checks if the response doesn't contain errors
$isSuccessful = $response->isSuccessful();

// Checks if the response has the status codes listed below and doesn't contain an "errors" member
$isSuccessful = $response->isSuccessful([200, 202]);

// The same as the isSuccessful() method, but also ensures the response contains a document
$isSuccessfulDocument = $response->isSuccessfulDocument();

// Retrieves and deserializes the JSON:API document in the response body
$document = $response->document();

The Document class has various useful methods too:

// Retrieves the "jsonapi" member as a JsonApi instance
$jsonApi = $document->jsonApi();

$jsonApiVersion = $jsonApi->version();
$jsonApiMeta = $jsonApi->meta();

// Checks if the document has the "meta" member
$hasMeta = $document->hasMeta();

// Retrieves the "meta" member as an array
$meta = $document->meta();

// Checks if the document has a "links" member
$hasLinks = $document->hasLinks();

// Retrieves the "links" member as a Links instance
$links = $document->links();

$selfLink = $links->self();         // Returns a Link instance or null
$firstLink = $links->first();       // Returns a Link instance or null
$nextLink = $links->link("next");   // Returns a Link instance or null

// Checks if the document has errors
$hasErrors = $document->hasErrors();

// Retrieves the "errors" member as an array of Error instances
$errors = $document->errors();

// Retrieves the first error as an Error instance or null
$firstError = $document->error(0);

// Checks if the document contains a single resource as the primary data
$isSingleResourceDocument = $document->isSingleResourceDocument();

// Checks if the document contains a collection of resources as the primary data
$isResourceCollectionDocument = $document->isResourceCollectionDocument();

// Checks if the document contains any primary data
$hasPrimaryData = $document->hasAnyPrimaryResources();

// Returns the primary resource as a ResourceObject instance or null if it is a collection document
$primaryResource = $document->primaryResource();

// Returns the primary resources as an array of ResourceObject instances or null if it is a single resource document
$primaryResources = $document->primaryResources();

// Checks if there are any included resources in the document
$hasIncludedResources = $document->hasAnyIncludedResources();

// Checks if there is a specific included resource in the document
$isUserIncluded = $document->hasIncludedResource("user", "abcdefg");

// Retrieves all the included resources as an array of ResourceObject instances
$includedResources = $document->includedResources();

The ResourceObject class has useful methods too:

// Returns the type of the resource
$type = $primaryResource->type();

// Returns the id of the resource
$id = $primaryResource->id();

// Checks if the resource has the "meta" member
$hasMeta = $primaryResource->hasMeta();

// Returns the "meta" member as an array
$meta = $primaryResource->meta();

// Checks if the resource has links
$hasLinks = $primaryResource->hasLinks();

// Returns the "links" member as a Links instance
$links = $primaryResource->links();

// Returns the attributes of the resource as an array
$attributes = $primaryResource->attributes();

// Returns the ID and attributes of the resource as an array
$idAndAttributes = $primaryResource->idAndAttributes();

// Checks if the resource has an attribute
$hasFirstName = $primaryResource->hasAttribute("first_name");

// Returns an attribute of the resource or null if it is missing
$firstName = $primaryResource->attribute("first_name");

// Returns all relationships of the resource
$relationships = $primaryResource->relationships();

// Checks if the resource has a relationship
$hasAddress = $primaryResource->hasRelationship("address");

// Returns a relationship of the resource or null if it is missing
$address = $primaryResource->relationship("address");

The Relationship object supports the following methods:

// Checks if it is a to-one relationship
$isToOneRelationship = $address->isToOneRelationship(); 

// Checks if it is a to-many relationship 
$isToManyRelationship = $address->isToManyRelationship();

// Returns the name of the relationship
$name = $address->name();

// Checks if the relationship has the "meta" member
$hasMeta = $address->hasMeta();

// Returns the "meta" member of the relationship as an array
$meta = $address->meta();

// Returns the "links" member of the relationship as a Links instance
$links = $address->links();

// Returns the resource linkage as an array of a to-one relationship
// or null if there isn't any related data
$resourceLinkage = $address->resourceLink();
 
// Returns the resource linkage as an array of a to-many relationship
$resourceLinkage = $address->resourceLinks();

// Checks if the resource object is included
$isIncluded = $address->isIncluded("address", "abcd");

// Returns the resource object of a to-one relationship as a `ResourceObject` instance
// if the relationship is included, or null otherwise
$resource = $address->resource();

// Returns the resource objects of a to-many relationship as an array of `ResourceObject` instances
// if the relationship is included, or null otherwise
$resources = $address->resources();

Hydration

JSON:API responses with many related resources are not easily to process with the above approach. For example, if you want to retrieve the value of an attribute of a related resource, you need the following code:

$dogResource = $response->document()->primaryResource();

$breedName = $dogResource->relationship("breed")->resource()->attribute("name");

This is a bit too much code to write, and it gets a lot worse when you want to map complex response documents with many relationships to objects:

$dogResource = $response->document()->primaryResource();

$dog = new stdClass();
$dog->name = $dogResource->attribute("name");
$dog->age = $dogResource->attribute("age");
$dog->breed = $dogResource->relationship("breed")->resource()->attribute("name");
foreach ($dogResource->relationship("owners")->resources() as $ownerResource) {
    $owner = new stdClass();
    $owner->name = $ownerResource->attribute("name");
    
    $addressResource = $ownerResource->relationship("address")->resource();
    $owner->address = new stdClass();
    $owner->address->city = $addressResource->attribute("city");
    $owner->address->addressLine = $addressResource->attribute("city");

    $dog->owners[] = $owner;
}

This is the situation when using a hydrator can help you. Currently, Yang has only one hydrator, the ClassHydrator which - if the response was successful - maps the specified document to an stdClass along with all the resource attributes and relationships. It means that errors, links, meta data won't be present in the returned object! However, relationships are very easy to access now.

Let's use the document from the last example for demonstrating the power of hydrators:

$hydrator = new ClassHydrator();
$dog = $hydrator->hydrate($response->document());

That's all you need to do in order to create the same $dog object as in the first example! Now, you can display its properties:

echo "Dog:\n";
echo "Name : " . $dog->name . "\n";
echo "Breed: " . $dog->breed->name . "\n\n";

echo "Owners:\n";
foreach ($dog->owners as $owner) {
    echo "Name   : " . $dog->owner->name . "\n";
    echo "Address: " . $dog->owner->address->city . ", " . $dog->owner->address->addressLine . "\n";
    echo "------------------\n";
}

Note: The method ClassHydrator::hydrate() returns an empty stdClass if the document doesn't have any primary data, it returns an stdClass if the document has a single primary resource, and it returns an array of stdObjects if the document contains multiple primary resources.

You may also use the ClassHydrator::hydrateCollection() method for retrieving many dogs:

$hydrator = new ClassHydrator();
$dogs = $hydrator->hydrateCollection($response->document());

Note: The method ClassHydrator::hydrateCollection() returns an empty array if the document doesn't have any primary data, it returns an array with only one stdClass if the document has a single primary resource, and it returns an array of stdObjects if the document contains multiple primary resources.

Advanced Usage

Custom serialization

Sometimes you might need to be tricky, and customly serialize a request body. For example if you dispatch a server request internally (within the original request), then you can send the request body as an array thanks to this feature - so you don't need to serialize at client-side and then deserialize at server-size. If you use Woohoo Labs. Yin and a custom deserializer at server-side, then this is an easy task to do.

At client-side, if you use Yang with the Request Builder, then you only have to pass a second constructor argument to it like below:

// Instantiate a PSR-7 request
$request = new Request();

// Instantiate your custom serializer
$mySerializer = new MyCustomSerializer();

// Instantiate the request builder with a custom serializer
$requestBuilder = new JsonApiRequestBuilder($request, $mySerializer);

You only have to make sure that your custom serializer implements the SerializerInterface.

Custom deserialization

Sometimes you might need to be tricky, and customly deserialize a server response. For example if you dispatch a server request internally (within the original request), then you can receive the response body as an array thanks to this feature - so you don't need to serialize at server-side and then deserialize at client-size. If you use Woohoo Labs. Yin and a custom serializer at server-side, then this is an easy task to do.

At client-side, if you use Yang with the default HTTP Clients then you only have to pass a second constructor argument to them like below:

use Http\Adapter\Guzzle6\Client;

// Instantiate the Guzzle HTTP Client
$guzzleClient = Client::createWithConfig([]);

// Instantiate your custom deserializer
$myDeserializer = new MyCustomDeserializer();

// Instantiate the syncronous JSON:API Client with a custom deserializer
$syncClient = new JsonApiClient($guzzleClient, $myDeserializer);

// Instantiate the asyncronous JSON:API Client with a custom deserializer
$asyncClient = new JsonApiAsyncClient($guzzleClient, $myDeserializer);

Otherwise pass your deserializer to the JsonApiResponse as its second argument like below:

// Instantiate a JSON:API response from a PSR-7 response with a custom deserializer
$response = new JsonApiResponse($psr7Response, new MyCustomDeserializer());

You only have to make sure that your custom deserializer implements the DeserializerInterface.

Examples

Have a look at the examples directory for a really basic example.

Versioning

This library follows SemVer v2.0.0.

Change Log

Please see CHANGELOG for more information what has changed recently.

Testing

Woohoo Labs. Yang has a PHPUnit test suite. To run the tests, run the following command from the project folder after you have copied phpunit.xml.dist to phpunit.xml:

$ phpunit

Additionally, you may run docker-compose up in order to execute the tests.

Contributing

Please see CONTRIBUTING for details.

Support

Please see SUPPORT for details.

Credits

License

The MIT License (MIT). Please see the License File for more information.