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ext-direct

A base component to integrate Sencha Ext JS Ext.direct into a PHP application

Introduction

This library provides a server-side implementation for Sencha Ext.direct an RPC-style communication component that is part of Sencha's Ext JS and Sencha Touch.

Ext Direct is a platform and language agnostic remote procedure call (RPC) protocol. Ext Direct allows for seamless communication between the client side of an Ext JS application and any server platform that conforms to the specification. Ext Direct is stateless and lightweight, supporting features like API discovery, call batching, and server to client events.

Currently this library is only used as the foundation of teqneers/ext-direct-bundle, a Symfony bundle that integrates * Ext.direct* into a Symfony based application. We have not tried to use the library as a stand-alone component or in any other context than a Symfony environment, so the following is only how it should work theoretically without the bundle. We'd appreciate any help and contribution to make the library more useful outside the bundle.

Installation

You can install this library using composer

composer require teqneers/ext-direct

or add the package to your composer.json file directly.

Example

The naming strategy determins how PHP class names and namespaces are translated into Javascript-compatible Ext.direct action names. The default naming strategy translates the \ namspapce separator into a .. So My\Namespace\Service is translated into My.namespace.Service. Please note that the transformation must be reversible (My.namespace.Service => My\Namespace\Service).

$namingStrategy = new TQ\ExtDirect\Service\DefaultNamingStrategy();

The service registry uses a metadata factory from the jms/metadata library and an associated annotation driver (which in turn uses a doctrine/annotations annotation reader) to read meta information about possible annotated service classes.

$serviceRegistry = new TQ\ExtDirect\Service\DefaultServiceRegistry(
    new Metadata\MetadataFactory(
        new TQ\ExtDirect\Metadata\Driver\AnnotationDriver(
            new Doctrine\Common\Annotations\AnnotationReader()
        )
    ),
    $namingStrategy
);

The service registry can be filled manually by calling addServices() or addService() or by importing services using a TQ\ExtDirect\Service\ServiceLoader. The default implementation \TQ\ExtDirect\Service\PathServiceLoader can read classes from a set of given paths.

The event dispatcher is optional but is required to use features like argument conversion and validation, result conversion of the profiling listener.

$eventDispatcher = new Symfony\Component\EventDispatcher\EventDispatcher();

The router is used to translate incoming Ext.direct requests into PHP method calls to the correct service class. The ContainerServiceFactory supports retrieving services from a Symfony dependency injection container or instantiating simple services which take no constructor arguments at all. Static service calls bypass the service factory.

$router = new TQ\ExtDirect\Router\Router(
    new TQ\ExtDirect\Router\ServiceResolver(
        $serviceRegistry,
        new TQ\ExtDirect\Service\ContainerServiceFactory(
            /* a Symfony\Component\DependencyInjection\ContainerInterface */
        )
    ),
    $eventDispatcher
);

The endpoint object is a facade in front of all the Ext.direct server-side components. With its createServiceDescription() method one can obtain a standard-compliant API- description while handleRequest() takes a Symfony\Component\HttpFoundation\Request and returns a Symfony\Component\HttpFoundation\Response which contains the Ext.direct response for the service calls received.

$endpoint = TQ\ExtDirect\Service\Endpoint(
    'default', // endpoint id
    new TQ\ExtDirect\Description\ServiceDescriptionFactory(
        $serviceRegistry,
        'My.api',
        $router,
        new TQ\ExtDirect\Router\RequestFactory(),
        'My.api.REMOTING_API'
    )
);

The endpoint manager is just a simple collection of endpoints which allow retrieval using the endpoint id. This allows easy exposure of multiple independent APIs.

$manager = new TQ\ExtDirect\Service\EndpointManager();
$manager->addEndpoint($endpoint);
$defaultEndpoint = $manager->getEndpoint('default');

$apiResponse = $defaultEndpoint->createServiceDescription('/path/to/router');
$apiResponse->send();

$request = Symfony\Component\HttpFoundation\Request::createFromGlobals();
$response = $defaultEndpoint->handleRequest($request);
$response->send();

The routing process can be manipulated and augmented by using event listeners on the event dispatcher passed into the router. The library provides four event subscribers that allow

• converting arguments prior to calling the service method
• validation of arguments prior to calling the service method
• converting the service method call result before sending it back to the client
• instrumenting the router to gain timing information (used to augment the Symfony profiler timeline)

The shipped argument and result converters use the jms/serializer library to provide extended (de-)serialization capabilities, while the default argument validator makes use of the symfony/validator library.

$eventDispatcher->addSubscriber(
    new TQ\ExtDirect\Router\EventListener\ArgumentConversionListener(
        new TQ\ExtDirect\Router\ArgumentConverter(/* a JMS\Serializer\Serializer */)
    )
);
$eventDispatcher->addSubscriber(
    new TQ\ExtDirect\Router\EventListener\ArgumentValidationListener(
        new TQ\ExtDirect\Router\ArgumentValidator(/* a Symfony\Component\Validator\Validator\ValidatorInterface */)
    )
);
$eventDispatcher->addSubscriber(
    new TQ\ExtDirect\Router\EventListener\ResultConversionListener(
        new TQ\ExtDirect\Router\ResultConverter(/* a JMS\Serializer\Serializer */)
    )
);
$eventDispatcher->addSubscriber(
    new TQ\ExtDirect\Router\EventListener\StopwatchListener(
        /* a Symfony\Component\Stopwatch\Stopwatch */
    )
);

Service Annotations

Services to be exposed via the Ext.direct API must be decorated with appropriate meta information. Currently this is only possible using annotations (like the ones known from Doctrine, Symfony or other modern PHP libraries).

Each service class that will be exposed as an Ext.direct action is required to be annotated with TQ\ExtDirect\Annotation\Action. The Action annotation optionally takes a service id parameter for services that are neither static nor can be instantiated with a parameter-less constructor.

use TQ\ExtDirect\Annotation as Direct;

/**
 * @Direct\Action()
 */
class Service1
{
    // service will be instantiated using the parameter-less constructor if called method is not static
}

/**
 * @Direct\Action("app.direct.service2")
 */
class Service2
{
    // service will be retrieved from the dependency injection container using id "app.direct.service2" if called method is not static
}

Additionally each method that ill be exposed on an Ext.direct action is required to be annotated with TQ\ExtDirect\Annotation\Method. The Method annotation optionally takes either true to designate the method as being a form handler (taking regular form posts) or false to designate the method as being a regular Ext.direct method (this is the default).

/**
 * @Direct\Action("app.direct.service3")
 */
class Service3
{
    /**
     * @Direct\Method()
     */
    public function methodA()
    {
        // regular method
    }

    /**
     * @Direct\Method(true)
     */
    public function methodB()
    {
        // form handler method
    }
}

Extended features such as named parameters and strict named parameters described the in the Ext.direct specification are currently not exposed through the annotation system.

Parameters that go into a method that is being called via an Ext.direct request can be annotated as well to apply parameter validation. This requires that the TQ\ExtDirect\Router\EventListener\ArgumentValidationListener is registered with the appropriate event dispatcher.

use Symfony\Component\Validator\Constraints as Assert;

/**
 * @Direct\Action("app.direct.service4")
 */
class Service4
{
    /**
     * @Direct\Method()
     * @Direct\Parameter("a", { @Assert\NotNull(), @Assert\Type("int") })
     *
     * @param int $a
     */
    public function methodA($a)
    {
    }
}

If the signature of the method being called exposes parameter(s) with a type-hint for Symfony\Component\HttpFoundation\Request and/or TQ\ExtDirect\Router\Request, the incoming Symfony HTTP request and/or the raw Ext.direct request are injected into the method call automatically. This is especially important form form handling methods because there is no other way to access the incoming HTTP request parameters (form post).

As soon as the TQ\ExtDirect\Router\EventListener\ArgumentConversionListener is enabled, one can use strictly-typed object parameters on service methods. These arguments will be automatically deserialized from the incoming JSON request and will be injected into the method call.

The same is true for returning objects from a service method call. If the TQ\ExtDirect\Router\EventListener\ResultConversionListener is enabled, return values are automatically serialized to JSON even if they are non-trivial objects.

Both the argument as well as the return value conversion is based on the excellent jms/serializer library by Johannes Schmitt. See the documentation for more information.

Specification

The Ext Direct Specification can be found on Sencha's documentation website.

License

The MIT License (MIT)

Copyright (c) 2015 TEQneers GmbH & Co. KG

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.