Symfony2 Dependency Injection to custom/business classes

1
votes

I didn't find similar questions/solutions Googleing, or on Stackoverflow, so here I am, in need for help. I'm porting a PHP project from a custom framework to the Symfony framework (v2.5) which had it's custom dependency injection (based on class reflection). Many of the business logic classes have injected properties and I'm interested if there's a way to do something similar in Symfony without declaring those classes as services, because some of the classes are used for temporary holding/manipulating content coming from 3rd party endpoints and I need different instances of them.

More precisely is there a way to use Dependency Injection in combination with instantiating objects using the new keyword. So if I needed a new class that's dependent on logger or a validator, how could I do something like this.

Content class that I want to solve dependency injection for:


class Content extends SomeObject
{
    private $pictureUrl;
    ...

    public __construct(array $array = null)
    {
        parent::__construct($array);
    }

    public setPicture(...\Picture $picture)
    {
        // what's the best way to inject/enable this into my class
        $errors = $this->get('validator')->validate($picture->getUrl());
        ...
        $this->pictureUrl = $picture->getUrl();
    }

    ...
}

The class that instantiates the previous class (in this particular case this could be a service, but there are other cases where this is another business logic related class):


class EndpointService extends Service
{
    ...

    public fetchContent()
    {
        $dataArray = $this->endpoint->fetch();
        $contentArray = array();

        foreach ($dataArray as $key => $value) {
            $content = new Content(array());
            $content->setPicture($value->picture);
            ...
            $contentArray[$key] = $content;
        }
    }
    ...
}

Note: If there are logical/syntactical errors please ignore them, this is an example through which I demonstrate my problem, and is a distant abstraction from my code base.

2
phpsymfonydependency-injection

2 Answers

0
votes

I see one way you could do it, by passing the validator depedency to your EndpointService through dependency injection. You could then pass it to the new Content.

class EndpointService extends Service
{
    ...
    public function construct($validator)
    {
        $this->validator = $validator;
    }


    public fetchContent()
    {
        $dataArray = $this->endpoint->fetch();
        $contentArray = array();

        foreach ($dataArray as $key => $value) {
            $content = new Content($this->validator, array());
            $content->setPicture($value->picture);
            ...
            $contentArray[$key] = $content;
        }
    }
    ...
}

class Content extends SomeObject
{
    private $pictureUrl;
    ...

    public __construct($validator, array $array = null)
    {
        $this->validator = $validator;

        parent::__construct($array);
    }

    public setPicture(...\Picture $picture)
    {
        // what's the best way to inject/enable this into my class
        $errors = $this->validator->validate($picture->getUrl());
        ...
        $this->pictureUrl = $picture->getUrl();
    }

    ...
}
0
votes

It looks to me that your Content is a model, and that the validation should be done in the EndpointService class.

You might consider refactoring so that the validator can be injected to the Service parent class that EndpointService inherits from, if you don't want to inject it to the EndpointService directly.

class EndpointService extends Service
{
    protected $validator;

    public __construct(Validator $validator) {
        $this->validator = $validator;
    }

    ...

    public fetchContent()
    {
        $dataArray = $this->endpoint->fetch();
        $contentArray = array();

        foreach ($dataArray as $key => $value) {
            $content = new Content(array());
            $errors = $this->validator->validate($value->picture->getUrl());
            $content->setPicture($value->picture);
            ...
            $contentArray[$key] = $content;
        }
    }

    ...
}

And in your config:

// config.yml
services:
    app.endpoint_service:
        class: Acme\DemoBundle\External\EndpointService
        arguments: [@validator]