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Using Extractors to Retrieve the Seo Metadata

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Using Extractors to Retrieve the Seo Metadata

Instead of setting every value to the SeoMetadata manually, an extractor can do the work for you. Extractors are executed when the content object implements a specific interface. The method required by that interface will return the value for the specific SEO data. The extractor will then update the SeoMetadata object for the current object with the returned value.

Available Extractors

ExtractorInterface Method Type
DescriptionReadInterface getSeoDescription() Returns the meta description
TitleReadInterface getSeoTitle() Returns the page title
getTitle() If the document has a getTitle() method, it'll be used as the page title
OriginalUrlReadInterface getSeoOriginalUrl() Returns a absolute url object to redirect to or create a canonical link from
OriginalRouteReadInterface getSeoOriginalRoute() Return a Route object to redirect to or create a canonical link from
ExtrasReadInterface getSeoExtras() Returns an associative array using property, http-equiv and name as keys (see below from an example).

Note

The interfaces live in the Symfony\Cmf\Bundle\SeoBundle\Extractor namespace.

An Example

Assume you have an Article object and you want to use both the $title and $date properties as page title and the $intro property as description, you can implement both interfaces and your result will be:

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// src/AppBundle/Document/Article.php
namespace AppBundle\Document;

use Symfony\Cmf\Bundle\SeoBundle\Extractor\TitleReadInterface;
use Symfony\Cmf\Bundle\SeoBundle\Extractor\DescriptionReadInterface;
use Symfony\Cmf\Bundle\SeoBundle\Extractor\ExtrasReadInterface;

class Article implements TitleReadInterface, DescriptionReadInterface, ExtrasReadInterface
{
    protected $title;
    protected $publishDate;
    protected $intro;

    // ...
    public function getSeoTitle()
    {
        return $this->title.' ~ '.date($this->publishDate, 'm-Y');
    }

    public function getSeoDescription()
    {
        return $this->intro;
    }

    public function getSeoExtras()
    {
        return array(
            'property' => array(
                'og:title'       => $this->title,
                'og:description' => $this->description,
            ),
        );
    }
}

Creating Your Own Extractor

To customize the extraction process, you can create your own extractor. Just create a class which implements the SeoExtractorInterface and tag it with cmf_seo.extractor:

  • YAML
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    services:
    extractor.custom:
        class: "AppBundle\Extractor\MyCustomExtractor"
        tags:
            - { name: cmf_seo.extractor }
  • XML
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    <?xml version="1.0" ?>
<container xmlns="http://symfony.com/schema/dic/services"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">
    <services>
        <service id="extractor.custom" class="AppBundle\Extractor\MyCustomExtractor">
            <tag name="cmf_seo.extractor"/>
        </service>
    </services>
</container>
  • PHP
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    $container->register('extractor.custom', 'AppBundle\Extractor\MyCustomExtractor')
    ->addTag('cmf_seo.extractor')
;

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.