---
title: "HTML Link (PSR-13)"
version: "4.2"
---

> Documentation Index
> Fetch the complete documentation index at: https://docs.phalcon.io/llms.txt
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# HTML Link (PSR-13)

## Overview
[Phalcon\Html\Link\EvolvableLink][html-link-evolvablelink], [Phalcon\Html\Link\EvolvableLinkProvider][html-link-evolvablelinkprovider], [Phalcon\Html\Link\Link][html-link-link] and [Phalcon\Html\Link\LinkProvider][html-link-linkprovider] are classes that implement the interfaces as defined by [PHP-FIG][php-fig].

![](/assets/images/implements-psr--13-blue.svg)

These components aid in creating Link objects as defined by the [PSR-13][psr-13] standard.

:::info[NOTE]
This component does not generate any HTML links. It just stores the links and offers methods as defined by the [PSR-13][psr-13] standard. You will need to create your own serializers that will parse these objects and generate the necessary output. The [Phalcon\Html\Link\Serializer\Header][html-link-serializer-header] serializer is available for you to use.
:::

## Link
The [Phalcon\Html\Link\Link][html-link-link] is used to create a link and assign attributes to it upon construction.

```php
<?php

use Phalcon\Html\Link\Link;

$href       = 'https://dev.phalcon.ld';
$attributes = [
'one'   => true,
'two'   => 123,
'three' => 'four',
'five'  => [
    'six',
    'seven',
],
];

$link = new Link('payment', $href, $attributes);
```

## LinkProvider
The [Phalcon\Html\Link\LinkProvider][html-link-linkprovider] is used as a container of [Phalcon\Html\Link\Link][html-link-link] objects. You can add them in the provider and then access them as a whole or retrieve them by `rel`.

```php
<?php

use Phalcon\Html\Link\Link;
use Phalcon\Html\Link\LinkProvider;

$links = [
new Link('canonical', 'https://dev.phalcon.ld'),
new Link('cite-as', 'https://test.phalcon.ld'),
];
$link  = new LinkProvider($links);

var_dump(
$link->getLinksByRel('cite-as')
);

// [
//     Link('cite-as', 'https://test.phalcon.ld'),
// ]
```

## EvolvableLink
Link objects are immutable. However, there is a need to manipulate them based on your application needs. The [Phalcon\Html\Link\EvolvableLink][html-link-evolvablelink] is available, allowing you to manipulate the link.

```php
<?php

use Phalcon\Html\Link\EvolvableLink;

$href       = 'https://dev.phalcon.ld';
$attributes = ['one' => true];

$link = new EvolvableLink('payment', $href, $attributes);

$newInstance = $link->withAttribute('two', 'three');

var_dump(
$newInstance->getAttributes()
);

//  [
//      'one' => true,
//      'two' => 'three',
//  ];
```

## EvolvableLinkProvider
The [Phalcon\Html\Link\LinkProvider][html-link-linkprovider] is used as a container of [Phalcon\Html\Link\EvolvableLink][html-link-evolvablelink] objects. You can add them in the provider and then access them as a whole or retrieve them by `rel`.

```php
<?php

use Phalcon\Html\Link\EvolvableLink;
use Phalcon\Html\Link\EvolvableLinkProvider;

$links = [
new Link('canonical', 'https://dev.phalcon.ld'),
new Link('cite-as', 'https://test.phalcon.ld'),
];
$link  = new EvolvableLinkProvider($links);

var_dump(
$link->getLinksByRel('cite-as')
);

// [
//     Link('cite-as', 'https://test.phalcon.ld'),
// ]
```

## Serializers
### Header
You can use a serializer to parse the `Phalcon\Html\Links` objects and create the necessary headers. Phalcon comes with the [Phalcon\Html\Link\Serializer\Header][html-link-serializer-header] serializer, to help with the task of serializing links for the headers:

```php
<?php

use Phalcon\Html\Link\EvolvableLink;
use Phalcon\Html\Link\Serializer\Header;

$serializer = new Header();

$link = new EvolvableLink('prefetch', '/images/apple-icon-114.png');

echo $serializer->serialize([$link]);
// </images/apple-icon-114.png>; rel="prefetch"';

$links = [
(new EvolvableLink('preload', '/1'))
    ->withAttribute('as', 'image')
    ->withAttribute('nopush', true),
(new EvolvableLink('alternate', '/2'))
    ->withRel('next')
    ->withAttribute('hreflang', ['en', 'es'])
];

echo $serializer->serialize([$link]);
// </1>; rel="preload"; as="image"; nopush,
//     </2>; rel="alternate next"; hreflang="en"; hreflang="es"
;
```

### Custom
You can create your own serializers for relevant links by extending the [Phalcon\Html\Link\Serializer\SerializerInterface][html-link-serializer-serializerinterface]

```php
<?php

namespace MyApp\Html\Serializers;

use Phalcon\Html\Link\Serializer\SerializerInterface;

class Custom implements SerializerInterface 
{
public function serialize(array $links): ?string
{
    // ....
}
}
```

[php-fig]: https://www.php-fig.org/
[psr-13]: https://www.php-fig.org/psr/psr-13/
[html-link-evolvablelink]: /4.2/api/phalcon_html/#html-link-evolvablelink
[html-link-evolvablelinkprovider]: /4.2/api/phalcon_html/#html-link-evolvablelinkprovider
[html-link-link]: /4.2/api/phalcon_html/#html-link-link
[html-link-linkprovider]: /4.2/api/phalcon_html/#html-link-linkprovider
[html-link-serializer-header]: /4.2/api/phalcon_html/#html-link-serializer-header
[html-link-serializer-serializerinterface]: /4.2/api/phalcon_html/#html-link-serializer-serializerinterface

Source: https://docs.phalcon.io/4.2/html-link/index.mdx