Add link_names to Slack Notification

SlackMessage.php

<?php

namespace Illuminate\Notifications\Messages;

use Closure;

class SlackMessage
{
    /**
     * The "level" of the notification (info, success, warning, error).
     *
     * @var string
     */
    public $level = 'info';

    /**
     * The username to send the message from.
     *
     * @var string|null
     */
    public $username;

    /**
     * The user emoji icon for the message.
     *
     * @var string|null
     */
    public $icon;

    /**
     * The user image icon for the message.
     *
     * @var string|null
     */
    public $image;

    /**
     * The channel to send the message on.
     *
     * @var string|null
     */
    public $channel;

    /**
     * The text content of the message.
     *
     * @var string
     */
    public $content;
  
    /**
     * Linkify channel names and usernames.
     *
     * @var bool
     */
    public $linkNames = 0;

    /**
     * The message's attachments.
     *
     * @var array
     */
    public $attachments = [];

    /**
     * Additional request options for the Guzzle HTTP client.
     *
     * @var array
     */
    public $http = [];

    /**
     * Indicate that the notification gives information about a successful operation.
     *
     * @return $this
     */
    public function success()
    {
        $this->level = 'success';

        return $this;
    }

    /**
     * Indicate that the notification gives information about a warning.
     *
     * @return $this
     */
    public function warning()
    {
        $this->level = 'warning';

        return $this;
    }

    /**
     * Indicate that the notification gives information about an error.
     *
     * @return $this
     */
    public function error()
    {
        $this->level = 'error';

        return $this;
    }

    /**
     * Set a custom username and optional emoji icon for the Slack message.
     *
     * @param  string  $username
     * @param  string|null  $icon
     * @return $this
     */
    public function from($username, $icon = null)
    {
        $this->username = $username;

        if (! is_null($icon)) {
            $this->icon = $icon;
        }

        return $this;
    }

    /**
     * Set a custom image icon the message should use.
     *
     * @param  string $channel
     * @return $this
     */
    public function image($image)
    {
        $this->image = $image;

        return $this;
    }

    /**
     * Set the Slack channel the message should be sent to.
     *
     * @param  string $channel
     * @return $this
     */
    public function to($channel)
    {
        $this->channel = $channel;

        return $this;
    }

    /**
     * Set the content of the Slack message.
     *
     * @param  string  $content
     * @return $this
     */
    public function content($content)
    {
        $this->content = $content;

        return $this;
    }
  
    /**
     * Linkify channel names and usernames.
     *
     * @return $this
     */
    public function linkNames()
    {
        $this->linkNames = 1;

        return $this;
    }

    /**
     * Define an attachment for the message.
     *
     * @param  \Closure  $callback
     * @return $this
     */
    public function attachment(Closure $callback)
    {
        $this->attachments[] = $attachment = new SlackAttachment;

        $callback($attachment);

        return $this;
    }

    /**
     * Get the color for the message.
     *
     * @return string
     */
    public function color()
    {
        switch ($this->level) {
            case 'success':
                return 'good';
            case 'error':
                return 'danger';
            case 'warning':
                return 'warning';
        }
    }

    /**
     * Set additional request options for the Guzzle HTTP client.
     *
     * @param  array  $options
     * @return $this
     */
    public function http(array $options)
    {
        $this->http = $options;

        return $this;
    }
}

SlackWebhookChannel.php

<?php

namespace Illuminate\Notifications\Channels;

use GuzzleHttp\Client as HttpClient;
use Illuminate\Notifications\Notification;
use Illuminate\Notifications\Messages\SlackMessage;
use Illuminate\Notifications\Messages\SlackAttachment;
use Illuminate\Notifications\Messages\SlackAttachmentField;

class SlackWebhookChannel
{
    /**
     * The HTTP client instance.
     *
     * @var \GuzzleHttp\Client
     */
    protected $http;

    /**
     * Create a new Slack channel instance.
     *
     * @param  \GuzzleHttp\Client  $http
     * @return void
     */
    public function __construct(HttpClient $http)
    {
        $this->http = $http;
    }

    /**
     * Send the given notification.
     *
     * @param  mixed  $notifiable
     * @param  \Illuminate\Notifications\Notification  $notification
     * @return \Psr\Http\Message\ResponseInterface
     */
    public function send($notifiable, Notification $notification)
    {
        if (! $url = $notifiable->routeNotificationFor('slack')) {
            return;
        }

        $this->http->post($url, $this->buildJsonPayload(
            $notification->toSlack($notifiable)
        ));
    }

    /**
     * Build up a JSON payload for the Slack webhook.
     *
     * @param  \Illuminate\Notifications\Messages\SlackMessage  $message
     * @return array
     */
    protected function buildJsonPayload(SlackMessage $message)
    {
        $optionalFields = array_filter([
            'username' => data_get($message, 'username'),
            'icon_emoji' => data_get($message, 'icon'),
            'icon_url' => data_get($message, 'image'),
            'channel' => data_get($message, 'channel'),
            'link_names' => data_get($message, 'linkNames'),
        ]);

        return array_merge([
            'json' => array_merge([
                'text' => $message->content,
                'attachments' => $this->attachments($message),
            ], $optionalFields),
        ], $message->http);
    }

    /**
     * Format the message's attachments.
     *
     * @param  \Illuminate\Notifications\Messages\SlackMessage  $message
     * @return array
     */
    protected function attachments(SlackMessage $message)
    {
        return collect($message->attachments)->map(function ($attachment) use ($message) {
            return array_filter([
                'color' => $attachment->color ?: $message->color(),
                'fallback' => $attachment->fallback,
                'fields' => $this->fields($attachment),
                'footer' => $attachment->footer,
                'footer_icon' => $attachment->footerIcon,
                'image_url' => $attachment->imageUrl,
                'mrkdwn_in' => $attachment->markdown,
                'text' => $attachment->content,
                'title' => $attachment->title,
                'title_link' => $attachment->url,
                'ts' => $attachment->timestamp,
            ]);
        })->all();
    }

    /**
     * Format the attachment's fields.
     *
     * @param  \Illuminate\Notifications\Messages\SlackAttachment  $attachment
     * @return array
     */
    protected function fields(SlackAttachment $attachment)
    {
        return collect($attachment->fields)->map(function ($value, $key) {
            if ($value instanceof SlackAttachmentField) {
                return $value->toArray();
            }

            return ['title' => $key, 'value' => $value, 'short' => true];
        })->values()->all();
    }
}