MediaTable for CakePHP 3.x for managing media like images on the app.

MediaTable.php

<?php
namespace App\Model\Table;

use App\Model\Entity\Media;
use Cake\ORM\Query;
use Cake\ORM\RulesChecker;
use Cake\ORM\Table;
use Cake\Validation\Validator;
use Cake\Routing\Router;

/**
 * Media Model
 *
 * @property \Cake\ORM\Association\BelongsToMany $Articles
 */
class MediaTable extends Table
{

    /**
     * Initialize method
     *
     * @param array $config The configuration for the Table.
     * @return void
     */
    public function initialize(array $config)
    {
        parent::initialize($config);

        $this->table('media');
        $this->displayField('filename');
        $this->primaryKey('id');

        $this->hasMany('FeaturedArticles', [
            'className' => 'Articles',
            'foreignKey' => 'featured_image',
            'propertyName' => 'featured_articles'
        ]);

        $this->belongsToMany('Articles', [
            'foreignKey' => 'media_id',
            'targetForeignKey' => 'article_id',
            'joinTable' => 'articles_media'
        ]);
    }

    /**
     * Default validation rules.
     *
     * @param \Cake\Validation\Validator $validator Validator instance.
     * @return \Cake\Validation\Validator
     */
    public function validationDefault(Validator $validator)
    {
        $validator
            ->add('id', 'valid', ['rule' => 'numeric'])
            ->allowEmpty('id', 'create');

        $validator
            ->requirePresence('filename', 'create')
            ->notEmpty('filename');

        $validator
            ->allowEmpty('description');

        return $validator;
    }

    protected function saveFile($file)
    {
        if (isset($file['error']) && $file['error'] == 0) {

            $allowedExts = array("gif", "jpeg", "jpg", "png");
            $temp = explode(".", $file["name"]);
            $extension = end($temp);

            if ((($file["type"] == "image/gif")
                    || ($file["type"] == "image/jpeg")
                    || ($file["type"] == "image/jpg")
                    || ($file["type"] == "image/pjpeg")
                    || ($file["type"] == "image/x-png")
                    || ($file["type"] == "image/png"))
                && ($file["size"] < 2000000)
                && in_array($extension, $allowedExts)
            ) {
                if (file_exists(WWW_ROOT . 'img' . DS . $file["name"])) {
                    return null;
                } else {
                    $rand = substr(md5(microtime()), rand(0, 26), 5);
                    move_uploaded_file($file["tmp_name"],
                        WWW_ROOT . 'img' . DS . $rand . '.' . $file["name"]);
                    chmod(WWW_ROOT . 'img' . DS . $rand . '.' . $file["name"], 0777);
                    // Önce veritabanı sorgumuzu hazırlayalım.
                    return $rand . '.' . $file["name"];
                }
            } else {
                return null;
            }
        } elseif (!empty($file)) {
            return $file;
        }
        return null;
    }

    public function beforeDelete($event, $entity, $options)
    {
        @unlink(WWW_ROOT . 'img' . DS . $entity['filename']);
    }

    public function getIdFromFilename($filename)
    {
        $query = $this->find('all', ['conditions' => ['filename' => $filename]]);
        if (!empty($query->first())) {
            return $query->first()->id;
        }
    }

    public function beforeMarshal($event, \ArrayObject $data, \ArrayObject $options)
    {
        $data['filename'] = $this->saveFile($data['filename']);
    }

    public function afterSave($event, $entity, $options)
    {

    }
    // public function beforeSave($event, $entity, $options)
    // {
    //   return false;
    // }
}