firebase.php

<?php

    
    /**
     * Firebase Notification Class
     *
     * @category  Firebase FCM Notification
     * @package   FCM
     * @author    Emmanuel O. Sobande <eosobande@gmail.com>
     * @copyright Copyright (c) 2017
     * @link      http://github.com/eosobande/php-firebase-class
     * @version   1.0
     */

    class FCM {

        const CONTENT_JSON = 'application/json';
        const CONTENT_TEXT = 'application/x-www-form-urlencoded;charset=UTF-8';

        const ERROR = 'error';
        const SUCCESS = 'success';
        const FAILURE = 'failure';
        const CANONICAL_IDS = 'canonical_ids';
        const REGISTRATION_ID = 'registration_id';
        const REGISTRATION_IDS = 'registration_ids';
        const RESULTS = 'results';

        const UNAVAILABLE = 'Unavailable';
        const INVALID = 'InvalidRegistration';
        const NOT_REGISTERED = 'NotRegistered';
        const EXCEEDED = 'TopicsMessageRateExceeded';

        private $header;
        private $content_type;
        private $message;
        private $response;
        private $token;
        private $time_to_live;
        private $collapse_key;

        function __construct($content_type, $time_to_live, $collapse_key) {

            $this->content_type = $content_type;
            $this->time_to_live = (int) $time_to_live;
            $this->collapse_key = $collapse_key;
            $this->headers();

        }

        private function headers() {

            $this->headers = [

                'Content-Type:' . $this->content_type,
                'Authorization:key=' . FB_API_KEY

            ];

        }

        public function topics($to, $condition, $body=null, $data=null, $title=null) {

            if ($to != null) {
                $this->message['to'] = '/topics/' . $to;
            } elseif ($condition != null) {
                $this->message['condition'] = $condition;
            }

            $this->message($body, $data, $title);

        }

        public function notification($token, $body, $data=null, $title=null) {
            
            $this->token = $token;
            $this->message[self::REGISTRATION_IDS] = $this->token;
            $this->message($body, $data, $title);

        }

        private function message($body, $data, $title) {

            if ($body != null) {
                $this->message['notification'] = ['title' => $title ? $title : APP_NAME, 'body' => $body];
            }

            if ($data != null) {
                $this->message['data'] = $data;
            }

            if ($this->time_to_live != null) {
                $this->message['time_to_live'] = $this->time_to_live;
            }

            if ($this->collapse_key != null) {
                $this->message['collapse_key'] = $this->collapse_key;
            }
            $this->send();

        }

        private function response() {

            if ((isset($this->response[self::FAILURE]) && $this->response[self::FAILURE] > 0) || 
                (isset($this->response[self::CANONICAL_IDS]) && $this->response[self::CANONICAL_IDS] > 0)) {

                foreach ($this->response[self::RESULTS] as $key => $result) {

                    if (isset($result[self::ERROR])) {

                        switch ($result[self::ERROR]) {

                            case self::UNAVAILABLE:
                                // do something

                                break;

                            case self::INVALID:
                                // do something

                                unset($this->token[$key]);
                                break;

                            case self::NOT_REGISTERED:
                                $this->remove_registration_id($this->token[$key]);
                                unset($this->token[$key]);
                                break;

                            case self::EXCEEDED:
                                // do something
                                break;

                        }

                    } elseif (isset($result[self::REGISTRATION_ID])) {
                        $this->update_registration_id($this->token[$key], $result[self::REGISTRATION_ID]);
                        unset($this->token[$key]);
                    } else {
                        unset($this->token[$key]);
                    }
                }

                $this->send(); // resending     
            }

        }

        private function remove_registration_id($token) {
            // do something
        }

        private function update_registration_id($old, $new) {
            // do something
        }

        private function send() {

            if ($this->message != null) {

                $ch = curl_init();
                curl_setopt_array($ch, [

                    CURLOPT_URL             => FB_URL,
                    CURLOPT_HTTPHEADER      => $this->headers,
                    CURLOPT_POST            => true,
                    CURLOPT_RETURNTRANSFER  => true,
                    CURLOPT_SSL_VERIFYPEER  => false,
                    CURLOPT_POSTFIELDS      => json_encode($this->message)

                ]);

                $this->response = json_decode(curl_exec($ch), true);
                curl_close($ch);
                $this->response();
            }

        }

    }