ionic - firebase notification using PHP not working - php

Question

I want to push notification to my Ionic 2 app using firebase. I can push notification directly using firebase console, but I want to send it via php file.
when I send I get a response from PHP as: {"message_id":5718309985299480645}
And there is no notification in the phone.
I have placed this.fcm.subscribeToTopic('all') in the app.component.ts constructor.
I dont know what I am doing wrong..
this.fcm.subscribeToTopic('all') is the only code related to fcm in my app.
MY PHP CODE:
<?php
$data = array('title'=>'FCM Push Notifications');
$target = '/topics/mytopic';
//FCM API end-point
$url = 'https://fcm.googleapis.com/fcm/send';
//api_key available in Firebase Console -> Project Settings -> CLOUD MESSAGING -> Server key
$server_key = 'my_server_key_from_firebase';
$fields = array();
$fields['data'] = $data;
if(is_array($target)){
$fields['registration_ids'] = $target;
}else{
$fields['to'] = $target;
}
//header with content_type api key
$headers = array(
'Content-Type:application/json',
'Authorization:key='.$server_key
);
//CURL request to route notification to FCM connection server (provided by Google)
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($fields));
$result = curl_exec($ch);
if ($result === FALSE) {
die('Oops! FCM Send Error: ' . curl_error($ch));
}
curl_close($ch);
echo $result;
?>
I EVEN TRIED PUSHBOTS BUT COULD NOT GET NOTFICATIONS ON THE DEVICE WITH PHP

Answer 1

I solved the problem by looking at fcm docs.
I changed the PHP file to:
$data = array('title'=>'Title of the notification', 'body'=>$msg, 'sound'=>'default');
$target = '/topics/notetoall';
$url = 'https://fcm.googleapis.com/fcm/send';
$server_key = 'my_server_api_key_from_firebase';
$fields = array();
$fields['notification'] = $data; // <-- this is what I changed from $fields['body']
if(is_array($target)){
$fields['registration_ids'] = $target;
}else{
$fields['to'] = $target;
}

Answer 2

All plugins must be called after the device ready, specially if they're beeing used in app.components (in some pages, that are not the first one, it can be used inside constructor since the app is already ready and plugins are loaded).
So subscribe to a topic on device ready
this.platform.ready().then(() => {
this.fcm.subscribeToTopic('all')
});
Hope this helps.