How to properly use the hook_insert in Drupal 8 - php

Question

I created a custom module for Drupal 8. I made a hook that is to detect whenever a new node is created, then send a notification to a subscriber. The code I have is this:
<?php
/**
* #file
* Contains onesignal_api.module.
*
*/
use Drupal\Core\Entity\EntityInterface;
/***
* Hook into OneSignal API to send push notifications once a new node is created
*/
function onesignal_api_insert(\Drupal\Core\Entity\EntityInterface $node) {
if($node->isNew()) {
function sendMessage() {
$content = array(
"en" => 'New Node Created'
);
$hashes_array = array();
array_push($hashes_array, array(
"id" => "like-button",
"text" => "Like",
"icon" => "http://i.imgur.com/N8SN8ZS.png",
"url" => "http://push-test/"
));
array_push($hashes_array, array(
"id" => "like-button-2",
"text" => "Like2",
"icon" => "http://i.imgur.com/N8SN8ZS.png",
"url" => "http://push-test/"
));
$fields = array(
'app_id' => "XXXXXXXXX",
'include_player_ids' => array("XXXXXX","XXXXX","XXXXXX"),
'data' => array(
"foo" => "bar"
),
'contents' => $content,
'web_buttons' => $hashes_array
);
$fields = json_encode($fields);
print("\nJSON sent:\n");
print($fields);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "https://onesignal.com/api/v1/notifications");
curl_setopt($ch, CURLOPT_HTTPHEADER, array(
'Content-Type: application/json; charset=utf-8',
'Authorization: Basic XXXXXXX'
));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
curl_setopt($ch, CURLOPT_HEADER, FALSE);
curl_setopt($ch, CURLOPT_POST, TRUE);
curl_setopt($ch, CURLOPT_POSTFIELDS, $fields);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
$response = curl_exec($ch);
curl_close($ch);
return $response;
}
$response = sendMessage();
$return["allresponses"] = $response;
$return = json_encode($return);
$data = json_decode($response, true);
print_r($data);
$id = $data['id'];
print_r($id);
print("\n\nJSON received:\n");
print($return);
print("\n");
}//if Node is new
}//func hook signal
Is there something that I need to change to get this to work? all of the code inside of the if statement works outside of the if statement.

Answer 1

You probably want to implement hook_node_presave.
It acts on a node being created or updated before it is saved to the database :
function onesignal_api_node_presave(\Drupal\Core\Entity\EntityInterface $node) {
if ($node->isNew()) {
// $node is about to be created...
}
}
#see hook_ENTITY_TYPE_presave

Answer 2

Please look below code and add your code as per your requirements.
function onesignal_api_entity_insert(Drupal\Core\Entity\EntityInterface $entity) {
if ($entity->getEntityType()->id() == 'node') {
switch ($entity->bundle()) {
case 'content-type-name': // if multiple entities
}
}
}