Unable to Get Response Header from Php PDO on Google App Engine - php

Question

I am trying to send back the last inserted id after I insert some data into my database. I am successfully entering the data into the database, but there is no response data being sent back. I am using Php PDO and it is hosted on Google App Engine and my headers are set to application/json in the dbconnect.php file. What do I need to add to make it successfully send back response data.
<?php
require('dbconnect.php');
$statement=$con->prepare('INSERT INTO customers (fname, lname) VALUES (:fname,:lname)');
$statement->execute(array(':fname' => $_POST['fname'], ':lname' => $_POST['lname'] ));
$orderId = $statement->lastInsertId();
$json = $json_encode($orderId);
echo $json;
$con = null;
?>

Answer 1

I got Notice: Undefined index: fname and Notice: Undefined index: lname and Fatal error: Call to undefined method PDOStatement::lastInsertId() – Moustache_Me_A_Question 10 mins ago
You have no name attributes for the form elements.
Therefore you need to add them to your elements.
Here is an example form you can base yourself on:
<form action="" method="post">
First name:
<input type="text" name="fname">
<br>
Last name:
<input type="text" name="lname">
<br>
<input type="submit" name="submit" value="Submit">
</form>
That is why you're getting undefined index notices.
$json = $json_encode($orderId); should read as $json = json_encode($orderId); - json_encode() shouldn't be a variable but the function itself.
http://php.net/manual/en/function.json-encode.php
Also:
$orderId = $statement->lastInsertId();
to
$orderId = $con->lastInsertId();
which is why you're getting this message:
Fatal error: Call to undefined method PDOStatement::lastInsertId()
lastInsertId() is a method of the PDO class, not the PDOStatement class.
which I found in Bill Karwin's answer when Googling the error:
https://stackoverflow.com/a/8580768/