PHP code failing to authenticate with 23andme API - php

Question

<?php
$client_id = "XXXXXXXXX1";
$client_secret = "XXXXXXXXXX2";
$redirect_URI = "XXXXXXXXX3";
$auth_code = htmlspecialchars($_GET["code"]);
$post_field_array = array(
'client_id' => $client_id,
'client_secret' => $client_secret,
'grant_type' => 'authorization_code',
'code' => $auth_code,
'redirect_uri' => $redirect_uri,
'scope' => 'basic genomes');
$post_fields = '';
foreach ($post_field_array as $key => $value)
$post_fields .= "$key=" . urlencode($value) . '&';
$post_fields = rtrim($post_fields, '&');
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'https://api.23andme.com/token/');
curl_setopt($ch, CURLOPT_POST, count($post_field_array));
curl_setopt($ch, CURLOPT_POSTFIELDS, $post_fields);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
$encoded_json = curl_exec($ch);
$response = json_decode($encoded_json, true);
$access_token = $response['access_token'];
print $access_token;
?>
This script is run from the same URL as $redirect_URI, per the specifications of the 23andMe API (https://api.23andme.com/docs/authentication/). However, no matter what I try, the script simply outputs nothing. What am I doing wrong here?

Answer 1

I do not know why it doesn't work but I would suggest you to do some debugging. Start with
print_r($encoded_json)
(or use var_dump) and see what the output of that might be. Does curl_exec fail?
Try setting the verbose flag to curl and see if that will throw any errors(warnings) that can push you towards the issue
curl_setopt($ch, CURLOPT_VERBOSE, true);

Answer 2

First up, I get these 3 notices,
code doesn't exist unless I pass it on the querystring, redirect_uri has different case in both uses, access_token probably doesn't exist, because an error authenticating occurred
Notice: Undefined index: code in test.php on line 6
Notice: Undefined variable: redirect_uri in test.php on line 13
Notice: Undefined index: access_token in test.php on line 29
<?php
$client_id = "XXXXXXXXX1";
$client_secret = "XXXXXXXXXX2";
$redirect_uri = "XXXXXXXXX3"; // FIXED VARIABLE NAMING HERE
$auth_code = htmlspecialchars($_GET["code"]);
$post_field_array = array(
'client_id' => $client_id,
'client_secret' => $client_secret,
'grant_type' => 'authorization_code',
'code' => $auth_code,
'redirect_uri' => $redirect_uri,
'scope' => 'basic genomes');
$post_fields = '';
foreach ($post_field_array as $key => $value)
$post_fields .= "$key=" . urlencode($value) . '&';
$post_fields = rtrim($post_fields, '&');
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'https://api.23andme.com/token/');
curl_setopt($ch, CURLOPT_POST, count($post_field_array));
curl_setopt($ch, CURLOPT_POSTFIELDS, $post_fields);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
$encoded_json = curl_exec($ch);
$response = json_decode($encoded_json, true);
// DUMP RESPONSE IF ERROR OCCURS, ACCESS WON'T EXIST
var_dump($response);
$access_token = $response['access_token'];
print $access_token;