<?php

function get_access_token() {

  // OPS API credentials (details at http://documents.epo.org/projects/babylon/eponet.nsf/0/F3ECDCC915C9BCD8C1258060003AA712/$File/ops_v3.2_documentation_-_version_1.3.16_en.pdf)
  $ops_url = $_ENV["OPS_URL"] . '3.2/auth/accesstoken';
  $auth = base64_encode($_ENV["CONSUMER_KEY"] . ":" . $_ENV["CONSUMER_SECRET"]);

  // Set up API call
  $ch = curl_init();
  curl_setopt($ch, CURLOPT_URL, $ops_url);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($ch, CURLOPT_HTTPHEADER, array("Authorization: Basic $auth","Content-Type: application/x-www-form-urlencoded"));
  curl_setopt($ch, CURLOPT_POSTFIELDS, 'grant_type=client_credentials');
  curl_setopt($ch, CURLOPT_POST, true);

  // Give back curl result
  $response = curl_exec($ch);
  curl_close($ch);

  // Turn the API response into useful Json
  $json = json_decode($response);
  $access_token = $json->access_token;

  return $access_token;

}

function get_publication_details($document_reference) {

  $access_token = get_access_token();

  // OPS API credentials (details at http://documents.epo.org/projects/babylon/eponet.nsf/0/F3ECDCC915C9BCD8C1258060003AA712/$File/ops_v3.2_documentation_-_version_1.3.16_en.pdf)
  $ops_url = $_ENV["OPS_URL"] . 'rest-services/published-data/publication/epodoc/' . $document_reference . '/biblio';

  // Set up API call
  $ch = curl_init();
  curl_setopt($ch, CURLOPT_URL, $ops_url);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($ch, CURLOPT_HTTPHEADER, array("Authorization: Bearer $access_token"));

  // Give back curl result
  $response = curl_exec($ch);
  curl_close($ch);

  if (strpos($response,"No results found") === false ) {
    print_r($response);
  }

}

?>