bitly.php

<?php

const LOGIN = 'o_1233211233';
const API_KEY = 'R_2131233211234232111112223232323232';

function httpGet(string $url) : string
{
  if (false === $result = file_get_contents($url)) {
    throw new RuntimeException('Request failed');
  }
  return $result;
}

function shortURL(string $urlTarget, string $login, string $apiKey) : string
{
  $uri = implode('', [
    'http://api.bit.ly/v3/shorten',
    '?login=' . $login,
    '&apiKey=' . $apiKey,
    '&uri=' . urlencode($urlTarget)
  ]);

  [
    'data' => ['url' => $shortUrl],
    'status_txt' => $status
  ] = json_decode(httpGet($uri), true);

  if ($status !== "OK") {
    throw new RuntimeException($status);
  }

  return $shortUrl;
}

$result = shortURL('https://github.com/gustavonovaes', LOGIN, API_KEY);