Google Maps Sign URL

google-sign.php

#!/usr/bin/env php
<?php

/**
 * @see https://github.com/geocoder-php/Geocoder/blob/21e562a5ad595c6fee7a33ae90e0b42dc8866c23/src/Geocoder/Provider/GoogleMapsBusinessProvider.php#L82
 */
function signQuery($query, $privateKey)
{
    $url = parse_url($query);

    $urlPartToSign = $url['path'].'?'.$url['query'];

    // Decode the private key into its binary format
    $decodedKey = base64_decode(str_replace(array('-', '_'), array('+', '/'), $privateKey));

    // Create a signature using the private key and the URL-encoded
    // string using HMAC SHA1. This signature will be binary.
    $signature = hash_hmac('sha1', $urlPartToSign, $decodedKey, true);

    $encodedSignature = str_replace(array('+', '/'), array('-', '_'), base64_encode($signature));

    return sprintf('%s&signature=%s', $query, $encodedSignature);
}

$argv = $_SERVER['argv'];
$basename = $argv[0];
$usage = <<<USAGE
Usage: $basename <url> <private-key>
USAGE;

if (count($argv) < 3) {
    echo $usage.PHP_EOL;
    exit(1);
}

echo signQuery($argv[1], $argv[2]).PHP_EOL;