Send data to AWS SQS (Simple Queue Service) from Halon MTA (with signature)

sqs.hsl

function signedHeaders($headers) {
  return array_join(array_sort(function ($a, $b) { return $a < $b; }, array_map(function($key) { return str_lower($key); }, array_keys($headers))), ";");
}

function canonicalRequest($method, $uriPath, $queryString, $headers, $signedHeaders, $requestBody) {
  $headersString = array_join(array_sort(function ($a, $b) { return $a < $b; }, array_map(function($key) closure($headers) { return str_lower($key) . ":" . $headers[$key]. "\n"; }, array_keys($headers))));
  $payloadHash = sha2($requestBody, 256);
  return $method . "\n" . $uriPath . "\n" . $queryString . "\n" . $headersString . "\n" . $signedHeaders . "\n" . $payloadHash;
}

function stringToSign($timeStamp, $scope, $canonicalRequest) {
  return "AWS4-HMAC-SHA256\n" . $timeStamp . "\n" . $scope . "\n" . sha2($canonicalRequest, 256);
}

function signingKey($secretAccessKey, $date, $region, $service) {
  $kSecret = $secretAccessKey;
  $kDate = pack("H*", hmac_sha2("AWS4" . $kSecret, $date, 256));
  $kRegion = pack("H*", hmac_sha2($kDate, $region, 256));
  $kService = pack("H*", hmac_sha2($kRegion, $service, 256));
  return pack("H*", hmac_sha2($kService, "aws4_request", 256));
}

function signature($signingKey, $stringToSign) {
  return hmac_sha2($signingKey, $stringToSign, 256);
}

function authorizationHeader($accessKeyID, $scope, $signedHeaders, $signature) {
  return "AWS4-HMAC-SHA256 Credential=" . $accessKeyID . "/" . $scope . ", SignedHeaders=" . $signedHeaders . ", Signature=" . $signature;
}

function makeAWSRequest($method, $hostname, $path, $queryString, $headers, $requestBody, $accessKeyID, $secretAccessKey, $region, $service) {
  $time = time();
  $timeStamp = strftime("%Y%m%dT%H%M%SZ", $time);
  $date = strftime("%Y%m%d", $time);

  $headers["Host"] = $hostname;
  $headers["Content-Type"] = "application/x-www-form-urlencoded";
  $headers["X-Amz-Date"] = $timeStamp;

  $signedHeaders = signedHeaders($headers);

  $requestString = canonicalRequest($method, $path, $queryString, $headers, $signedHeaders, $requestBody);

  $scope = $date . "/" . $region . "/" . $service . "/aws4_request";

  $stringToSign = stringToSign($timeStamp, $scope, $requestString);

  $signingKey = signingKey($secretAccessKey, $date, $region, $service);
  $signature = signature($signingKey, $stringToSign);

  $authorizationHeader = authorizationHeader($accessKeyID, $scope, $signedHeaders, $signature);

  $headers["Authorization"] = $authorizationHeader;

  $url = "https://" . $hostname . $path;

  $headers_for_http = array_map(function($key) closure($headers) { return $key . ": " . $headers[$key];}, array_keys($headers));

  $response = http($url, ["headers" => $headers_for_http, "method" => $method, "extended_result" => true, "tls_verify_peer" => false], $queryString, $requestBody);

  return $response;
}

$region = "XXX";
$service = "sqs";

$host = "sqs." . $region . ".amazonaws.com";
$path = "/ACCOUNT_ID/QUEUE_NAME";
$requestBody = "Action=SendMessage&MessageBody=XXX";

$keyID = "SOME_AWS_ACCESS_KEY_ID";
$secret = "SOME_AWS_SECRET_KEY";

echo makeAWSRequest("POST", $host, $path, "", [], $requestBody, $keyID, $secret, $region, $service);