public static function verifySignature()

in src/conduit/ConduitClient.php [274:357]
73 lines of code
8 McCabe index (conditional complexity)

  public static function verifySignature(
    $method,
    array $params,
    array $meta,
    $openssl_public_key) {

    $auth_type = idx($meta, 'auth.type');
    switch ($auth_type) {
      case self::AUTH_ASYMMETRIC:
        break;
      default:
        throw new Exception(
          pht(
            'Unable to verify request signature, specified "%s" '.
            '("%s") is unknown.',
            'auth.type',
            $auth_type));
    }

    $public_key = idx($meta, 'auth.key');
    if (!strlen($public_key)) {
      throw new Exception(
        pht(
          'Unable to verify request signature, no "%s" present in '.
          'request protocol information.',
          'auth.key'));
    }

    $signature = idx($meta, 'auth.signature');
    if (!strlen($signature)) {
      throw new Exception(
        pht(
          'Unable to verify request signature, no "%s" present '.
          'in request protocol information.',
          'auth.signature'));
    }

    $prefix = self::SIGNATURE_CONSIGN_1;
    if (strncmp($signature, $prefix, strlen($prefix)) !== 0) {
      throw new Exception(
        pht(
          'Unable to verify request signature, signature format is not '.
          'known.'));
    }
    $signature = substr($signature, strlen($prefix));

    $input = self::encodeRequestDataForSignature(
      $method,
      $params,
      $meta);

    $signature = base64_decode($signature);

    $trap = new PhutilErrorTrap();
      $result = @openssl_verify(
        $input,
        $signature,
        $openssl_public_key);
      $err = $trap->getErrorsAsString();
    $trap->destroy();

    if ($result === 1) {
      // Signature is good.
      return true;
    } else if ($result === 0) {
      // Signature is bad.
      throw new Exception(
        pht(
          'Request signature verification failed: signature is not correct.'));
    } else {
      // Some kind of error.
      if (strlen($err)) {
        throw new Exception(
          pht(
            'OpenSSL encountered an error verifying the request signature: %s',
            $err));
      } else {
        throw new Exception(
          pht(
            'OpenSSL encountered an unknown error verifying the request: %s',
            $err));
      }
    }
  }