export function tryGetMatchingRoute()

in src/msha/routes-engine/rules/routes.ts [112:166]
43 lines of code
10 McCabe index (conditional complexity)

export function tryGetMatchingRoute(req: http.IncomingMessage, userConfig: SWAConfigFile | undefined) {
  const host = `${SWA_CLI_APP_PROTOCOL}://${req?.headers?.host}`;
  const sanitizedUrl = new URL(req.url!, host);
  const requestPathFileExtension = path.extname(sanitizedUrl.toString());
  const isFileRequest = !!requestPathFileExtension;
  const requestMethod = req.method;
  const isLegacyConfigFile = userConfig?.isLegacyConfigFile;

  if (userConfig?.routes?.length === 0) {
    return;
  }

  let routeDef: SWAConfigFileRoute | undefined = undefined;

  for (let i = 0; i < userConfig?.routes?.length!; i++) {
    routeDef = userConfig?.routes[i];
    let route = routeDef?.route;

    if (!route) {
      // this is an invalid route, ignore it
      continue;
    }

    const isMatchingRoute = isLegacyConfigFile
      ? doesRequestPathMatchLegacyRoute(sanitizedUrl.pathname, routeDef, isAuthRequest(req), isFileRequest)
      : doesRequestPathMatchRoute(
          sanitizedUrl.pathname,
          routeDef,
          requestMethod,
          routeDef?.methods,
          AUTH_STATUS.NoAuth /* TODO get the right auth status */
        );

    if (isMatchingRoute) {
      // if the rule isn't a redirect rule, no need to check for circular redirect
      if (!routeDef?.redirect) {
        return routeDef;
      }

      // this rule will result in an infinite redirect loop so keep searching for another rule
      const redirectUrl = new URL(routeDef.redirect || "/", host);
      if (sanitizedUrl.toString() === redirectUrl.pathname || sanitizedUrl.toString() === redirectUrl.toString()) {
        continue;
      }

      routeDef = {
        ...routeDef,
        redirect: redirectUrl.toString(),
      };
      return routeDef;
    }
  }

  return;
}