static String _findProxyFromEnvironment()

in lib/src/http_impl.dart [2221:2285]
58 lines of code
20 McCabe index (conditional complexity)

  static String _findProxyFromEnvironment(
      Uri url, Map<String, String> environment) {
    checkNoProxy(String option) {
      if (option == null) return null;
      Iterator<String> names = option.split(",").map((s) => s.trim()).iterator;
      while (names.moveNext()) {
        var name = names.current;
        if ((name.startsWith("[") &&
                name.endsWith("]") &&
                "[${url.host}]" == name) ||
            (name.isNotEmpty && url.host.endsWith(name))) {
          return "DIRECT";
        }
      }
      return null;
    }

    checkProxy(String option) {
      if (option == null) return null;
      option = option.trim();
      if (option.isEmpty) return null;
      int pos = option.indexOf("://");
      if (pos >= 0) {
        option = option.substring(pos + 3);
      }
      pos = option.indexOf("/");
      if (pos >= 0) {
        option = option.substring(0, pos);
      }
      // Add default port if no port configured.
      if (option.indexOf("[") == 0) {
        var pos = option.lastIndexOf(":");
        if (option.indexOf("]") > pos) option = "$option:1080";
      } else {
        if (!option.contains(":")) option = "$option:1080";
      }
      return "PROXY $option";
    }

    // Default to using the process current environment.
    environment ??= _platformEnvironmentCache;

    String proxyCfg;

    String noProxy = environment["no_proxy"];
    noProxy ??= environment["NO_PROXY"];
    if ((proxyCfg = checkNoProxy(noProxy)) != null) {
      return proxyCfg;
    }

    if (url.scheme == "http") {
      String proxy = environment["http_proxy"];
      proxy ??= environment["HTTP_PROXY"];
      if ((proxyCfg = checkProxy(proxy)) != null) {
        return proxyCfg;
      }
    } else if (url.scheme == "https") {
      String proxy = environment["https_proxy"];
      proxy ??= environment["HTTPS_PROXY"];
      if ((proxyCfg = checkProxy(proxy)) != null) {
        return proxyCfg;
      }
    }
    return "DIRECT";
  }