actions-test/lib/tools/fetch_wrapper.dart

import 'package:flutter/material.dart';
import 'package:outbag_app/backend/errors.dart';
import 'package:outbag_app/backend/request.dart';
import 'package:outbag_app/tools/snackbar.dart';

void doNetworkRequest(ScaffoldMessengerState? sm,
  {required Future<Response> Function() req,
    Function(Map<String, dynamic> body)? onOK,
    bool Function()? onNetworkErr,
    bool Function()? onUnknownErr,
    Function()? onAnyErr,
    Function()? after,
    bool Function(Map<String, dynamic>)? onServerErr}) async {
  Response res;
  try {
    res = await req();
  } catch (_) {
    // network error
    bool showBar = true;

    if (onNetworkErr != null) {
      showBar = onNetworkErr();
    }

    if (showBar && sm != null) {
      showSimpleSnackbar(sm, text: 'Network Error', action: 'Dismiss');
    }
    if (onAnyErr != null) {
      onAnyErr();
    }
    if (after != null) {
      after();
    }
    return;
  }

  try {
    if (res.res == Result.ok) {
      if (onOK != null) {
        await onOK(res.body);
      }
    } else {
      // server error
      bool showBar = true;

      if (onServerErr != null) {
        showBar = onServerErr(res.body);
      }
      if (showBar && sm != null) {
        showSimpleSnackbar(sm, text: errorAsString(res.body), action: 'OK');
      }
      if (onAnyErr != null) {
        onAnyErr();
      }
    }
  } catch (_) {
    bool showBar = true;

    if (onUnknownErr != null) {
      showBar = onUnknownErr();
    }

    if (showBar && sm != null) {
      showSimpleSnackbar(sm, text: 'Unknown Error', action: 'OK');
    }
  }

  if (after != null) {
    after();
  }
}