functional_status_codes 2.1.0

This package offers a functional approach to handling HTTP status codes.

example/lib/main.dart

// ignore_for_file: avoid_print, avoid-unused-parameters, prefer-static-class

import 'dart:convert' as convert;

import 'package:functional_status_codes/functional_status_codes.dart';
import 'package:http/http.dart' as http;

Future<int?> main(List<String> args, [http.Client? client]) =>
    args.join().contains('simple') ? _simple(args) : _realClient(args, client);

/// Run with `dart run lib/main.dart --simple` command from the example folder.
Future<int?> _simple(List<String> args) async {
  /// Checks if status code is >=200 & <299.
  print(105.isSuccess); // Prints false.
  print(200.isSuccess); // Prints true.

  /// Prints true in all those cases.
  print(105.isInformational); // Prints true, when status code is >=100 & <199.
  print(300.isRedirection); // Prints true, when status code is >=300 & <399.
  print(404.isClientError); // Prints true, when status code is >=400 & <499.
  print(501.isServerError); // Prints true, when status code is >=500 & <599.

  /// Checks if status code is >=100 & <600.
  print(16.isStatusCode); // Prints false.
  print(160.isStatusCode); // Prints true.

  /// Also with functional style methods like:
  /// - `mapStatusCode`, `maybeMapStatusCode`, `mapToRegisteredStatusCode`,
  /// - `whenStatusCode`, `whenConstStatusCodeOrNull`, `whenConstStatusCode`.
  // Prints 'ok'.
  print(200.maybeMapStatusCode(orElse: (_) => '?', isSuccess: (_) => 'ok'));
  // Prints '?'.
  print(600.whenConstStatusCodeOrNull(isSuccess: () => 'ok') ?? '?');

  /// Any of those `num?` based codes it's possible additionally map to
  /// a registered status code (official and non-official ones).:
  var registeredCode = 160.toRegisteredStatusCode(); // Is null.
  registeredCode = 200.toRegisteredStatusCode(); // Is StatusCode.okHttp200.
  // Handle any type of registered status codes via functional methods:
  registeredCode?.whenOrNull(
    okHttp200: () => print('ok'),
    // Includes all official IAN codes.
    badRequestHttp400: () => print('oh no!'),
    // Includes common unofficial codes too.
    unauthorizedHttp561: () => print('refresh token'),
  );

  /// And much more in the [num?] based extensions and [StatusCode] enum.
  return StatusCode.tryParse(args.join())?.code;
}

Future<int?> _realClient(List<String> arguments, [http.Client? client]) async {
  /// This example uses the Google Books API to search for books about http:
  /// https://developers.google.com/books/docs/overview
  final url =
      Uri.https('www.googleapis.com', '/books/v1/volumes', {'q': '{http}'});

  final httpClient = client ?? http.Client();

  // Await the http get response, then decode the json-formatted response.
  final response = await httpClient.get(url);
  httpClient.close(); // Close the client to release resources.

  // Check if the status code is a valid HTTP status code.
  if (response.statusCode.isStatusCode) {
    // If the status code is a success status code, check if it is a 201
    // (Created) or 200 (OK) code.
    return response.statusCode.maybeWhenStatusCode(
      isSuccess: () {
        // If the status code is success one, convert it to a registered
        // status code object.
        final registeredCode = response.statusCode.toRegisteredStatusCode();

        // Use the [StatusCode] object to determine the specific status code
        // type.
        return registeredCode?.maybeMap(
              createdHttp201: (status) {
                print(
                  'Response has registered success status but not 200 code',
                );

                // Return the status code.
                return status.code;
              },
              okHttp200: (_) {
                // Decode the JSON response.
                final jsonResponse =
                    convert.jsonDecode(response.body) as Map<String, dynamic>;
                // Get the total number of books in the response.
                final itemCount = jsonResponse['totalItems'] as int?;
                print('Number of books about http: $itemCount.');

                // Return the books count.
                return itemCount;
              },
              orElse: () {
                print('Response has success status but not 200 code');

                // Return the status code.
                return response.statusCode;
              },
            ) ??
            // If the status code is not a registered status code, return the
            // status code.
            response.statusCode;
      },
      orElse: () {
        // If the status code is not a success status code, print an error
        // message and return the status code.
        print('Request failed with status: ${response.statusCode}.');

        return response.statusCode;
      },
    );
  }

// If the status code is not a valid HTTP status code, return null.
  return null;
}