Github Search example

import 'dart:async';
import 'dart:convert';

import 'package:github_search/models/models.dart';
import 'package:http/http.dart' as http;

class GithubClient {
  GithubClient({
    http.Client? httpClient,
    this.baseUrl = 'https://api.github.com/search/repositories?q=',
  }) : httpClient = httpClient ?? http.Client();

  final String baseUrl;
  final http.Client httpClient;

  Future<SearchResult> search(String term) async {
    final response = await httpClient.get(Uri.parse('$baseUrl$term'));
    final results = json.decode(response.body) as Map<String, dynamic>;

    if (response.statusCode == 200) {
      return SearchResult.fromJson(results);
    } else {
      throw SearchResultError.fromJson(results);
    }
  }
}

import 'package:meta/meta.dart';

/// Provides an inmemory cache used to avoid repeating an async callback within a
/// certain [duration]
@immutable
class InMemoryCache<T> {
  InMemoryCache(this.duration);

  final Duration duration;
  final Map<Object, _CacheEntry<T>?> _cache = {};

  void _cacheValue(T value, Object key) {
    _cache[key] = _CacheEntry(
      timestamp: DateTime.now(),
      data: value,
    );
  }

  /// Returns a cached value from a previous call to [fetch], or runs [callback]
  /// to compute a new one.
  ///
  /// If [fetch] has been called recently enough, returns its previous return
  /// value. Otherwise, runs [callback] and returns its new return value.
  Future<T> fetch(
    Future<T> Function() callback, {
    String? key,
  }) async {
    final effectiveKey = key ?? callback;
    final entry = _cache[effectiveKey];

    Future<T> fetchAndCache() async {
      final value = await callback();
      _cacheValue(value, effectiveKey);
      return value;
    }

    if (entry == null) {
      return fetchAndCache();
    } else {
      final now = DateTime.now();
      final difference = now.difference(entry.timestamp);
      if (difference > duration) {
        return fetchAndCache();
      }
    }

    return entry.data;
  }
}

class _CacheEntry<T> {
  _CacheEntry({
    required this.timestamp,
    required this.data,
  });

  final DateTime timestamp;
  final T data;
}

import 'package:github_search/models/models.dart';
import 'package:github_search/service/client.dart';
import 'package:github_search/service/in_memory_cache.dart';

class GithubRepository {
  GithubRepository({
    required this.client,
    required this.cache,
  });

  final InMemoryCache cache;
  final GithubClient client;

  Future<SearchResult> search(String term) async {
    return await cache.fetch(() => client.search(term));
  }
}

import 'package:flutter_solidart/flutter_solidart.dart';
import 'package:github_search/models/models.dart';
import 'package:github_search/repo/repository.dart';
import 'package:github_search/service/client.dart';
import 'package:github_search/service/in_memory_cache.dart';

import 'package:meta/meta.dart';

@immutable
class GithubSearchBloc {
  GithubSearchBloc({GithubRepository? repository})
      : _repository = repository ??
            GithubRepository(
              client: GithubClient(),
              cache: InMemoryCache(const Duration(minutes: 5)),
            );

  final GithubRepository _repository;

  final _searchTerm = Signal('');
  late final searchResult =
      Resource(fetcher: _search, source: _searchTerm);

  void search(String term) => _searchTerm.set(term);

  Future<SearchResult> _search() async {
    if (_searchTerm().isEmpty) return SearchResult.empty();
    return _repository.search(_searchTerm());
  }

  void dispose() {
    _searchTerm.dispose();
    searchResult.dispose();
  }
}

class SearchPage extends StatelessWidget {
  const SearchPage({super.key});

  @override
  Widget build(BuildContext context) {
    return Solid(
      providers: [
        Provider<GithubSearchBloc>(
          create: () => GithubSearchBloc(),
          dispose: (bloc) => bloc.dispose(),
        ),
      ],
      child: const SearchPageBody(),
    );
  }
}

class _SearchBar extends StatefulWidget {
  // ignore: unused_element
  const _SearchBar({super.key});

  @override
  State<_SearchBar> createState() => __SearchBarState();
}

class __SearchBarState extends State<_SearchBar> {
  final textController = TextEditingController();
  late final bloc = context.get<GithubSearchBloc>();

  @override
  void dispose() {
    textController.dispose();
    super.dispose();
  }

  void onClear() {
    textController.clear();
    bloc.search('');
  }

  @override
  Widget build(BuildContext context) {
    return TextField(
      controller: textController,
      decoration: InputDecoration(
        hintText: 'Enter a search term',
        suffixIcon: IconButton(
          onPressed: onClear,
          icon: const Icon(Icons.clear),
        ),
      ),
      onSubmitted: (value) {
        bloc.search(value);
      },
    );
  }
}

class _SearchBody extends StatelessWidget {
  // ignore: unused_element
  const _SearchBody({super.key});

  @override
  Widget build(BuildContext context) {
    return SizedBox.expand(
      child: SignalBuilder(
        builder: (context, child) {
          final searchResultState = context.get<GithubSearchBloc>().searchResult.state;
          return Stack(
            children: [
              searchResultState.on(
                ready: (searchResult) {
                  if (searchResult.items.isEmpty) {
                    return const Text('No Results');
                  }
                  return _SearchResults(items: searchResult.items);
                },
                error: (error, _) => Text(error.toString()),
                loading: () => const CircularProgressIndicator(),
              ),
              if (searchResultState.isRefreshing)
                Positioned.fill(
                  child: Container(
                    alignment: Alignment.center,
                    color: Colors.black.withOpacity(0.3),
                    child: const CircularProgressIndicator(),
                  ),
                ),
            ],
          );
        },
      ),
    );
  }
}