76 lines
2.3 KiB
Dart
76 lines
2.3 KiB
Dart
import 'dart:io';
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import 'package:flutter/foundation.dart';
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import 'package:freezed_annotation/freezed_annotation.dart';
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import 'package:lemmy_api_client/v3.dart';
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import 'package:mobx/mobx.dart';
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part 'async_store.freezed.dart';
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part 'async_store.g.dart';
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/// [AsyncState] but observable with helper methods/getters
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class AsyncStore<T> = _AsyncStore<T> with _$AsyncStore<T>;
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abstract class _AsyncStore<T> with Store {
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@observable
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AsyncState<T> asyncState = const AsyncState.initial();
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@computed
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bool get isLoading => asyncState is AsyncStateLoading;
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@computed
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String? get errorTerm =>
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asyncState.whenOrNull(error: (errorTerm) => errorTerm);
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/// runs some async action and reflects the progress in [asyncState].
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/// If successful, the result is returned, otherwise null is returned.
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/// If this [AsyncStore] is already running some action, it will exit immediately and do nothing
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@action
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Future<T?> run(AsyncValueGetter<T> callback) async {
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if (isLoading) return null;
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asyncState = const AsyncState.loading();
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try {
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final result = await callback();
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asyncState = AsyncState.data(result);
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return result;
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} on SocketException {
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// TODO: use an existing l10n key
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asyncState = const AsyncState.error('network_error');
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} catch (err) {
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asyncState = AsyncState.error(err.toString());
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rethrow;
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}
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}
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/// [run] but specialized for a [LemmyApiQuery].
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/// Will catch [LemmyApiException] and map to its error term.
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@action
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Future<T?> runLemmy(String instanceHost, LemmyApiQuery<T> query) async {
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try {
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return await run(() => LemmyApiV3(instanceHost).run(query));
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} on LemmyApiException catch (err) {
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asyncState = AsyncState.error(err.message);
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}
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}
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}
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/// State in which an async action can be
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@freezed
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class AsyncState<T> with _$AsyncState {
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/// async action has not yet begun
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const factory AsyncState.initial() = AsyncStateInitial;
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/// async action completed successfully with [T]
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const factory AsyncState.data(T data) = AsyncStateData;
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/// async action is running at the moment
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const factory AsyncState.loading() = AsyncStateLoading;
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/// async action failed with a translatable error term
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const factory AsyncState.error(String errorTerm) = AsyncStateError;
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}
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