Data

ProtocolMappers and ServerpodBookRepository. Wire types do not leave this folder.

clean-architecturetutorialflutter

data/ is the only folder that imports BookDto and SaveBookInput, aside from main.dart constructing Client. A page that imports package:shelf_client has skipped the boundary.

Create lib/data/protocol_mappers.dart. toBook reads dto.id.toString() and ReadingStatus.values.byName(dto.status.name). toSaveBookInput writes ReadingStatusWire.values.byName(book.status.name) and does not send book.id. throwDomain turns the three generated exceptions back into ValidationFailure, NotFound, and Conflict, and returns Never so the repository methods can call it from a catch and still type-check. toShelf and toSaveShelfInput are added with the shelf screen, after serverpod generate has written those types.

dart

import 'package:shelf_client/shelf_client.dart';
import 'package:shelf_flutter/domain/book/book.dart';
import 'package:shelf_flutter/domain/book/reading_status.dart';
import 'package:shelf_flutter/domain/shared/conflict.dart';
import 'package:shelf_flutter/domain/shared/not_found.dart';
import 'package:shelf_flutter/domain/shared/validation_failure.dart';

/// Protocol types in, domain types out. This file is the wire boundary.
class ProtocolMappers {
  const ProtocolMappers();

  Book toBook(BookDto dto) {
    return Book(
      id: dto.id.toString(),
      title: dto.title,
      authorName: dto.authorName,
      status: ReadingStatus.values.byName(dto.status.name),
      shelfId: dto.shelfId?.toString(),
      createdAt: dto.createdAt,
    );
  }

  SaveBookInput toSaveBookInput(Book book) {
    return SaveBookInput(
      title: book.title,
      authorName: book.authorName,
      status: ReadingStatusWire.values.byName(book.status.name),
    );
  }

  Never throwDomain(Object error) {
    if (error is ApiValidationException) {
      throw ValidationFailure(error.message);
    }
    if (error is ApiNotFoundException) {
      throw NotFound(error.message);
    }
    if (error is ApiConflictException) {
      throw Conflict(error.message);
    }
    throw error;
  }
}

The page catches the domain types. It does not catch ApiValidationException. That name stays in this file.

Create lib/data/serverpod_book_repository.dart:

dart

import 'package:shelf_client/shelf_client.dart';
import 'package:shelf_flutter/data/protocol_mappers.dart';
import 'package:shelf_flutter/domain/book/book.dart';
import 'package:shelf_flutter/domain/book/book_repository.dart';

class ServerpodBookRepository implements BookRepository {
  ServerpodBookRepository(this._client, {ProtocolMappers? mappers})
    : _mappers = mappers ?? const ProtocolMappers();

  final Client _client;
  final ProtocolMappers _mappers;

  @override
  Future<Book> save(Book book) async {
    try {
      final dto = await _client.book.save(_mappers.toSaveBookInput(book));
      return _mappers.toBook(dto);
    } catch (error) {
      _mappers.throwDomain(error);
    }
  }

  @override
  Future<List<Book>> list() async {
    final response = await _client.book.list();
    return response.books.map(_mappers.toBook).toList();
  }
}

This file implements save and list only. placeOnShelf calls client.shelf.place, and that method does not exist until Place a book on a shelf has been generated. Add the method in the place control.

Next: the providers.