pubspec.yaml

dependencies:
  embla: ^0.1.13
  embla_trestle: ^0.1.0

server.dart

import 'dart:async';

import 'package:embla/http.dart';
import 'package:embla/http_annotations.dart' as http;
import 'package:embla/http_basic_middleware.dart';

import 'package:embla_trestle/embla_trestle.dart';

export 'package:embla/bootstrap.dart';

get embla => [
  // As a default, the DatabaseBootstrapper connects to an in-memory database.
  // This is configurable in this constructor.
  new DatabaseBootstrapper(),
  
  new HttpBootstrapper(
    pipeline: pipe(
      // Since we will be receiving POST and PUT requests, we must parse the
      // request body first. This middleware will make it possible to inject
      // an Input object in the handlers.
      InputParserMiddleware,

      // This routes the entire PostsController to the /posts namespace.
      Route.all('posts/*', PostsController)
    )
  )
];

/// The [Model] superclass is provided by Trestle, whose API is exposed
/// via the embla_trestle import.
class Post extends Model {
  @field String title;
  @field String body;

  /// For convenience
  void apply(Map<String, dynamic> map) {
    title = map['title'] ?? title;
    body = map['body'] ?? body;
  }
}

class PostsController extends Controller {
  final Repository<Post> posts;

  /// We use Dependency Injection to inject the Trestle Repository
  PostsController(this.posts);

  /// A method with the name [index] is automatically bound to the
  /// root of the current routing namespace. So the annotation below
  /// is equivalent to
  ///
  ///     @http.Get('/')
  ///     // or
  ///     @http.Get('')
  @http.Get() index() {
    return posts.all();
  }

  /// If we type annotate the wildcard parameter with [int] it will
  /// only be provided if the wildcard is numeric (^\d+$). Else it
  /// be set to null. The [_findById] method helps with this case.
  @http.Get(':id') show({int id}) {
    return _findById(id);
  }

  /// Thanks to the [InputParserMiddleware] we can inject the [Input]
  /// object, whose [body] property will contain the body of the request.
  ///
  /// We use that to create a new Post, and save it to the database.
  @http.Post('') store(Input input) async {
    final post = new Post()
      ..apply(input.body);

    await posts.save(post);

    return post;
  }

  /// Update is similar to store, but instead of creating a new
  /// [Post], we find the one with the provided id and update it.
  @http.Put(':id') update(Input input, {int id}) async {
    final post = (await _findById(id))
      ..apply(input.body);

    await posts.save(post);
    
    return post;
  }

  /// Deleting is trivial.
  @http.Delete(':id') delete({int id}) async {
    final post = await _findById(id);

    await posts.delete(post);

    return { 'message': 'OK' };
  }

  /// This method is a convenience method to get the [Post] with the
  /// provided [id] out of the database.
  Future<Post> _findById(int id) async {

    // If the id is null, that means the wildcard did not match ^\d+$,
    // so we can return a 400 message (Bad Request).
    if (id == null) {
      abortBadRequest({ 'message': 'The id must be numeric' });
    }

    // The find method below will get the first Post it can find with
    // the id. If it find none it will throw a StateError, so we'll
    // have to catch that.
    try {
      return await posts.find(id);
    } on StateError {
      abortNotFound({ 'message': 'No post has an id of $id' });
    }
  }
}

uncommented_server.dart

import 'dart:async';

import 'package:embla/http.dart';
import 'package:embla/http_annotations.dart' as http;
import 'package:embla/http_basic_middleware.dart';

import 'package:embla_trestle/embla_trestle.dart';

export 'package:embla/bootstrap.dart';

get embla => [
  new DatabaseBootstrapper(),
  
  new HttpBootstrapper(
    pipeline: pipe(
      InputParserMiddleware,

      Route.all('posts/*', PostsController)
    )
  )
];

class Post extends Model {
  @field String title;
  @field String body;

  void apply(Map<String, dynamic> map) {
    title = map['title'] ?? title;
    body = map['body'] ?? body;
  }
}

class PostsController extends Controller {
  final Repository<Post> posts;

  PostsController(this.posts);

  @http.Get() index() {
    return posts.all();
  }

  @http.Get(':id') show({int id}) {
    return _findById(id);
  }

  @http.Post('') store(Input input) async {
    final post = new Post()
      ..apply(input.body);

    await posts.save(post);

    return post;
  }

  @http.Put(':id') update(Input input, {int id}) async {
    final post = (await _findById(id))
      ..apply(input.body);

    await posts.save(post);
    
    return post;
  }

  @http.Delete(':id') delete({int id}) async {
    final post = await _findById(id);

    await posts.delete(post);

    return { 'message': 'OK' };
  }

  Future<Post> _findById(int id) async {
    if (id == null) {
      abortBadRequest({ 'message': 'The id must be numeric' });
    }

    try {
      return await posts.find(id);
    } on StateError {
      abortNotFound({ 'message': 'No post has an id of $id' });
    }
  }
}