Dart Cookbook

Table of Contents

Dart Cookbook

Credits

About the Author

About the Reviewers

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Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Errata

Piracy

Questions

1. Working with Dart Tools

Introduction

Configuring the Dart environment

Getting ready

How to do it...

How it works...

Setting up the checked and production modes

Getting ready

How to do it...

How it works...

There's more...

See also

Rapid Dart Editor troubleshooting

Getting ready

How to do it...

How it works...

There's more...

Hosting your own private pub mirror

How to do it...

How it works...

Using Sublime Text 2 as an IDE

Getting ready

How to do it...

How it works...

See also

Compiling your app to JavaScript

How to do it...

How it works...

There's more...

Producing more readable JavaScript code

Producing a single Dart file

See also

Debugging your app in JavaScript for Chrome

How to do it…

How it works...

There's more...

Debugging your app in JavaScript for Firefox

Using the command-line tools

How to do it...

See also

Solving problems when pub get fails

Getting ready

How to do it...

How it works...

There's more...

Shrinking the size of your app

How to do it...

How it works...

There's more...

More Information Section 1

See also

Making a system call

How to do it...

How it works...

Using snapshotting

How to do it...

How it works...

There's more...

See also

Getting information from the operating system

Getting ready

How to do it...

How it works...

There's more...

2. Structuring, Testing, and Deploying an Application

Introduction

Exiting from an app

How to do it...

How it works...

Parsing command-line arguments

How to do it...

How it works...

See also

Structuring an application

Getting ready

How to do it...

How it works...

There's more...

See also

Using a library from within your app

How to do it...

How it works...

There's more...

Microtesting your code with assert

How to do it...

How it works...

There's more...

Unit testing a Polymer web app

Getting ready

How to do it...

How it works...

See also

Adding logging to your app

Getting ready

How to do it...

How it works...

There's more...

Documenting your app

Getting ready

How to do it...

How it works...

There's more...

Profiling and benchmarking your app

Getting ready

How to do it...

How it works...

See also

Publishing and deploying your app

Getting ready

How to do it...

How it works...

There's more...

Using different settings in the checked and production modes

How to do it...

How it works...

3. Working with Data Types

Introduction

Concatenating strings

How to do it...

How it works...

There's more...

Using regular expressions

How to do it...

How it works...

There's more...

Strings and Unicode

How to do it...

How it works...

There's more...

Using complex numbers

How to do it...

How it works...

There's more...

Creating an enum

How to do it...

How it works...

There's more...

Flattening a list

How to do it...

How it works...

There's more...

Generating a random number within a range

How to do it...

How it works...

Getting a random element from a list

How to do it...

How it works...

See also

Working with dates and times

How to do it...

How it works...

There's more...

Improving performance in numerical computations

How to do it...

How it works...

There's more...

Working with JavaScript

Parsing numbers

See also

Using SIMD for enhanced performance

How to do it…

How it works...

See also

4. Object Orientation

Introduction

Testing and converting types

How to do it...

How it works...

There's more...

See also

Comparing two objects

How to do it...

How it works...

There's more...

See also

Using a factory constructor

How to do it...

How it works...

There's more...

Building a singleton

How to do it...

How it works...

Using reflection

Getting ready

How to do it...

How it works...

There's more...

See also

Using mixins

How to do it...

How it works...

There's more...

Using annotations

How to do it...

How it works...

There's more...

See also

Using the call method

How to do it...

How it works...

There's more...

Using noSuchMethod

How to do it...

How it works...

There's more...

See also

Making toJSON and fromJSON methods in your class

Getting ready

How to do it...

How it works...

There's more...

Creating common classes for client and server apps

How to do it...

How it works...

There's more…

See also

5. Handling Web Applications

Introduction

Responsive design

How to do it...

How it works...

See also

Sanitizing HTML

How to do it...

How it works...

Using a browser's local storage

How to do it...

How it works...

There's more...

See also

Using application cache to work offline

How to do it...

How it works...

There's more...

Preventing an onSubmit event from reloading the page

How to do it...

How it works...

Dynamically inserting rows in an HTML table

How to do it...

How it works...

See also...

Using CORS headers

How to do it...

How it works...

There's more...

Using keyboard events

How to do it...

How it works...

There's more...

Enabling drag-and-drop

How to do it...

How it works...

See also

Enabling touch events

How to do it...

How it works...

There's more...

See also

Creating a Chrome app

How to do it...

How it works...

There's more...

See also

Structuring a game project

How to do it...

How it works...

There's more...

See also

Using WebGL in your app

How to do it...

How it works...

There's more...

See also

Authorizing OAuth2 to Google services

How to do it...

How it works...

There's more...

See also

Talking with JavaScript

How to do it...

How it works...

There's more...

See also

Using JavaScript libraries

How to do it...

How it works...

See also

6. Working with Files and Streams

Introduction

Reading and processing a file line by line

How to do it...

How it works...

See also

Writing to a file

How to do it...

How it works...

There's more...

Searching in a file

How to do it...

How it works...

See also

Concatenating files

How to do it...

How it works...

There's more...

See also

Downloading a file

Getting ready

How to do it...

How it works...

There's more...

Using pipe

Using the http package

See also

Working with blobs

Getting ready

How to do it...

How it works...

Transforming streams

How to do it...

How it works...

There's more...

See also

7. Working with Web Servers

Introduction

Creating a web server

How to do it...

How it works...

There is more...

Posting JSON-formatted data

How to do it...

How it works...

See also

Receiving data on the web server

How to do it...

How it works...

There's more...

Writing data to a file on the server

See also

Serving files with http_server

How to do it...

How it works...

There's more...

Using sockets

How to do it...

How it works...

There's more...

Using WebSockets

Getting ready

How to do it...

How it works...

There's more...

See also

Using secure sockets and servers

Getting ready

How to do it...

How it works...

See also

Using a JSON web service

Getting ready

How to do it...

How it works...

See also

8. Working with Futures, Tasks, and Isolates

Introduction

Writing a game loop

How to do it...

How it works...

There's more...

See also

Error handling with Futures

Getting ready

How to do it...

How it works...

Scheduling tasks using Futures

How to do it...

How it works...

See also

Running a recurring function

How to do it...

How it works...

There's more...

See also

Using isolates in the Dart VM

How to do it...

How it works...

There's more...

See also

Using isolates in web apps

How to do it...

How it works...

See also

Using multiple cores with isolates

How to do it...

How it works...

Using the Worker Task framework

How to do it...

How it works...

There's more…

See also

9. Working with Databases

Introduction

Storing data locally with IndexedDB

How to do it...

How it works...

See also

Using Lawndart to write offline web apps

How to do it...

How it works...

See also

Storing data in MySQL

Getting ready

How to do it...

How it works...

There's more...

Storing data in PostgreSQL

Getting ready

How to do it...

How it works...

See also

Storing data in Oracle

Getting ready

How to do it...

How it works...

There's more…

Storing data in MongoDB

Getting ready

How to do it...

How it works...

See also

Storing data in RethinkDB

Getting ready

How to do it...

How it works...

See also

10. Polymer Dart Recipes

Introduction

Data binding with polymer.dart

How to do it...

How it works...

There's more…

Binding and repeating over a list

How to do it...

How it works...

There's more...

Binding to a map

How to do it...

How it works...

See also

Using custom attributes and template conditionals

How to do it...

How it works...

See also

Binding to an input text field or a text area

How to do it...

How it works...

Binding to a checkbox

How to do it...

How it works...

See also

Binding to radio buttons

How to do it...

How it works...

Binding to a selected field

How to do it...

How it works...

Event handling

How to do it...

How it works...

Polymer elements with JavaScript interop

How to do it...

How it works...

See also

Extending DOM elements

How to do it...

How it works...

Working with custom elements

How to do it...

How it works...

There's more...

Automatic node finding

How to do it...

How it works...

Internationalizing a Polymer app

How to do it...

How it works...

There's more...

11. Working with Angular Dart

Introduction

Setting up an Angular app

How to do it...

How it works...

There's more...

Using a controller

How to do it...

How it works...

There's more...

Using a component

How to do it...

How it works...

There's more...

See also

Using formatters as filters

How to do it...

How it works...

See also

Creating a view

How to do it...

How it works...

Using a service

How to do it...

How it works...

See also

Deploying your app

How to do it...

How it works...

See also

Index

Dart Cookbook

Dart Cookbook

Copyright © 2014 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: October 2014

Production reference: 1171014

Published by Packt Publishing Ltd.

Livery Place

35 Livery Street

Birmingham B3 2PB, UK.

ISBN 978-1-78398-962-1

www.packtpub.com

Credits

Author

Ivo Balbaert

Reviewers

Sergey Akopkokhyants

Claudio d'Angelis

Joris Hermans

Acquisition Editor

Sam Wood

Content Development Editor

Azharuddin Sheikh

Technical Editor

Anand Singh

Copy Editors

Sarang Chari

Adithi Shetty

Project Coordinator

Kinjal Bari

Proofreaders

Simran Bhogal

Maria Gould

Ameesha Green

Indexer

Monica Ajmera Mehta

Production Coordinator

Alwin Roy

Cover Work

Alwin Roy

About the Author

Ivo Balbaert is currently a lecturer in (Web) Programming and Databases at CVO Antwerpen (www.cvoantwerpen.be), a community college in Belgium. He received a PhD in Applied Physics from the University of Antwerp in 1986. He worked for 20 years in the software industry as a developer and consultant for several companies, and for 10 years as a project manager at the Antwerp University Hospital. In 2000, he switched to partly teaching and partly developing software (KHM Mechelen, CVO Antwerp).

Ivo also wrote an introductory book in Dutch about developing in Ruby and Rails called Programmeren met Ruby en Rails, Van Duuren Media, 2009. In 2012, he authored a book on the Go programming language called The Way To Go, iUniverse. Last year, in collaboration with Dzenan Ridzanovic, he also wrote Learning Dart, Packt Publishing.

I would like to thank my wife, Christiane, for her support and patience during the development of this book.

About the Reviewers

Sergey Akopkokhyants is a software architect with more than 20 years of professional experience in designing and developing client- and server-side applications. He is also a certified Java developer and project manager. He has general knowledge of many tools, languages, and platforms. For the last 5 years, he has been responsible for customizing and producing web-oriented applications for wholesale business management solutions projects; he has been doing this for several worldwide mobile communication companies. Sergey's responsibilities include architecture design and guidance of client software development using Flex, ActionScript, HTML, JavaScript, and client-server integration with Java. He is also the founder of and an active contributor to several open source projects on GitHub, including the Dart Web Toolkit (DWT) and Angular Dart UI. He is passionate about web design and development and likes sharing his expertise with others, helping them to increase their skills and productivity. Also, he was one of the reviewers of Learning Dart, Packt Publishing.

Claudio d'Angelis is an Italian programmer with 10 years of experience in document digitization, web development, and Linux administration. As an early adopter of Dart, he continues to contribute to the community. His contributions include writing articles, open source projects, speaking at conferences, and presenting episodes on Google Developers Live.

Joris Hermans is a web developer enthusiast who works for Truvo, an online directory company. He is also the proud owner of lots of Dart packages, a real-time dart framework named force, a search engine named Bounty Hunter, a persistent abstraction layer named cargo, a dependency injection for Dart called wired, and so on. He also likes to speak about the Web and Dart, so it is possible that you will meet him at a conference.

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Preface

Dart is the new open source programming language for the Web, developed by Google with a steadily growing popularity; it is a single language for both the client and server, which is appropriate for a full range of devices on the Web—including phones, tablets, laptops, and servers. It encompasses the lessons of the last two decades of web programming. This book provides you with a broad range of step-by-step recipes that will increase your expertise in writing all kinds of Dart applications, including web apps, scripts, and server-side apps. It can be used as a companion to Learning Dart, Dzenan Ridzanovic and Ivo Balbaert, Packt Publishing.

What this book covers

Chapter 1, Working with Dart Tools, talks about increasing your mastery of the Dart tools and platform. We discuss some of the more advanced and hidden features of the Dart Editor, such as configuration, compilation to JavaScript, and the pub package manager. When relevant, we also take a look at how to perform tasks with command-line tools.

Chapter 2, Structuring, Testing, and Deploying an Application, focuses mainly on all the different tasks in the life cycle of your project that make it more professional, helping you save a lot of time during the maintenance phase. This includes structuring the project and installing a logging tool in it and then testing, documenting, profiling, and publishing it.

Chapter 3, Working with Data Types, is about working with the different data types Dart has to offer. We will talk about the basic data types as well as strings, random numbers, complex numbers, dates and times, enums, and lists. Along the way, we will cover many tricks that will help you out in specific circumstances.

Chapter 4, Object Orientation, delves deeper into the object-oriented nature of Dart to find some new techniques and insights that will help us to be more productive in building our apps.

Chapter 5, Handling Web Applications, covers a wide range of web-related topics dealing with safety, browser storage, caching, event handling, WebGL, and of course, Dart working together with JavaScript.

Chapter 6, Working with Files and Streams, shows you how to work with files in different circumstances, both in synchronous and asynchronous ways. We will delve into the code to download a file both on a web and server clients, with blobs as a special case. We also discuss how transforming a stream works.

Chapter 7, Working with Web Servers, looks at how you can write full-fledged and performant web servers in Dart, more specifically how to receive data on the server, how to serve files, and how to deploy a web service. Sockets and their secure variants, as well as web sockets, are also discussed.

Chapter 8, Working with Futures, Tasks, and Isolates, concentrates on the asynchronous tools in Dart to write elegant code in future and combine their possibilities with the execution of tasks and isolates to enhance the concurrency of our apps.

Chapter 9, Working with Databases, explains how to store data in databases, on the client or server or both. On the client side, we look at IndexedDB and the Lawndart data manager. Then, we investigate how to store data on the server in SQL as well as NoSQL database systems.

Chapter 10, Polymer Dart Recipes, shows how to use Polymer to modularize the way a web client interface is built by using web components that encapsulate structure, style, and behavior. The structure and style come from a combination of HTML5 and CSS with special extensions that enable two-way data binding. Behavior is described by code contained in a class that hooks up with the component.

Chapter 11, Working with Angular Dart, covers how Angular makes it possible to write web-based apps with Model-View-Controller (MVC) capabilities in order to make both development and testing easier. The templating system is discussed along with controllers, components, views, formatters, and services.

What you need for this book

To work with this book's code, you need the Dart SDK and Dart Editor, which you can download from www.dartlang.org. Simply unzip the downloaded file and you are good to go. Because Dart Editor is based on Eclipse, you also need a Java Runtime (http://www.oracle.com/technetwork/java/javase/downloads/jre8-downloads-2133155.html). Choose the appropriate version for your system (32-bit or 64-bit); after the download, double-click on the .exe file to install it.

Who this book is for

If you want to become a better Dart developer and get insights and tips on how to put that knowledge into practice, then this book is for you. Because Dart runs on both clients and servers, web, mobile, and server-side developers alike can benefit from these recipes. The book assumes you know the basics of Dart and have some Dart code. You should also have a basic knowledge of HTML and how web applications with browser clients and servers work.

Conventions

In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: In the checked mode, types are checked by calling assertions of the form assert (var1 is T), to control that var1 is of type T.

A block of code is set as follows:

main() {