Professional Twitter Development E-Book

Daniel Crenna

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 482

Veröffentlichungsjahr: 2009

Beschreibung

Twitter is rapidly moving up the social networking food chainand is currently outranked by only Facebook and MySpace. Itfeatures a programming API that allows you to build Web sites andapplications (both desktop and mobile) for reading and posting toTwitter, finding other Twitter users, aggregating Twitter content,and other uses. This book walks you through the process ofcombining many programming tools in order to build exciting,useful, and profitable applications.You'll begin with a look at RESTful services and examine how tostructure your queries, handle asynchronous operations, useheaders, and post binary data. From there, author and TweetSharpdeveloper Daniel Crenna explains how to authenticate with the OAuthspecification for Web and Windows applications.* Twitter is growing in popularity at a rapid pace and this bookshows you how to take advantage of its programming API to buildapplications* Explains the various ways to design a Twitter application,including caching, third party application interoperability,real-time data binding, push vs. pull data scenarios, and more* Takes an in-depth look at TweetSharp, a .NET library fordeveloping Twitter applications-whose creator is also the author ofthis book* Walks you through requesting and retrieving responses fromTwitter's API* Warns you of considerations to take into account regardingauthentication and securityProfessional Twitter Development shows you how to get themost out of Twitter so that you can build your own applications forthis exciting new platform.

Leseprobe

Professional Twitter® Development With Examples in .NET 3.5

Table of Contents

Chapter 1: Working with Restful Services

What is REST?

The REST Paradigm

HTTP and URIs

The Anatomy of a URI

The Anatomy of HTTP Requests and Responses

Planning Features using HTTP Headers

Twitter and REST

Communicating with the Web and .NET

WebClient, HttpWebRequest and HttpWebResponse

Creating a Request Utility

Summary

Chapter 2: The Twitter Rest Api

Obtaining a Twitter Account

Overview

Resources

Representations

Authenticating Users

API Rate Limits

Twitter Features

Statuses

Users

Direct Messages [A] [R]

Friendships

Social Graphing

Account

Favorites

Notifications

Blocks

Help

Twitter Objects

Statuses

Users

Direct Messages

Rate Limit Status

Errors

Working with the API

Twitter’s DateTime Format

Configuring a Custom Application Source

Handling Errors

Requesting Data from Twitter

Summary

Chapter 3: Working with XML, JSON, and Jsonp

Working with XML Responses

Using LINQ to XML

Using XML Attributes and XmlSerializer

Working with JSON Responses

Using ASP.NET AJAX’s JavaScriptSerializer

Using WCF’s DataContractJsonSerializer

Calling Back to Client Code with JSONP

Using Silverlight

Security Restrictions with JSONP

Summary

Chapter 4: The Twitter Search API

Overview

Search Features

Search Operators

Boolean Logic

Exact Phrase

Exclusions

Hashtags

Referencing Users

Timelines

Context

Search Parameters

Pagination

Timelines

Callbacks

Globalization

Search Objects

Queries

Trends

Converting Queries and Trends

Summary

Chapter 5: Working with RSS and Atom Syndication

Syndication on the Web

Feed Objects

RSS 2.0

Atom 1.0

Consuming Feeds

Why Syndication?

With LINQ to XML

Synchronizing Applications with Feed Updates

Summary

Chapter 6: Basic Authentication and OAuth

The Pitfalls of Basic Authentication

User Credentials are Visible

Credentials are Reusable

Credentials are One-Way

Existing Alternatives to Basic Authentication

What Is Data Portability?

What Is OAuth?

User Credentials are Hidden

Credentials are Not Reusable

Credentials are Two-Way

The OAuth Specification

OAuth Workflow

Retrieving an Unauthorized Request Token

Walkthroughs

Setting Up Your Twitter Application to Use OAuth

Authenticating an ASP.NET Web Application

Authenticating a Desktop, Console, or Mobile Application

Summary

Chapter 7: Maximizing Performance and Functionality

Caching

User Photos

Statuses and Users

Working with Twitter Constraints

Storing Authentication Values

Uploading Files with Multi-Part Form Posts

Rate Limiting in the Response

Designing Applications with Rate Limits

Retrieving Data for Popular Users

Filtering Data

Compressing Response Data

Extending Twitter with Third-Party Applications

Adding Photo Features with TwitPic, yFrog and Twitgoo

Stay on Top of Trends with TwitScoop

Twitter Application Directories

Unit Testing Twitter

Mocking RESTful Services

Generating Data

Summary

Chapter 8: Data Push vs. Pull

Pushing Data

Advantages

Disadvantages

Using WCF Duplex Services

Using Gnip

Using the Twitter Streaming API

Summary

Chapter 9: Introduction to TweetSharp

Hello, TweetSharp!

What Is a Fluent Interface?

Core Feature Overview

Hello, Twitter!

Fetching Timelines

Performance

Caching Queries

Features

Unit Testing

Summary

Chapter 10: Building a Cross-Platform Twitter Application

The Application: Twiticism.com

Problem

Design

The Azure Cloud

Shared Key Authentication

Designing Applications for the Cloud

Working with Azure Queues

Working with Azure Tables

Hosting a Twitter Proxy in the Cloud

Running a Global User Cache in the Cloud

ASP.NET Membership in the Cloud

Silverlight Application Highlights

Building a Twitter Image Handler

Building a Twitter Search Poller

Going Cross-Platform

Summary

Professional Twitter® Development With Examples in .NET 3.5

by Daniel Crenna

Professional Twitter® Development With Examples in .NET 3.5

Published by

Wiley Publishing, Inc.

10475 Crosspoint Boulevard

Indianapolis, IN 46256

www.wiley.com

Copyright © 2009 by Wiley Publishing, Inc., Indianapolis, Indiana

ISBN: 978-0-470-53132-7

Manufactured in the United States of America

10 9 8 7 6 5 4 3 2 1

No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, [phone], fax [phone]. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, [phone], fax [phone], or online atwww.wiley.com/go/permissions.

Limit of Liability/Disclaimer of Warranty: The publisher and the author make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation warranties of fitness for a particular purpose. No warranty may be created or extended by sales or promotional materials. The advice and strategies contained herein may not be suitable for every situation. This work is sold with the understanding that the publisher is not engaged in rendering legal, accounting, or other professional services. If professional assistance is required, the services of a competent professional person should be sought. Neither the publisher nor the author shall be liable for damages arising herefrom. The fact that an organization or Web site is referred to in this work as a citation and/or a potential source of further information does not mean that the author or the publisher endorses the information the organization or Web site may provide or recommendations it may make. Further, readers should be aware that Internet Web sites listed in this work may have changed or disappeared between when this work was written and when it is read.

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Trademarks: Wiley, the Wiley logo, Wrox, the Wrox logo, Wrox Programmer to Programmer, and related trade dress are trademarks or registered trademarks of John Wiley & Sons, Inc. and/or its affiliates, in the United States and other countries, and may not be used without written permission. Twitter is a registered trademark of Twitter, Inc. All other trademarks are the property of their respective owners. Wiley Publishing, Inc., is not associated with any product or vendor mentioned in this book.

Dedicated to my family:

Those we recently lost who remain, those who will join with us soon, and those yet to be. There is so much love here, and if we seldom speak of our feelings it is only because it is difficult to express the irreplaceable.

About the Author

Daniel Crenna is a Microsoft MVP and the creator of TweetSharp, an open-source .NET Twitter API development library. He runs www.dimebrain.com, a blog and software company in Canada. His Twitter client project, currently in development in partnership with Jason Diller, was a Top 5 Finalist in the Microsoft BlueSky Innovation Excellence Awards in 2009. Daniel was a contributor to the Microsoft AJAX Control Toolkit, and is a Microsoft Certified Professional Developer.

Credits

Acquisitions Editor

Paul Reese

Project Editor

Ed Connor

Technical Editor

Jason Diller

Production Editor

Rebecca Anderson

Copy Editor

Tricia Liebig

Editorial Director

Robyn B. Siesky

Editorial Manager

Mary Beth Wakefield

Production Manager

Tim Tate

Vice President and Executive Group Publisher

Richard Swadley

Vice President and Executive Publisher

Barry Pruett

Associate Publisher

Jim Minatel

Project Coordinator, Cover

Lynsey Stanford

Proofreader

Nate Pritts, Word One

Indexer

J&J Indexing

Acknowledgments

Writing a book is never a solo effort. This particular one would not exist without the efforts of Ed Connor at Wiley keeping me on track and focused on the next milestone, and Jason Diller for a matchless technical review and development assistance, and keeping the lights on our community efforts whileI was consumed by this project. Ingrid Alongi at Gnip was an immediate source of encouragement and advice, and I was fortunate to have Doug Williams and Alex Payne at Twitter on tap for any questions I had throughout the evolutions that occurred with the Twitter API. Above all my wife Beth, who single-handedly moved us across the country and tolerated my mental and physical absence during the writing of this book, is as much a part of this project as I am.

Introduction

Chapter 1: Working with Restful Services

Chapter 2: The Twitter Rest Api

Chapter 3: Working with XML, JSON, and Jsonp

Chapter 4: The Twitter Search API

Chapter 5: Working with RSS and Atom Syndication

Chapter 6: Basic Authentication and OAuth

Chapter 7: Maximizing Performance and Functionality

Chapter 8: Data Push vs. Pull

Chapter 9: Introduction to TweetSharp

Chapter 10: Building a Cross-Platform Twitter Application

Since Twitter launched in March 2006, it has grown steadily into one of the simplest, most popular, and most powerful social networking platforms. Perhaps more compelling than Twitter itself is the growing community of developers building applications for the service and taking it far beyond its roots as a simple messaging service. This book will teach you how to get the best out of Twitter to build your own applications for this exciting new technology, as well as provide some guidance on using some of the latest developer evolutions in the .NET Framework, like Silverlight and Windows Azure.

After spending a great deal of time building TweetSharp, an open source Twitter library, as well as a prototype for a commercial Twitter client application, it was clear that many developers would find a single resource on consuming RESTful services, and Twitter’s RESTful API in particular, a valuable addition to their capacity to build applications on this new and exciting service. With Twitter’s growth exploding and already enjoying major mainstream adoption, application developers need a timely resource to prepare to build applications for this new and lively audience. Twitter has many millions of users and this book can help you support that growth in the developer community.

Who This Book Is For

The primary readers for this book are web or Windows developers who are pursuing Twitter application or client development, or are developing part of a system that integrates core Twitter functionality, such as a web-based widget. The early chapters of the book deal with establishing a foundation for web programming using HTTP and RESTful service concepts. If you have lots of experience working with social APIs in multiple data formats using REST, you might want to advance to Chapter 2 and Chapter 4 right away to start learning the particulars of Twitter’s API, otherwise beginning at the beginning will help you understand Twitter, but also any social web API that employs REST concepts.

What This Book Covers

The book will focus on C# and .NET with supporting examples using a broad range of .NET technologies, such as Windows Forms, ASP.NET, Silverlight 3, WCF, LINQ, and Windows Azure. At the time of writing, Silverlight 3 is in Beta 1, and Windows Azure is in Community Technology Preview (CTP) status. Most of the examples of the book are designed to run in .NET 3.5, though you may reasonably adapt the code and understanding to function in previous versions of .NET, by rewriting any LINQ expressions to programmatically achieve similar results, and replacing extension methods with classic static methods. You will get the most benefit out of this book by using .NET 3.5, however, which supports development for Silverlight and Azure, which, combined with Twitter, will allow you to build next generation applications that will appeal to the broadest base of users.

How This Book Is Structured

Chapters 1 through 6 focus on RESTful services, the backbone of Twitter and many social data APIs are covered in sufficient depth for the developer to know how to structure their queries, handle asynchronous operations, utilize headers and post binary data. Continuing from an understanding of RESTful web communication, you will learn how to request and retrieve responses from Twitter’s API, with forays into data processing with XML and JSON (for REST API data), and RSS and Atom (for Search API data). Core topics conclude with coverage for application authentication and security, including Twitter’s upcoming OAuth security model at the forefront; you will learn how to authenticate with the OAuth specification for web and Windows applications.

Following from authentication and security are performance and feature considerations. In Chapters 7 through 10 you are introduced to a variety of important topics for developing custom applications; caching, third party application interoperability, push vs. pull data scenarios, and Twitter’s anatomy and constraints are explored in detail to paint a bigger picture of how a Twitter application is best designed. Next, you will get an in-depth look of TweetSharp, a .NET library for developing Twitter applications that will speed up your development and time to market for your own application ideas. Finally, you will bring many new concepts together using Windows Azure to go through the steps needed to build a Twitter application in the cloud.

Armed with a solid understanding of Twitter’s API, and the ability to fetch and process web data, you can now tackle the specific challenges of Twitter application development. You’ll learn how to design and build responsive applications that consider caching, multi-threading, and real time data binding to ensure your ideas convert smoothly to compelling experiences for Twitter users.

What You Need to Use This Book

This book focuses on building Twitter applications on the .NET Framework 3.5 SP1, including some emerging technologies like Silverlight 3 Beta 1 and the Windows Azure CTP. To ensure your environment is ready to work with the concepts and code provided in the book and its accompanying source, you can follow along with this introductory chapter. While some nascent technologies are showcased, using them is not necessary to benefit from the fundamentals of web programming and Twitter development and design concepts that you’ll learn and employ.

Setting Up Your Development Environment

The following steps outline the required server components, frameworks, and tools necessary for the various examples provided in the book. To help streamline the process, you will use a new Microsoft installation experience designed specifically for web application development; the Microsoft Web Platform Installer. With it, you can easily locate, download, install, and configure your web environment, saving time locating and setting up separate libraries around the web.

Using the Microsoft Web Platform Installer

Microsoft’s new Web Platform Installer, available at http://www.microsoft.com/Web/, provides a unified experience for installing and configuring most Microsoft web infrastructure components as well as popular open source software from a simple interface. After downloading and running the application, you are presented with an interface similar to Figure I-1, which shows the Web Platform Installer 2.0 Beta in action.

Figure I-1

IIS 7.0 with ASP.NET Components

Windows Azure’s SDK relies on Internet Information Services (IIS) 7, which means your development operating system must be Windows Vista or above to work with those features. You can find the required ASP.NET support through the Web Server section of this installer. Selecting ASP.NET from the menu will install several dependencies to enable .NET extensions in IIS 7.

ASP.NET MVC 1.0

While the book doesn’t cover the particulars of ASP.NET MVC, most of the code examples apply to any .NET environment. If you are planning to build your Twitter application on the ASP.NET MVC framework, now is a great time to install the bits. You can find this download under Frameworks and Runtimes.

Microsoft® Silverlight™ 3 Tools Beta 1 for Visual Studio 2008 SP1

To take advantage of the latest advancements in rich client technology, including running Silverlight applications out of the browser, you can download this dependency from the Tools section of the platform installer. You can also elect to download Silverlight 2, instead, if your projects don’t require or are not ready for out of browser support.

SQL Server 2008 Express

While not specifically required, SQL Server 2008 is installed as part of the Web Platform Installer components, and is used by Windows Azure to run a simulated cloud service environment locally, so you are able to test your applications before deploying them.

Visual Studio Web Developer Express and Above

Both the Windows Azure CTP and Silverlight 3 Tools for Visual Studio Beta 1 support Visual Studio Web Developer Express, so it is possible to run the examples in this book without a full-fledged professional development environment. You will also need to ensure you have installed the .NET Framework 3.5 SP1 from either Windows Update or the web before installing supporting libraries and SDKs. Figure I-2 demonstrates Visual Studio Web Developer Express with the code examples loaded and ready for testing.

Figure I-2

There are a few Windows Forms-based examples in the book as well, which you can run as executables, or use Visual C# Express available at http://www.microsoft.com/express/vcsharp/ to compile and edit those examples.

SDKs and Libraries

Beyond the Web Platform Installer are an SDK and a third-party library you will use to build cloud-based web applications. The SDK provides utility code for communicating with core Azure services, and the library helps you to work effectively with .NET and the Twitter API to simplify the programming tasks and challenges you’ll learn throughout the book.

Windows Azure Tools for Microsoft Visual Studio (including the Azure SDK)

You can download this SDK directly from Microsoft at http://go.microsoft.com/fwlink/?LinkId=128752 to enable an integrated environment to develop cloud-based services in a familiar setting in Visual Studio. The SDK examples also include valuable libraries for communicating with Azure Storage, and activating ASP.NET Provider model support for cloud services.

TweetSharp v1.0

You’ll need the official first release of TweetSharp, an open source .NET Twitter library that is useful for both beginning Twitter API developers and those who are already experienced (or have read this book) and want to accelerate development time by using TweetSharp to abstract away the details and get a prototype running quickly. You can fetch the latest release by visiting http://tweetsharp.googlecode.com/downloads. To use it on your projects, choose Add Reference from your Visual Studio project and select both Dimebrain.TweetSharp.dll and Newtonsoft.Json.dll if you are targeting ASP.NET, and the corresponding Compact and Silverlight suffixed libraries of the same name for mobile and rich development targets, respectively. Figure I-3 shows the TweetSharp page on Google Code, where you can find additional support, releases, and documentation.

Figure I-3

After installing your environment and its dependencies, you may want to visit http://www.microsoft.com/azure to familiarize yourself with the Azure platform and sign up for a Windows Live ID and Microsoft Connect account if you do not have either of these. You will go through the Azure sign up and configuration process in Chapter 10 when learning how to build a cloud-hosted web application, but you will save time if these services are in place.

Debugging HTTP Traffic

The vast majority of your time developing modern web applications is spent consuming external web services. Twitter application development is no exception, and the ability to work with HTTP traffic at a lower level than what’s immediately available in the .NET Framework provides valuable insight into what occurs under the hood when you program against the live web. To help you diagnose and understand what you send and receive when communicating with Twitter, you can download and configure Wireshark at http://wireshark.org, a free and open source HTTP analysis tool whose homepage is shown in Figure I-4. This section will explain how to use it effectively when consuming the Twitter API.

Figure I-4

Configuring Wireshark

Wireshark is a detailed and comprehensive tool, and as such requires customization to filter out all traffic other than what aids your development efforts with Twitter. To trace Twitter HTTP traffic in Wireshark exclusively, first locate the network adapter that is associated with your live Internet connection, as highlighted in Figure I-5. You can reach the dialog displayed by visiting the Capture menu and choosing Interfaces . . . from the options provided.

Figure I-5

Clicking the Options button for the network adapter you intend to trace will bring you to a form where it is possible to focus tracing efforts on a single domain. Following the example in Figure I-6, specifying host twitter.com and clicking Start will begin a new session for Twitter.

Wireshark will now display all communication occurring between your network card and http://twitter.com. The next step is to further constrain these results by protocol, so that only HTTP requests and responses are shown, to avoid viewing raw TCP traffic that occurs frequently when establishing connections. To accomplish this, Figure I-7 illustrates applying a visual filter, specifying http.request || http.response as a filter expression.

Figure I-6

After the filter expression is enabled using the Apply command, Twitter API traffic is displayed conveniently. Figure I-7 shows the HTTP GET request to Twitter for statuses on a user’s timeline, followed by the HTTP response from Twitter containing special headers and the XML message result. You will learn how to interpret this data in Chapter 1, but for now, you can set up Wireshark so that you’re ready to get into the details at a lower level. Whenever you encounter unexpected behavior, remember that you have an excellent diagnostic tool at your disposal.

Figure I-7

Summary

You set up a development environment to build, run, and modify the examples in this book to build your own Twitter applications in ASP.NET, Silverlight 3, and Windows Azure, as well as monitor and troubleshoot the Twitter API with an HTTP traffic monitoring tool. You used the new Microsoft Web Platform Installer to streamline your configuration experience, installing most key components of your environment in one place. In the first chapter, you’ll begin at the beginning, with HTTP web programming and the services model that embraces it. You’re ready to build your next Twitter application!

Conventions

To help you get the most from the text and keep track of what’s happening, we’ve used a number of conventions throughout the book.

Notes, tips, hints, tricks, and asides to the current discussion are offset and placed in italics like this.

As for styles in the text:

We highlight new terms and important words when we introduce them.

We show keyboard strokes like this: Ctrl+A.

We show file names, URLs, and code within the text like so: persistence.properties.

We present code in two different ways:

We use a monofont type with no highlighting for most code examples.

We use gray highlighting to emphasize code that is of particularly importance in

the present context.

Source Code

As you work through the examples in this book, you may choose either to type in all the code manually or to use the source code files that accompany the book. All of the source code used in this book is available for download at http://www.wrox.com. Once at the site, simply locate the book’s title (either by using the Search box or by using one of the title lists) and click the Download Code link on the book’s detail page to obtain all the source code for the book.

Because many books have similar titles, you may find it easiest to search by ISBN; this book’s ISBN is 978-0-470-53132-7.

Once you download the code, just decompress it with your favorite compression tool. Alternately, you can go to the main Wrox code download page at http://www.wrox.com/dynamic/books/download.aspx to see the code available for this book and all other Wrox books.

Errata

We make every effort to ensure that there are no errors in the text or in the code. However, no one is perfect, and mistakes do occur. If you find an error in one of our books, like a spelling mistake or faulty piece of code, we would be very grateful for your feedback. By sending in errata you may save another reader hours of frustration and at the same time you will be helping us provide even higher quality information.

To find the errata page for this book, go to www.wrox.com and locate the title using the Search box or one of the title lists. Then, on the book details page, click the Book Errata link. On this page you can view all errata that has been submitted for this book and posted by Wrox editors. A complete book list including links to each book’s errata is also available at www.wrox.com/misc-pages/booklist.shtml.

If you don’t spot “your” error on the Book Errata page, go to www.wrox.com/contact/techsupport.shtml and complete the form there to send us the error you have found. We’ll check the information and, if appropriate, post a message to the book’s errata page and fix the problem in subsequent editions of the book.

p2p.wrox.com

For author and peer discussion, join the P2P forums at p2p.wrox.com. The forums are a Web-based system for you to post messages relating to Wrox books and related technologies and interact with other readers and technology users. The forums offer a subscription feature to e-mail you topics of interest of your choosing when new posts are made to the forums. Wrox authors, editors, other industry experts, and your fellow readers are present on these forums.

At http://p2p.wrox.com you will find a number of different forums that will help you not only as you read this book, but also as you develop your own applications. To join the forums, just follow these steps:

1. Go to p2p.wrox.com and click the Register link.

2. Read the terms of use and click Agree.

3. Complete the required information to join as well as any optional information you wish to provide and click Submit.

4. You will receive an e-mail with information describing how to verify your account and complete the joining process.

You can read messages in the forums without joining P2P but in order to post your own messages, you must join.

Once you join, you can post new messages and respond to messages other users post. You can read messages at any time on the Web. If you would like to have new messages from a particular forum e-mailed to you, click the Subscribe to this Forum icon by the forum name in the forum listing.

For more information about how to use the Wrox P2P, be sure to read the P2P FAQs for answers to questions about how the forum software works as well as many common questions specific to P2P and Wrox books. To read the FAQs, click the FAQ link on any P2P page.