Code in the cloud : programming Google App Engine

One of the most exciting recent changes in the computing world is cloud computing. Cloud computing is a dramatic shift in how applications are developed and used---and even in what applications are. With cloud computing, developers are no longer building applications that run on a user's desktop computer. Instead, they're building services on the network that can be used by thousands of users at the same time. Cloud services are an exciting opportunity for developers: the cloud is a platform for creating services, a new kind of application that can reach more users, and provide those users with more capabilities than a desktop application ever could. Building applications as cloud services also makes them scalable: cloud applications can easily and smoothly adapt from running on a single computer for a single user to running on thousands of computers for millions of users.Code in the Cloud will teach you what a cloud service is, and how it differs from traditional applications. It will show you how to build a cloud service, taking advantage of the services that AppEngine makes available to you, using iterative development of a simple application to guide you through the different aspects of AppEngine development, using either Python or Java. Through the process of working on a simple application, you'll learn about how to build an application as a service; how to manage persistent data using AppEngine; how to build dynamic, interactive user interfaces that run in a user's web-browser; how to manage security in a web application; and how to interact with other services running in the AppEngine cloud. Contents 5 Getting Started with Google App Engine 9 Introduction 10 What's Cloud Computing? 10 Cloud Computing Programming Systems 16 Acknowledgments 19 Getting Started 20 Setting Up a Google App Engine Account 20 Setting Up Your Development Environment 22 Starting to Program in Python with App Engine 25 Monitoring Your Application 32 Programming Google App Engine with Python 36 A First Real Cloud Application 37 The Basic Chat Application 37 The Basics of HTTP 41 Mapping Chat into HTTP 45 Managing Data in the Cloud 53 Why Didn't Chat Work? 53 Making Chat Persistent 56 Google App Engine Services for Login Authentication 65 Introducing the Users Service 65 The Users Service 66 Integrating the Users Service into Chat 67 Organizing Code: Separating UI and Logic 70 Getting Started with Templates 70 Building Related Views with Templates 75 Multiple Chat Rooms 81 Making the UI Pretty: Templates and CSS 87 Introducing CSS 88 Styling Text Using CSS 89 Page Layouts Using CSS 94 Building Our Interface Using Flowed Layout 102 Including CSS Files in App Engine Applications 105 Getting Interactive 107 Interactive Web Services: The Basics 107 The Model-View-Controller Design Pattern 110 Talking to the Server without Disruption 113 References and Resources 121 Programming Google App Engine with Java 122 Google App Engine and Java 123 Introducing GWT 125 Getting Started with Java and GWT 127 RPC in GWT 135 Testing and Deploying with GWT 140 Managing Server-Side Data 141 Data Persistence in Java 141 Storing Persistent Objects in GWT 145 Retrieving Persistent Objects in GWT 149 Gluing the Client and the Server Together 151 References and Resources 153 Building User Interfaces in Java 154 Why Use GWT? 154 Building GWT UIs with Widgets 155 Making the UI Active: Handling Events 162 Making the UI Active: Updating the Display 167 Wrapping Up with GWT 169 References and Resources 170 Building the Server Side of a Java Application 171 Filling in Gaps: Supporting Chat Rooms 171 Proper Interactive Design: Being Incremental 176 Updating the Client 184 Chat Administration 185 Running and Deploying the Chat Application 187 Wrapping Up the Server Side 189 Advanced Google App Engine 190 Advanced Datastore: Property Types 191 Building a Filesystem Service 191 Modeling the Filesystem: A First Cut 195 Property Types Reference 212 Wrapping Up Property Types 215 Advanced Datastore: Queries and Indices 216 Indices and Queries in Datastore 217 More Flexible Models 223 Transactions, Keys, and Entity Groups 224 Policy and Consistency Models 226 Incremental Retrieval 230 Google App Engine Services 232 The Memcache Service 233 Accessing Other Stuff: The URL Fetch Service 238 Communicating with People: Mail and Chat Services 239 Sending and Receiving Email 243 Wrapping Up Services 246 Server Computing in the Cloud 248 Scheduling Jobs with App Engine Cron 249 Running Jobs Dynamically Using the Task Queue 253 Wrapping Up Server Computing 259 Security in App Engine Services 260 What Is Security? 260 Basic Security 261 Advanced Security 269 Administering Your App Engine Deployment 277 Monitoring 277 Peeking at the Datastore 281 Logs and Debugging 282 Managing Your Application 284 Paying for What You Use 285 Wrapping Up 287 Cloud Concepts 287 Google App Engine Concepts 288 Where to Go from Here 290 References and Resources 292 Index 293 A 293 B 293 C 294 D 295 E 295 F 296 G 296 H 297 I 297 J 297 K 298 L 298 M 298 N 299 O 299 P 299 Q 299 R 300 S 300 T 301 U 301 V 301 W 302 X 302 Join the next wave of Web 2.0 software development in the cloud! Cloud applications are the next big shift in application instead of building single-user applications to run on a personal computer, new applications are being built as multi-user services that run in data centers around the world. One of the most exciting new environments for building services in the cloud is Google's AppEngine. AppEngine is a powerful, easy-to-use framework for developing cloud-based services. This book will teach you what you need to make the shift to cloud development using AppEngine. One of the most exciting recent changes in the computing world is cloud computing. Cloud computing is a dramatic shift in how applications are developed and used---and even in what applications are. With cloud computing, developers are no longer building applications that run on a user's desktop computer. Instead, they're building services on the network that can be used by thousands of users at the same time. Cloud services are an exciting opportunity for the cloud is a platform for creating services, a new kind of application that can reach more users, and provide those users with more capabilities than a desktop application ever could. Building applications as cloud services also makes them scalable : cloud applications can easily and smoothly adapt from running on a single computer for a single user to running on thousands of computers for millions of users. Code in the Cloud will teach you what a cloud service is, and how it differs from traditional applications. It will show you how to build a cloud service, taking advantage of the services that AppEngine makes available to you, using iterative development of a simple application to guide you through the different aspects of AppEngine development, using either Python or Java. Through the process of working on a simple application, you'll learn about how to build an application as a service; how to manage persistent data using AppEngine; how to build dynamic, interactive user interfaces that run in a user's web-browser; how to manage security in a web application; and how to interact with other services running in the AppEngine cloud. Provides information on building scalable Web applications using Google App Engine. Cloud computing refers to the use and access of multiple server-based computational resources via a digital network (WAN, Internet connection using the World Wide Web, etc.). Cloud users may access the server resources using a computer, netbook, pad computer, smart phone, or other device. In cloud computing, applications are provided and managed by the cloud server and data is also stored remotely in the cloud configuration. This volume will show readers what a cloud service is, and how it differs from traditional applications. It will demonstrate how to build a cloud service, taking advantage of the services that AppEngine makes available, using iterative development of a simple application to guide you through the different aspects of AppEngine development, using either Python or Java. Through the process of working on a simple application, readers will learn about how to build an application as a service; how to manage persistent data using AppEngine; how to build dynamic, interactive user interfaces that run in a user's web-browser; how to manage security in a web application; and how to interact with other services running in the AppEngine cloud.-- Cloud services are an exciting opportunity for developers: the cloud is a platform for creating services, a new kind of application that can reach more users, and provide those users with more capabilities than a desktop application ever could. Building applications as cloud services also makes them scalable: cloud applications can easily and smoothly adapt from running on a single computer for a single user to running on thousands of computers for millions of users. Code in the Cloud will teach you what a cloud service is, and how it differs from traditional applications. It shows you how to build a cloud service by taking advantage of the services that AppEngine makes available to you, and by using iterative development of a simple application to guide you through the different aspects of AppEngine development, using either Python or Java. Through the process of working on a simple application, you’ll learn about how to build an application as a service how to manage persistent data using AppEngine how to build dynamic, interactive user interfaces that run in a user’s web-browser how to manage security in a web application and how to interact with other services running in the AppEngine cloud. pt. 1 : Getting started with Google app engine. Introduction Getting started pt. 2 : Programming Google app engine with Python. A first Real Cloud application Managing data in the cloud Google app engine services for login authentication Organizing code : separating UI and logic Making the UI pretty : templates and CSS Getting interactive pt. 3 : Programming Google app engine with Java. Google app engine and Java Managing server-side data Building user interfaces in Java Building the server side of a Java application pt. 4 : Advanced Google app engine. Advanced datastore : property types Advanced datastore : queries and indices Google app engine services Server computing in the cloud Security in app engine services Administering your app engine deployment Wrapping up. Cloud applications are the next big shift in application development: instead of building single-user applications to run on a personal computer, new applications are being built as multi-user services that run in data centers around the world. One of the most exciting new environments for building services in the cloud is Google's AppEngine.