Web Application Architecture Principles Protocols and Practices 2nd Edition by Leon Shklar, Rich Rosen ISBN 9780470518601 047051860X

CHAPTER 1 Introduction

1.1 History and Pre-History of the Web

1.2 From Web Pages to Web Sites

1.3 From Web Sites to Web Applications

1.4 Web 2.0: On-line Communities and Collaboration

1.5 The Brave New World of AJAX

1.6 Focus of This Book

1.7 What Is Covered in This Book

1.8 Bibliography

CHAPTER 2 Core Internet Protocols

2.1 Historical Perspective

2.2 TCP/IP Architecture

2.2.1 Protocol layers

2.2.2 Comparison with OSI model

2.2.3 The client–server paradigm

Command line vs GUI

Client–server communications

2.3 TCP/IP Application Services

2.3.1 Telnet

2.3.2 E-mail

SMTP

Figure 2.1 Command-line interaction with an SMTP server.

POP

Figure 2.2 Message header block.

Figure 2.3 Command-line interaction with a POP3 server.

IMAP

Web-based e-mail services

2.3.3 Message forums

2.3.4 Chat and messaging protocols

2.3.5 Security and encryption

2.3.6 File server protocols

2.4 And Then Came the Web …

QUESTIONS AND EXERCISES

2.5 Bibliography

CHAPTER 3 Birth of the Web: HTTP

3.1 Historical Perspective

3.1.1 CERN: birthplace of the web

3.1.2 Building blocks of the web

3.2 Uniform Resource Locator

3.3 Fundamentals of HTTP

3.3.1 Request–response paradigm

3.3.2 Stateless protocol

Figure 3.1 The request–response virtual circuit.

3.3.3 Structure of HTTP messages

3.3.4 Request methods

Figure 3.2 Sequence of requests and responses to load a simple web page.

Figure 3.3 A web form (a) displayed in a browser and (b) the HTML that creates the form.

GET method

POST method

3.3.5 Status codes

Informational status codes (1xx)

Successful response status codes (2xx)

Redirection status codes (3xx)

Client request error status codes (4xx)

Server error status codes (5xx)

3.4 Better Information Through Headers

3.4.1 Support for content types

3.4.2 Caching control

3.4.3 Security

HTTP authentication

3.4.4 Session support

3.5 Evolution of the HTTP Protocol

3.5.1 Virtual hosting

3.5.2 Caching support

3.5.3 Persistent connections

3.6 Summary

QUESTIONS AND EXERCISES

3.7 Bibliography

CHAPTER 4 HTML and Its Roots

Figure 4.1 SGML, XML, and their applications.

4.1 Standard Generalized Markup Language

4.1.1 SGML declaration

Document character set

Figure 4.2 An SGML character set definition for EBCDIC characters.

Figure 4.3 SGML character set definition for HTML 4.

Concrete syntax

Figure 4.4 SGML syntax specification for HTML 4.

Feature usage

4.1.2 Document Type Definition

Entity definitions

Element definitions

Figure 4.5 Entity definitions.

Figure 4.6 Element definitions.

Figure 4.7 Valid HTML tables.

Figure 4.8 Invalid HTML table (TFOOT occurs after TBODY).

Attribute definitions

Figure 4.9 Attribute definitions for the TABLE and TH elements.

4.2 HTML

4.2.1 Evolution of HTML

4.2.2 Structure and syntax

Figure 4.10 Document compliant with HTML 4.01.

HTML header

Figure 4.11 META elements.

Figure 4.12 STYLE element.

Figure 4.13 SCRIPT element.

HTML body

Content accessibility

Figure 4.14 Simple HTML page.

HTTP requests

Figure 4.15 File submission form.

Figure 4.16 Sample file transfer request.

4.3 HTML Rendering

4.3.1 Cascading Style Sheets

Figure 4.17 CSS rules for the

element.

Figure 4.18 Sample box and classification properties.

4.3.2 Associating styles with HTML documents

Linked style sheet

Figure 4.19 Using the HTML element to associate styles.

Embedded style sheet

Inline style

Figure 4.20 Embedded style sheet.

Figure 4.21 Inline styles.

Figure 4.22 Associating styles with portions of HTML documents.

4.4 Summary

QUESTIONS AND EXERCISES

4.5 Bibliography

CHAPTER 5 XML Languages and Applications

5.1 Core XML

5.1.1 XML documents

Figure 5.1 Sample XML document.

5.1.2 XML DTD

Figure 5.2 XML element tree for the document in Figure 5.1.

Figure 5.3 XML DTD for the document in Figure 5.1.

Figure 5.4 Fragment of an SGML DTD for the document in Figure 5.1.

5.1.3 XML Schema

Figure 5.5 Schema-based validation for the XML document in Figure 5.1.

Figure 5.6 XML Schema for the sample document in Figure 5.1.

Figure 5.7 Improved schema design for the sample document in Figure 5.1.

Figure 5.8 Defining constraints on simple types.

Figure 5.9 Using defined simple types in the XML schema from Figure 5.7.

5.2 XHTML

Figure 5.10 XHTML document.

Figure 5.11 Examples of valid HTML and XHTML.

Figure 5.12 XHTML script syntax.

5.2.1 HTML 5

5.2.2 XHTML MP

Figure 5.13 XHTML MP document.

Figure 5.14 Screen captures for the XHTML MP document in Figure 5.13.

5.3 Web Services

5.3.1 SOAP

Figure 5.15 A SOAP request with multiple parameters.

Figure 5.16 The SOAP request from Figure 5.15 transmitted over HTTP.

Web Services Definition Language (WSDL)

Figure 5.17 The response to the SOAP request in Figure 5.16.

Figure 5.18 A WSDL definition for the weather service in Figure 5.15.

Universal Description, Discovery, and Integration (UDDI)

Figure 5.19 A UDDI request from a SOAP client.

Figure 5.20 A UDDI response to the request in Figure 5.19.

5.3.2 Representational State Transfer (REST)

Figure 5.21 A request to publish a web service in a UDDI registry.

Figure 5.22 A REST-compliant URL.

Figure 5.23 A representation of a REST resource.

Figure 5.24 Representation of the weather report.

5.4 XSL

5.4.1 XSLT

Figure 5.25 XSLT style sheet.

Figure 5.26 Result of applying the transformation in Figure 5.25 to the document in Figure 5.1.

5.4.2 XSL Formatting Objects

Figure 5.27 Using a CSS style sheet to render HTML and XHTML documents.

Figure 5.28 One way of using an XSL style sheet to print an XML document.

Figure 5.29 Another way of using XSL style sheets to print XML documents.

Figure 5.30 XSL-FO version of the XSL style sheet from Figure 5.25.

Figure 5.31 The pagelayout.xsl file referenced from the style sheet in Figure 5.30.

Figure 5.32 The attributes.xsl file referenced from the XSL style sheet in Figure 5.30.

5.4.3 What is so important about XSL?

Figure 5.33 Output of the XSLT processor.

Figure 5.34 PDF output of the XSL-FO processor.

5.5 Summary

QUESTIONS AND EXERCISES

5.6 Bibliography

5.7 Web Links

5.8 Endnotes

CHAPTER 6 Web Servers

6.1 Basic Operation

Figure 6.1 Server operation.

6.1.1 HTTP request processing

Figure 6.2 Browser request to load the page.

Figure 6.3 Simple HTML page returned to browser.

Figure 6.4 Browser request to load the school.html page.

6.1.2 Delivery of static content

Static content pages

Figure 6.5 Response to the request in Figure 6.4.

As-is pages

6.1.3 Delivery of dynamic content

CGI

Table 6.1 CGI environment variables

Figure 6.6 Form for submitting user name and zip code.

Figure 6.7 HTTP request submitted by the browser for the form in Figure 6.6.

Figure 6.8 Form and query string processing in CGI code.

Figure 6.9 Printing parameters in CGI code.

SSI

Figure 6.10 Using SSI instead of the CGI program from Figure 6.9.

Figure 6.11 Companion CGI program for the SSI instruction in Figure 6.10.

6.2 Mechanisms for Dynamic Content Delivery

6.2.1 Beyond CGI and SSI

6.2.2 Native APIs (ISAPI and Apache Server API)

6.2.3 FastCGI

6.2.4 Template processing

Figure 6.12 Template for Cold Fusion.

6.2.5 Servlets

Figure 6.13 Parameter processing in servlets.

6.2.6 Java Server Pages

Figure 6.14 Parameter processing in JSP.

6.2.7 Future directions

6.3 Advanced Functionality

6.3.1 Virtual hosting

6.3.2 Chunked transfers

Figure 6.15 HTTP response for a chunked transfer.

6.3.3 Caching support

6.3.4 Extensibility

6.4 Server Configuration

6.4.1 Directory structure

6.4.2 Execution

Figure 6.16 Fragment of a configuration file.

6.4.3 Address resolution

Figure 6.17 A configuration fragment.

6.4.4 MIME support

Figure 6.18 Fragment of the Apache MIME configuration file.

6.4.5 Server extensions

Figure 6.19 Defining server extensions in Apache.

6.5 Server Security

6.5.1 Securing the installation

6.5.2 Dangerous practices

6.5.3 Secure HTTP

6.5.4 Firewall configurations

6.5.5 HTTP proxies

6.6 Summary

QUESTIONS AND EXERCISES

6.7 Bibliography

CHAPTER 7 Web Browsers

7.1 Overview of Browser Functionality

7.2 Architectural Considerations

7.3 Overview of Processing Flow in a Browser

7.3.1 Transmitting a request

Figure 7.1 Browser request generation flow.

Table 7.1 Resolution of Relative URLs

7.3.2 Receiving a response

Figure 7.2 Browser response processing flow.

7.4 Processing HTTP Requests

7.4.1 Constructing the request line

7.4.2 Constructing the headers

7.4.3 Constructing the request body

7.4.4 Transmitting the request

7.5 Processing HTTP Responses

7.5.1 Processing successful responses

7.5.2 Processing responses with other status codes

7.6 Cookie Coordination

7.7 Privacy and P3P

7.8 Complex HTTP Interactions

7.8.1 Caching

Figure 7.3 Optimized usage of cached resources with HTTP/1.0 and HTTP/1.1.

7.8.2 Authorization: challenge and response

7.8.3 Using common mechanisms for data persistence

Table 7.2 Browser Mechanisms for Persistence

7.8.4 Requesting supporting data items

Figure 7.4 Browser steps for requesting supporting data items.

7.8.5 Multimedia support: helpers and plug-ins

7.9 Summary

Table 7.3 Browser modules and their respective responsibilities

QUESTIONS AND EXERCISES

7.10 Bibliography

7.11 Web Links

7.12 Endnotes

CHAPTER 8 Active Browser Pages: From JavaScript to AJAX

8.1 Pre-History

8.2 JavaScript

8.2.1 Manipulating page content

8.2.2 Client-side form validation

Figure 8.1 Example of client-side form validation using JavaScript.

Figure 8.2 Simple implementation of onmouseover behavior.

8.2.3 Hovering behaviors: image rollover

8.2.4 JavaScript Object Notation

Figure 8.3 A complex JavaScript object defined using JSON.

Figure 8.4 Accessing attributes of the JavaScript object defined in Figure 8.3.

8.2.5 Summary

8.3 Cascading Style Sheets

8.3.1 Format of CSS rules

8.3.2 Hovering behaviors: the a:hover pseudo-class

Figure 8.5 Using the a:hover pseudo-class to implement image rollover.

8.3.3 Summary

8.4 DHTML

8.4.1 Inner workings

8.4.2 Controlling content visibility

Figure 8.6 Using CSS to create a tabbed interface.

8.4.3 Leveraging toolkits

Figure 8.7 Creating a tabbed interface using the Prototype toolkit.

Figure 8.8 Creating a tabbed interface using Scriptaculous effects.

8.4.4 Client-side validation using toolkits

Table 8.1 Validation Classes Defined in validation.js

8.4.5 Hovering behaviors using toolkits

Figure 8.9 Using Dexagogo’s validation.js toolkit.

8.4.6 Widgets

Google AdSense

Amazon Associates

Snap Shots

8.4.7 Summary

8.5 AJAX

8.5.1 Content injection: manual approach

Figure 8.10 Manual coding of AJAX functionality with custom callback function.

8.5.2 Content injection: using toolkits

8.5.3 Auto-completion

Figure 8.11 Content injection using the Dojo toolkit.

Figure 8.12 Content injection using Prototype’s Ajax.Updater.

8.5.4 Remote validation

Figure 8.13 Using Scriptaculous’s Ajax.AutoCompleter.

8.5.5 Where does DHTML end and AJAX begin?

Figure 8.14 Using Prototype’s Ajax.Request to perform remote validation.

8.5.6 Summary

8.6 Case Study: 5-Star Rating

Figure 8.15 Star-rating images: unrated (gray), mouse-over highlighting (yellow) and recorded (red).

8.6.1 Designing a star-rating component

Figure 8.16 CSS style sheet definitions for list items representing each star type.

Figure 8.17 Code fragment containing the highlightAllToLeft function.

Figure 8.18 Code fragment containing the unhighlightAll function.

Figure 8.19 Code fragment containing the unhighlightAll function.

Figure 8.20 Code fragment that sets up handlers for all rating blocks.

8.6.2 When you click upon a star: what happens on the server?

8.7 Summary

QUESTIONS AND EXERCISES

8.8 Bibliography

8.9 Web Links

8.10 Endnotes

CHAPTER 9 Approaches to Web Application Development

9.1 Taxonomy of Web Application Approaches and Frameworks

9.1.1 Programmatic approaches

9.1.2 Template approaches

9.1.3 Hybrid approaches

9.1.4 Frameworks

Application flexibility

Figure 9.1 Model–View–Controller design pattern.

Division of responsibility for processing modules

9.2 Comparative Survey of Web Application Approaches and Frameworks

9.2.1 CGI and FastCGI

9.2.2 Server-Side Includes (SSI)

9.2.3 PHP

9.2.4 Java Servlet API

9.2.5 Cold Fusion

Figure 9.2 Simple Cold Fusion example involving a database query

9.2.6 Velocity

9.2.7 Active Server Pages and .NET

Figure 9.3 ASP example

9.2.8 Java Server Pages

Figure 9.4 Sample JSP page

Figure 9.5 The result of translating the JSP page in Figure 9.4 into servlet code

Figure 9.6 Using a JavaBean property with the < syntax

9.2.9 JSP Model 2

9.2.10 Java Standard Tag Library

Figure 9.7 A JSP page using JSTL

9.2.11 Struts

Figure 9.8 Sample struts-config.xml file

9.2.12 Java Server Faces

9.2.13 JBoss Seam

9.2.14 Rapid application development: Ruby on Rails

Figure 9.9 Parameter substitution using embedded Ruby syntax

9.3 Summary

Table 9.1 Comparison of Web Application Development Approaches

QUESTIONS AND EXERCISES

9.4 Bibliography

CHAPTER 10 Web Application Primer 1: Struts and JSTL

10.1 Case Study: Virtual Realty Listing Services

Figure 10.1 Search and access scenario.

10.2 Application Requirements

10.3 Technology Choices

10.4 Overview of Struts

Figure 10.2 Fragment of a struts-config.xml file.

Figure 10.3 Example of an Action class.

10.5 Structure of the VRLS Application

10.5.1 Configuration

Figure 10.4 Fragment of the web.xml configuration file for the VRLS application.

Table 10.1 Action Mapping Summary for the VRLS Application

10.5.2 Controller components

/action/home

/action/authcheck

Figure 10.5 Action class hierarchy for the VRLS application.

Figure 10.6 Simplified code for VrlsBaseAction class.

/action/login

/action/profile

/action/search

/action/details

/action/images

/action/contact

10.5.3 View components

Figure 10.7 ActionForm class hierarchy for the VRLS application.

Figure 10.8 Shared include.jsp file.

Figure 10.9 Shared main.jsp file.

Figure 10.10 Label definitions for the navigation bar.

home.jsp

login.jsp

profile.jsp

Figure 10.11 Template fragment for login.jsp

profileConfirm.jsp

search.jsp

results.jsp

details.jsp

contact.jsp

10.5.4 Model components

CustomerProfile

Figure 10.12 Model class hierarchy.

Partner

Listing

Database schema

10.6 Design Decisions

10.6.1 Abstracting functionality into service classes

Figure 10.13 Entity–relationship diagram for application database schema.

Benefits

Alternatives or improvements

10.6.2 Including embedded pages to support co-branding

Benefits

Alternatives or improvements

10.6.3 Creating and modifying customer profiles in one task

10.7 Suggested Enhancements

10.7.1 Adding an administrative interface

10.7.2 Enhancing the signup process through e-mail authentication

10.7.3 Improving partner recognition through a persistent cookie

10.7.4 Adding caching functionality to the DomainService Class

Figure 10.14 Object caching.

10.7.5 Paging through cached search results

10.7.6 Using XML and XSLT for view presentation

Figure 10.15 Example of parsing XML documents using the JSTL tag.

10.7.7 Tracking user behavior

10.7.8 Using an object-relational mapping tool

10.7.9 Adding DHTML and AJAX for an enhanced user experience

10.8 Summary

QUESTIONS AND EXERCISES

10.9 Bibliography

CHAPTER 11 Web Application Primer 2: Ruby on Rails

11.1 Comparing Rails with Java EE

11.1.1 Similarities

11.1.2 Differences

11.2 Application Requirements

11.3 Building the Administrative Interface as a Rails Application

11.3.1 Downloading and installing Ruby and Rails

11.3.2 Building an application skeleton

Figure 11.1 Output from executing the rails example command.

Table 11.1 Directories and Files Created by the rails Command

Figure 11.2 Browser error when example_app/hello.html.erb does not exist.

Figure 11.3 Browser display after creating example_app/hello.html.erb.

11.3.3 Creating a new project and configuring the database

Figure 11.4 Modified config/database.yml file.

11.3.4 Scaffolding for the model, view, and controller classes

Figure 11.5 The script/generate scaffold command.

Figure 11.6 Modified contents of app/models/listing.rb.

Figure 11.7 Displaying https://localhost:3000/listings.

Figure 11.8 Displaying https://localhost:3000/listings/1.

Figure 11.9 Displaying https://localhost:3000/listings/1/edit.

Table 11.2 URL Mapping Scheme for the Entity Class

11.3.5 Enhancing the application

Completing the data model

Customizing views and using lookup tables

Figure 11.10 Enhanced display using modified app/views/listing/index.html.erb.

Figure 11.11 Display of https://localhost:3000/listings/1 after customization.

Figure 11.12 Display of https://localhost:3000/listings/1/edit after customization.

Form validation

Figure 11.13 New customer form page with validation errors highlighted.

Pagination

Reusable layout components

Figure 11.14 Browser display with pagination.

Figure 11.15 Content of generated app/views/layouts/listing.html.erb.

Figure 11.16 Content of modi ed app/views/layouts/listing.html.erb.

Figure 11.17 Browser display for listings page with modified layout.

Authentication and authorization

Replacing the Rails home page

Summary

11.4 Benefits and Drawbacks of Using Rails

11.4.1 How rapid is rapid application development?

11.4.2 Database support

11.4.3 Limitations of scaffolding

11.4.4 Scalability

11.4.5 Performance and clustering

11.4.6 Version 2.0 issues

11.4.7 Is Rails web-designer-friendly?

Figure 11.18 Nested tags.

11.5 Whither Enterprise Java?

11.6 Summary

QUESTIONS AND EXERCISES

11.7 Bibliography

11.8 Web Links

11.9 Endnotes

CHAPTER 12 Search Technologies

12.1 Overview of Algorithms

12.1.1 Historical perspective

12.1.2 Basic vector-space algorithm

Figure 12.1 Documents to be indexed.

Figure 12.2 Documents with stop words identified for removal.

Figure 12.3 Documents with stemming changes identified.

Figure 12.4 Documents with unique words identified.

Figure 12.5 Search dictionary.

Figure 12.6 Representation of documents as 40-dimensional vectors.

Example

Enhancement 1: weighting for multiple occurrences

Enhancement 2: weighting for phrases

Figure 12.7 Search dictionary with synonymous phrases.

Figure 12.8 Vector space with synonymous phrases.

Figure 12.9 Vector space with heuristic multiple for phrases.

12.1.3 Common enhancements

12.1.4 Word clustering

12.1.5 Custom biases

12.2 Searching the Web

12.2.1 Google page ranking

12.2.2 Web spiders

Figure 12.10 Spider architecture.

12.2.3 Summary

12.3 Site Search Applications

12.3.1 General architecture

Figure 12.11 Structure of a search application.

12.3.2 Lucene

Figure 12.12 Alternative structure of a search application.

Figure 12.13 Creating indexable Lucene documents for Microsoft Word files.

Figure 12.14 Creating indexable Lucene documents for HTML files.

Figure 12.15 Creating a Lucene index.

Figure 12.16 Querying a Lucene index.

12.3.3 OneBox applications

Figure 12.17 OneBox quote retrieval using the Prototype toolkit.

Figure 12.18 HTML fragment that enables OneBox quote retrieval.

12.4 Search Engine Optimization

12.4.1 Robots.txt

Figure 12.19 Sample robots.txt configurations.

Figure 12.20 Meta tag instructions for spiders.

Figure 12.21 Common robots.txt extensions.

12.4.2 Sitemaps

Figure 12.22 Sitemap instructions in robots.txt.

Figure 12.23 Sample sitemap.

Figure 12.24 Sample sitemap index file.

Figure 12.25 Sample sitemap file for current local news (sitemap_local_news_current.xml).

Figure 12.26 Sample sitemap file for recent local news (sitemap_local_news_ recent.xml).

12.4.3 Sitemap extensions

12.4.4 Site and URL structure

Figure 12.27 Google News sitemap extension.

12.4.5 Black Hat SEO

12.5 Summary

QUESTIONS AND EXERCISES

12.6 Bibliography

12.7 Web Links

12.8 Endnotes

CHAPTER 13 Trends and Directions

13.1 XML Query Language

Figure 13.1 Modified sample.xml file.

Figure 13.2 Sample XQuery expressions.

Figure 13.3 Daily sales log in XML format.

Figure 13.4 XQuery statement for the sales log.

13.2 Semantic Web

13.2.1 Resource Description Framework (RDF)

Dublin Core

Figure 13.5 Sample RDF model.

Figure 13.6 N3 representation of the RDF model in Figure 13.5.

Figure 13.7 XML representation of the RDF model in Figure 13.5.

Figure 13.8 Extending the RDF model from Figure 13.5.

Figure 13.9 N3 representation of the RDF model in Figure 13.8.

Figure 13.10 XML representation of the RDF model in Figure 13.8.

RDF Schema

Figure 13.11 Sample RDF schema.

Figure 13.12 An invalid RDF model according to the schema in Figure 13.11.

Figure 13.13 A valid version of the model according to the schema in Figure 13.11.

13.2.2 Composite Capabilities/Preference Profiles

Figure 13.14 Sample device description.

13.2.3 RDF query language

Figure 13.15 Sample description of device software.

Figure 13.16 Individual hardware profile.

Figure 13.17 Querying the RDF model: a) two SPARQL queries, b) the result of the first query and c) the result of the second query.

Figure 13.18 a) A multi-pattern SPARQL query and b) its result.

13.3 Future of Web Application Frameworks

13.3.1 One more time: separate content from presentation

13.3.2 Use the right tools for the job

Figure 13.19 Example of page fragment using JSTL foreach and if tags.

Figure 13.20 Browser preview of the page fragment without framework integration.

13.3.3 Simplicity

Figure 13.21 Dialog box for specifying content to be displayed by an iterative page construct.

Figure 13.22 Browser preview of the page fragment with framework integration.

13.4 Current Trends

13.4.1 Everything old is new again

13.4.2 Social networking and community web sites

13.4.3 Cloud computing and ‘‘Weblications’’

13.5 Summary

QUESTIONS AND EXERCISES

13.6 Bibliography

13.7 Web Links

13.8 Endnotes

CHAPTER 14 Conclusions

Back Matter

Index