Introduction to middleware

INTRODUCTION

TO

MIDDLEWARE

Web Services, Object Components,

and Cloud Computing

INTRODUCTION

TO

MIDDLEWARE

Web Services, Object

Components, and

Cloud Computing

Letha Hughes Etzkorn

CRC Press

Taylor & Francis Group

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© 2017 by Taylor & Francis Group, LLC

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Dedication

To my husband and sweetheart, Dave, who always does so much for me

(he did most of the review of the proofs for this textbook), to the other centers

of my heart: Tricia and Chris, and to the memory of Daddy and Mama.

Mama always wanted one of her kids to write a book, although I don't think

a textbook was what she had in mind.

Contents

Online Resources ............................................................................................................................xix

Preface.............................................................................................................................................xxi

Author ............................................................................................................................................ xxv

SECTION I The Different Paradigms

Chapter 1 Introduction ..................................................................................................................3

1.1 What Is Middleware? ........................................................................................ 4

1.2 Technology Review: Sockets............................................................................ 5

1.2.1 Socket Data Structures......................................................................... 5

1.2.2 Socket Library Calls ........................................................................... 7

1.2.3 Network Byte Order and How It Is Used with Sockets ..................... 8

1.2.4 General Socket Operation.................................................................... 9

1.2.5 Simple Socket Example..................................................................... 10

1.2.6 Sending Data Other than Char Data—Problems with Endianness...... 17

1.3 Brief Introduction to Other Middlewares........................................................ 18

1.3.1 What Are Remote Procedure Calls?—Also Introduction to

Synchronous and Asynchronous Operation ...................................... 18

1.3.2 What Are Distributed Object-Oriented Components?....................... 20

1.3.3 What Is Message-Oriented Middleware? .......................................... 20

1.3.4 What Are Service-Oriented Architectures? ....................................... 21

1.3.5 What Are Web Services?................................................................... 22

1.3.6 What Is Cloud Computing?............................................................... 23

1.4 Environmental Monitoring Project.................................................................. 23

1.5 Sailboat Marina Management Project ............................................................. 25

Exercises .................................................................................................................... 26

Conceptual Questions ................................................................................................ 27

Bibliography............................................................................................................... 27

Chapter 2 Software Architectural Styles/Patterns for Middleware .............................................31

2.1 Just What Is a “Software Architecture,” Anyway?......................................... 31

2.2 Architectural Styles/Patterns ........................................................................... 33

2.3 Architectural Styles/Patterns for Middleware ................................................. 35

2.3.1 Gomaa’s Architectural Patterns ......................................................... 35

2.3.2 Fielding’s Architectural Styles .......................................................... 37

2.3.3 Fielding’s Architectural Properties .................................................... 39

2.4 Architectural Styles/Patterns for Distributed Object-Oriented Components......43

2.5 Architectural Styles/Patterns for Service-Oriented Architectures ................... 44

2.6 Architectural Styles/Patterns for Web Services .............................................. 46

2.7 Architectural Styles/Patterns for Cloud Computing........................................ 46

Exercises .................................................................................................................... 48

Conceptual Questions ................................................................................................ 48

Bibliography............................................................................................................... 48

vii

SECTION II Enabling Technologies for Middleware

Chapter 3 Introduction to Internet Technologies ........................................................................55

3.1 Just What Is the Internet, Anyway? ................................................................ 55

3.2 Brief Introduction to TCP/IP and UDP........................................................... 55

3.3 IP Addresses (IPv4 and IPv6) and Subnetting................................................ 57

3.3.1 IPv4 Addresses .................................................................................. 57

3.3.1.1 Private IP Addresses and Network Address Translation ..... 58

3.3.2 IPv6 Addresses .................................................................................. 58

3.3.3 Subnetting ......................................................................................... 59

3.4 Port Numbers .................................................................................................. 60

3.5 Other Important Network Information............................................................ 61

3.5.1 Internet Control Message Protocol .................................................... 61

3.5.2 LAN Protocols: Ethernet and Wi-Fi.................................................. 61

3.5.3 Media Access Control Addresses ...................................................... 62

3.5.4 Hubs, Bridges, Switches, and Routers............................................... 62

3.5.5 Autoconfiguration for IPv4: Dynamic Host

Configuration Protocol ...................................................................... 63

3.5.6 Autoconfiguration for IPv6................................................................ 64

3.5.6.1 DHCP for IPv6 .................................................................. 65

3.5.7 Virtual Local Area Network .............................................................. 65

3.6 Universally Unique Identifiers ........................................................................ 66

Exercises .................................................................................................................... 68

Conceptual Questions ................................................................................................ 68

Bibliography............................................................................................................... 69

Chapter 4 Introduction to World Wide Web Technologies........................................................71

4.1 Just What Is the Web, Anyway?..................................................................... 71

4.2 Hypertext Transfer Protocol............................................................................ 71

4.3 HTML, XML, and HTML Forms................................................................... 72

4.4 XML Schema Basics....................................................................................... 79

4.5 JavaScript Object Notation (JSON) ................................................................ 81

4.6 Internet Media Types (MIME Types)............................................................. 82

4.7 Base 64 Encoding ........................................................................................... 82

4.8 URL Encoding (Percent Encoding) and URL Base 64 Encoding .................. 85

4.9 Domain Names and Domain Name Servers ................................................... 85

4.10 Document Object Model and Browser Object Model .................................... 87

4.11 Popular Web Servers....................................................................................... 88

4.11.1 Web/Application Servers: LAMP versus Windows/ASP

versus Java......................................................................................... 89

4.11.1.1 MySQL—The M in LAMP................................................ 89

4.11.1.2 Using Java Database Connectivity (JDBC) with MySQL ....91

4.11.1.3 Using MySQLi in PHP with MySQL ................................ 93

4.11.2 GlassFish Application Server ............................................................ 95

4.11.2.1 How to Start GlassFish and Run an Application

on GlassFish ....................................................................... 95

4.12 cURL............................................................................................................... 99

Exercises .................................................................................................................. 101

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Conceptual Questions .............................................................................................. 101

Bibliography............................................................................................................. 102

Chapter 5 Security Basics .........................................................................................................105

5.1 Just Why Should Anyone Care About Security, Anyway? .......................... 105

5.2 Symmetric Key Cryptography and Asymmetric Key/Public

Key Cryptography ........................................................................................ 105

5.3 Hash (Message Digest) Functions ................................................................ 105

5.4 Digital Signatures and Message Authentication Codes ................................ 106

5.5 Public Key Infrastructure and Certificate Authorities................................... 107

5.6 Transport Layer Security and Secure Sockets Layer .................................... 108

5.6.1 But How Does TLS Work? ............................................................. 108

5.7 Cryptographic Message Syntax..................................................................... 110

Exercises .................................................................................................................. 112

Conceptual Questions .............................................................................................. 112

Bibliography............................................................................................................. 112

Chapter 6 Microsoft Technologies Basics ................................................................................115

6.1 Microsoft “World” versus the Rest of the World ......................................... 115

6.2 Dynamic Link Library Files and Windows Side by Side ............................. 115

6.3 Common Language Runtime (CLR)............................................................. 116

6.4 Global Assemblies Cache ............................................................................. 117

6.5 Named Pipes in Windows............................................................................. 118

Exercises .................................................................................................................. 119

Conceptual Questions .............................................................................................. 120

Bibliography............................................................................................................. 120

Chapter 7 Cloud Technologies Basics ...................................................................................... 121

7.1 What You Need to Know for the Cloud....................................................... 121

7.2 Just What Are Disk Images and Virtual Machine Images, Anyway?........... 121

7.2.1 Various Kinds of Disk Images and Virtual Machine Images.......... 121

7.3 Just What Are Hypervisors and Virtual Machines, Anyway? ...................... 123

7.3.1 Some Examples of Type 2 Hypervisors .......................................... 124

7.3.1.1 Some VirtualBox Installation Hints ................................. 125

7.3.2 Some Examples of Type 1 Hypervisors .......................................... 125

7.3.2.1 libvirt ................................................................................ 126

7.4 Software-Defined Networking and Network Virtualization ......................... 126

7.4.1 Open vSwitch/OpenFlow and Linux Bridge ................................... 128

7.4.1.1 OpenFlow ......................................................................... 129

7.4.1.2 How Open vSwitch Works............................................... 130

7.5 Virtualization Security .................................................................................. 130

7.5.1 Hypervisor Security ......................................................................... 131

7.6 Cloud Security............................................................................................... 134

7.6.1 Physical Data Center Security ......................................................... 136

Exercises .................................................................................................................. 137

Conceptual Questions .............................................................................................. 137

Bibliography............................................................................................................. 137

Contents ix

SECTION III Middleware Using Distributed Object-Oriented

Components

Chapter 8 Distributed Object-Oriented Components................................................................ 143

8.1 Just What Do We Mean by “Object-Oriented Middleware” and

“Component Middleware,” Anyway?........................................................... 143

8.2 Technology Review: Common Object Request Broker Architecture

(CORBA) ...................................................................................................... 144

8.2.1 Basic CORBA Concepts.................................................................. 145

8.2.1.1 First Look at CORBA: Overview of Simple

Echo Example................................................................... 147

8.2.2 Interface Description Language....................................................... 151

8.2.3 CORBA IDL to C++/C and CORBA IDL to Java Bindings .......... 158

8.2.3.1 CORBA IDL to C++ Binding .......................................... 160

8.2.3.2 CORBA IDL to Java Binding .......................................... 166

8.2.4 CORBA Addressing—How Does the Client Find the Server

and Associated Servant?.................................................................. 169

8.2.4.1 Interoperable Object Reference and the CORBA

Naming Service ................................................................ 170

8.2.4.2 CORBA Interoperable Naming Service (corbaloc

and corbaname) ................................................................ 177

8.2.5 Simplest Echo Example................................................................... 179

8.2.5.1 Echo Example—Server Side ............................................ 179

8.2.5.2 Echo Example—Client Side............................................. 185

8.2.6 Echo Example Using Naming Service ............................................ 188

8.2.7 CORBA Under the Hood and Some Leftover CORBA Stuff......... 191

8.2.7.1 CORBA Under the Hood ................................................. 191

8.2.7.2 Some Leftover CORBA Stuff .......................................... 193

8.2.8 Portable Object Adapter .................................................................. 195

8.2.8.1 Introduction to POA Policies ........................................... 196

8.2.9 Echo Example—Default Servant..................................................... 200

8.2.10 Echo Example—Persistent POA and Default Servant .................... 203

8.3 Technology Review: .NET Remoting........................................................... 206

8.3.1 .NET Remoting Basics .................................................................... 206

8.3.1.1 Application Domains (Appdomains)................................ 207

8.3.1.2 Assemblies and Metadata................................................. 208

8.3.1.3 Manifest Files ................................................................... 208

8.3.1.4 .NET Library Files ........................................................... 212

8.3.2 Call C# from C#, Not Using Remoting........................................... 212

8.3.3 .NET Remoting Using Marshaling by Value .................................. 214

8.3.4 Marshal by Reference: The Heart of .NET Remoting..................... 214

8.3.5 Client-Activated Object ................................................................... 218

8.3.6 Server-Activated Single Call ........................................................... 221

8.3.7 Server-Activated Singleton.............................................................. 223

8.3.8 How to Handle Different Kinds of Channels .................................. 225

8.3.9 How to Handle Different Kinds of Formatters................................ 227

8.3.10 Remote Object Lifetimes—Leases on Objects................................ 228

8.3.11 Asynchronous .NET Remoting ....................................................... 232

8.3.11.1 Asynchronous .NET Remoting—Polling......................... 233

8.3.11.2 Asynchronous .NET Remoting—Callback Function....... 236

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8.4 Technology Review: Enterprise Java Beans................................................. 242

8.4.1 A Brief Introduction to Session Bean Concepts.............................. 243

8.4.2 Environment and Procedures Used to Build and Run

EJB Examples.................................................................................. 244

8.4.3 Stateless Session Beans ................................................................... 245

8.4.3.1 Very Simple Stateless Session Bean Example ................. 245

8.4.3.2 Very Simple Stateless Session Bean Example Passes

an Array Parameter........................................................... 248

8.4.3.3 Very Simple Stateless Session Bean Example Passes

an Object Parameter ......................................................... 249

8.4.3.4 Very Simple Stateless Session Bean Example with

Injection, and Local and Remote Interfaces..................... 250

8.4.3.5 Simple Stateless Session Bean Example That

Illustrates Stateless Characteristics................................... 254

8.4.4 Singleton Session Beans.................................................................. 258

8.4.5 Stateful Session Beans..................................................................... 260

8.4.5.1 Stateful Session Bean Example........................................ 261

8.4.5.2 Stateful Session Bean Asynchronous ............................... 264

8.4.5.3 Stateful Session Bean Lifecycle Callbacks ...................... 267

8.4.5.4 Stateful Session Bean Lifecycle Callbacks Forces

Passivate ........................................................................... 272

CORBA Exercises.................................................................................................... 279

.NET Remoting Exercises........................................................................................ 280

EJB Exercises........................................................................................................... 280

Conceptual Questions .............................................................................................. 281

Bibliography............................................................................................................. 281

SECTION IV Middleware Using Web Services

Chapter 9 Web Services Architectures ..................................................................................... 287

9.1 Service-Oriented Architectures ..................................................................... 287

9.1.1 In-Depth Look at Service-Oriented Architecture ............................ 288

9.1.2 The Relationship between SOA and Cloud Computing.................. 291

9.1.3 Implementations of Service-Oriented Architectures........................ 292

9.2 RESTful Architectural Style and Non-RESTful versus RESTful

Web Services................................................................................................. 293

9.2.1 RESTful Architectural Style............................................................ 293

9.2.2 Non-RESTful versus RESTful Web Services ................................. 295

Exercises .................................................................................................................. 297

Conceptual Questions .............................................................................................. 297

Bibliography............................................................................................................. 298

Chapter 10 Non-RESTful Web Services ....................................................................................301

10.1 Just What Do We Mean by “Non-RESTful Web Services,” Anyway? ....... 301

10.2 SOAP Messaging Protocol ........................................................................... 302

10.2.1 Overall SOAP Message Format ...................................................... 303

10.2.2 Encoding of SOAP Messages.......................................................... 303

Contents xi

10.2.3 SOAP Message Formats.................................................................. 305

10.2.3.1 RPC-SOAP Encoded Message Format ............................ 306

10.2.3.2 RPC-Literal Message Format ........................................... 307

10.2.3.3 Document-Literal Message Format .................................. 307

10.2.3.4 Document-Literal Wrapped Message Format .................. 309

10.2.3.5 Summary of Pros and Cons of the Different SOAP

Message Formats.............................................................. 310

10.2.4 SOAP Faults .................................................................................... 312

10.2.5 SOAP Headers................................................................................. 316

10.2.6 SOAP Binding to HTTP.................................................................. 317

10.3 Technology Review: Web Services Description Language (WSDL)........... 317

10.3.1 WSDL 1.1 Format ........................................................................... 318

10.3.2 WSDL 2.0 Format ........................................................................... 320

10.3.3 WSDL Message Exchange Patterns ................................................ 322

10.3.4 RESTful Web Services through WADL and WSDL 2.0 ................ 323

10.3.4.1 Web Application Description Language (WADL)........... 323

10.3.4.2 Web Services Description Language 2.0

RESTful Mapping ............................................................ 324

10.4 Technology Review: Java API for XML Web Services (JAX-WS)............. 325

10.4.1 Brief Introduction to JAX-WS Concepts......................................... 325

10.4.2 Creating JAX-WS Clients ............................................................... 329

10.4.2.1 Client Created Using wsimport ........................................ 329

10.4.2.2 Dynamic Proxy Client...................................................... 331

10.4.2.3 Dynamic Dispatch Client—SOAP 1.1 ............................. 332

10.4.2.4 Dynamic Dispatch Client—SOAP 1.2 ............................. 335

10.4.3 Service Endpoint Implementation Bindings.................................... 336

10.4.4 A Few Other Comments.................................................................. 337

10.4.5 Building RESTful Web Services with JAX-WS ............................. 337

10.4.6 JAX-WS Asynchronous Example ................................................... 338

10.5 Technology Review: Windows Communication Foundation (WCF)........... 340

10.5.1 Brief Introduction to WCF Concepts .............................................. 341

10.5.1.1 Address............................................................................. 341

10.5.1.2 Binding ............................................................................. 341

10.5.1.3 Contract ............................................................................ 342

10.5.1.4 Channels ........................................................................... 344

10.5.2 Examination of Specific WCF Examples........................................ 347

10.5.2.1 HelloWorld Service .......................................................... 348

10.5.2.2 Self-Host of the HelloWorld Service ............................... 349

10.5.2.3 Clients to Call the HelloWorld Service............................ 350

10.5.2.4 Metadata ........................................................................... 355

10.5.3 Message Exchange Patterns in WCF............................................... 357

SOAP Exercises ....................................................................................................... 358

WSDL and WADL Exercises .................................................................................. 359

JAX-WS Exercises................................................................................................... 359

WCF Exercises......................................................................................................... 359

Conceptual Questions .............................................................................................. 359

Bibliography............................................................................................................. 360

Chapter 11 RESTful Web Services.............................................................................................363

11.1 Technology Review: Asynchronous JavaScript and XML (AJAX)............. 364

11.1.1 Simple XMLHttpRequest Example................................................. 365

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11.1.2 Response Codes Example................................................................ 367

11.1.3 Example Clearly Illustrating Asynchronous XMLHttpRequest ...... 368

11.2 Technology Review: Java Servlets ............................................................... 375

11.2.1 Are Servlets RESTful ...................................................................... 375

11.2.2 Java Servlet Lifecycle...................................................................... 377

11.2.3 Simple Servlet Example Uses WebServlet...................................... 378

11.2.4 How to Pass Parameters to a Web Servlet

(Still Using WebServlet).................................................................. 380

11.2.5 Slightly More Complicated Servlet Example Uses WebServlet ..... 383

11.2.6 Simple Servlet Uses web.xml.......................................................... 387

11.2.7 Asynchronous Servlet...................................................................... 389

11.2.8 Servlet Storage between HTTP Request/Response Calls and

Servlet Sessions ............................................................................... 392

11.3 Technology Review: Java API for RESTful Web Services (JAX-RS) ........ 394

11.3.1 JAX-RS Basics Including JAX-RS Annotations............................. 394

11.3.2 Simple JAX-RS Example ................................................................ 398

11.3.3 How to Deploy a JAX-RS Server ................................................... 403

11.3.3.1 Using a web.xml File to Deploy a JAX-RS Server ......... 405

11.3.3.2 Using an ApplicationConfig Class to Deploy a

JAX-RS Server ................................................................. 406

11.3.4 Passing Parameters to a JAX-RS Server ......................................... 407

11.3.4.1 @PathParam Parameters .................................................. 407

11.3.4.2 @QueryParam Parameters................................................ 410

11.3.4.3 @FormParam Parameters................................................. 411

11.3.4.4 Expanded Parameter Example Shows Need for

@Consumes/@Produces ................................................. 412

11.3.5 JAX-RS Client API ......................................................................... 415

11.3.5.1 JAX-RS Client Using Generic Invocation—Runs

Inside Servlet Container ................................................... 415

11.3.5.2 JAX-RS Client Using Specific Invocations—Runs

as Separate Java Application............................................ 418

11.3.6 JSON API ........................................................................................ 421

11.3.7 Asynchronous JAX-RS Example .................................................... 423

11.3.7.1 Very Simple Asynchronous JAX-RS Example................ 424

11.3.7.2 Asynchronous JAX-RS Example—Multiple Clients ....... 425

11.3.8 Why Do You Need JAX-RS When You’ve Got Servlets? ............. 431

AJAX Exercises ....................................................................................................... 434

Java Servlets Exercises ............................................................................................ 434

JAX-RS Exercises.................................................................................................... 434

Conceptual Questions .............................................................................................. 435

Bibliography............................................................................................................. 435

Chapter 12 RESTful Web Services in .NET...............................................................................439

12.1 Technology Review: Windows Communication Foundation—RESTful..... 439

12.1.1 RESTful Bindings and Behavior ..................................................... 439

12.1.2 Self-Hosted RESTful Web Service ................................................. 439

12.1.3 Extremely Simple RESTful Web Service Client............................. 441

12.1.4 Web Service Contract Specifying Which HTTP Commands

to Use............................................................................................... 442

12.1.5 WCF-RESTful Web Service That Returns JSON Data................... 444

Contents xiii

12.2 Technology Review: ASP.NET Model–View–Controller and ASP.NET

CORE............................................................................................................ 447

12.2.1 The Model–View–Controller Pattern .............................................. 447

12.2.2 What Are ASP.NET, ASP.NET MVC, and ASP.NET

CORE, Anyway? ............................................................................. 448

12.2.2.1 Razor............................................................................... 449

12.2.2.2 Roadmap for Examining ASP.NET MVC and

ASP.NET CORE............................................................. 449

12.2.3 The Marina Project .......................................................................... 450

12.2.4 ASP.NET MVC4 in Visual Studio 2012......................................... 450

12.2.4.1 Create MVC Project........................................................ 450

12.2.4.2 Create Model................................................................... 450

12.2.4.3 Create Controller............................................................. 454

12.2.4.4 Do a Build Followed by Start without Debugging......... 456

12.2.4.5 Examine Default Views of Marina Database ................. 456

12.2.4.6 Enter Data in Database ................................................... 456

12.2.4.7 Show Data Directly from Database ................................ 458

12.2.4.8 Use Other Default Views of Marina Database ............... 459

12.2.4.9 Change Layout in Shared View...................................... 462

12.2.4.10 Create a New Controller Method (Action Method)

and Its New View........................................................... 464

12.2.5 Add Asynchronous Controller to Marina Project in

ASP.NET MVC4............................................................................. 464

12.2.5.1 Scheduling Maintenance Using PHP Server ................. 464

12.2.5.2 Scheduling Maintenance Using Internal ASP.NET

MVC4 Server.................................................................. 469

12.2.6 How Asynchronous Calls Really Work in ASP.NET MVC........... 471

12.2.6.1 Simple Asynchronous Example...................................... 471

12.2.6.2 (Async or Sync?) Example Using Two PHP Servers..... 474

12.2.7 Redirect............................................................................................ 476

12.2.8 How to Access ASP.NET MVC Capabilities with

cURL Commands ............................................................................ 478

12.2.9 Access Controller Using HTTP Commands Other than GET......... 482

12.2.10 Routing in ASP.NET MVC............................................................. 484

12.2.11 HTML Helpers ................................................................................ 486

12.2.11.1 EditorFor versus TextBoxFor ......................................... 488

12.2.11.2 ValidationMessageFor .................................................... 491

12.2.11.3 RadioButton .................................................................... 492

12.2.11.4 TextArea and TextAreaFor Example.............................. 492

12.2.11.5 ListBoxFor ...................................................................... 494

12.2.11.6 DropDownList ................................................................ 494

12.2.12 ASP.NET Core 1.0 in Visual Studio 2015...................................... 497

12.2.12.1 Create MVC Project........................................................ 497

12.2.12.2 Create Model................................................................... 497

12.2.12.3 Create Controller............................................................. 498

12.2.12.4 Enter Data ....................................................................... 502

12.2.12.5 Use Other Default Views of Marina Database ............... 505

12.2.12.6 Add RequestMaintenance Action Method and

Associated View ............................................................. 506

12.2.12.7 Add Asynchronous Controller to Marina Project in

ASP.NET CORE............................................................. 510

12.2.13 Is ASP.NET MVC Really RESTful?............................................... 517

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