Ruby Phrasebook

Introduction 1

Audience 1

How to Use This Book 2

Conventions 2

Acknowledgments 4



1 Converting Between Types 5

Number from a String 6

Number to Formatted String 7

String to Array and Back Again 10

String to Regular Expression and Back Again 12

Array to Hash and Back Again 13

Array to Set and Back Again 15

Floating-Point, Integer, and Rational Numbers 15



2 Working with Strings 19

Searching Strings 20

Searching Strings with Regular Expressions 21

Replacing Substrings 23

Replacing Substrings using SprintF 24

Replacing Substrings using Regu 26

Working with Unicode 26

Sanitizing Input 27

Working with Line Endings 28

Processing Large Strings 30

Comparing Strings 31

Checksumming a String (MD5 or Otherwise) 31

Encrypting a String 32



3 Working with Collections 35

Slicing an Array 35

Iterating over an Array 37

Creating Enumerable Classes 38

Sorting an Array 40

Iterating over Nested Arrays 41

Modifying All the Values in an Array 42

Sorting Nested Arrays 42

Building a Hash from a Config File 44

Sorting a Hash by Key or Value 45

Eliminating Duplicate Data from Arrays (Sets) 46

Working with Nested Sets 47



4 Working with Objects 49

Inspecting Objects and Classes 50

String Presentation of Objects 50

Ruby-Style Polymorphisms ("Duck Typing") 51

Comparing Objects 52

Serializing Objects 53

Duplication 54

Protecting an Object Instance 55

Garbage Collecting 56

Using Symbols 57



5 Working with Pipes 61

Determining Interactive Standard Pipes 62

Synchronizing STDERR with STDOUT 63

Capturing the Output of a Child Process 64

Implementing a Progress Bar 65

Creating a Secured Password Prompt 66



6 Working with Files 69

Opening and Closing Files 69

Searching and Seeking Large File Contents 70

When to Use Binary Mode (Win32) 73

Obtaining an Exclusive Lock 74

Copying, Moving, and Deleting Files 74



7 Manipulating Text 77

Parsing an LDIF 77

Parsing a Simple Config File 78

Interpolating One Text File 79

Sorting the Contents of a File 80

Processing a passwd File 81



8 Ruby One-Liners 83

Simple Search 84

Counting Lines in a File 84

Head or Tail of a File 84

MD5 or SHA1 Hash 85

Simple HTTP Fetch 86

Simple TCP Connect 87

Escaping HTML 87

Deleting Empty Directories 88

Adding Users from a Text File 88

Delete All the Files Just Extracted 89



9 Processing XML 91

Opening an XML File 92

Accessing an Element (Node) 93

Getting a List of Attributes 95

Adding an Element 96

Changing an Element's Enclosed Text 97

Deleting an Element 98

Adding an Attribute 98

Changing an Attribute 99

Deleting an Attribute 99

Escaping Characters for XML 100

Transforming Using XSLT 100

Validating Your XML 102

A Simple RSS Parser 103



10 Rapid Applications Development with GUI

Toolkits 107

A Simple GTK+ Hello World 108

Using Glade 110

A Simple Qt Hello World 115

Attaching a Signal Handler to a Qt

Widget Slot 116

Using Qt Designer 118

Attaching Signal Handlers to Qt Designer

Generated Code 124



11 Simple CGI Forms 127

Processing a Web Form 128

Returning Tabled Results 131

Escaping Input 134

Locking Down Ruby 136

Receiving an Uploaded File 137

Representing Data Graphically 138



12 Connecting to Databases 143

Opening (and Closing) a MySQL Database

Connection 144

Creating a Table 145

Getting a List of Tables 146

Adding Rows to a Table 146

Iterating Over Queried Rows 147

Deleting Rows 147

Deleting a Table 148



13 Working with Networking and Sockets 151

Connecting to a TCP Socket 152

Running a TCP Server on a Socket 153

Serializing Objects with YAML 156

Network Objects with Distributed Ruby 158

Using Net::HTTP 159

Using Webrick 160



14 Working with Threads 163

Creating a Thread 164

Using a Timer 165

Killing a Thread 168

Synchronizing Thread Communication 169

Multithreaded Exception Gathering 172



15 Documenting Your Ruby 175

Documenting Ruby Code 176

Typographic Conventions Used 177

Overriding Method Signatures in

Documentation 179

Hiding a Module, Class, or Method 180

Providing Program Usage Help 180

Generating HTML Documentation 182

Generating and Installing Documentation for ri 183



16 Working with Ruby Packages 185

Installing a Module 187

Removing a Module 188

Searching for a Module 188

Updating Modules 188

Examining a Module 189

Packaging Your Module with Hoe 189

Creating a Simple Test Case 190

Distributing Your Module on RubyForge 191

Making Rakefile Standalone 192



Index 195