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Subjects

JAVASCRIPTHTMLCSSPYTHONSQLJAVACPPCSHARPPHPTYPESCRIPTCRUBYGOSWIFTKOTLINRUSTRBASHSCALAOBJECTIVE-CDARTPERLLUAMATLABXMLJSONMARKDOWNASSEMBLYLATEXYAMLSOLIDITYBLOCKCHAIN

Topics

Ruby Basics

Introduction to RubyInstalling RubyRuby SyntaxRuby CommentsRuby VariablesRuby Data TypesRuby OperatorsRuby ConstantsRuby OutputRuby InputRuby String Interpolation

Control Structures

Ruby If-Else StatementsRuby Case StatementsRuby Unless StatementRuby While LoopsRuby For LoopsRuby Each IteratorRuby Break and NextRuby Redo and Retry

Ruby Methods

Defining Ruby MethodsRuby Method ArgumentsRuby Default ArgumentsRuby Keyword ArgumentsRuby Variable ArgumentsRuby Return ValuesRuby Method Aliases

Ruby Collections

Ruby ArraysRuby Array MethodsRuby HashesRuby Hash MethodsRuby RangesRuby Sets

Ruby OOP

Ruby ClassesRuby ObjectsRuby InheritanceRuby ModulesRuby MixinsRuby EncapsulationRuby PolymorphismRuby Method OverridingRuby Class VariablesRuby Instance VariablesRuby Getters and SettersRuby attr_* Methods

Ruby Advanced Concepts

Ruby BlocksRuby ProcsRuby LambdasRuby ClosuresRuby MetaprogrammingRuby ReflectionRuby Dynamic Method CreationRuby Singleton ClassesRuby Method MissingRuby Symbols

Ruby Exception Handling

Ruby Begin-Rescue-EndRuby Raise ExceptionsRuby Custom ExceptionsRuby Ensure ClauseRuby Retry Statement

Ruby File I/O

Ruby File Open and CloseRuby File Read OperationsRuby File Write OperationsRuby File ModesRuby Directory Operations

Ruby Modules and Gems

Ruby Module CreationRuby Module InclusionRuby NamespacesRuby Gem BasicsRuby Gem InstallationRuby Bundler

Ruby Testing

Ruby Unit TestingRuby Test::Unit FrameworkRuby RSpec BasicsRuby Mocking and Stubbing

Ruby Concurrency

Ruby ThreadsRuby FibersRuby GIL (Global Interpreter Lock)Ruby Parallel Processing

Ruby and the Web

Ruby CGI ProgrammingRuby ERB TemplatesRuby and HTTPRuby JSON ParsingRuby XML Parsing

Ruby Performance

Ruby ProfilingRuby BenchmarkingRuby Memory ManagementRuby Garbage Collection

Ruby Best Practices

Ruby Code Style GuideRuby Naming ConventionsRuby Design PatternsRuby Refactoring Techniques

Ruby CGI Programming

CGI (Common Gateway Interface) programming in Ruby allows developers to create dynamic web applications. It provides a standard way for web servers to interact with external programs, enabling the generation of dynamic content.

What is CGI?

CGI is a protocol that defines how web servers communicate with external programs. In Ruby, the CGI library facilitates the creation of CGI scripts, handling form data, and generating HTML responses.

Getting Started with Ruby CGI

To begin CGI programming in Ruby, you'll need to include the CGI library:

require 'cgi'

Once included, you can create a new CGI object:

cgi = CGI.new

Handling Form Data

One of the primary uses of CGI is to process form data. Ruby's CGI library makes this task straightforward:


name = cgi['name']
email = cgi['email']

This code retrieves the values of the 'name' and 'email' fields from a submitted form.

Generating HTML Responses

CGI scripts typically generate HTML responses. Ruby provides methods to simplify this process:


puts cgi.header
puts cgi.html {
  cgi.head { cgi.title{"Welcome"} } +
  cgi.body { cgi.h1{"Hello, #{name}!"} }
}

This example generates a complete HTML page with a header and a personalized greeting.

Important Considerations

  • Always sanitize user input to prevent security vulnerabilities.
  • Use appropriate content types in the header for different response types.
  • Consider using Ruby ERB Templates for more complex HTML generation.

CGI Environment Variables

CGI provides access to various environment variables. These can be accessed through the CGI object:


request_method = cgi.request_method
remote_addr = cgi.remote_addr

These variables provide information about the request and the server environment.

File Uploads

Handling file uploads is another common task in CGI programming. Ruby's CGI library simplifies this process:


uploaded_file = cgi.params['file'].first
file_name = uploaded_file.original_filename
file_content = uploaded_file.read

This code snippet demonstrates how to access an uploaded file's name and content.

Conclusion

Ruby CGI programming offers a straightforward way to create dynamic web applications. While more modern frameworks like Ruby and HTTP are often preferred for larger applications, CGI remains useful for simple scripts and learning server-side programming concepts.

For more advanced web development in Ruby, consider exploring frameworks like Ruby on Rails or Sinatra, which build upon these fundamental CGI concepts.