book.cgi (requires ruby)

book.cgi

#!/usr/local/bin/ruby

require 'webrick/cgi'

BookFile = 'book.txt'

class Book
  attr_reader :page

  def initialize(io, page)
    @io = io
    @page = page
  end

  def html
    return left if text.nil?
    "#{right} #{page}<hr>#{text}<hr>#{right} #{page} #{left}"
  end

  private
  def paragraph_at(n)
    n.times { @io.gets('') }
    @io.gets('')
  end
  
  def read_text
    text = paragraph_at(@page)
    text && text.chomp.gsub(%_\n_, ' ')
  end
  
  def text
    @text ||= read_text
  end
  
  def link(text, href)
    %_<a href="#{href}">#{text}</a>_
  end

  def left
    if 0 < page
      ''
    else
      link('<', "./?#{page - 1}")
    end
  end
  
  def right
    link('>', "./?#{page + 1}")
  end
end

class BookCGI < WEBrick::CGI
  def do_GET(req, res)
    page = req.query_string ? req.query_string.to_i : 1
    html = open(BookFile) {|f| Book.new(f, page).html }
    
    res["content-type"] = "text/html"
    res.body = html
  end
end

BookCGI.new.start if __FILE__ == $0