Here’s a fun library that’s gone under the radar. Catapult lets you serve objects over HTTP using over-the-counter WEBrick. Your object simply needs two methods:

 run( path_info_string ) -> response string
 content_type() -> HTTP content type string

For example, here’s a Wiki which uses Catapult and stores its pages in a single Textile+YAML document. It’s all gluey! If you’re hankering for a custom Wiki, it’s a good start.

 require 'cgi'
 require 'redcloth'
 require 'yaml/store'
 class Wiki

   def initialize
     @hp = "HomePage" 
     @c = CGI.new('html4')
     @wiki = YAML::Store.new('wiki.yml')
   end

   def content_type; "text/html"; end

   def run( path_info )
     @v = path_info.gsub!( /\?(.+)\Z/m, '' ) ? CGI::parse( $1 ) : {}
     action, path = path_info.split( '/', 2 )
     @wiki.transaction do
       title, body = method( action ).call( path.to_s )
       @c.html { @c.head { @c.title { title } } + @c.body { body } }
     end
   end

   # Wiki actions: 'show' and 'edit'
   def show( p )
     p = @hp if p.empty?
     body = @c.h1 { p }
     body += @c.a(@hp) { @hp } unless p == @hp
     body +=
       if @wiki[p]
         RedCloth.new( @wiki[p] ).to_html.
           gsub(/([A-Z]\w+){2}/){ @c.a($&){$&} } +
           @c.a("../edit/#{p}") { "Edit" }
       else
         @c.p { "No page #{ p }. " +
           @c.a("../edit/#{p}") { "Create?" } }
       end
     [p, body]
   end

   def edit( p )
     @wiki[p] = @v['c'].to_s if @v['c']
     title = "Editing " + p
     body = @c.h1 { title } + 
       @c.a("../show/#{ p }" ) { "Show" } +
       @c.form("post") { 
         @c.textarea('c') { @wiki[p] } + @c.submit 
       }
     [title, body]
   end
 end

To run the Wiki, put it in a directory with catapult.rb. Then, run: ruby -rwiki catapult.rb 2005.

Access the wiki at http://host:2005/wiki/show.