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Class: WEBrick::HTTPServlet::AbstractServlet

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Subclasses:
CGIHandler, DefaultFileHandler, ERBHandler, FileHandler, WEBrick::HTTPServlet::ProcHandler
Inherits: Object
Defined in: lib/webrick/httpservlet/abstract.rb

Overview

AbstractServlet allows HTTP server modules to be reused across multiple servers and allows encapsulation of functionality.

By default a servlet will respond to GET, HEAD (through an alias to GET) and OPTIONS requests.

By default a new servlet is initialized for every request. A servlet instance can be reused by overriding .get_instance in the AbstractServlet subclass.

A Simple Servlet

class Simple < WEBrick::HTTPServlet::AbstractServlet
  def do_GET request, response
    status, content_type, body = do_stuff_with request

    response.status = status
    response['Content-Type'] = content_type
    response.body = body
  end

  def do_stuff_with request
    return 200, 'text/plain', 'you got a page'
  end
end

This servlet can be mounted on a server at a given path:

server.mount '/simple', Simple

Servlet Configuration

Servlets can be configured via initialize. The first argument is the HTTP server the servlet is being initialized for.

class Configurable < Simple
  def initialize server, color, size
    super server
    @color = color
    @size = size
  end

  def do_stuff_with request
    content = "<p " \
              %q{style="color: #{@color}; font-size: #{@size}"} \
              ">Hello, World!"

    return 200, "text/html", content
  end
end

This servlet must be provided two arguments at mount time:

server.mount '/configurable', Configurable, 'red', '2em'

Class Method Summary

Instance Method Summary

Constructor Details

.new(server, *options) ⇒ AbstractServlet

Initializes a new servlet for server using options which are stored as-is in @options. @logger is also provided.

[ GitHub ]

  
# File 'lib/webrick/httpservlet/abstract.rb', line 92

def initialize(server, *options)
  @server = @config = server
  @logger = @server[:Logger]
  @options = options
end

Class Method Details

.get_instance(server, *options)

Factory for servlet instances that will handle a request from server using options from the mount point. By default a new servlet instance is created for every call.

[ GitHub ]

  
# File 'lib/webrick/httpservlet/abstract.rb', line 84

def self.get_instance(server, *options)
  self.new(server, *options)
end

Instance Method Details

#do_GET(req, res)

Raises a NotFound exception

Raises:

  • (HTTPStatus::NotFound)
[ GitHub ]

  
# File 'lib/webrick/httpservlet/abstract.rb', line 116

def do_GET(req, res)
  raise HTTPStatus::NotFound, "not found."
end

#do_HEAD(req, res)

Dispatches to do_GET

[ GitHub ]

  
# File 'lib/webrick/httpservlet/abstract.rb', line 123

def do_HEAD(req, res)
  do_GET(req, res)
end

#do_OPTIONS(req, res)

Returns the allowed HTTP request methods

[ GitHub ]

  
# File 'lib/webrick/httpservlet/abstract.rb', line 130

def do_OPTIONS(req, res)
  m = self.methods.grep(/\Ado_([A-Z]+)\z/) {$1}
  m.sort!
  res["allow"] = m.join(",")
end

#redirect_to_directory_uri(req, res) (private)

Redirects to a path ending in /

[ GitHub ]

  
# File 'lib/webrick/httpservlet/abstract.rb', line 141

def redirect_to_directory_uri(req, res)
  if req.path[-1] != ?/
    location = WEBrick::HTTPUtils.escape_path(req.path + "/")
    if req.query_string && req.query_string.bytesize > 0
      location << "?" << req.query_string
    end
    res.set_redirect(HTTPStatus::MovedPermanently, location)
  end
end

#service(req, res)

Dispatches to a do_ method based on req if such a method is available. (#do_GET for a GET request). Raises a MethodNotAllowed exception if the method is not implemented.

[ GitHub ]

  
# File 'lib/webrick/httpservlet/abstract.rb', line 103

def service(req, res)
  method_name = "do_" + req.request_method.gsub(/-/, "_")
  if respond_to?(method_name)
    __send__(method_name, req, res)
  else
    raise HTTPStatus::MethodNotAllowed,
          "unsupported method `#{req.request_method}'."
  end
end