Class: WEBrick::HTTPServlet::AbstractServlet

Inherits:
Object
  • Object
show all
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 collapse

Instance Method Summary collapse

Constructor Details

#initialize(server, *options) ⇒ AbstractServlet

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



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# File 'lib/webrick/httpservlet/abstract.rb', line 91

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

Class Method Details

.get_instance(server, *options) ⇒ Object

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.



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# File 'lib/webrick/httpservlet/abstract.rb', line 83

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

Instance Method Details

#do_GET(req, res) ⇒ Object

Raises a NotFound exception

Raises:

  • (HTTPStatus::NotFound) 


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# File 'lib/webrick/httpservlet/abstract.rb', line 115

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

#do_HEAD(req, res) ⇒ Object

Dispatches to do_GET



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# File 'lib/webrick/httpservlet/abstract.rb', line 122

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

#do_OPTIONS(req, res) ⇒ Object

Returns the allowed HTTP request methods



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# File 'lib/webrick/httpservlet/abstract.rb', line 129

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

#service(req, res) ⇒ Object

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.



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# File 'lib/webrick/httpservlet/abstract.rb', line 102

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