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'
# File tmp/rubies/ruby-2.5.9/lib/webrick/httpservlet/abstract.rb, line 83
def self.get_instance(server, *options)
self.new(server, *options)
end
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.
# File tmp/rubies/ruby-2.5.9/lib/webrick/httpservlet/abstract.rb, line 91
def initialize(server, *options)
@server = @config = server
@logger = @server[:Logger]
@options = options
end
Initializes a new servlet for server using options which are stored as-is in +@options+. +@logger+ is also provided.
# File tmp/rubies/ruby-2.5.9/lib/webrick/httpservlet/abstract.rb, line 115
def do_GET(req, res)
raise HTTPStatus::NotFound, "not found."
end
Raises a NotFound exception
# File tmp/rubies/ruby-2.5.9/lib/webrick/httpservlet/abstract.rb, line 122
def do_HEAD(req, res)
do_GET(req, res)
end
Dispatches to do_GET
# File tmp/rubies/ruby-2.5.9/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
Returns the allowed HTTP request methods
# File tmp/rubies/ruby-2.5.9/lib/webrick/httpservlet/abstract.rb, line 140
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
Redirects to a path ending in /
# File tmp/rubies/ruby-2.5.9/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
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.