hello.lua

 
require "orbit"
require "orbit.routes"

local R = orbit.routes.R
 
local hello = orbit.new()

hello:dispatch_get(function (web)
		      return string.format('<h1>Welcome to %s!</h1>', web.real_path)
		   end, R'/')

hello:dispatch_get(function(web, params)
		      return string.format('Hello %s!', params.name)
		   end, R'/hello/:name')

hello:dispatch_get(function(web, params)
		      return string.format('Hi %s!', params.splat[1])
		   end, R'/hi/*')

hello:dispatch_get(function(web, params)
		      return string.format('Hey %s!', params.name or "stranger")
		   end, R'/hey/?:name?')
 
return hello

routes.lua

require "lpeg"
require "re"
require "wsapi.util"

-- monkeypatching
wsapi.util.url_decode = function (str)
			   if type(str) ~= "string" then return str end
			   str = string.gsub (str, "+", " ")
			   str = string.gsub (str, "%%(%x%x)", function(h) 
                                                                 return string.char(tonumber(h,16))
                                                               end)
			   str = string.gsub (str, "\r\n", "\n")
			   return str
			end

module("orbit.routes", package.seeall)

local function foldr(t, f, acc)
   for i = #t, 1, -1 do
      acc = f(t[i], acc)
   end
   return acc
end

param = re.compile[[ [/%.] ':' {[%w_]+} &('/' / {'.'} / !.) ]] / 
             function (name, dot)
		local extra = { inner = (lpeg.P(1) - lpeg.S("/" .. (dot or "")))^1,
				close = lpeg.P"/" + lpeg.P(dot or -1) + lpeg.P(-1) }
		return { cap = lpeg.Carg(1) * re.compile([[ [/%.] {%inner+} &(%close) ]], extra) / 
		                   function (params, item, delim)
				      params[name] = wsapi.util.url_decode(item)
				   end,
				clean = re.compile([[ [/%.] %inner &(%close) ]], extra) }
	     end

opt_param = re.compile[[ [/%.] '?:' {[%w_]+} '?' &('/' / {'.'} / !.) ]] / 
             function (name, dot)
		local extra = { inner = (lpeg.P(1) - lpeg.S("/" .. (dot or "")))^1,
				close = lpeg.P"/" + lpeg.P(dot or -1) + lpeg.P(-1) }
		return { cap = (lpeg.Carg(1) * re.compile([[ [/%.] {%inner+} &(%close) ]], extra) / 
		                   function (params, item, delim)
				      params[name] = wsapi.util.url_decode(item)
				   end)^-1,
				clean = re.compile([[ [/%.] %inner &(%close) ]], extra)^-1 }
	     end

splat = re.compile[[ {[/%.]} {'*'} &('/' / '.' / !.) ]]

rest = lpeg.C((lpeg.P(1) - param - opt_param - splat)^1)

fold_caps = function (cap, acc)
	       if cap == "*" then
		  return { cap = (lpeg.Carg(1) * lpeg.C((lpeg.P(1) - acc.clean)^1) / 
                                      function (params, splat)
					 if not params.splat then params.splat = {} end
					 params.splat[#params.splat+1] = wsapi.util.url_decode(splat)
				      end) * acc.cap,
			   clean = (lpeg.P(1) - acc.clean)^1 * acc.clean }
	       elseif type(cap) == "string" then
		  return { cap = lpeg.P(cap) * acc.cap, clean = lpeg.P(cap) * acc.clean }
	       else
		  return { cap = cap.cap * acc.cap, clean = cap.clean * acc.clean }
	       end
	    end

route = lpeg.Ct((param + opt_param + splat + rest)^1 * lpeg.P(-1)) / 
           function (caps)
	      return foldr(caps, fold_caps, { cap = lpeg.P("/")^-1 * lpeg.P(-1), 
                                              clean = lpeg.P("/")^-1 * lpeg.P(-1) })
	   end

function R(path)
   local p = route:match(path)
   return setmetatable({ patt = p.cap }, { __index = { match = function (t, s)
							      local params = {}
							      if t.patt:match(s, 1, params) then
								 return params
							      else
								 return nil
							      end
							   end } })
end

test_routes.lua

require "orbit.routes"

local R = orbit.routes.R

do
   local r = R('/foo')
   local t = r:match("/foo")
   assert(t)
end

do
   local r = R('/foo')
   local t = r:match("/bar")
   assert(not t)
end

do
   local r = R('/foo')
   local t = r:match("/foobar")
   assert(not t)
end

do
   local r = R("/foo/bar/:baz")
   local t = r:match("/foo/bar/boo")
   assert(t.baz == "boo")
end

do
   local r = R("/foo/bar/:baz")
   local t = r:match("/bar/boo")
   assert(not t)
end

do
   local r = R("/foo/bar/:baz")
   local t = r:match("/foo/bar/boo/bloo")
   assert(not t)
end

do
   local r = R("/say/:msg/to/:to")
   local t = r:match("/say/hello/to/world")
   assert(t.msg == "hello")
   assert(t.to == "world")
end

do
   local r = R('/say/*/to/*')
   local t = r:match('/say/hello/to/world')
   assert(#t.splat == 2)
   assert(t.splat[1] == "hello")
   assert(t.splat[2] == "world")
end

do
   local r = R('/download/*.*')
   local t = r:match('/download/path/to/file.xml')
   assert(#t.splat == 2)
   assert(t.splat[1] == "path/to/file")
   assert(t.splat[2] == "xml")
end

do
   local r = R('/*/foo/*/*')
   local t = r:match('/bar/foo/bling/baz/boom')
   assert(#t.splat == 3)
   assert(t.splat[1] == "bar")
   assert(t.splat[2] == "bling")
   assert(t.splat[3] == "baz/boom")
end

do
   local r = R('/:foo/*')
   local t = r:match('/foo/bar/baz')
   assert(#t.splat == 1)
   assert(t.foo == "foo")
   assert(t.splat[1] == "bar/baz")
end

do
   local r = R('/:foo/:bar')
   local t = r:match('/user@example.com/name')
   assert(t.foo == "user@example.com")
   assert(t.bar == "name")
end

do
   local r = R('/:foo.:bar')
   local t = r:match('/user@example.com')
   assert(t.foo == "user@example")
   assert(t.bar == "com")
end

do
   local r = R('/*')
   local t = r:match("/foo/bar/baz")
   assert(t.splat[1] == "foo/bar/baz")
end

do
   local r = R('/?:foo?/?:bar?')
   local t = r:match('/hello/world')
   assert(t.foo == 'hello')
   assert(t.bar == 'world')
end

do
   local r = R('/?:foo?/?:bar?')
   local t = r:match('/hello')
   assert(t.foo == 'hello')
   assert(not t.bar)
end

do
   local r = R('/?:foo?/?:bar?')
   local t = r:match('/')
   assert(not t.foo)
   assert(not t.bar)
end

do
   local r = R('/:foo/*')
   local t = r:match('/hello%20world/how%20are%20you')
   assert(t.foo == "hello world")
   assert(t.splat[1] == "how are you")
end