--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/url.lua	Tue Aug 26 18:40:01 2008 -0700
@@ -0,0 +1,297 @@
+-----------------------------------------------------------------------------
+-- URI parsing, composition and relative URL resolution
+-- LuaSocket toolkit.
+-- Author: Diego Nehab
+-- RCS ID: $Id: url.lua,v 1.38 2006/04/03 04:45:42 diego Exp $
+-----------------------------------------------------------------------------
+
+-----------------------------------------------------------------------------
+-- Declare module
+-----------------------------------------------------------------------------
+local string = require("string")
+local base = _G
+local table = require("table")
+module("socket.url")
+
+-----------------------------------------------------------------------------
+-- Module version
+-----------------------------------------------------------------------------
+_VERSION = "URL 1.0.1"
+
+-----------------------------------------------------------------------------
+-- Encodes a string into its escaped hexadecimal representation
+-- Input
+--   s: binary string to be encoded
+-- Returns
+--   escaped representation of string binary
+-----------------------------------------------------------------------------
+function escape(s)
+    return string.gsub(s, "([^A-Za-z0-9_])", function(c)
+        return string.format("%%%02x", string.byte(c))
+    end)
+end
+
+-----------------------------------------------------------------------------
+-- Protects a path segment, to prevent it from interfering with the
+-- url parsing.
+-- Input
+--   s: binary string to be encoded
+-- Returns
+--   escaped representation of string binary
+-----------------------------------------------------------------------------
+local function make_set(t)
+	local s = {}
+	for i,v in base.ipairs(t) do
+		s[t[i]] = 1
+	end
+	return s
+end
+
+-- these are allowed withing a path segment, along with alphanum
+-- other characters must be escaped
+local segment_set = make_set {
+    "-", "_", ".", "!", "~", "*", "'", "(",
+	")", ":", "@", "&", "=", "+", "$", ",",
+}
+
+local function protect_segment(s)
+	return string.gsub(s, "([^A-Za-z0-9_])", function (c)
+		if segment_set[c] then return c
+		else return string.format("%%%02x", string.byte(c)) end
+	end)
+end
+
+-----------------------------------------------------------------------------
+-- Encodes a string into its escaped hexadecimal representation
+-- Input
+--   s: binary string to be encoded
+-- Returns
+--   escaped representation of string binary
+-----------------------------------------------------------------------------
+function unescape(s)
+    return string.gsub(s, "%%(%x%x)", function(hex)
+        return string.char(base.tonumber(hex, 16))
+    end)
+end
+
+-----------------------------------------------------------------------------
+-- Builds a path from a base path and a relative path
+-- Input
+--   base_path
+--   relative_path
+-- Returns
+--   corresponding absolute path
+-----------------------------------------------------------------------------
+local function absolute_path(base_path, relative_path)
+    if string.sub(relative_path, 1, 1) == "/" then return relative_path end
+    local path = string.gsub(base_path, "[^/]*$", "")
+    path = path .. relative_path
+    path = string.gsub(path, "([^/]*%./)", function (s)
+        if s ~= "./" then return s else return "" end
+    end)
+    path = string.gsub(path, "/%.$", "/")
+    local reduced
+    while reduced ~= path do
+        reduced = path
+        path = string.gsub(reduced, "([^/]*/%.%./)", function (s)
+            if s ~= "../../" then return "" else return s end
+        end)
+    end
+    path = string.gsub(reduced, "([^/]*/%.%.)$", function (s)
+        if s ~= "../.." then return "" else return s end
+    end)
+    return path
+end
+
+-----------------------------------------------------------------------------
+-- Parses a url and returns a table with all its parts according to RFC 2396
+-- The following grammar describes the names given to the URL parts
+-- <url> ::= <scheme>://<authority>/<path>;<params>?<query>#<fragment>
+-- <authority> ::= <userinfo>@<host>:<port>
+-- <userinfo> ::= <user>[:<password>]
+-- <path> :: = {<segment>/}<segment>
+-- Input
+--   url: uniform resource locator of request
+--   default: table with default values for each field
+-- Returns
+--   table with the following fields, where RFC naming conventions have
+--   been preserved:
+--     scheme, authority, userinfo, user, password, host, port,
+--     path, params, query, fragment
+-- Obs:
+--   the leading '/' in {/<path>} is considered part of <path>
+-----------------------------------------------------------------------------
+function parse(url, default)
+    -- initialize default parameters
+    local parsed = {}
+    for i,v in base.pairs(default or parsed) do parsed[i] = v end
+    -- empty url is parsed to nil
+    if not url or url == "" then return nil, "invalid url" end
+    -- remove whitespace
+    -- url = string.gsub(url, "%s", "")
+    -- get fragment
+    url = string.gsub(url, "#(.*)$", function(f)
+        parsed.fragment = f
+        return ""
+    end)
+    -- get scheme
+    url = string.gsub(url, "^([%w][%w%+%-%.]*)%:",
+        function(s) parsed.scheme = s; return "" end)
+    -- get authority
+    url = string.gsub(url, "^//([^/]*)", function(n)
+        parsed.authority = n
+        return ""
+    end)
+    -- get query stringing
+    url = string.gsub(url, "%?(.*)", function(q)
+        parsed.query = q
+        return ""
+    end)
+    -- get params
+    url = string.gsub(url, "%;(.*)", function(p)
+        parsed.params = p
+        return ""
+    end)
+    -- path is whatever was left
+    if url ~= "" then parsed.path = url end
+    local authority = parsed.authority
+    if not authority then return parsed end
+    authority = string.gsub(authority,"^([^@]*)@",
+        function(u) parsed.userinfo = u; return "" end)
+    authority = string.gsub(authority, ":([^:]*)$",
+        function(p) parsed.port = p; return "" end)
+    if authority ~= "" then parsed.host = authority end
+    local userinfo = parsed.userinfo
+    if not userinfo then return parsed end
+    userinfo = string.gsub(userinfo, ":([^:]*)$",
+        function(p) parsed.password = p; return "" end)
+    parsed.user = userinfo
+    return parsed
+end
+
+-----------------------------------------------------------------------------
+-- Rebuilds a parsed URL from its components.
+-- Components are protected if any reserved or unallowed characters are found
+-- Input
+--   parsed: parsed URL, as returned by parse
+-- Returns
+--   a stringing with the corresponding URL
+-----------------------------------------------------------------------------
+function build(parsed)
+    local ppath = parse_path(parsed.path or "")
+    local url = build_path(ppath)
+    if parsed.params then url = url .. ";" .. parsed.params end
+    if parsed.query then url = url .. "?" .. parsed.query end
+	local authority = parsed.authority
+	if parsed.host then
+		authority = parsed.host
+		if parsed.port then authority = authority .. ":" .. parsed.port end
+		local userinfo = parsed.userinfo
+		if parsed.user then
+			userinfo = parsed.user
+			if parsed.password then
+				userinfo = userinfo .. ":" .. parsed.password
+			end
+		end
+		if userinfo then authority = userinfo .. "@" .. authority end
+	end
+    if authority then url = "//" .. authority .. url end
+    if parsed.scheme then url = parsed.scheme .. ":" .. url end
+    if parsed.fragment then url = url .. "#" .. parsed.fragment end
+    -- url = string.gsub(url, "%s", "")
+    return url
+end
+
+-----------------------------------------------------------------------------
+-- Builds a absolute URL from a base and a relative URL according to RFC 2396
+-- Input
+--   base_url
+--   relative_url
+-- Returns
+--   corresponding absolute url
+-----------------------------------------------------------------------------
+function absolute(base_url, relative_url)
+    if base.type(base_url) == "table" then
+        base_parsed = base_url
+        base_url = build(base_parsed)
+    else
+        base_parsed = parse(base_url)
+    end
+    local relative_parsed = parse(relative_url)
+    if not base_parsed then return relative_url
+    elseif not relative_parsed then return base_url
+    elseif relative_parsed.scheme then return relative_url
+    else
+        relative_parsed.scheme = base_parsed.scheme
+        if not relative_parsed.authority then
+            relative_parsed.authority = base_parsed.authority
+            if not relative_parsed.path then
+                relative_parsed.path = base_parsed.path
+                if not relative_parsed.params then
+                    relative_parsed.params = base_parsed.params
+                    if not relative_parsed.query then
+                        relative_parsed.query = base_parsed.query
+                    end
+                end
+            else    
+                relative_parsed.path = absolute_path(base_parsed.path or "",
+                    relative_parsed.path)
+            end
+        end
+        return build(relative_parsed)
+    end
+end
+
+-----------------------------------------------------------------------------
+-- Breaks a path into its segments, unescaping the segments
+-- Input
+--   path
+-- Returns
+--   segment: a table with one entry per segment
+-----------------------------------------------------------------------------
+function parse_path(path)
+	local parsed = {}
+	path = path or ""
+	--path = string.gsub(path, "%s", "")
+	string.gsub(path, "([^/]+)", function (s) table.insert(parsed, s) end)
+	for i = 1, table.getn(parsed) do
+		parsed[i] = unescape(parsed[i])
+	end
+	if string.sub(path, 1, 1) == "/" then parsed.is_absolute = 1 end
+	if string.sub(path, -1, -1) == "/" then parsed.is_directory = 1 end
+	return parsed
+end
+
+-----------------------------------------------------------------------------
+-- Builds a path component from its segments, escaping protected characters.
+-- Input
+--   parsed: path segments
+--   unsafe: if true, segments are not protected before path is built
+-- Returns
+--   path: corresponding path stringing
+-----------------------------------------------------------------------------
+function build_path(parsed, unsafe)
+	local path = ""
+	local n = table.getn(parsed)
+	if unsafe then
+		for i = 1, n-1 do
+			path = path .. parsed[i]
+			path = path .. "/"
+		end
+		if n > 0 then
+			path = path .. parsed[n]
+			if parsed.is_directory then path = path .. "/" end
+		end
+	else
+		for i = 1, n-1 do
+			path = path .. protect_segment(parsed[i])
+			path = path .. "/"
+		end
+		if n > 0 then
+			path = path .. protect_segment(parsed[n])
+			if parsed.is_directory then path = path .. "/" end
+		end
+	end
+	if parsed.is_absolute then path = "/" .. path end
+	return path
+end