| Current Path : /usr/share/nmap/nselib/ |
| Current File : //usr/share/nmap/nselib/url.lua |
---
-- URI parsing, composition, and relative URL resolution.
--
-- @author Diego Nehab
-- @author Eddie Bell <ejlbell@gmail.com>
--[[
URI parsing, composition and relative URL resolution
LuaSocket toolkit.
Author: Diego Nehab
RCS ID: $Id: url.lua,v 1.37 2005/11/22 08:33:29 diego Exp $
parse_query and build_query added For nmap (Eddie Bell <ejlbell@gmail.com>)
--]]
-----------------------------------------------------------------------------
-- Declare module
-----------------------------------------------------------------------------
local string = require("string")
local base = _G
local table = require("table")
module(... or "url",package.seeall)
_VERSION = "URL 1.0"
--[[ Internal functions --]]
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 {
"-", "_", ".", "!", "~", "*", "'", "(",
")", ":", "@", "&", "=", "+", "$", ",",
}
---
-- Protects a path segment, to prevent it from interfering with the
-- URL parsing.
-- @param s Binary string to be encoded.
-- @return Escaped representation of string.
local function protect_segment(s)
return string.gsub(s, "([^A-Za-z0-9_])", function (c)
if segment_set[c] then return c
else return string.format("%%%02x", string.byte(c)) end
end)
end
---
-- Builds a path from a base path and a relative path
-- @param base_path A base path.
-- @param relative_path A relative path.
-- @return The corresponding absolute path.
-----------------------------------------------------------------------------
local function absolute_path(base_path, relative_path)
if string.sub(relative_path, 1, 1) == "/" then return relative_path end
local path = string.gsub(base_path, "[^/]*$", "")
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
--[[ External functions --]]
---
-- Encodes a string into its escaped hexadecimal representation.
-- @param s Binary string to be encoded.
-- @return Escaped representation of string.
-----------------------------------------------------------------------------
function escape(s)
return string.gsub(s, "([^A-Za-z0-9_])", function(c)
return string.format("%%%02x", string.byte(c))
end)
end
---
-- Decodes an escaped hexadecimal string.
-- @param s Hexadecimal-encoded string.
-- @return Decoded string.
-----------------------------------------------------------------------------
function unescape(s)
return string.gsub(s, "%%(%x%x)", function(hex)
return string.char(base.tonumber(hex, 16))
end)
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.
-- <code>
-- <url> ::= <scheme>://<authority>/<path>;<params>?<query>#<fragment>
-- <authority> ::= <userinfo>@<host>:<port>
-- <userinfo> ::= <user>[:<password>]
-- <path> :: = {<segment>/}<segment>
-- </code>
--
-- The leading <code>/</code> in <code>/<path></code> is considered part of
-- <code><path></code>.
-- @param url URL of request.
-- @param default Table with default values for each field.
-- @return A table with the following fields, where RFC naming conventions have
-- been preserved:
-- <code>scheme</code>, <code>authority</code>, <code>userinfo</code>,
-- <code>user</code>, <code>password</code>, <code>host</code>,
-- <code>port</code>, <code>path</code>, <code>params</code>,
-- <code>query</code>, and <code>fragment</code>.
-----------------------------------------------------------------------------
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.
-- @param parsed Parsed URL, as returned by parse.
-- @return A string 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 an absolute URL from a base and a relative URL according to RFC 2396.
-- @param base_url A base URL.
-- @param relative_url A relative URL.
-- @return The corresponding absolute URL.
-----------------------------------------------------------------------------
function absolute(base_url, relative_url)
local base_parsed;
if 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.
-- @param path A path to break.
-- @return 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.
-- @param parsed Path segments.
-- @param unsafe If true, segments are not protected before path is built.
-- @return The corresponding path string
-----------------------------------------------------------------------------
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
---
-- Breaks a query string into name/value pairs.
--
-- This function takes a <code><query></code> of the form
-- <code>"name1=value1&name2=value2"</code>
-- and returns a table containing the name-value pairs, with the name as the key
-- and the value as its associated value.
-- @param query Query string.
-- @return A table of name-value pairs following the pattern
-- <code>table["name"]</code> = <code>value</code>.
-----------------------------------------------------------------------------
function parse_query(query)
local parsed = {}
local pos = 0
query = string.gsub(query, "&", "&")
query = string.gsub(query, "<", "<")
query = string.gsub(query, ">", ">")
local function ginsert(qstr)
local first, last = string.find(qstr, "=")
if first then
parsed[string.sub(qstr, 0, first-1)] = string.sub(qstr, first+1)
end
end
while true do
local first, last = string.find(query, "&", pos)
if first then
ginsert(string.sub(query, pos, first-1));
pos = last+1
else
ginsert(string.sub(query, pos));
break;
end
end
return parsed
end
---
-- Builds a query string from a table.
--
-- This is the inverse of <code>parse_query</code>.
-- @param query A dictionary table where <code>table['name']</code> =
-- <code>value</code>.
-- @return A query string (like <code>"name=value2&name=value2"</code>).
-----------------------------------------------------------------------------
function build_query(query)
local qstr = ""
for i,v in pairs(query) do
qstr = qstr .. i .. '=' .. v .. '&'
end
return string.sub(qstr, 0, string.len(qstr)-1)
end
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