327 lines
11 KiB
Lua
327 lines
11 KiB
Lua
-----------------------------------------------------------------------------
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-- URI parsing, composition and relative URL resolution
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-- LuaSocket toolkit.
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-- Author: Diego Nehab
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-----------------------------------------------------------------------------
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-----------------------------------------------------------------------------
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-- Declare module
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-----------------------------------------------------------------------------
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socket.url = {}
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local _M = socket.url
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-----------------------------------------------------------------------------
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-- Module version
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-----------------------------------------------------------------------------
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_M._VERSION = "URL 1.0.3"
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-----------------------------------------------------------------------------
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-- Encodes a string into its escaped hexadecimal representation
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-- Input
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-- s: binary string to be encoded
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-- Returns
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-- escaped representation of string binary
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-----------------------------------------------------------------------------
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function _M.escape(s)
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return (string.gsub(s, "([^A-Za-z0-9_])", function(c)
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return string.format("%%%02x", string.byte(c))
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end))
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end
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-----------------------------------------------------------------------------
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-- Protects a path segment, to prevent it from interfering with the
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-- url parsing.
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-- Input
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-- s: binary string to be encoded
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-- Returns
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-- escaped representation of string binary
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-----------------------------------------------------------------------------
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local function make_set(t)
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local s = {}
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for i,v in ipairs(t) do
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s[t[i]] = 1
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end
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return s
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end
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-- these are allowed within a path segment, along with alphanum
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-- other characters must be escaped
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local segment_set = make_set {
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"-", "_", ".", "!", "~", "*", "'", "(",
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")", ":", "@", "&", "=", "+", "$", ",",
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}
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local function protect_segment(s)
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return string.gsub(s, "([^A-Za-z0-9_])", function (c)
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if segment_set[c] then return c
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else return string.format("%%%02X", string.byte(c)) end
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end)
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end
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-----------------------------------------------------------------------------
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-- Unencodes a escaped hexadecimal string into its binary representation
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-- Input
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-- s: escaped hexadecimal string to be unencoded
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-- Returns
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-- unescaped binary representation of escaped hexadecimal binary
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-----------------------------------------------------------------------------
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function _M.unescape(s)
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return (string.gsub(s, "%%(%x%x)", function(hex)
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return string.char(tonumber(hex, 16))
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end))
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end
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-----------------------------------------------------------------------------
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-- Removes '..' and '.' components appropriately from a path.
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-- Input
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-- path
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-- Returns
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-- dot-normalized path
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local function remove_dot_components(path)
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local marker = string.char(1)
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repeat
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local was = path
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path = path:gsub('//', '/'..marker..'/', 1)
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until path == was
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repeat
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local was = path
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path = path:gsub('/%./', '/', 1)
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until path == was
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repeat
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local was = path
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path = path:gsub('[^/]+/%.%./([^/]+)', '%1', 1)
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until path == was
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path = path:gsub('[^/]+/%.%./*$', '')
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path = path:gsub('/%.%.$', '/')
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path = path:gsub('/%.$', '/')
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path = path:gsub('^/%.%./', '/')
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path = path:gsub(marker, '')
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return path
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end
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-----------------------------------------------------------------------------
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-- Builds a path from a base path and a relative path
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-- Input
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-- base_path
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-- relative_path
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-- Returns
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-- corresponding absolute path
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-----------------------------------------------------------------------------
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local function absolute_path(base_path, relative_path)
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if string.sub(relative_path, 1, 1) == "/" then
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return remove_dot_components(relative_path) end
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base_path = base_path:gsub("[^/]*$", "")
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if not base_path:find'/$' then base_path = base_path .. '/' end
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local path = base_path .. relative_path
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path = remove_dot_components(path)
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return path
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end
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-----------------------------------------------------------------------------
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-- Parses a url and returns a table with all its parts according to RFC 2396
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-- The following grammar describes the names given to the URL parts
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-- <url> ::= <scheme>://<authority>/<path>;<params>?<query>#<fragment>
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-- <authority> ::= <userinfo>@<host>:<port>
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-- <userinfo> ::= <user>[:<password>]
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-- <path> :: = {<segment>/}<segment>
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-- Input
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-- url: uniform resource locator of request
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-- default: table with default values for each field
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-- Returns
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-- table with the following fields, where RFC naming conventions have
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-- been preserved:
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-- scheme, authority, userinfo, user, password, host, port,
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-- path, params, query, fragment
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-- Obs:
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-- the leading '/' in {/<path>} is considered part of <path>
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-----------------------------------------------------------------------------
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function _M.parse(url, default)
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-- initialize default parameters
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local parsed = {}
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for i,v in pairs(default or parsed) do parsed[i] = v end
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-- empty url is parsed to nil
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if not url or url == "" then return nil, "invalid url" end
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-- remove whitespace
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-- url = string.gsub(url, "%s", "")
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-- get scheme
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url = string.gsub(url, "^([%w][%w%+%-%.]*)%:",
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function(s) parsed.scheme = s; return "" end)
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-- get authority
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url = string.gsub(url, "^//([^/]*)", function(n)
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parsed.authority = n
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return ""
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end)
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-- get fragment
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url = string.gsub(url, "#(.*)$", function(f)
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parsed.fragment = f
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return ""
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end)
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-- get query string
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url = string.gsub(url, "%?(.*)", function(q)
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parsed.query = q
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return ""
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end)
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-- get params
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url = string.gsub(url, "%;(.*)", function(p)
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parsed.params = p
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return ""
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end)
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-- path is whatever was left
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if url ~= "" then parsed.path = url end
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local authority = parsed.authority
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if not authority then return parsed end
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authority = string.gsub(authority,"^([^@]*)@",
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function(u) parsed.userinfo = u; return "" end)
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authority = string.gsub(authority, ":([^:%]]*)$",
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function(p) parsed.port = p; return "" end)
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if authority ~= "" then
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-- IPv6?
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parsed.host = string.match(authority, "^%[(.+)%]$") or authority
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end
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local userinfo = parsed.userinfo
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if not userinfo then return parsed end
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userinfo = string.gsub(userinfo, ":([^:]*)$",
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function(p) parsed.password = p; return "" end)
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parsed.user = userinfo
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return parsed
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end
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-----------------------------------------------------------------------------
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-- Rebuilds a parsed URL from its components.
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-- Components are protected if any reserved or unallowed characters are found
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-- Input
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-- parsed: parsed URL, as returned by parse
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-- Returns
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-- a stringing with the corresponding URL
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-----------------------------------------------------------------------------
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function _M.build(parsed)
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--local ppath = _M.parse_path(parsed.path or "")
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--local url = _M.build_path(ppath)
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local url = parsed.path or ""
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if parsed.params then url = url .. ";" .. parsed.params end
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if parsed.query then url = url .. "?" .. parsed.query end
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local authority = parsed.authority
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if parsed.host then
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authority = parsed.host
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if string.find(authority, ":") then -- IPv6?
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authority = "[" .. authority .. "]"
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end
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if parsed.port then authority = authority .. ":" .. tostring(parsed.port) end
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local userinfo = parsed.userinfo
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if parsed.user then
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userinfo = parsed.user
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if parsed.password then
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userinfo = userinfo .. ":" .. parsed.password
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end
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end
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if userinfo then authority = userinfo .. "@" .. authority end
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end
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if authority then url = "//" .. authority .. url end
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if parsed.scheme then url = parsed.scheme .. ":" .. url end
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if parsed.fragment then url = url .. "#" .. parsed.fragment end
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-- url = string.gsub(url, "%s", "")
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return url
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end
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-----------------------------------------------------------------------------
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-- Builds a absolute URL from a base and a relative URL according to RFC 2396
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-- Input
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-- base_url
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-- relative_url
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-- Returns
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-- corresponding absolute url
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-----------------------------------------------------------------------------
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function _M.absolute(base_url, relative_url)
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local base_parsed
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if type(base_url) == "table" then
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base_parsed = base_url
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base_url = _M.build(base_parsed)
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else
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base_parsed = _M.parse(base_url)
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end
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local result
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local relative_parsed = _M.parse(relative_url)
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if not base_parsed then
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result = relative_url
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elseif not relative_parsed then
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result = base_url
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elseif relative_parsed.scheme then
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result = relative_url
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else
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relative_parsed.scheme = base_parsed.scheme
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if not relative_parsed.authority then
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relative_parsed.authority = base_parsed.authority
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if not relative_parsed.path then
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relative_parsed.path = base_parsed.path
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if not relative_parsed.params then
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relative_parsed.params = base_parsed.params
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if not relative_parsed.query then
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relative_parsed.query = base_parsed.query
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end
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end
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else
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relative_parsed.path = absolute_path(base_parsed.path or "",
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relative_parsed.path)
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end
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end
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result = _M.build(relative_parsed)
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end
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return remove_dot_components(result)
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end
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-----------------------------------------------------------------------------
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-- Breaks a path into its segments, unescaping the segments
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-- Input
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-- path
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-- Returns
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-- segment: a table with one entry per segment
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-----------------------------------------------------------------------------
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function _M.parse_path(path)
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local parsed = {}
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path = path or ""
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--path = string.gsub(path, "%s", "")
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string.gsub(path, "([^/]+)", function (s) table.insert(parsed, s) end)
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for i = 1, #parsed do
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parsed[i] = _M.unescape(parsed[i])
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end
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if string.sub(path, 1, 1) == "/" then parsed.is_absolute = 1 end
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if string.sub(path, -1, -1) == "/" then parsed.is_directory = 1 end
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return parsed
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end
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-----------------------------------------------------------------------------
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-- Builds a path component from its segments, escaping protected characters.
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-- Input
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-- parsed: path segments
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-- unsafe: if true, segments are not protected before path is built
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-- Returns
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-- path: corresponding path stringing
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-----------------------------------------------------------------------------
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function _M.build_path(parsed, unsafe)
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local path = ""
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local n = #parsed
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if unsafe then
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for i = 1, n-1 do
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path = path .. parsed[i]
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path = path .. "/"
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end
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if n > 0 then
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path = path .. parsed[n]
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if parsed.is_directory then path = path .. "/" end
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end
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else
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for i = 1, n-1 do
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path = path .. protect_segment(parsed[i])
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path = path .. "/"
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end
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if n > 0 then
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path = path .. protect_segment(parsed[n])
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if parsed.is_directory then path = path .. "/" end
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end
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end
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if parsed.is_absolute then path = "/" .. path end
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return path
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end
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return _M
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