share/lua/website/quvi/url.lua

   1
   2 -- libquvi-scripts
   3 -- A slightly modified copy of:
   4
   5 -- URI parsing, composition and relative URL resolution
   6 -- LuaSocket toolkit.
   7 -- Author: Diego Nehab
   8 -- RCS ID: $Id: url.lua,v 1.38 2006/04/03 04:45:42 diego Exp $
   9 -- License: MIT
  10 -- http://w3.impa.br/~diego/software/luasocket/url.html
  11
  12 local base = _G
  13 local M = {}
  14
  15 -----------------------------------------------------------------------------
  16 -- Encodes a string into its escaped hexadecimal representation
  17 -- Input
  18 --   s: binary string to be encoded
  19 -- Returns
  20 --   escaped representation of string binary
  21 -----------------------------------------------------------------------------
  22 function M.escape(s)
  23     return string.gsub(s, "([^A-Za-z0-9_])", function(c)
  24         return string.format("%%%02x", string.byte(c))
  25     end)
  26 end
  27
  28 -----------------------------------------------------------------------------
  29 -- Protects a path segment, to prevent it from interfering with the
  30 -- url parsing.
  31 -- Input
  32 --   s: binary string to be encoded
  33 -- Returns
  34 --   escaped representation of string binary
  35 -----------------------------------------------------------------------------
  36 local function make_set(t)
  37         local s = {}
  38         for i,v in base.ipairs(t) do
  39                 s[t[i]] = 1
  40         end
  41         return s
  42 end
  43
  44 -- these are allowed withing a path segment, along with alphanum
  45 -- other characters must be escaped
  46 local segment_set = make_set {
  47     "-", "_", ".", "!", "~", "*", "'", "(",
  48         ")", ":", "@", "&", "=", "+", "$", ",",
  49 }
  50
  51 local function protect_segment(s)
  52         return string.gsub(s, "([^A-Za-z0-9_])", function (c)
  53                 if segment_set[c] then return c
  54                 else return string.format("%%%02x", string.byte(c)) end
  55         end)
  56 end
  57
  58 -----------------------------------------------------------------------------
  59 -- Decodes a string from its escaped hexadecimal representation
  60 -- Input
  61 --   s: binary string to be decoded
  62 -- Returns
  63 --   unescaped representation of string binary
  64 -----------------------------------------------------------------------------
  65 function M.unescape(s)
  66     return string.gsub(s, "%%(%x%x)", function(hex)
  67         return string.char(base.tonumber(hex, 16))
  68     end)
  69 end
  70
  71 -----------------------------------------------------------------------------
  72 -- Builds a path from a base path and a relative path
  73 -- Input
  74 --   base_path
  75 --   relative_path
  76 -- Returns
  77 --   corresponding absolute path
  78 -----------------------------------------------------------------------------
  79 local function absolute_path(base_path, relative_path)
  80     if string.sub(relative_path, 1, 1) == "/" then return relative_path end
  81     local path = string.gsub(base_path, "[^/]*$", "")
  82     path = path .. relative_path
  83     path = string.gsub(path, "([^/]*%./)", function (s)
  84         if s ~= "./" then return s else return "" end
  85     end)
  86     path = string.gsub(path, "/%.$", "/")
  87     local reduced
  88     while reduced ~= path do
  89         reduced = path
  90         path = string.gsub(reduced, "([^/]*/%.%./)", function (s)
  91             if s ~= "../../" then return "" else return s end
  92         end)
  93     end
  94     path = string.gsub(reduced, "([^/]*/%.%.)$", function (s)
  95         if s ~= "../.." then return "" else return s end
  96     end)
  97     return path
  98 end
  99
 100 -----------------------------------------------------------------------------
 101 -- Parses a url and returns a table with all its parts according to RFC 2396
 102 -- The following grammar describes the names given to the URL parts
 103 -- <url> ::= <scheme>://<authority>/<path>;<params>?<query>#<fragment>
 104 -- <authority> ::= <userinfo>@<host>:<port>
 105 -- <userinfo> ::= <user>[:<password>]
 106 -- <path> :: = {<segment>/}<segment>
 107 -- Input
 108 --   url: uniform resource locator of request
 109 --   default: table with default values for each field
 110 -- Returns
 111 --   table with the following fields, where RFC naming conventions have
 112 --   been preserved:
 113 --     scheme, authority, userinfo, user, password, host, port,
 114 --     path, params, query, fragment
 115 -- Obs:
 116 --   the leading '/' in {/<path>} is considered part of <path>
 117 -----------------------------------------------------------------------------
 118 function M.parse(url, default)
 119     -- initialize default parameters
 120     local parsed = {}
 121     for i,v in base.pairs(default or parsed) do parsed[i] = v end
 122     -- empty url is parsed to nil
 123     if not url or url == "" then return nil, "invalid url" end
 124     -- remove whitespace
 125     -- url = string.gsub(url, "%s", "")
 126     -- get fragment
 127     url = string.gsub(url, "#(.*)$", function(f)
 128         parsed.fragment = f
 129         return ""
 130     end)
 131     -- get scheme
 132     url = string.gsub(url, "^([%w][%w%+%-%.]*)%:",
 133         function(s) parsed.scheme = s; return "" end)
 134     -- get authority
 135     url = string.gsub(url, "^//([^/]*)", function(n)
 136         parsed.authority = n
 137         return ""
 138     end)
 139     -- get query stringing
 140     url = string.gsub(url, "%?(.*)", function(q)
 141         parsed.query = q
 142         return ""
 143     end)
 144     -- get params
 145     url = string.gsub(url, "%;(.*)", function(p)
 146         parsed.params = p
 147         return ""
 148     end)
 149     -- path is whatever was left
 150     if url ~= "" then parsed.path = url end
 151     local authority = parsed.authority
 152     if not authority then return parsed end
 153     authority = string.gsub(authority,"^([^@]*)@",
 154         function(u) parsed.userinfo = u; return "" end)
 155     authority = string.gsub(authority, ":([^:]*)$",
 156         function(p) parsed.port = p; return "" end)
 157     if authority ~= "" then parsed.host = authority end
 158     local userinfo = parsed.userinfo
 159     if not userinfo then return parsed end
 160     userinfo = string.gsub(userinfo, ":([^:]*)$",
 161         function(p) parsed.password = p; return "" end)
 162     parsed.user = userinfo
 163     return parsed
 164 end
 165
 166 -----------------------------------------------------------------------------
 167 -- Rebuilds a parsed URL from its components.
 168 -- Components are protected if any reserved or unallowed characters are found
 169 -- Input
 170 --   parsed: parsed URL, as returned by parse
 171 -- Returns
 172 --   a stringing with the corresponding URL
 173 -----------------------------------------------------------------------------
 174 function M.build(parsed)
 175     local ppath = M.parse_path(parsed.path or "")
 176     local url = M.build_path(ppath)
 177     if parsed.params then url = url .. ";" .. parsed.params end
 178     if parsed.query then url = url .. "?" .. parsed.query end
 179         local authority = parsed.authority
 180         if parsed.host then
 181                 authority = parsed.host
 182                 if parsed.port then authority = authority .. ":" .. parsed.port end
 183                 local userinfo = parsed.userinfo
 184                 if parsed.user then
 185                         userinfo = parsed.user
 186                         if parsed.password then
 187                                 userinfo = userinfo .. ":" .. parsed.password
 188                         end
 189                 end
 190                 if userinfo then authority = userinfo .. "@" .. authority end
 191         end
 192     if authority then url = "//" .. authority .. url end
 193     if parsed.scheme then url = parsed.scheme .. ":" .. url end
 194     if parsed.fragment then url = url .. "#" .. parsed.fragment end
 195     -- url = string.gsub(url, "%s", "")
 196     return url
 197 end
 198
 199 -----------------------------------------------------------------------------
 200 -- Builds a absolute URL from a base and a relative URL according to RFC 2396
 201 -- Input
 202 --   base_url
 203 --   relative_url
 204 -- Returns
 205 --   corresponding absolute url
 206 -----------------------------------------------------------------------------
 207 function M.absolute(base_url, relative_url)
 208     if base.type(base_url) == "table" then
 209         base_parsed = base_url
 210         base_url = M.build(base_parsed)
 211     else
 212         base_parsed = M.parse(base_url)
 213     end
 214     local relative_parsed = M.parse(relative_url)
 215     if not base_parsed then return relative_url
 216     elseif not relative_parsed then return base_url
 217     elseif relative_parsed.scheme then return relative_url
 218     else
 219         relative_parsed.scheme = base_parsed.scheme
 220         if not relative_parsed.authority then
 221             relative_parsed.authority = base_parsed.authority
 222             if not relative_parsed.path then
 223                 relative_parsed.path = base_parsed.path
 224                 if not relative_parsed.params then
 225                     relative_parsed.params = base_parsed.params
 226                     if not relative_parsed.query then
 227                         relative_parsed.query = base_parsed.query
 228                     end
 229                 end
 230             else
 231                 relative_parsed.path = absolute_path(base_parsed.path or "",
 232                     relative_parsed.path)
 233             end
 234         end
 235         return M.build(relative_parsed)
 236     end
 237 end
 238
 239 -----------------------------------------------------------------------------
 240 -- Breaks a path into its segments, unescaping the segments
 241 -- Input
 242 --   path
 243 -- Returns
 244 --   segment: a table with one entry per segment
 245 -----------------------------------------------------------------------------
 246 function M.parse_path(path)
 247         local parsed = {}
 248         path = path or ""
 249         --path = string.gsub(path, "%s", "")
 250         string.gsub(path, "([^/]+)", function (s) table.insert(parsed, s) end)
 251         for i = 1, #parsed do
 252                 parsed[i] = M.unescape(parsed[i])
 253         end
 254         if string.sub(path, 1, 1) == "/" then parsed.is_absolute = 1 end
 255         if string.sub(path, -1, -1) == "/" then parsed.is_directory = 1 end
 256         return parsed
 257 end
 258
 259 -----------------------------------------------------------------------------
 260 -- Builds a path component from its segments, escaping protected characters.
 261 -- Input
 262 --   parsed: path segments
 263 --   unsafe: if true, segments are not protected before path is built
 264 -- Returns
 265 --   path: corresponding path stringing
 266 -----------------------------------------------------------------------------
 267 function M.build_path(parsed, unsafe)
 268         local path = ""
 269         local n = #parsed
 270         if unsafe then
 271                 for i = 1, n-1 do
 272                         path = path .. parsed[i]
 273                         path = path .. "/"
 274                 end
 275                 if n > 0 then
 276                         path = path .. parsed[n]
 277                         if parsed.is_directory then path = path .. "/" end
 278                 end
 279         else
 280                 for i = 1, n-1 do
 281                         path = path .. protect_segment(parsed[i])
 282                         path = path .. "/"
 283                 end
 284                 if n > 0 then
 285                         path = path .. protect_segment(parsed[n])
 286                         if parsed.is_directory then path = path .. "/" end
 287                 end
 288         end
 289         if parsed.is_absolute then path = "/" .. path end
 290         return path
 291 end
 292
 293 return M