libs/http/luasrc/http/protocol/conditionals.lua

   1 --[[
   2
   3 HTTP protocol implementation for LuCI - RFC2616 / 14.19, 14.24 - 14.28
   4 (c) 2008 Freifunk Leipzig / Jo-Philipp Wich <xm@leipzig.freifunk.net>
   5
   6 Licensed under the Apache License, Version 2.0 (the "License");
   7 you may not use this file except in compliance with the License.
   8 You may obtain a copy of the License at
   9
  10         http://www.apache.org/licenses/LICENSE-2.0
  11
  12 $Id$
  13
  14 ]]--
  15
  16 module("luci.http.protocol.conditionals", package.seeall)
  17
  18 local date = require("luci.http.protocol.date")
  19
  20
  21 -- 14.19 / ETag
  22 function mk_etag( stat )
  23         if stat ~= nil then
  24                 return string.format( '"%x-%x-%x"', stat.ino, stat.size, stat.mtime )
  25         end
  26 end
  27
  28 -- 14.24 / If-Match
  29 function if_match( req, stat )
  30         local h    = req.headers
  31         local etag = mk_etag( stat )
  32
  33         -- Check for matching resource
  34         if type(h['If-Match']) == "string" then
  35                 for ent in h['If-Match']:gmatch("([^, ]+)") do
  36                         if ( ent == '*' or ent == etag ) and stat ~= nil then
  37                                 return true
  38                         end
  39                 end
  40
  41                 return false, 412
  42         end
  43
  44         return true
  45 end
  46
  47 -- 14.25 / If-Modified-Since
  48 function if_modified_since( req, stat )
  49         local h = req.headers
  50
  51         -- Compare mtimes
  52         if type(h['If-Modified-Since']) == "string" then
  53                 local since = date.to_unix( h['If-Modified-Since'] )
  54
  55                 if stat == nil or since < stat.mtime then
  56                         return true
  57                 end
  58
  59                 return false, 304, {
  60                         ["ETag"]          = mk_etag( stat );
  61                         ["Last-Modified"] = date.to_http( stat.mtime )
  62                 }
  63         end
  64
  65         return true
  66 end
  67
  68 -- 14.26 / If-None-Match
  69 function if_none_match( req, stat )
  70         local h    = req.headers
  71         local etag = mk_etag( stat )
  72
  73         -- Check for matching resource
  74         if type(h['If-None-Match']) == "string" then
  75                 for ent in h['If-None-Match']:gmatch("([^, ]+)") do
  76                         if ( ent == '*' or ent == etag ) and stat ~= nil then
  77                                 if req.request_method == "get"  or
  78                                    req.request_method == "head"
  79                                 then
  80                                         return false, 304, {
  81                                                 ["ETag"]          = mk_etag( stat );
  82                                                 ["Last-Modified"] = date.to_http( stat.mtime )
  83                                         }
  84                                 else
  85                                         return false, 412
  86                                 end
  87                         end
  88                 end
  89         end
  90
  91         return true
  92 end
  93
  94 -- 14.27 / If-Range
  95 function if_range( req, stat )
  96         -- Sorry, no subranges (yet)
  97         return false, 412
  98 end
  99
 100 -- 14.28 / If-Unmodified-Since
 101 function if_unmodified_since( req, stat )
 102         local h = req.headers
 103
 104         -- Compare mtimes
 105         if type(h['If-Unmodified-Since']) == "string" then
 106                 local since = date.to_unix( h['If-Unmodified-Since'] )
 107
 108                 if stat ~= nil and since <= stat.mtime then
 109                         return false, 412
 110                 end
 111         end
 112
 113         return true
 114 end