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                         ["Date"]          = date.to_http( os.time() );
  62                         ["Last-Modified"] = date.to_http( stat.mtime )
  63                 }
  64         end
  65
  66         return true
  67 end
  68
  69 -- 14.26 / If-None-Match
  70 function if_none_match( req, stat )
  71         local h    = req.headers
  72         local etag = mk_etag( stat )
  73
  74         -- Check for matching resource
  75         if type(h['If-None-Match']) == "string" then
  76                 for ent in h['If-None-Match']:gmatch("([^, ]+)") do
  77                         if ( ent == '*' or ent == etag ) and stat ~= nil then
  78                                 if req.request_method == "get"  or
  79                                    req.request_method == "head"
  80                                 then
  81                                         return false, 304, {
  82                                                 ["ETag"]          = mk_etag( stat );
  83                                                 ["Date"]          = date.to_http( os.time() );
  84                                                 ["Last-Modified"] = date.to_http( stat.mtime )
  85                                         }
  86                                 else
  87                                         return false, 412
  88                                 end
  89                         end
  90                 end
  91         end
  92
  93         return true
  94 end
  95
  96 -- 14.27 / If-Range
  97 function if_range( req, stat )
  98         -- Sorry, no subranges (yet)
  99         return false, 412
 100 end
 101
 102 -- 14.28 / If-Unmodified-Since
 103 function if_unmodified_since( req, stat )
 104         local h = req.headers
 105
 106         -- Compare mtimes
 107         if type(h['If-Unmodified-Since']) == "string" then
 108                 local since = date.to_unix( h['If-Unmodified-Since'] )
 109
 110                 if stat ~= nil and since <= stat.mtime then
 111                         return false, 412
 112                 end
 113         end
 114
 115         return true
 116 end