libs/http/luasrc/http/protocol/date.lua

   1 --[[
   2
   3 HTTP protocol implementation for LuCI - date handling
   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 --- LuCI http protocol implementation - date helper class.
  17 -- This class contains functions to parse, compare and format http dates.
  18 module("luci.http.protocol.date", package.seeall)
  19
  20 MONTHS = {
  21         "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug",
  22         "Sep", "Oct", "Nov", "Dec"
  23 }
  24
  25 --- The "TZ" table contains lowercased timezone names associated with their
  26 -- corresponding time offsets sepcified in seconds.
  27 -- @class table
  28 TZ = {
  29         -- DST zones
  30         ["brst"]  =   -2*3600;   -- Brazil Summer Time (East Daylight)
  31         ["adt"]   =   -3*3600;   -- Atlantic Daylight
  32         ["edt"]   =   -4*3600;   -- Eastern Daylight
  33         ["cdt"]   =   -5*3600;   -- Central Daylight
  34         ["mdt"]   =   -6*3600;   -- Mountain Daylight
  35         ["pdt"]   =   -7*3600;   -- Pacific Daylight
  36         ["ydt"]   =   -8*3600;   -- Yukon Daylight
  37         ["hdt"]   =   -9*3600;   -- Hawaii Daylight
  38         ["bst"]   =    1*3600;   -- British Summer
  39         ["mest"]  =    2*3600;   -- Middle European Summer
  40         ["sst"]   =    2*3600;   -- Swedish Summer
  41         ["fst"]   =    2*3600;   -- French Summer
  42         ["eest"]  =    3*3600;   -- Eastern European Summer
  43         ["cest"]  =    2*3600;   -- Central European Daylight
  44         ["wadt"]  =    8*3600;   -- West Australian Daylight
  45         ["kdt"]   =   10*3600;   -- Korean Daylight
  46         ["eadt"]  =   11*3600;   -- Eastern Australian Daylight
  47         ["nzdt"]  =   13*3600;   -- New Zealand Daylight
  48
  49         -- zones
  50         ["gmt"]   =   0;                 -- Greenwich Mean
  51         ["ut"]    =   0;                 -- Universal (Coordinated)
  52         ["utc"]   =   0;
  53         ["wet"]   =   0;                 -- Western European
  54         ["wat"]   =  -1*3600;    -- West Africa
  55         ["azost"] =  -1*3600;    -- Azores Standard Time
  56         ["cvt"]   =  -1*3600;    -- Cape Verde Time
  57         ["at"]    =  -2*3600;    -- Azores
  58         ["fnt"]   =  -2*3600;    -- Brazil Time (Extreme East - Fernando Noronha)
  59         ["ndt"]   =  -2*3600+1800;-- Newfoundland Daylight
  60         ["art"]   =  -3*3600;    -- Argentina Time
  61         ["nft"]   =  -3*3600+1800;-- Newfoundland
  62         ["mnt"]   =  -4*3600;    -- Brazil Time (West Standard - Manaus)
  63         ["ewt"]   =  -4*3600;    -- U.S. Eastern War Time
  64         ["ast"]   =  -4*3600;    -- Atlantic Standard
  65         ["bot"]   =  -4*3600;    -- Bolivia Time
  66         ["vet"]   =  -4*3600;    -- Venezuela Time
  67         ["est"]   =  -5*3600;    -- Eastern Standard
  68         ["cot"]   =  -5*3600;    -- Colombia Time
  69         ["act"]   =  -5*3600;    -- Brazil Time (Extreme West - Acre)
  70         ["pet"]   =  -5*3600;    -- Peru Time
  71         ["cst"]   =  -6*3600;    -- Central Standard
  72         ["cest"]  =   2*3600;    -- Central European Summer
  73         ["mst"]   =  -7*3600;    -- Mountain Standard
  74         ["pst"]   =  -8*3600;    -- Pacific Standard
  75         ["yst"]   =  -9*3600;    -- Yukon Standard
  76         ["hst"]   = -10*3600;    -- Hawaii Standard
  77         ["cat"]   = -10*3600;    -- Central Alaska
  78         ["ahst"]  = -10*3600;    -- Alaska-Hawaii Standard
  79         ["taht"]  = -10*3600;    -- Tahiti Time
  80         ["nt"]    = -11*3600;    -- Nome
  81         ["idlw"]  = -12*3600;    -- International Date Line West
  82         ["cet"]   =   1*3600;    -- Central European
  83         ["mez"]   =   1*3600;    -- Central European (German)
  84         ["met"]   =   1*3600;    -- Middle European
  85         ["mewt"]  =   1*3600;    -- Middle European Winter
  86         ["swt"]   =   1*3600;    -- Swedish Winter
  87         ["set"]   =   1*3600;    -- Seychelles
  88         ["fwt"]   =   1*3600;    -- French Winter
  89         ["west"]  =   1*3600;    -- Western Europe Summer Time
  90         ["eet"]   =   2*3600;    -- Eastern Europe; USSR Zone 1
  91         ["ukr"]   =   2*3600;    -- Ukraine
  92         ["sast"]  =   2*3600;    -- South Africa Standard Time
  93         ["bt"]    =   3*3600;    -- Baghdad; USSR Zone 2
  94         ["eat"]   =   3*3600;    -- East Africa Time
  95         ["irst"]  =   3*3600+1800;-- Iran Standard Time
  96         ["zp4"]   =   4*3600;    -- USSR Zone 3
  97         ["msd"]   =   4*3600;    -- Moscow Daylight Time
  98         ["sct"]   =   4*3600;    -- Seychelles Time
  99         ["zp5"]   =   5*3600;    -- USSR Zone 4
 100         ["azst"]  =   5*3600;    -- Azerbaijan Summer Time
 101         ["mvt"]   =   5*3600;    -- Maldives Time
 102         ["uzt"]   =   5*3600;    -- Uzbekistan Time
 103         ["ist"]   =   5*3600+1800;-- Indian Standard
 104         ["zp6"]   =   6*3600;    -- USSR Zone 5
 105         ["lkt"]   =   6*3600;    -- Sri Lanka Time
 106         ["pkst"]  =   6*3600;    -- Pakistan Summer Time
 107         ["yekst"] =   6*3600;    -- Yekaterinburg Summer Time
 108         ["wast"]  =   7*3600;    -- West Australian Standard
 109         ["ict"]   =   7*3600;    -- Indochina Time
 110         ["wit"]   =   7*3600;    -- Western Indonesia Time
 111         ["cct"]   =   8*3600;    -- China Coast; USSR Zone 7
 112         ["wst"]   =   8*3600;    -- West Australian Standard
 113         ["hkt"]   =   8*3600;    -- Hong Kong
 114         ["bnt"]   =   8*3600;    -- Brunei Darussalam Time
 115         ["cit"]   =   8*3600;    -- Central Indonesia Time
 116         ["myt"]   =   8*3600;    -- Malaysia Time
 117         ["pht"]   =   8*3600;    -- Philippines Time
 118         ["sgt"]   =   8*3600;    -- Singapore Time
 119         ["jst"]   =   9*3600;    -- Japan Standard; USSR Zone 8
 120         ["kst"]   =   9*3600;    -- Korean Standard
 121         ["east"]  =  10*3600;    -- Eastern Australian Standard
 122         ["gst"]   =  10*3600;    -- Guam Standard; USSR Zone 9
 123         ["nct"]   =  11*3600;    -- New Caledonia Time
 124         ["nzt"]   =  12*3600;    -- New Zealand
 125         ["nzst"]  =  12*3600;    -- New Zealand Standard
 126         ["fjt"]   =  12*3600;    -- Fiji Time
 127         ["idle"]  =  12*3600;    -- International Date Line East
 128 }
 129
 130 --- Return the time offset in seconds between the UTC and given time zone.
 131 -- @param tz    Symbolic or numeric timezone specifier
 132 -- @return              Time offset to UTC in seconds
 133 function tz_offset(tz)
 134
 135         if type(tz) == "string" then
 136
 137                 -- check for a numeric identifier
 138                 local s, v = tz:match("([%+%-])([0-9]+)")
 139                 if s == '+' then s = 1 else s = -1 end
 140                 if v then v = tonumber(v) end
 141
 142                 if s and v then
 143                         return s * 60 * ( math.floor( v / 100 ) * 60 + ( v % 100 ) )
 144
 145                 -- lookup symbolic tz
 146                 elseif TZ[tz:lower()] then
 147                         return TZ[tz:lower()]
 148                 end
 149
 150         end
 151
 152         -- bad luck
 153         return 0
 154 end
 155
 156 --- Parse given HTTP date string and convert it to unix epoch time.
 157 -- @param data  String containing the date
 158 -- @return              Unix epoch time
 159 function to_unix(date)
 160
 161         local wd, day, mon, yr, hr, min, sec, tz = date:match(
 162                 "([A-Z][a-z][a-z]), ([0-9]+) " ..
 163                 "([A-Z][a-z][a-z]) ([0-9]+) " ..
 164                 "([0-9]+):([0-9]+):([0-9]+) " ..
 165                 "([A-Z0-9%+%-]+)"
 166         )
 167
 168         if day and mon and yr and hr and min and sec then
 169                 -- find month
 170                 local month = 1
 171                 for i = 1, 12 do
 172                         if MONTHS[i] == mon then
 173                                 month = i
 174                                 break
 175                         end
 176                 end
 177
 178                 -- convert to epoch time
 179                 return tz_offset(tz) + os.time( {
 180                         year  = yr,
 181                         month = month,
 182                         day   = day,
 183                         hour  = hr,
 184                         min   = min,
 185                         sec   = sec
 186                 } )
 187         end
 188
 189         return 0
 190 end
 191
 192 --- Convert the given unix epoch time to valid HTTP date string.
 193 -- @param time  Unix epoch time
 194 -- @return              String containing the formatted date
 195 function to_http(time)
 196         return os.date( "%a, %d %b %Y %H:%M:%S GMT", time )
 197 end
 198
 199 --- Compare two dates which can either be unix epoch times or HTTP date strings.
 200 -- @param d1    The first date or epoch time to compare
 201 -- @param d2    The first date or epoch time to compare
 202 -- @return              -1  -  if d1 is lower then d2
 203 -- @return              0   -  if both dates are equal
 204 -- @return              1   -  if d1 is higher then d2
 205 function compare(d1, d2)
 206
 207         if d1:match("[^0-9]") then d1 = to_unix(d1) end
 208         if d2:match("[^0-9]") then d2 = to_unix(d2) end
 209
 210         if d1 == d2 then
 211                 return 0
 212         elseif d1 < d2 then
 213                 return -1
 214         else
 215                 return 1
 216         end
 217 end