build: introduce luci-base

[project/luci.git] / modules / base / luasrc / luasrc / http / protocol / date.lua

diff --git a/modules/base/luasrc/luasrc/http/protocol/date.lua b/modules/base/luasrc/luasrc/http/protocol/date.lua
new file mode 100644 (file)
index 0000000..83d11e2
--- /dev/null
+++ b/modules/base/luasrc/luasrc/http/protocol/date.lua
@@ -0,0 +1,115 @@
+--[[
+
+HTTP protocol implementation for LuCI - date handling
+(c) 2008 Freifunk Leipzig / Jo-Philipp Wich <xm@leipzig.freifunk.net>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+$Id$
+
+]]--
+
+--- LuCI http protocol implementation - date helper class.
+-- This class contains functions to parse, compare and format http dates.
+module("luci.http.protocol.date", package.seeall)
+
+require("luci.sys.zoneinfo")
+
+
+MONTHS = {
+       "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug",
+       "Sep", "Oct", "Nov", "Dec"
+}
+
+--- Return the time offset in seconds between the UTC and given time zone.
+-- @param tz   Symbolic or numeric timezone specifier
+-- @return             Time offset to UTC in seconds
+function tz_offset(tz)
+
+       if type(tz) == "string" then
+
+               -- check for a numeric identifier
+               local s, v = tz:match("([%+%-])([0-9]+)")
+               if s == '+' then s = 1 else s = -1 end
+               if v then v = tonumber(v) end
+
+               if s and v then
+                       return s * 60 * ( math.floor( v / 100 ) * 60 + ( v % 100 ) )
+
+               -- lookup symbolic tz
+               elseif luci.sys.zoneinfo.OFFSET[tz:lower()] then
+                       return luci.sys.zoneinfo.OFFSET[tz:lower()]
+               end
+
+       end
+
+       -- bad luck
+       return 0
+end
+
+--- Parse given HTTP date string and convert it to unix epoch time.
+-- @param data String containing the date
+-- @return             Unix epoch time
+function to_unix(date)
+
+       local wd, day, mon, yr, hr, min, sec, tz = date:match(
+               "([A-Z][a-z][a-z]), ([0-9]+) " ..
+               "([A-Z][a-z][a-z]) ([0-9]+) " ..
+               "([0-9]+):([0-9]+):([0-9]+) " ..
+               "([A-Z0-9%+%-]+)"
+       )
+
+       if day and mon and yr and hr and min and sec then
+               -- find month
+               local month = 1
+               for i = 1, 12 do
+                       if MONTHS[i] == mon then
+                               month = i
+                               break
+                       end
+               end
+
+               -- convert to epoch time
+               return tz_offset(tz) + os.time( {
+                       year  = yr,
+                       month = month,
+                       day   = day,
+                       hour  = hr,
+                       min   = min,
+                       sec   = sec
+               } )
+       end
+
+       return 0
+end
+
+--- Convert the given unix epoch time to valid HTTP date string.
+-- @param time Unix epoch time
+-- @return             String containing the formatted date
+function to_http(time)
+       return os.date( "%a, %d %b %Y %H:%M:%S GMT", time )
+end
+
+--- Compare two dates which can either be unix epoch times or HTTP date strings.
+-- @param d1   The first date or epoch time to compare
+-- @param d2   The first date or epoch time to compare
+-- @return             -1  -  if d1 is lower then d2
+-- @return             0   -  if both dates are equal
+-- @return             1   -  if d1 is higher then d2
+function compare(d1, d2)
+
+       if d1:match("[^0-9]") then d1 = to_unix(d1) end
+       if d2:match("[^0-9]") then d2 = to_unix(d2) end
+
+       if d1 == d2 then
+               return 0
+       elseif d1 < d2 then
+               return -1
+       else
+               return 1
+       end
+end