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--[[
HTTP protocol implementation for LuCI - RFC2616 / 14.19, 14.24 - 14.28
(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 - HTTP/1.1 bits.
-- This class provides basic ETag handling and implements most of the
-- conditional HTTP/1.1 headers specified in RFC2616 Sct. 14.24 - 14.28 .
module("luci.http.protocol.conditionals", package.seeall)
local date = require("luci.http.protocol.date")
--- Implement 14.19 / ETag.
-- @param stat A file.stat structure
-- @return String containing the generated tag suitable for ETag headers
function mk_etag( stat )
if stat ~= nil then
return string.format( '"%x-%x-%x"', stat.ino, stat.size, stat.mtime )
end
end
--- 14.24 / If-Match
-- Test whether the given message object contains an "If-Match" header and
-- compare it against the given stat object.
-- @param req HTTP request message object
-- @param stat A file.stat object
-- @return Boolean indicating whether the precondition is ok
-- @return Alternative status code if the precondition failed
function if_match( req, stat )
local h = req.headers
local etag = mk_etag( stat )
-- Check for matching resource
if type(h['If-Match']) == "string" then
for ent in h['If-Match']:gmatch("([^, ]+)") do
if ( ent == '*' or ent == etag ) and stat ~= nil then
return true
end
end
return false, 412
end
return true
end
--- 14.25 / If-Modified-Since
-- Test whether the given message object contains an "If-Modified-Since" header
-- and compare it against the given stat object.
-- @param req HTTP request message object
-- @param stat A file.stat object
-- @return Boolean indicating whether the precondition is ok
-- @return Alternative status code if the precondition failed
-- @return Table containing extra HTTP headers if the precondition failed
function if_modified_since( req, stat )
local h = req.headers
-- Compare mtimes
if type(h['If-Modified-Since']) == "string" then
local since = date.to_unix( h['If-Modified-Since'] )
if stat == nil or since < stat.mtime then
return true
end
return false, 304, {
["ETag"] = mk_etag( stat );
["Date"] = date.to_http( os.time() );
["Last-Modified"] = date.to_http( stat.mtime )
}
end
return true
end
--- 14.26 / If-None-Match
-- Test whether the given message object contains an "If-None-Match" header and
-- compare it against the given stat object.
-- @param req HTTP request message object
-- @param stat A file.stat object
-- @return Boolean indicating whether the precondition is ok
-- @return Alternative status code if the precondition failed
-- @return Table containing extra HTTP headers if the precondition failed
function if_none_match( req, stat )
local h = req.headers
local etag = mk_etag( stat )
local method = req.env and req.env.REQUEST_METHOD or "GET"
-- Check for matching resource
if type(h['If-None-Match']) == "string" then
for ent in h['If-None-Match']:gmatch("([^, ]+)") do
if ( ent == '*' or ent == etag ) and stat ~= nil then
if method == "GET" or method == "HEAD" then
return false, 304, {
["ETag"] = etag;
["Date"] = date.to_http( os.time() );
["Last-Modified"] = date.to_http( stat.mtime )
}
else
return false, 412
end
end
end
end
return true
end
--- 14.27 / If-Range
-- The If-Range header is currently not implemented due to the lack of general
-- byte range stuff in luci.http.protocol . This function will always return
-- false, 412 to indicate a failed precondition.
-- @param req HTTP request message object
-- @param stat A file.stat object
-- @return Boolean indicating whether the precondition is ok
-- @return Alternative status code if the precondition failed
function if_range( req, stat )
-- Sorry, no subranges (yet)
return false, 412
end
--- 14.28 / If-Unmodified-Since
-- Test whether the given message object contains an "If-Unmodified-Since"
-- header and compare it against the given stat object.
-- @param req HTTP request message object
-- @param stat A file.stat object
-- @return Boolean indicating whether the precondition is ok
-- @return Alternative status code if the precondition failed
function if_unmodified_since( req, stat )
local h = req.headers
-- Compare mtimes
if type(h['If-Unmodified-Since']) == "string" then
local since = date.to_unix( h['If-Unmodified-Since'] )
if stat ~= nil and since <= stat.mtime then
return false, 412
end
end
return true
end
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