From 7f56bf947599b20e2cf50018e160e602d5516e5f Mon Sep 17 00:00:00 2001
From: Jo-Philipp Wich <jow@openwrt.org>
Date: Sat, 28 Jun 2008 02:05:48 +0000
Subject: [PATCH] * libs/http:	prepare support for RFC2616 / 14.24 - 14.28

---
 libs/http/luasrc/http/protocol/conditionals.lua | 111 ++++++++++++++++++++++++
 libs/httpd/luasrc/httpd/handler/file.lua        |  18 ++--
 2 files changed, 118 insertions(+), 11 deletions(-)
 create mode 100644 libs/http/luasrc/http/protocol/conditionals.lua

diff --git a/libs/http/luasrc/http/protocol/conditionals.lua b/libs/http/luasrc/http/protocol/conditionals.lua
new file mode 100644
index 000000000..0bff274cd
--- /dev/null
+++ b/libs/http/luasrc/http/protocol/conditionals.lua
@@ -0,0 +1,111 @@
+--[[
+
+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
+
+$Id$
+
+]]--
+
+module("luci.http.protocol.conditionals", package.seeall)
+
+local date = require("luci.http.protocol.date")
+
+
+-- 14.19 / ETag
+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
+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
+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
+	end
+
+	return true
+end
+
+-- 14.26 / If-None-Match
+function if_none_match( req, stat )
+	local h    = req.headers
+	local etag = mk_etag( stat )
+
+	-- 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 req.request_method == "get"  or
+				   req.request_method == "head"
+				then
+					h['ETag']          = mk_etag( stat )
+					h['Last-Modified'] = date.to_http( stat.mtime )
+
+					return false, 304
+				else
+					return false, 412
+				end
+			end
+		end
+	end
+
+	return true
+end
+
+-- 14.27 / If-Range
+function if_range( req, stat )
+	-- Sorry, no subranges (yet)
+	return false, 412
+end
+
+-- 14.28 / If-Unmodified-Since
+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
diff --git a/libs/httpd/luasrc/httpd/handler/file.lua b/libs/httpd/luasrc/httpd/handler/file.lua
index e6311e839..f553e8292 100644
--- a/libs/httpd/luasrc/httpd/handler/file.lua
+++ b/libs/httpd/luasrc/httpd/handler/file.lua
@@ -18,6 +18,7 @@ module("luci.httpd.handler.file", package.seeall)
 require("luci.httpd.module")
 require("luci.http.protocol.date")
 require("luci.http.protocol.mime")
+require("luci.http.protocol.conditionals")
 require("luci.fs")
 require("ltn12")
 
@@ -39,28 +40,23 @@ function Simple.getfile(self, uri)
 	return file, stat
 end
 
-
-function Simple._mk_etag(self, stat)
-	return string.format( "%x-%x-%x", stat.ino, stat.size, stat.mtime )
-end
-
-function Simple._cmp_etag(self, stat, etag)
-	return ( self:_mk_etag(stat) == etag )
-end
-
-
 function Simple.handle_get(self, request, sourcein, sinkerr)
 	local file, stat = self:getfile(request.env.PATH_INFO)
 
 	if stat then
 		if stat.type == "regular" then
+
+			-- Generate Entity Tag
+			local etag = luci.http.protocol.conditionals.mk_etag( stat )
+
+			-- Send Response
 			return Response(
 				200, {
 					["Date"]           = self.date.to_http( os.time() );
 					["Last-Modified"]  = self.date.to_http( stat.mtime );
 					["Content-Type"]   = self.mime.to_mime( file );
 					["Content-Length"] = stat.size;
-					["ETag"]           = self:_mk_etag( stat );
+					["ETag"]           = etag;
 				}
 			), ltn12.source.file(io.open(file))
 		else
-- 
2.11.0