1 files changed, 110 insertions, 0 deletions
diff --git a/libs/luci-lib-httpprotoutils/luasrc/http/conditionals.lua b/libs/luci-lib-httpprotoutils/luasrc/http/conditionals.lua
new file mode 100644
index 0000000000..86b4db29cd
--- /dev/null
+++ b/libs/luci-lib-httpprotoutils/luasrc/http/conditionals.lua
@@ -0,0 +1,110 @@
+-- Copyright 2008 Freifunk Leipzig / Jo-Philipp Wich <jow@openwrt.org>
+-- Licensed to the public under the Apache License 2.0.
+
+-- 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.conditionals", package.seeall)
+
+local date = require("luci.http.date")
+
+
+function mk_etag( stat )
+	if stat ~= nil then
+		return string.format( '"%x-%x-%x"', stat.ino, stat.size, stat.mtime )
+	end
+end
+
+-- Test whether the given message object contains an "If-Match" header and
+-- compare it against the given stat object.
+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
+
+-- Test whether the given message object contains an "If-Modified-Since" header
+-- and compare it against the given stat object.
+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
+
+-- Test whether the given message object contains an "If-None-Match" header and
+-- compare it against the given stat object.
+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
+
+-- 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.
+function if_range( req, stat )
+	-- Sorry, no subranges (yet)
+	return false, 412
+end
+
+-- Test whether the given message object contains an "If-Unmodified-Since"
+-- header and compare it against the given stat object.
+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