-- Copyright 2008 Freifunk Leipzig / Jo-Philipp Wich -- Licensed to the public under the Apache License 2.0. --- 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